Implement --shm-path option for UST sessions (per-uid channels)
authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Tue, 8 Jul 2014 14:12:23 +0000 (10:12 -0400)
committerJérémie Galarneau <jeremie.galarneau@efficios.com>
Thu, 26 Mar 2015 22:07:24 +0000 (18:07 -0400)
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
29 files changed:
.gitignore
configure.ac
doc/man/lttng.1
include/lttng/session.h
src/bin/Makefile.am
src/bin/lttng-crash/Makefile.am [new file with mode: 0644]
src/bin/lttng-crash/lttng-crash.c [new file with mode: 0644]
src/bin/lttng-sessiond/buffer-registry.c
src/bin/lttng-sessiond/buffer-registry.h
src/bin/lttng-sessiond/cmd.c
src/bin/lttng-sessiond/cmd.h
src/bin/lttng-sessiond/consumer.c
src/bin/lttng-sessiond/consumer.h
src/bin/lttng-sessiond/main.c
src/bin/lttng-sessiond/session.h
src/bin/lttng-sessiond/trace-ust.h
src/bin/lttng-sessiond/ust-app.c
src/bin/lttng-sessiond/ust-app.h
src/bin/lttng-sessiond/ust-consumer.c
src/bin/lttng-sessiond/ust-metadata.c
src/bin/lttng-sessiond/ust-registry.c
src/bin/lttng-sessiond/ust-registry.h
src/bin/lttng/commands/create.c
src/common/consumer.c
src/common/consumer.h
src/common/kernel-consumer/kernel-consumer.c
src/common/sessiond-comm/sessiond-comm.h
src/common/ust-consumer/ust-consumer.c
src/lib/lttng-ctl/lttng-ctl.c

index a5d110b8a13bdcc42f41e11bf840bacc8070f510..ff19c8d0db09993f70cfee307393bcabb369c32d 100644 (file)
@@ -41,6 +41,7 @@ tags
 /src/bin/lttng-sessiond/lttng-sessiond
 /src/bin/lttng/lttng
 /src/bin/lttng-consumerd/lttng-consumerd
+/src/bin/lttng-crash/lttng-crash
 /src/bin/lttng-relayd/lttng-relayd
 /src/lib/lttng-ctl/lttng-ctl.pc
 /src/lib/lttng-ctl/filter/filter-grammar-test
index b664641beb10374c7fc94432e0a7bcfe62ba8657..75fe1e074a7ab6e4182c7db3d02faf6cf7e01f85 100644 (file)
@@ -496,6 +496,7 @@ AC_CONFIG_FILES([
        src/bin/lttng-sessiond/Makefile
        src/bin/lttng-relayd/Makefile
        src/bin/lttng/Makefile
+       src/bin/lttng-crash/Makefile
        tests/Makefile
        tests/regression/Makefile
        tests/regression/kernel/Makefile
index fd62558eec7a8e53ea60104be2c2c1b67727fa9f..9f642b812f8cefdff6d70961370bf963d4b40752 100644 (file)
@@ -302,6 +302,12 @@ $ lttng start
 After the start, you'll be able to read the events while they are being
 recorded in /tmp/lttng.
 
+.TP
+.BR "\-\-shm-path PATH"
+
+Path where shared memory holding buffers should be created. Useful
+when used with pramfs to extract trace data after crash.
+
 .TP
 .BR "\-U, \-\-set-url=URL"
 Set URL for the consumer output destination. It is persistent for the
index 2c9b842d4c693be23478c30d2e40c33e4d22d623..c87efbd1d1b54c7291b76ead401ddb0498220d7c 100644 (file)
@@ -104,6 +104,18 @@ extern int lttng_destroy_session(const char *name);
  */
 extern int lttng_list_sessions(struct lttng_session **sessions);
 
+/*
+ * Set the shared memory path for a session.
+ *
+ * Sets the (optional) file system path where shared memory buffers will
+ * be created for the session. This is useful for buffer extraction on
+ * crash, when used with filesystems like pramfs.
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+extern int lttng_set_session_shm_path(const char *session_name,
+               const char *shm_path);
+
 #ifdef __cplusplus
 }
 #endif
index c97d1a147ce65fe0868c5ccebe272b3949b1bd62..ebf9b57ff938511d12091560a16c16ffa79c6a1c 100644 (file)
@@ -3,4 +3,5 @@ ACLOCAL_AMFLAGS = -I config
 SUBDIRS = lttng-consumerd \
                  lttng \
           lttng-sessiond \
-          lttng-relayd
+          lttng-relayd \
+          lttng-crash
diff --git a/src/bin/lttng-crash/Makefile.am b/src/bin/lttng-crash/Makefile.am
new file mode 100644 (file)
index 0000000..a0adfbc
--- /dev/null
@@ -0,0 +1,9 @@
+AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/src \
+                         -DINSTALL_BIN_PATH=\""$(bindir)"\"
+
+bin_PROGRAMS = lttng-crash
+
+lttng_crash_SOURCES = lttng-crash.c
+
+lttng_crash_LDADD = $(top_builddir)/src/common/libcommon.la \
+                       $(top_builddir)/src/common/config/libconfig.la
diff --git a/src/bin/lttng-crash/lttng-crash.c b/src/bin/lttng-crash/lttng-crash.c
new file mode 100644 (file)
index 0000000..dda157b
--- /dev/null
@@ -0,0 +1,1109 @@
+/*
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#define _GNU_SOURCE
+#include <getopt.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <config.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <byteswap.h>
+#include <inttypes.h>
+
+#include <version.h>
+#include <lttng/lttng.h>
+#include <common/common.h>
+
+#define DEFAULT_VIEWER "babeltrace"
+
+#define COPY_BUFLEN            4096
+#define RB_CRASH_DUMP_ABI_LEN  32
+
+#define RB_CRASH_DUMP_ABI_MAGIC_LEN    16
+
+/*
+ * The 128-bit magic number is xor'd in the process data so it does not
+ * cause a false positive when searching for buffers by scanning memory.
+ * The actual magic number is:
+ *   0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1,
+ *   0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17,
+ */
+#define RB_CRASH_DUMP_ABI_MAGIC_XOR                                    \
+       {                                                               \
+               0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF,     \
+               0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF,     \
+               0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF,     \
+               0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF,     \
+       }
+
+/*
+ * Non-static to ensure the compiler does not optimize away the xor.
+ */
+uint8_t lttng_crash_expected_magic_xor[] = RB_CRASH_DUMP_ABI_MAGIC_XOR;
+
+#define RB_CRASH_ENDIAN                        0x1234
+#define RB_CRASH_ENDIAN_REVERSE                0x3412
+
+enum lttng_crash_type {
+       LTTNG_CRASH_TYPE_UST = 0,
+       LTTNG_CRASH_TYPE_KERNEL = 1,
+};
+
+/* LTTng ring buffer defines (copied) */
+
+#define HALF_ULONG_BITS(wl)    (((wl) * CHAR_BIT) >> 1)
+
+#define SB_ID_OFFSET_SHIFT(wl) (HALF_ULONG_BITS(wl) + 1)
+#define SB_ID_OFFSET_COUNT(wl) (1UL << SB_ID_OFFSET_SHIFT(wl))
+#define SB_ID_OFFSET_MASK(wl)  (~(SB_ID_OFFSET_COUNT(wl) - 1))
+/*
+ * Lowest bit of top word half belongs to noref. Used only for overwrite mode.
+ */
+#define SB_ID_NOREF_SHIFT(wl)  (SB_ID_OFFSET_SHIFT(wl) - 1)
+#define SB_ID_NOREF_COUNT(wl)  (1UL << SB_ID_NOREF_SHIFT(wl))
+#define SB_ID_NOREF_MASK(wl)   SB_ID_NOREF_COUNT(wl)
+/*
+ * In overwrite mode: lowest half of word is used for index.
+ * Limit of 2^16 subbuffers per buffer on 32-bit, 2^32 on 64-bit.
+ * In producer-consumer mode: whole word used for index.
+ */
+#define SB_ID_INDEX_SHIFT(wl)  0
+#define SB_ID_INDEX_COUNT(wl)  (1UL << SB_ID_INDEX_SHIFT(wl))
+#define SB_ID_INDEX_MASK(wl)   (SB_ID_NOREF_COUNT(wl) - 1)
+
+enum rb_modes {
+       RING_BUFFER_OVERWRITE = 0,      /* Overwrite when buffer full */
+       RING_BUFFER_DISCARD = 1,        /* Discard when buffer full */
+};
+
+struct crash_abi_unknown {
+       uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN];
+       uint64_t mmap_length;   /* Overall lenght of crash record */
+       uint16_t endian;        /*
+                                * { 0x12, 0x34 }: big endian
+                                * { 0x34, 0x12 }: little endian
+                                */
+       uint16_t major;         /* Major number. */
+       uint16_t minor;         /* Minor number. */
+       uint8_t word_size;      /* Word size (bytes). */
+       uint8_t layout_type;    /* enum lttng_crash_layout */
+} __attribute__((packed));
+
+struct crash_abi_0_0 {
+       struct crash_abi_unknown parent;
+
+       struct {
+               uint32_t prod_offset;
+               uint32_t consumed_offset;
+               uint32_t commit_hot_array;
+               uint32_t commit_hot_seq;
+               uint32_t buf_wsb_array;
+               uint32_t buf_wsb_id;
+               uint32_t sb_array;
+               uint32_t sb_array_shmp_offset;
+               uint32_t sb_backend_p_offset;
+               uint32_t content_size;
+               uint32_t packet_size;
+       } __attribute__((packed)) offset;
+       struct {
+               uint8_t prod_offset;
+               uint8_t consumed_offset;
+               uint8_t commit_hot_seq;
+               uint8_t buf_wsb_id;
+               uint8_t sb_array_shmp_offset;
+               uint8_t sb_backend_p_offset;
+               uint8_t content_size;
+               uint8_t packet_size;
+       } __attribute__((packed)) length;
+       struct {
+               uint32_t commit_hot_array;
+               uint32_t buf_wsb_array;
+               uint32_t sb_array;
+       } __attribute__((packed)) stride;
+
+       uint64_t buf_size;      /* Size of the buffer */
+       uint64_t subbuf_size;   /* Sub-buffer size */
+       uint64_t num_subbuf;    /* Number of sub-buffers for writer */
+       uint32_t mode;          /* Buffer mode: 0: overwrite, 1: discard */
+} __attribute__((packed));
+
+struct lttng_crash_layout {
+       struct {
+               int prod_offset, consumed_offset,
+                       commit_hot_array, commit_hot_seq,
+                       buf_wsb_array, buf_wsb_id,
+                       sb_array, sb_array_shmp_offset,
+                       sb_backend_p_offset, content_size,
+                       packet_size;
+       } offset;
+       struct {
+               int prod_offset, consumed_offset,
+                       commit_hot_seq, buf_wsb_id,
+                       sb_array_shmp_offset, sb_backend_p_offset,
+                       content_size, packet_size;
+       } length;
+       struct {
+               int commit_hot_array, buf_wsb_array, sb_array;
+       } stride;
+
+       int reverse_byte_order;
+       int word_size;
+
+       uint64_t mmap_length;   /* Length of crash record */
+       uint64_t buf_size;      /* Size of the buffer */
+       uint64_t subbuf_size;   /* Sub-buffer size */
+       uint64_t num_subbuf;    /* Number of sub-buffers for writer */
+       uint32_t mode;          /* Buffer mode: 0: overwrite, 1: discard */
+};
+
+/* Variables */
+static char *progname,
+       *opt_viewer_path = DEFAULT_VIEWER,
+       *opt_output_path;
+
+static int nr_input_paths;
+static char **input_paths;
+
+int lttng_opt_quiet, lttng_opt_verbose, lttng_opt_mi;
+
+enum {
+       OPT_DUMP_OPTIONS,
+};
+
+/* Getopt options. No first level command. */
+static struct option long_options[] = {
+       { "version",            0, NULL, 'V' },
+       { "help",               0, NULL, 'h' },
+       { "verbose",            0, NULL, 'v' },
+       { "viewer",             1, NULL, 'e' },
+       { "extract",            1, NULL, 'x' },
+       { "list-options",       0, NULL, OPT_DUMP_OPTIONS },
+       { NULL, 0, NULL, 0 },
+};
+
+static void usage(FILE *ofp)
+{
+       fprintf(ofp, "LTTng Crash Trace Viewer " VERSION " - " VERSION_NAME "%s\n\n",
+               GIT_VERSION[0] == '\0' ? "" : " - " GIT_VERSION);
+       fprintf(ofp, "usage: lttng [OPTIONS] FILE...\n");
+       fprintf(ofp, "\n");
+       fprintf(ofp, "Options:\n");
+       fprintf(ofp, "  -V, --version              Show version.\n");
+       fprintf(ofp, "  -h, --help                 Show this help.\n");
+       fprintf(ofp, "      --list-options         Simple listing of lttng-crash options.\n");
+       fprintf(ofp, "  -v, --verbose              Increase verbosity.\n");
+       fprintf(ofp, "  -e, --viewer               Specify viewer and/or options to use. This will\n"
+                    "                             completely override the default viewers so please\n"
+                    "                             make sure to specify the full command. The trace\n"
+                    "                             directory paths appended at the end to the\n"
+                    "                             arguments.\n");
+       fprintf(ofp, "  -x, --extract PATH         Extract trace(s) to specified path. Don't view\n"
+                    "                             trace.\n");
+       fprintf(ofp, "\n");
+       fprintf(ofp, "Please see the lttng-crash(1) man page for full documentation.\n");
+       fprintf(ofp, "See http://lttng.org for updates, bug reports and news.\n");
+}
+
+static void version(FILE *ofp)
+{
+       fprintf(ofp, "%s (LTTng Crash Trace Viewer) " VERSION " - " VERSION_NAME
+"%s\n",
+                       progname,
+                       GIT_VERSION[0] == '\0' ? "" : " - " GIT_VERSION);
+}
+
+/*
+ *  list_options
+ *
+ *  List options line by line. This is mostly for bash auto completion and to
+ *  avoid difficult parsing.
+ */
+static void list_options(FILE *ofp)
+{
+       int i = 0;
+       struct option *option = NULL;
+
+       option = &long_options[i];
+       while (option->name != NULL) {
+               fprintf(ofp, "--%s\n", option->name);
+
+               if (isprint(option->val)) {
+                       fprintf(ofp, "-%c\n", option->val);
+               }
+
+               i++;
+               option = &long_options[i];
+       }
+}
+
+/*
+ * Parse command line arguments.
+ *
+ * Return 0 if OK, else -1
+ */
+static int parse_args(int argc, char **argv)
+{
+       int opt, ret = 0;
+
+       if (argc < 2) {
+               usage(stderr);
+               exit(EXIT_FAILURE);
+       }
+
+       while ((opt = getopt_long(argc, argv, "+Vhvex:", long_options, NULL)) != -1) {
+               switch (opt) {
+               case 'V':
+                       version(stdout);
+                       ret = 1;
+                       goto end;
+               case 'h':
+                       usage(stdout);
+                       ret = 1;
+                       goto end;
+               case 'v':
+                       /* There is only 3 possible level of verbosity. (-vvv) */
+                       if (lttng_opt_verbose < 3) {
+                               lttng_opt_verbose += 1;
+                       }
+                       break;
+               case 'e':
+                       opt_viewer_path = strdup(optarg);
+                       break;
+               case 'x':
+                       opt_output_path = strdup(optarg);
+                       break;
+               case OPT_DUMP_OPTIONS:
+                       list_options(stdout);
+                       ret = 1;
+                       goto end;
+               default:
+                       usage(stderr);
+                       goto error;
+               }
+       }
+
+       /* No leftovers, print usage and quit */
+       if ((argc - optind) == 0) {
+               usage(stderr);
+               goto error;
+       }
+
+       input_paths = &argv[optind];
+       nr_input_paths = argc - optind;
+end:
+       return ret;
+
+error:
+       return -1;
+}
+
+static
+int copy_file(const char *file_dest, const char *file_src)
+{
+       int fd_src, fd_dest;
+       ssize_t readlen, writelen;
+       char buf[COPY_BUFLEN];
+
+       DBG("Copy metadata file '%s' into '%s'", file_src, file_dest);
+
+       fd_src = open(file_src, O_RDONLY);
+       if (fd_src < 0) {
+               PERROR("Error opening %s for reading", file_src);
+               return fd_src;
+       }
+       fd_dest = open(file_dest, O_RDWR | O_CREAT | O_EXCL,
+                       S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+       if (fd_dest < 0) {
+               PERROR("Error opening %s for writing", file_dest);
+               return fd_dest;
+       }
+
+       for (;;) {
+               readlen = lttng_read(fd_src, buf, COPY_BUFLEN);
+               if (readlen < 0) {
+                       PERROR("Error reading input file");
+                       return -1;
+               }
+               if (!readlen) {
+                       break;
+               }
+               writelen = lttng_write(fd_dest, buf, readlen);
+               if (writelen < readlen) {
+                       PERROR("Error writing to output file");
+                       return -1;
+               }
+       }
+       return 0;
+}
+
+static
+uint64_t _crash_get_field(const struct lttng_crash_layout *layout,
+               const char *ptr, size_t size)
+{
+       switch (size) {
+       case 1: return *(uint8_t *) ptr;
+       case 2: if (layout->reverse_byte_order) {
+                       return __bswap_16(*(uint16_t *) ptr);
+               } else {
+                       return *(uint16_t *) ptr;
+
+               }
+       case 4: if (layout->reverse_byte_order) {
+                       return __bswap_32(*(uint32_t *) ptr);
+               } else {
+                       return *(uint32_t *) ptr;
+
+               }
+       case 8: if (layout->reverse_byte_order) {
+                       return __bswap_64(*(uint64_t *) ptr);
+               } else {
+                       return *(uint64_t *) ptr;
+               }
+       default:
+               abort();
+               return -1;
+       }
+
+}
+
+#define crash_get_field(layout, map, name)                             \
+       _crash_get_field(layout, (map) + (layout)->offset.name,         \
+               layout->length.name)
+
+#define crash_get_array_field(layout, map, array_name, idx, field_name)        \
+       _crash_get_field(layout,                                        \
+               (map) + (layout)->offset.array_name                     \
+                       + (idx * (layout)->stride.array_name)           \
+                       + (layout)->offset.field_name,                  \
+               (layout)->length.field_name)
+
+#define crash_get_hdr_raw_field(layout, hdr, name)     ((hdr)->name)
+
+#define crash_get_hdr_field(layout, hdr, name)                         \
+       _crash_get_field(layout, (const char *) &(hdr)->name,           \
+               sizeof((hdr)->name))
+
+#define crash_get_layout(layout, hdr, name)                            \
+       do {                                                            \
+               (layout)->name = crash_get_hdr_field(layout, hdr,       \
+                                       name);                          \
+               DBG("layout.%s = %" PRIu64, #name,                      \
+                       (uint64_t) (layout)->name);                     \
+       } while (0)
+
+static
+int get_crash_layout_0_0(struct lttng_crash_layout *layout,
+               char *map)
+{
+       const struct crash_abi_0_0 *abi = (const struct crash_abi_0_0 *) map;
+
+       crash_get_layout(layout, abi, offset.prod_offset);
+       crash_get_layout(layout, abi, offset.consumed_offset);
+       crash_get_layout(layout, abi, offset.commit_hot_array);
+       crash_get_layout(layout, abi, offset.commit_hot_seq);
+       crash_get_layout(layout, abi, offset.buf_wsb_array);
+       crash_get_layout(layout, abi, offset.buf_wsb_id);
+       crash_get_layout(layout, abi, offset.sb_array);
+       crash_get_layout(layout, abi, offset.sb_array_shmp_offset);
+       crash_get_layout(layout, abi, offset.sb_backend_p_offset);
+       crash_get_layout(layout, abi, offset.content_size);
+       crash_get_layout(layout, abi, offset.packet_size);
+
+       crash_get_layout(layout, abi, length.prod_offset);
+       crash_get_layout(layout, abi, length.consumed_offset);
+       crash_get_layout(layout, abi, length.commit_hot_seq);
+       crash_get_layout(layout, abi, length.buf_wsb_id);
+       crash_get_layout(layout, abi, length.sb_array_shmp_offset);
+       crash_get_layout(layout, abi, length.sb_backend_p_offset);
+       crash_get_layout(layout, abi, length.content_size);
+       crash_get_layout(layout, abi, length.packet_size);
+
+       crash_get_layout(layout, abi, stride.commit_hot_array);
+       crash_get_layout(layout, abi, stride.buf_wsb_array);
+       crash_get_layout(layout, abi, stride.sb_array);
+
+       crash_get_layout(layout, abi, buf_size);
+       crash_get_layout(layout, abi, subbuf_size);
+       crash_get_layout(layout, abi, num_subbuf);
+       crash_get_layout(layout, abi, mode);
+
+       return 0;
+}
+
+static
+void print_dbg_magic(const uint8_t *magic)
+{
+       DBG("magic: 0x%X%X%X%X%X%X%X%X%X%X%X%X%X%X%X%X",
+               magic[0], magic[1], magic[2], magic[3],
+               magic[4], magic[5], magic[6], magic[7],
+               magic[8], magic[9], magic[10], magic[11],
+               magic[12], magic[13], magic[14], magic[15]);
+}
+
+static
+int check_magic(const uint8_t *magic)
+{
+       int i;
+
+       for (i = 0; i < RB_CRASH_DUMP_ABI_MAGIC_LEN; i++) {
+               if ((magic[i] ^ 0xFF) != lttng_crash_expected_magic_xor[i]) {
+                       return -1;
+               }
+       }
+       return 0;
+}
+
+static
+int get_crash_layout(struct lttng_crash_layout *layout, int fd)
+{
+       char *map;
+       int ret = 0, unmapret;
+       const uint8_t *magic;
+       uint64_t mmap_length;
+       uint16_t major, minor;
+       uint8_t word_size;
+       const struct crash_abi_unknown *abi;
+       uint16_t endian;
+       enum lttng_crash_type layout_type;
+
+       map = mmap(NULL, RB_CRASH_DUMP_ABI_LEN, PROT_READ, MAP_PRIVATE,
+               fd, 0);
+       if (map == MAP_FAILED) {
+               PERROR("Mapping file");
+               return -1;
+       }
+       abi = (const struct crash_abi_unknown *) map;
+       magic = crash_get_hdr_raw_field(layout, abi, magic);
+       print_dbg_magic(magic);
+       if (check_magic(magic)) {
+               DBG("Unknown magic number");
+               ret = 1;        /* positive return value, skip */
+               goto end;
+       }
+       endian = crash_get_hdr_field(layout, abi, endian);
+       switch (endian) {
+       case RB_CRASH_ENDIAN:
+               break;
+       case RB_CRASH_ENDIAN_REVERSE:
+               layout->reverse_byte_order = 1;
+               break;
+       default:
+               DBG("Unknown endianness value: 0x%X", (unsigned int) endian);
+               ret = 1;        /* positive return value, skip */
+               goto end;
+       }
+       layout_type = (enum lttng_crash_type) crash_get_hdr_field(layout, abi, layout_type);
+       switch (layout_type) {
+       case LTTNG_CRASH_TYPE_UST:
+               break;
+       case LTTNG_CRASH_TYPE_KERNEL:
+               ERR("lttng-modules buffer layout support not implemented");
+               ret = 1;        /* positive return value, skip */
+               goto end;
+       default:
+               ERR("Unknown layout type %u", (unsigned int) layout_type);
+               ret = 1;        /* positive return value, skip */
+               goto end;
+       }
+       mmap_length = crash_get_hdr_field(layout, abi, mmap_length);
+       DBG("mmap_length: %" PRIu64, mmap_length);
+       layout->mmap_length = mmap_length;
+       major = crash_get_hdr_field(layout, abi, major);
+       DBG("major: %u", major);
+       minor = crash_get_hdr_field(layout, abi, minor);
+       DBG("minor: %u", minor);
+       word_size = crash_get_hdr_field(layout, abi, word_size);
+       DBG("word_size: %u", word_size);
+       switch (major) {
+       case 0:
+               switch (minor) {
+               case 0:
+                       ret = get_crash_layout_0_0(layout, map);
+                       if (ret)
+                               goto end;
+                       break;
+               default:
+                       ret = -1;
+                       ERR("Unsupported crash ABI %u.%u\n", major, minor);
+                       goto end;
+               }
+               break;
+       default:
+               ERR("Unsupported crash ABI %u.%u\n", major, minor);
+               ret = -1;
+               goto end;
+       }
+       layout->word_size = word_size;
+end:
+       unmapret = munmap(map, RB_CRASH_DUMP_ABI_LEN);
+       if (unmapret) {
+               PERROR("munmap");
+       }
+       return ret;
+}
+
+/* buf_trunc mask selects only the buffer number. */
+static inline
+uint64_t buf_trunc(uint64_t offset, uint64_t buf_size)
+{
+       return offset & ~(buf_size - 1);
+}
+
+/* subbuf_trunc mask selects the subbuffer number. */
+static inline
+uint64_t subbuf_trunc(uint64_t offset, uint64_t subbuf_size)
+{
+       return offset & ~(subbuf_size - 1);
+}
+
+/* buf_offset mask selects only the offset within the current buffer. */
+static inline
+uint64_t buf_offset(uint64_t offset, uint64_t buf_size)
+{
+       return offset & (buf_size - 1);
+}
+
+/* subbuf_offset mask selects the offset within the current subbuffer. */
+static inline
+uint64_t subbuf_offset(uint64_t offset, uint64_t subbuf_size)
+{
+       return offset & (subbuf_size - 1);
+}
+
+/* subbuf_index returns the index of the current subbuffer within the buffer. */
+static inline
+uint64_t subbuf_index(uint64_t offset, uint64_t buf_size, uint64_t subbuf_size)
+{
+       return buf_offset(offset, buf_size) / subbuf_size;
+}
+
+static inline
+uint64_t subbuffer_id_get_index(uint32_t mode, uint64_t id,
+               unsigned int wl)
+{
+       if (mode == RING_BUFFER_OVERWRITE)
+               return id & SB_ID_INDEX_MASK(wl);
+       else
+               return id;
+}
+
+static
+int copy_crash_subbuf(const struct lttng_crash_layout *layout,
+               int fd_dest, char *buf, uint64_t offset)
+{
+       uint64_t buf_size, subbuf_size, num_subbuf, sbidx, id,
+               sb_bindex, rpages_offset, p_offset, seq_cc,
+               committed, commit_count_mask, consumed_cur,
+               packet_size;
+       char *subbuf_ptr;
+       ssize_t writelen;
+
+       /*
+        * Get the current subbuffer by applying the proper mask to
+        * "offset", and looking up the subbuf location within the
+        * source file buf.
+        */
+
+       buf_size = layout->buf_size;
+       subbuf_size = layout->subbuf_size;
+       num_subbuf = layout->num_subbuf;
+
+       switch (layout->word_size) {
+       case 4: commit_count_mask = 0xFFFFFFFFULL / num_subbuf;
+               break;
+       case 8: commit_count_mask = 0xFFFFFFFFFFFFFFFFULL / num_subbuf;
+               break;
+       default:
+               ERR("Unsupported word size: %u",
+                       (unsigned int) layout->word_size);
+               return -EINVAL;
+       }
+
+       DBG("Copy crash subbuffer at offset %lu", offset);
+       sbidx = subbuf_index(offset, buf_size, subbuf_size);
+
+       /*
+        * Find where the seq cc is located. Compute length of data to
+        * copy.
+        */
+       seq_cc = crash_get_array_field(layout, buf, commit_hot_array,
+               sbidx, commit_hot_seq);
+       consumed_cur = crash_get_field(layout, buf, consumed_offset);
+
+       /*
+        * Check that the buffer we are getting is after or at
+        * consumed_cur position.
+        */
+       if ((long) subbuf_trunc(offset, subbuf_size)
+                       - (long) subbuf_trunc(consumed_cur, subbuf_size) < 0) {
+               DBG("No data: position is before consumed_cur");
+               goto nodata;
+       }
+
+       /*
+        * Check if subbuffer has been fully committed.
+        */
+       if (((seq_cc - subbuf_size) & commit_count_mask)
+                       - (buf_trunc(offset, buf_size) / num_subbuf)
+                       == 0) {
+               committed = subbuf_size;
+       } else {
+               committed = subbuf_offset(seq_cc, subbuf_size);
+               if (!committed) {
+                       DBG("No data committed, seq_cc: %" PRIu64, seq_cc);
+                       goto nodata;
+               }
+       }
+
+       /* Find actual physical offset in subbuffer table */
+       id = crash_get_array_field(layout, buf, buf_wsb_array,
+               sbidx, buf_wsb_id);
+       sb_bindex = subbuffer_id_get_index(layout->mode, id,
+               layout->word_size);
+       rpages_offset = crash_get_array_field(layout, buf, sb_array,
+               sb_bindex, sb_array_shmp_offset);
+       p_offset = crash_get_field(layout, buf + rpages_offset,
+               sb_backend_p_offset);
+       subbuf_ptr = buf + p_offset;
+
+       if (committed == subbuf_size) {
+               /*
+                * Packet header can be used.
+                */
+               if (layout->length.packet_size) {
+                       memcpy(&packet_size,
+                               subbuf_ptr + layout->offset.packet_size,
+                               layout->length.packet_size);
+                       if (layout->reverse_byte_order) {
+                               packet_size = __bswap_64(packet_size);
+                       }
+                       packet_size /= CHAR_BIT;
+               } else {
+                       packet_size = subbuf_size;
+               }
+       } else {
+               uint64_t patch_size;
+
+               /*
+                * Find where to patch the sub-buffer header with actual
+                * readable data len and packet len, derived from seq
+                * cc. Patch it in our in-memory copy.
+                */
+               patch_size = committed * CHAR_BIT;
+               if (layout->reverse_byte_order) {
+                       patch_size = __bswap_64(patch_size);
+               }
+               if (layout->length.content_size) {
+                       memcpy(subbuf_ptr + layout->offset.content_size,
+                               &patch_size, layout->length.content_size);
+               }
+               if (layout->length.packet_size) {
+                       memcpy(subbuf_ptr + layout->offset.packet_size,
+                               &patch_size, layout->length.packet_size);
+               }
+               packet_size = committed;
+       }
+
+       /*
+        * Copy packet into fd_dest.
+        */
+       writelen = lttng_write(fd_dest, subbuf_ptr, packet_size);
+       if (writelen < packet_size) {
+               PERROR("Error writing to output file");
+               return -1;
+       }
+       DBG("Copied %" PRIu64 " bytes of data", packet_size);
+       return 0;
+
+nodata:
+       return -ENODATA;
+}
+
+static
+int copy_crash_data(const struct lttng_crash_layout *layout, int fd_dest,
+               int fd_src)
+{
+       char *buf;
+       int ret = 0, has_data = 0;
+       struct stat statbuf;
+       size_t src_file_len;
+       uint64_t prod_offset, consumed_offset;
+       uint64_t offset, subbuf_size;
+       ssize_t readlen;
+
+       ret = fstat(fd_src, &statbuf);
+       if (ret) {
+               return ret;
+       }
+       src_file_len = layout->mmap_length;
+       buf = zmalloc(src_file_len);
+       if (!buf) {
+               return -1;
+       }
+       readlen = lttng_read(fd_src, buf, src_file_len);
+       if (readlen < 0) {
+               PERROR("Error reading input file");
+               return -1;
+       }
+
+       prod_offset = crash_get_field(layout, buf, prod_offset);
+       DBG("prod_offset: 0x%" PRIx64, prod_offset);
+       consumed_offset = crash_get_field(layout, buf, consumed_offset);
+       DBG("consumed_offset: 0x%" PRIx64, consumed_offset);
+       subbuf_size = layout->subbuf_size;
+
+       for (offset = consumed_offset; offset < prod_offset;
+                       offset += subbuf_size) {
+               ret = copy_crash_subbuf(layout, fd_dest, buf, offset);
+               if (!ret) {
+                       has_data = 1;
+               }
+               if (ret) {
+                       goto end;
+               }
+       }
+end:
+       free(buf);
+       if (ret && ret != -ENODATA) {
+               return ret;
+       }
+       if (has_data) {
+               return 0;
+       } else {
+               return -ENODATA;
+       }
+}
+
+static
+int extract_file(int output_dir_fd, const char *output_file,
+               int input_dir_fd, const char *input_file)
+{
+       int fd_dest, fd_src, ret = 0, closeret;
+       struct lttng_crash_layout layout;
+
+       layout.reverse_byte_order = 0;  /* For reading magic number */
+
+       DBG("Extract file '%s'", input_file);
+       fd_src = openat(input_dir_fd, input_file, O_RDONLY);
+       if (fd_src < 0) {
+               PERROR("Error opening '%s' for reading",
+                       input_file);
+               ret = -1;
+               goto end;
+       }
+
+       /* Query the crash ABI layout */
+       ret = get_crash_layout(&layout, fd_src);
+       if (ret) {
+               goto close_src;
+       }
+
+       fd_dest = openat(output_dir_fd, output_file,
+                       O_RDWR | O_CREAT | O_EXCL,
+                       S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+       if (fd_dest < 0) {
+               PERROR("Error opening '%s' for writing",
+                       output_file);
+               ret = -1;
+               goto close_src;
+       }
+
+       ret = copy_crash_data(&layout, fd_dest, fd_src);
+       if (ret) {
+               goto close_dest;
+       }
+
+close_dest:
+       closeret = close(fd_dest);
+       if (closeret) {
+               PERROR("close");
+       }
+       if (ret == -ENODATA) {
+               closeret = unlinkat(output_dir_fd, output_file, 0);
+               if (closeret) {
+                       PERROR("unlinkat");
+               }
+       }
+close_src:
+       closeret = close(fd_src);
+       if (closeret) {
+               PERROR("close");
+       }
+end:
+       return ret;
+}
+
+static
+int extract_all_files(const char *output_path,
+               const char *input_path)
+{
+       DIR *input_dir, *output_dir;
+       int input_dir_fd, output_dir_fd, ret = 0, closeret;
+       struct dirent *entry;   /* input */
+
+       /* Open input directory */
+       input_dir = opendir(input_path);
+       if (!input_dir) {
+               PERROR("Cannot open '%s' path", input_path);
+               return -1;
+       }
+       input_dir_fd = dirfd(input_dir);
+       if (input_dir_fd < 0) {
+               PERROR("dirfd");
+               return -1;
+       }
+
+       /* Open output directory */
+       output_dir = opendir(output_path);
+       if (!output_dir) {
+               PERROR("Cannot open '%s' path", output_path);
+               return -1;
+       }
+       output_dir_fd = dirfd(output_dir);
+       if (output_dir_fd < 0) {
+               PERROR("dirfd");
+               return -1;
+       }
+
+       while ((entry = readdir(input_dir))) {
+               if (!strcmp(entry->d_name, ".")
+                               || !strcmp(entry->d_name, ".."))
+                       continue;
+               ret = extract_file(output_dir_fd, entry->d_name,
+                       input_dir_fd, entry->d_name);
+               if (ret == -ENODATA) {
+                       DBG("No data in file '%s', skipping", entry->d_name);
+                       ret = 0;
+                       continue;
+               } else if (ret < 0) {
+                       break;
+               } else if (ret > 0) {
+                       DBG("Skipping file '%s'", entry->d_name);
+                       ret = 0;
+                       continue;
+               }
+       }
+       closeret = closedir(output_dir);
+       if (closeret) {
+               PERROR("closedir");
+       }
+       closeret = closedir(input_dir);
+       if (closeret) {
+               PERROR("closedir");
+       }
+       return ret;
+}
+
+static
+int extract_one_trace(const char *output_path,
+               const char *input_path)
+{
+       char dest[PATH_MAX], src[PATH_MAX];
+       int ret;
+
+       DBG("Extract crash trace '%s' into '%s'", input_path, output_path);
+
+       /* Copy metadata */
+       strncpy(dest, output_path, PATH_MAX);
+       dest[PATH_MAX - 1] = '\0';
+       strncat(dest, "/metadata", PATH_MAX - strlen(dest) - 1);
+
+       strncpy(src, input_path, PATH_MAX);
+       src[PATH_MAX - 1] = '\0';
+       strncat(src, "/metadata", PATH_MAX - strlen(dest) - 1);
+
+       ret = copy_file(dest, src);
+       if (ret) {
+               return ret;
+       }
+
+       /* Extract each other file that has expected header */
+       return extract_all_files(output_path, input_path);
+}
+
+static
+int extract_all_traces(const char *output_path,
+               char **input_paths,
+               int nr_input_paths)
+{
+       int ret, i;
+       int has_warning = 0;
+
+       /* Only one input path is currently supported */
+       if (nr_input_paths != 1) {
+               ERR("Only a single input path is currently supported.\n");
+               return -1;
+       }
+
+       for (i = 0; i < nr_input_paths; i++) {
+               ret = extract_one_trace(output_path,
+                       input_paths[i]);
+               if (ret) {
+                       WARN("Error extracting trace '%s', continuing anyway.",
+                               input_paths[i]);
+                       has_warning = 1;
+               }
+       }
+       return has_warning;
+}
+
+static
+int delete_trace(const char *trace_path)
+{
+       DIR *trace_dir;
+       int trace_dir_fd, ret = 0, closeret;
+       struct dirent *entry;
+
+       /* Open trace directory */
+       trace_dir = opendir(trace_path);
+       if (!trace_dir) {
+               PERROR("Cannot open '%s' path", trace_path);
+               return -1;
+       }
+       trace_dir_fd = dirfd(trace_dir);
+       if (trace_dir_fd < 0) {
+               PERROR("dirfd");
+               return -1;
+       }
+
+       while ((entry = readdir(trace_dir))) {
+               if (!strcmp(entry->d_name, ".")
+                               || !strcmp(entry->d_name, ".."))
+                       continue;
+               switch (entry->d_type) {
+               case DT_DIR:
+                       unlinkat(trace_dir_fd, entry->d_name, AT_REMOVEDIR);
+                       break;
+               case DT_REG:
+                       unlinkat(trace_dir_fd, entry->d_name, 0);
+                       break;
+               default:
+                       ret = -EINVAL;
+                       goto end;
+               }
+       }
+end:
+       closeret = closedir(trace_dir);
+       if (closeret) {
+               PERROR("closedir");
+       }
+       if (!ret) {
+               ret = rmdir(trace_path);
+       }
+       return ret;
+}
+
+
+static
+int view_trace(const char *viewer_path, const char *trace_path)
+{
+       pid_t pid;
+
+       pid = fork();
+       if (pid < 0) {
+               /* Error */
+               PERROR("fork");
+               return -1;
+       } else if (pid > 0) {
+               /* Parent */
+               int status;
+
+               pid = waitpid(pid, &status, 0);
+               if (pid < 0 || !WIFEXITED(status)) {
+                       return -1;
+               }
+       } else {
+               /* Child */
+               int ret;
+
+               ret = execlp(viewer_path, viewer_path,
+                       trace_path, (char *) NULL);
+               if (ret) {
+                       PERROR("execlp");
+                       exit(EXIT_FAILURE);
+               }
+               exit(EXIT_SUCCESS);     /* Never reached */
+       }
+       return 0;
+}
+
+/*
+ *  main
+ */
+int main(int argc, char *argv[])
+{
+       int ret, has_warning = 0;
+       const char *output_path = NULL;
+       char tmppath[] = "/tmp/lttng-crash-XXXXXX";
+
+       progname = argv[0] ? argv[0] : "lttng-crash";
+
+       ret = parse_args(argc, argv);
+       if (ret > 0) {
+               exit(EXIT_SUCCESS);
+       } else if (ret < 0) {
+               exit(EXIT_FAILURE);
+       }
+
+       if (opt_output_path) {
+               output_path = opt_output_path;
+               ret = mkdir(output_path, S_IRWXU | S_IRWXG);
+               if (ret) {
+                       PERROR("mkdir");
+                       exit(EXIT_FAILURE);
+               }
+       } else {
+               output_path = mkdtemp(tmppath);
+               if (!output_path) {
+                       PERROR("mkdtemp");
+                       exit(EXIT_FAILURE);
+               }
+       }
+
+       ret = extract_all_traces(output_path, input_paths,
+               nr_input_paths);
+       if (ret < 0) {
+               exit(EXIT_FAILURE);
+       } else if (ret > 0) {
+               has_warning = 1;
+       }
+       if (!opt_output_path) {
+               /* View trace */
+               ret = view_trace(opt_viewer_path, output_path);
+               if (ret)
+                       has_warning = 1;
+
+               /* unlink temporary trace */
+               ret = delete_trace(output_path);
+               if (ret)
+                       has_warning = 1;
+       }
+       if (has_warning)
+               exit(EXIT_FAILURE);
+       exit(EXIT_SUCCESS);
+}
index 0ff76defbdcce18ad8aae47b28f9b7a43951af19..b96e585001c9bf7f420b0aac1ce274329550ce7c 100644 (file)
@@ -106,7 +106,8 @@ void buffer_reg_init_uid_registry(void)
  * Return 0 on success else a negative value and regp is untouched.
  */
 int buffer_reg_uid_create(uint64_t session_id, uint32_t bits_per_long, uid_t uid,
-               enum lttng_domain_type domain, struct buffer_reg_uid **regp)
+               enum lttng_domain_type domain, struct buffer_reg_uid **regp,
+               const char *shm_path)
 {
        int ret = 0;
        struct buffer_reg_uid *reg = NULL;
@@ -131,7 +132,12 @@ int buffer_reg_uid_create(uint64_t session_id, uint32_t bits_per_long, uid_t uid
        reg->bits_per_long = bits_per_long;
        reg->uid = uid;
        reg->domain = domain;
-
+       if (shm_path[0]) {
+               strncpy(reg->shm_path, shm_path, sizeof(reg->shm_path));
+               reg->shm_path[sizeof(reg->shm_path) - 1] = '\0';
+               DBG3("shm path '%s' is assigned to uid buffer registry for session id %" PRIu64,
+                       reg->shm_path, session_id);
+       }
        reg->registry->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
        if (!reg->registry->channels) {
                ret = -ENOMEM;
@@ -226,7 +232,8 @@ void buffer_reg_init_pid_registry(void)
  *
  * Return 0 on success else a negative value and regp is untouched.
  */
-int buffer_reg_pid_create(uint64_t session_id, struct buffer_reg_pid **regp)
+int buffer_reg_pid_create(uint64_t session_id, struct buffer_reg_pid **regp,
+               const char *shm_path)
 {
        int ret = 0;
        struct buffer_reg_pid *reg = NULL;
@@ -249,7 +256,12 @@ int buffer_reg_pid_create(uint64_t session_id, struct buffer_reg_pid **regp)
 
        /* A cast is done here so we can use the session ID as a u64 ht node. */
        reg->session_id = session_id;
-
+       if (shm_path[0]) {
+               strncpy(reg->shm_path, shm_path, sizeof(reg->shm_path));
+               reg->shm_path[sizeof(reg->shm_path) - 1] = '\0';
+               DBG3("shm path '%s' is assigned to pid buffer registry for session id %" PRIu64,
+                               reg->shm_path, session_id);
+       }
        reg->registry->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
        if (!reg->registry->channels) {
                ret = -ENOMEM;
index 656fc9175b7d1bd6415ed3a2fd63ad9cc8def4f4..d17bbab623d5ae34a707d46b9d6bbf871213a8c7 100644 (file)
@@ -88,6 +88,8 @@ struct buffer_reg_uid {
        struct lttng_ht_node_u64 node;
        /* Node of a linked list used to teardown object at a destroy session. */
        struct cds_list_head lnode;
+
+       char shm_path[PATH_MAX];
 };
 
 /*
@@ -100,12 +102,15 @@ struct buffer_reg_pid {
 
        /* Indexed by session id. */
        struct lttng_ht_node_u64 node;
+
+       char shm_path[PATH_MAX];
 };
 
 /* Buffer registry per UID. */
 void buffer_reg_init_uid_registry(void);
 int buffer_reg_uid_create(uint64_t session_id, uint32_t bits_per_long, uid_t uid,
-               enum lttng_domain_type domain, struct buffer_reg_uid **regp);
+               enum lttng_domain_type domain, struct buffer_reg_uid **regp,
+               const char *shm_path);
 void buffer_reg_uid_add(struct buffer_reg_uid *reg);
 struct buffer_reg_uid *buffer_reg_uid_find(uint64_t session_id,
                uint32_t bits_per_long, uid_t uid);
@@ -115,7 +120,8 @@ void buffer_reg_uid_destroy(struct buffer_reg_uid *regp,
 
 /* Buffer registry per PID. */
 void buffer_reg_init_pid_registry(void);
-int buffer_reg_pid_create(uint64_t session_id, struct buffer_reg_pid **regp);
+int buffer_reg_pid_create(uint64_t session_id, struct buffer_reg_pid **regp,
+               const char *shm_path);
 void buffer_reg_pid_add(struct buffer_reg_pid *reg);
 struct buffer_reg_pid *buffer_reg_pid_find(uint64_t session_id);
 void buffer_reg_pid_remove(struct buffer_reg_pid *regp);
index cdc58b8cf1d4b534d959a5e4eb408bfe637c0f09..bf6097b64609097b1cdf60d97400baf72098cc27 100644 (file)
@@ -3333,6 +3333,29 @@ error:
        return ret;
 }
 
+/*
+ * Command LTTNG_SET_SESSION_SHM_PATH processed by the client thread.
+ */
+int cmd_set_session_shm_path(struct ltt_session *session,
+               const char *shm_path)
+{
+       /* Safety net */
+       assert(session);
+
+       /*
+        * Can only set shm path before session is started.
+        */
+       if (session->has_been_started) {
+               return LTTNG_ERR_SESSION_STARTED;
+       }
+
+       strncpy(session->shm_path, shm_path,
+               sizeof(session->shm_path));
+       session->shm_path[sizeof(session->shm_path) - 1] = '\0';
+
+       return 0;
+}
+
 /*
  * Init command subsystem.
  */
index 69c931a38e1814cbd45db36194d4a799398fafd3..7144690ca5f5d2eb96f0c0191ee15ecd584dc747 100644 (file)
@@ -97,4 +97,7 @@ int cmd_snapshot_del_output(struct ltt_session *session,
 int cmd_snapshot_record(struct ltt_session *session,
                struct lttng_snapshot_output *output, int wait);
 
+int cmd_set_session_shm_path(struct ltt_session *session,
+               const char *shm_path);
+
 #endif /* CMD_H */
index b7394d97d2def451211fcf1d993d77350340ca8c..628201e07c0f4477eafb1079a5cd96cf0677ecee 100644 (file)
@@ -801,7 +801,8 @@ void consumer_init_ask_channel_comm_msg(struct lttcomm_consumer_msg *msg,
                uint64_t tracefile_count,
                uint64_t session_id_per_pid,
                unsigned int monitor,
-               uint32_t ust_app_uid)
+               uint32_t ust_app_uid,
+               const char *shm_path)
 {
        assert(msg);
 
@@ -839,6 +840,12 @@ void consumer_init_ask_channel_comm_msg(struct lttcomm_consumer_msg *msg,
 
        strncpy(msg->u.ask_channel.name, name, sizeof(msg->u.ask_channel.name));
        msg->u.ask_channel.name[sizeof(msg->u.ask_channel.name) - 1] = '\0';
+
+       if (shm_path) {
+               strncpy(msg->u.ask_channel.shm_path, shm_path,
+                       sizeof(msg->u.ask_channel.shm_path));
+               msg->u.ask_channel.shm_path[sizeof(msg->u.ask_channel.shm_path) - 1] = '\0';
+       }
 }
 
 /*
index a9266d5b939798882377bc2caeb0e67251464fa2..0b67c08287df7be67430e3c7c76465d22e94a80b 100644 (file)
@@ -240,7 +240,8 @@ void consumer_init_ask_channel_comm_msg(struct lttcomm_consumer_msg *msg,
                uint64_t tracefile_count,
                uint64_t session_id_per_pid,
                unsigned int monitor,
-               uint32_t ust_app_uid);
+               uint32_t ust_app_uid,
+               const char *shm_path);
 void consumer_init_stream_comm_msg(struct lttcomm_consumer_msg *msg,
                enum lttng_consumer_command cmd,
                uint64_t channel_key,
index e68aa79d4c053ecd5aa598a7f10d7cee4ac383e4..c542179371327b951d71255902b949c789f265fd 100644 (file)
@@ -2765,7 +2765,13 @@ static int create_ust_session(struct ltt_session *session,
        lus->snapshot_mode = session->snapshot_mode;
        lus->live_timer_interval = session->live_timer;
        session->ust_session = lus;
-
+       if (session->shm_path[0]) {
+               strncpy(lus->shm_path, session->shm_path,
+                       sizeof(lus->shm_path));
+               lus->shm_path[sizeof(lus->shm_path) - 1] = '\0';
+               strncat(lus->shm_path, "/ust",
+                       sizeof(lus->shm_path) - strlen(lus->shm_path) - 1);
+       }
        /* Copy session output to the newly created UST session */
        ret = copy_session_consumer(domain->type, session);
        if (ret != LTTNG_OK) {
@@ -2890,6 +2896,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_SNAPSHOT_LIST_OUTPUT:
        case LTTNG_SNAPSHOT_RECORD:
        case LTTNG_SAVE_SESSION:
+       case LTTNG_SET_SESSION_SHM_PATH:
                need_domain = 0;
                break;
        default:
@@ -3830,6 +3837,12 @@ skip_domain:
                        &cmd_ctx->creds);
                break;
        }
+       case LTTNG_SET_SESSION_SHM_PATH:
+       {
+               ret = cmd_set_session_shm_path(cmd_ctx->session,
+                               cmd_ctx->lsm->u.set_shm_path.shm_path);
+               break;
+       }
        default:
                ret = LTTNG_ERR_UND;
                break;
index 368b352fa22388c9edae452fda760535b767ccf5..48dc44a33d632efaff87598d1057f7569b83e584 100644 (file)
@@ -109,6 +109,10 @@ struct ltt_session {
         * Timer set when the session is created for live reading.
         */
        unsigned int live_timer;
+       /*
+        * Path where to keep the shared memory files.
+        */
+       char shm_path[PATH_MAX];
 };
 
 /* Prototypes */
index 795389e9da3f34e55c6eae7fc7bffc46c4b09c80..63564ff71f296e3eed9c7ec7159c590db78cb076 100644 (file)
@@ -113,6 +113,11 @@ struct ltt_ust_session {
 
        /* Metadata channel attributes. */
        struct lttng_ust_channel_attr metadata_attr;
+
+       /*
+        * Path where to keep the shared memory files.
+        */
+       char shm_path[PATH_MAX];
 };
 
 /*
index c8cff2386fc36658cb0ef99d2d477cf1e3785dfb..480971b8982287e980ca09836d72b2105b869b23 100644 (file)
@@ -1593,6 +1593,7 @@ static void shadow_copy_session(struct ust_app_session *ua_sess,
        struct tm *timeinfo;
        char datetime[16];
        int ret;
+       char tmp_shm_path[PATH_MAX];
 
        /* Get date and time for unique app path */
        time(&rawtime);
@@ -1636,6 +1637,35 @@ static void shadow_copy_session(struct ust_app_session *ua_sess,
                goto error;
        }
 
+       strncpy(ua_sess->shm_path, usess->shm_path,
+               sizeof(ua_sess->shm_path));
+       ua_sess->shm_path[sizeof(ua_sess->shm_path) - 1] = '\0';
+       if (ua_sess->shm_path[0]) {
+               switch (ua_sess->buffer_type) {
+               case LTTNG_BUFFER_PER_PID:
+                       ret = snprintf(tmp_shm_path, sizeof(tmp_shm_path),
+                                       DEFAULT_UST_TRACE_PID_PATH "/%s-%d-%s",
+                                       app->name, app->pid, datetime);
+                       break;
+               case LTTNG_BUFFER_PER_UID:
+                       ret = snprintf(tmp_shm_path, sizeof(tmp_shm_path),
+                                       DEFAULT_UST_TRACE_UID_PATH,
+                                       app->uid, app->bits_per_long);
+                       break;
+               default:
+                       assert(0);
+                       goto error;
+               }
+               if (ret < 0) {
+                       PERROR("sprintf UST shadow copy session");
+                       assert(0);
+                       goto error;
+               }
+               strncat(ua_sess->shm_path, tmp_shm_path,
+                       sizeof(ua_sess->shm_path) - strlen(ua_sess->shm_path) - 1);
+               ua_sess->shm_path[sizeof(ua_sess->shm_path) - 1] = '\0';
+       }
+
        /* Iterate over all channels in global domain. */
        cds_lfht_for_each_entry(usess->domain_global.channels->ht, &iter.iter,
                        uchan, node.node) {
@@ -1727,7 +1757,8 @@ static int setup_buffer_reg_pid(struct ust_app_session *ua_sess,
                 * This is the create channel path meaning that if there is NO
                 * registry available, we have to create one for this session.
                 */
-               ret = buffer_reg_pid_create(ua_sess->id, &reg_pid);
+               ret = buffer_reg_pid_create(ua_sess->id, &reg_pid,
+                       ua_sess->shm_path);
                if (ret < 0) {
                        goto error;
                }
@@ -1741,7 +1772,8 @@ static int setup_buffer_reg_pid(struct ust_app_session *ua_sess,
                        app->uint16_t_alignment, app->uint32_t_alignment,
                        app->uint64_t_alignment, app->long_alignment,
                        app->byte_order, app->version.major,
-                       app->version.minor);
+                       app->version.minor, reg_pid->shm_path,
+                       ua_sess->euid, ua_sess->egid);
        if (ret < 0) {
                /*
                 * reg_pid->registry->reg.ust is NULL upon error, so we need to
@@ -1774,6 +1806,7 @@ error:
  * Return 0 on success or else a negative value.
  */
 static int setup_buffer_reg_uid(struct ltt_ust_session *usess,
+               struct ust_app_session *ua_sess,
                struct ust_app *app, struct buffer_reg_uid **regp)
 {
        int ret = 0;
@@ -1791,7 +1824,7 @@ static int setup_buffer_reg_uid(struct ltt_ust_session *usess,
                 * registry available, we have to create one for this session.
                 */
                ret = buffer_reg_uid_create(usess->id, app->bits_per_long, app->uid,
-                               LTTNG_DOMAIN_UST, &reg_uid);
+                               LTTNG_DOMAIN_UST, &reg_uid, ua_sess->shm_path);
                if (ret < 0) {
                        goto error;
                }
@@ -1805,7 +1838,8 @@ static int setup_buffer_reg_uid(struct ltt_ust_session *usess,
                        app->uint16_t_alignment, app->uint32_t_alignment,
                        app->uint64_t_alignment, app->long_alignment,
                        app->byte_order, app->version.major,
-                       app->version.minor);
+                       app->version.minor, reg_uid->shm_path,
+                       usess->uid, usess->gid);
        if (ret < 0) {
                /*
                 * reg_uid->registry->reg.ust is NULL upon error, so we need to
@@ -1880,7 +1914,7 @@ static int create_ust_app_session(struct ltt_ust_session *usess,
                break;
        case LTTNG_BUFFER_PER_UID:
                /* Look for a global registry. If none exists, create one. */
-               ret = setup_buffer_reg_uid(usess, app, NULL);
+               ret = setup_buffer_reg_uid(usess, ua_sess, app, NULL);
                if (ret < 0) {
                        delete_ust_app_session(-1, ua_sess, app);
                        goto error;
index 9347cd709153fcaf7b00b486dfc7d56d0fd14a22..59ef85b78cf9c082eb00b407066a1e78a272acb7 100644 (file)
@@ -215,6 +215,8 @@ struct ust_app_session {
 
        /* Metadata channel attributes. */
        struct ustctl_consumer_channel_attr metadata_attr;
+
+       char shm_path[PATH_MAX];
 };
 
 /*
index 611b54dcdb17d392f14bd42dc98320a0cb098b61..8a3533ba10c360097a8fb2cb0099a4f3d986f324 100644 (file)
@@ -109,6 +109,7 @@ static int ask_channel_creation(struct ust_app_session *ua_sess,
        char *pathname = NULL;
        struct lttcomm_consumer_msg msg;
        struct ust_registry_channel *chan_reg;
+       char shm_path[PATH_MAX] = "";
 
        assert(ua_sess);
        assert(ua_chan);
@@ -136,10 +137,25 @@ static int ask_channel_creation(struct ust_app_session *ua_sess,
 
        if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
                chan_id = -1U;
+               /*
+                * Metadata channels shm_path (buffers) are handled within
+                * session daemon. Consumer daemon should not try to create
+                * those buffer files.
+                */
        } else {
                chan_reg = ust_registry_channel_find(registry, chan_reg_key);
                assert(chan_reg);
                chan_id = chan_reg->chan_id;
+               if (ua_sess->shm_path[0]) {
+                       strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
+                       shm_path[sizeof(shm_path) - 1] = '\0';
+                       strncat(shm_path, "/",
+                               sizeof(shm_path) - strlen(shm_path) - 1);
+                       strncat(shm_path, ua_chan->name,
+                                       sizeof(shm_path) - strlen(shm_path) - 1);
+                               strncat(shm_path, "_",
+                                       sizeof(shm_path) - strlen(shm_path) - 1);
+               }
        }
 
        switch (ua_chan->attr.output) {
@@ -171,7 +187,8 @@ static int ask_channel_creation(struct ust_app_session *ua_sess,
                        ua_chan->tracefile_count,
                        ua_sess->id,
                        ua_sess->output_traces,
-                       ua_sess->uid);
+                       ua_sess->uid,
+                       shm_path);
 
        health_code_update();
 
index 379429285ad6af7f033ce3950c29190eacf706ac..f4f273b16cc7021e2f4869e52b42dfd7f14799dd 100644 (file)
@@ -120,6 +120,23 @@ ssize_t metadata_reserve(struct ust_registry_session *session, size_t len)
        return ret;
 }
 
+static
+int metadata_file_append(struct ust_registry_session *session,
+               const char *str, size_t len)
+{
+       ssize_t written;
+
+       if (session->metadata_fd < 0) {
+               return 0;
+       }
+       /* Write to metadata file */
+       written = lttng_write(session->metadata_fd, str, len);
+       if (written != len) {
+               return -1;
+       }
+       return 0;
+}
+
 /*
  * We have exclusive access to our metadata buffer (protected by the
  * ust_lock), so we can do racy operations such as looking for
@@ -149,6 +166,11 @@ int lttng_metadata_printf(struct ust_registry_session *session,
                goto end;
        }
        memcpy(&session->metadata[offset], str, len);
+       ret = metadata_file_append(session, str, len);
+       if (ret) {
+               PERROR("Error appending to metadata file");
+               goto end;
+       }
        DBG3("Append to metadata: \"%s\"", str);
        ret = 0;
 
@@ -575,6 +597,15 @@ int ust_metadata_session_statedump(struct ust_registry_session *session,
                uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
                uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
 
+       /* For crash ABI */
+       ret = lttng_metadata_printf(session,
+               "/* CTF %u.%u */\n\n",
+               CTF_SPEC_MAJOR,
+               CTF_SPEC_MINOR);
+       if (ret) {
+               goto end;
+       }
+
        ret = lttng_metadata_printf(session,
                "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
                "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
index 1a00e9349fb2f04c6052a5222acaf7d927fdd471..26f306d52d516ac6091e74a1cb26ef73821dbbbd 100644 (file)
@@ -546,7 +546,10 @@ int ust_registry_session_init(struct ust_registry_session **sessionp,
                uint32_t long_alignment,
                int byte_order,
                uint32_t major,
-               uint32_t minor)
+               uint32_t minor,
+               const char *shm_path,
+               uid_t euid,
+               gid_t egid)
 {
        int ret;
        struct ust_registry_session *session;
@@ -567,6 +570,38 @@ int ust_registry_session_init(struct ust_registry_session **sessionp,
        session->uint64_t_alignment = uint64_t_alignment;
        session->long_alignment = long_alignment;
        session->byte_order = byte_order;
+       session->metadata_fd = -1;
+       if (shm_path[0]) {
+               strncpy(session->shm_path, shm_path,
+                       sizeof(session->shm_path));
+               session->shm_path[sizeof(session->shm_path) - 1] = '\0';
+               strncpy(session->metadata_path, shm_path,
+                       sizeof(session->metadata_path));
+               session->metadata_path[sizeof(session->metadata_path) - 1] = '\0';
+               strncat(session->metadata_path, "/metadata",
+                       sizeof(session->metadata_path)
+                               - strlen(session->metadata_path) - 1);
+       }
+       if (session->shm_path[0]) {
+               ret = run_as_mkdir_recursive(session->shm_path,
+                       S_IRWXU | S_IRWXG,
+                       euid, egid);
+               if (ret) {
+                       PERROR("run_as_mkdir_recursive");
+                       goto error;
+               }
+       }
+       if (session->metadata_path[0]) {
+               /* Create metadata file */
+               ret = open(session->metadata_path,
+                       O_WRONLY | O_CREAT | O_EXCL,
+                       S_IRUSR | S_IWUSR);
+               if (ret < 0) {
+                       PERROR("Opening metadata file");
+                       goto error;
+               }
+               session->metadata_fd = ret;
+       }
 
        session->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
        if (!session->channels) {
@@ -631,4 +666,14 @@ void ust_registry_session_destroy(struct ust_registry_session *reg)
        }
 
        free(reg->metadata);
+       if (reg->metadata_fd >= 0) {
+               ret = close(reg->metadata_fd);
+               if (ret) {
+                       PERROR("close");
+               }
+               ret = unlink(reg->metadata_path);
+               if (ret) {
+                       PERROR("unlink");
+               }
+       }
 }
index 0cba8a334e54609df98d5e615662d68a73654c70..a22009efa996263cf9a17b2fe08941b5a088f92a 100644 (file)
@@ -66,6 +66,11 @@ struct ust_registry_session {
        size_t metadata_len, metadata_alloc_len;
        /* Length of bytes sent to the consumer. */
        size_t metadata_len_sent;
+
+       char shm_path[PATH_MAX];
+       char metadata_path[PATH_MAX];
+       int metadata_fd;        /* file-backed metadata FD */
+
        /*
         * Hash table containing channels sent by the UST tracer. MUST
         * be accessed with a RCU read side lock acquired.
@@ -225,7 +230,10 @@ int ust_registry_session_init(struct ust_registry_session **sessionp,
                uint32_t long_alignment,
                int byte_order,
                uint32_t major,
-               uint32_t minor);
+               uint32_t minor,
+               const char *shm_path,
+               uid_t euid,
+               gid_t egid);
 void ust_registry_session_destroy(struct ust_registry_session *session);
 
 int ust_registry_create_event(struct ust_registry_session *session,
index 1ebe590ad279915e8e3e7ba05784e0333eb9064f..b8d9f3b5655c56975bfa1716a08065b86ca1ca14 100644 (file)
@@ -44,6 +44,7 @@ static char *opt_session_name;
 static char *opt_url;
 static char *opt_ctrl_url;
 static char *opt_data_url;
+static char *opt_shm_path;
 static int opt_no_consumer;
 static int opt_no_output;
 static int opt_snapshot;
@@ -69,6 +70,7 @@ static struct poptOption long_options[] = {
        {"no-consumer",     0, POPT_ARG_VAL, &opt_no_consumer, 1, 0, 0},
        {"snapshot",        0, POPT_ARG_VAL, &opt_snapshot, 1, 0, 0},
        {"live",            0, POPT_ARG_INT | POPT_ARGFLAG_OPTIONAL, 0, OPT_LIVE_TIMER, 0, 0},
+       {"shm-path",        0, POPT_ARG_STRING, &opt_shm_path, 0, 0, 0},
        {0, 0, 0, 0, 0, 0, 0}
 };
 
@@ -106,6 +108,9 @@ static void usage(FILE *ofp)
        fprintf(ofp, "                       By default, %u is used for the timer and the\n",
                                                                                        DEFAULT_LTTNG_LIVE_TIMER);
        fprintf(ofp, "                       network URL is set to net://127.0.0.1.\n");
+       fprintf(ofp, "      --shm-path PATH  Path where shared memory holding buffers\n");
+       fprintf(ofp, "                       should be created. Useful when used with pramfs\n");
+       fprintf(ofp, "                       to extract trace data after crash.\n");
        fprintf(ofp, "\n");
        fprintf(ofp, "Extended Options:\n");
        fprintf(ofp, "\n");
@@ -297,6 +302,7 @@ static int create_session(void)
        char session_name_date[NAME_MAX + 17], *print_str_url = NULL;
        time_t rawtime;
        struct tm *timeinfo;
+       char shm_path[PATH_MAX] = "";
 
        /* Get date and time for automatic session name/path */
        time(&rawtime);
@@ -481,6 +487,21 @@ static int create_session(void)
                }
        }
 
+       if (opt_shm_path) {
+               ret = snprintf(shm_path, sizeof(shm_path),
+                               "%s/%s", opt_shm_path, session_name_date);
+               if (ret < 0) {
+                       PERROR("snprintf shm_path");
+                       goto error;
+               }
+
+               ret = lttng_set_session_shm_path(session_name, shm_path);
+               if (ret < 0) {
+                       lttng_destroy_session(session_name);
+                       goto error;
+               }
+       }
+
        MSG("Session %s created.", session_name);
        if (print_str_url && !opt_snapshot) {
                MSG("Traces will be written in %s", print_str_url);
@@ -495,6 +516,10 @@ static int create_session(void)
                MSG("Snapshot mode set. Every channel enabled for that session will "
                                "be set in overwrite mode and mmap output.");
        }
+       if (opt_shm_path) {
+               MSG("Session %s set to shm_path: %s.", session_name,
+                       shm_path);
+       }
 
        /* Mi output */
        if (lttng_opt_mi) {
index 0af994fc421c5b00c4ca11615cee2c9220aa5466..1cb1c47431303e6ed3c516948a78b5807855c48c 100644 (file)
@@ -936,7 +936,8 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
                uint64_t tracefile_count,
                uint64_t session_id_per_pid,
                unsigned int monitor,
-               unsigned int live_timer_interval)
+               unsigned int live_timer_interval,
+               const char *shm_path)
 {
        struct lttng_consumer_channel *channel;
 
@@ -993,6 +994,11 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
        strncpy(channel->name, name, sizeof(channel->name));
        channel->name[sizeof(channel->name) - 1] = '\0';
 
+       if (shm_path) {
+               strncpy(channel->shm_path, shm_path, sizeof(channel->shm_path));
+               channel->shm_path[sizeof(channel->shm_path) - 1] = '\0';
+       }
+
        lttng_ht_node_init_u64(&channel->node, channel->key);
 
        channel->wait_fd = -1;
index 790cb6b135d9b9983a9826e4713112ad586da247..a80bc40ab9128e8ae3c5987bd4c8870736cc35bb 100644 (file)
@@ -206,6 +206,8 @@ struct lttng_consumer_channel {
 
        /* Timer value in usec for live streaming. */
        unsigned int live_timer_interval;
+
+       char shm_path[PATH_MAX];
 };
 
 /*
@@ -599,7 +601,8 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
                uint64_t tracefile_count,
                uint64_t session_id_per_pid,
                unsigned int monitor,
-               unsigned int live_timer_interval);
+               unsigned int live_timer_interval,
+               const char *shm_path);
 void consumer_del_stream(struct lttng_consumer_stream *stream,
                struct lttng_ht *ht);
 void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
index 7622a22537738b2164f57d8fb15caf0b46963606..0af417b9cdb701f657bb34ddcf0d65a1487bb455 100644 (file)
@@ -480,7 +480,8 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                msg.u.channel.tracefile_size,
                                msg.u.channel.tracefile_count, 0,
                                msg.u.channel.monitor,
-                               msg.u.channel.live_timer_interval);
+                               msg.u.channel.live_timer_interval,
+                               NULL);
                if (new_channel == NULL) {
                        lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
                        goto end_nosignal;
index 1426fcf203548dfe8c95ebeeae6050662ca917a1..baf608ffd748fd3036e52547d850ccb84c66be98 100644 (file)
@@ -91,6 +91,9 @@ enum lttcomm_sessiond_command {
        LTTNG_CREATE_SESSION_SNAPSHOT       = 29,
        LTTNG_CREATE_SESSION_LIVE           = 30,
        LTTNG_SAVE_SESSION                  = 31,
+
+       /* Session daemon commands (cont.) */
+       LTTNG_SET_SESSION_SHM_PATH          = 40,
 };
 
 enum lttcomm_relayd_command {
@@ -296,6 +299,9 @@ struct lttcomm_session_msg {
                struct {
                        struct lttng_save_session_attr attr; /* struct already packed */
                } LTTNG_PACKED save_session;
+               struct {
+                       char shm_path[PATH_MAX];
+               } LTTNG_PACKED set_shm_path;
        } u;
 } LTTNG_PACKED;
 
@@ -424,6 +430,7 @@ struct lttcomm_consumer_msg {
                         * because the application can be in the tracing for instance.
                         */
                        uint32_t ust_app_uid;
+                       char shm_path[PATH_MAX];
                } LTTNG_PACKED ask_channel;
                struct {
                        uint64_t key;
index bf0208f1d67adb0dd92e840b03a0c43910771b5d..81f6859124c1353d89dbb36b38f8549761f33d53 100644 (file)
@@ -124,14 +124,16 @@ static struct lttng_consumer_channel *allocate_channel(uint64_t session_id,
                uint64_t relayd_id, uint64_t key, enum lttng_event_output output,
                uint64_t tracefile_size, uint64_t tracefile_count,
                uint64_t session_id_per_pid, unsigned int monitor,
-               unsigned int live_timer_interval)
+               unsigned int live_timer_interval,
+               const char *shm_path)
 {
        assert(pathname);
        assert(name);
 
        return consumer_allocate_channel(key, session_id, pathname, name, uid,
                        gid, relayd_id, output, tracefile_size,
-                       tracefile_count, session_id_per_pid, monitor, live_timer_interval);
+                       tracefile_count, session_id_per_pid, monitor,
+                       live_timer_interval, shm_path);
 }
 
 /*
@@ -1210,7 +1212,8 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                msg.u.ask_channel.tracefile_count,
                                msg.u.ask_channel.session_id_per_pid,
                                msg.u.ask_channel.monitor,
-                               msg.u.ask_channel.live_timer_interval);
+                               msg.u.ask_channel.live_timer_interval,
+                               msg.u.ask_channel.shm_path);
                if (!channel) {
                        goto end_channel_error;
                }
@@ -1230,6 +1233,9 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                attr.read_timer_interval = msg.u.ask_channel.read_timer_interval;
                attr.chan_id = msg.u.ask_channel.chan_id;
                memcpy(attr.uuid, msg.u.ask_channel.uuid, sizeof(attr.uuid));
+               strncpy(attr.shm_path, channel->shm_path,
+                       sizeof(attr.shm_path));
+               attr.shm_path[sizeof(attr.shm_path) - 1] = '\0';
 
                /* Match channel buffer type to the UST abi. */
                switch (msg.u.ask_channel.output) {
index f879d8ddfd2ea7b036df41a12d256809cee3a715..4332881c6eb7a41f538189a3dd3dcc41aed0ae30 100644 (file)
@@ -1452,6 +1452,26 @@ int lttng_list_sessions(struct lttng_session **sessions)
        return ret / sizeof(struct lttng_session);
 }
 
+int lttng_set_session_shm_path(const char *session_name,
+               const char *shm_path)
+{
+       struct lttcomm_session_msg lsm;
+
+       if (session_name == NULL) {
+               return -LTTNG_ERR_INVALID;
+       }
+
+       memset(&lsm, 0, sizeof(lsm));
+       lsm.cmd_type = LTTNG_SET_SESSION_SHM_PATH;
+
+       lttng_ctl_copy_string(lsm.session.name, session_name,
+                       sizeof(lsm.session.name));
+       lttng_ctl_copy_string(lsm.u.set_shm_path.shm_path, shm_path,
+                       sizeof(lsm.u.set_shm_path.shm_path));
+
+       return lttng_ctl_ask_sessiond(&lsm, NULL);
+}
+
 /*
  *  Ask the session daemon for all available domains of a session.
  *  Sets the contents of the domains array.
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