baddr statedump: remove dependency on file streams

None of the rest of UST used by applications use file streams (only the
sessiond uses a file streams for metadata). Therefore, use file
descriptors directly for baddr statedump.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/include/lttng/ust-elf.h b/include/lttng/ust-elf.h
index 41e3c9b775e10104f1e60014ba58d9922c280b9e..fee52f9ef2ff0f5f432968f524e1e6dd0051d926 100644 (file)
--- a/include/lttng/ust-elf.h
+++ b/include/lttng/ust-elf.h
@@ -199,7 +199,7 @@ struct lttng_ust_elf {
        /* Size in bytes of section names string table. */
        uint64_t section_names_size;
        char *path;
-       FILE *file;
+       int fd;
        struct lttng_ust_elf_ehdr *ehdr;
        uint8_t bitness;
        uint8_t endianness;

diff --git a/liblttng-ust/lttng-tracer-core.h b/liblttng-ust/lttng-tracer-core.h
index 4e0d2c69d70f2510811a80432e22ab2a43e79a3b..7d9beaaf92ca70ae0e48eb317f718ff759e93aee 100644 (file)
--- a/liblttng-ust/lttng-tracer-core.h
+++ b/liblttng-ust/lttng-tracer-core.h
@@ -50,4 +50,6 @@ void lttng_ust_sockinfo_session_enabled(void *owner);
 
 void lttng_ust_malloc_wrapper_init(void);
 
+ssize_t lttng_ust_read(int fd, void *buf, size_t len);
+
 #endif /* _LTTNG_TRACER_CORE_H */

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 0a3de32263c068fbffa7c2968218df8dcc14c8a9..08e6299ce3a5bd7793e4ddf04c556e9d04e2e7f8 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -329,6 +329,24 @@ extern void lttng_ring_buffer_client_discard_exit(void);
 extern void lttng_ring_buffer_client_discard_rt_exit(void);
 extern void lttng_ring_buffer_metadata_client_exit(void);
 
+ssize_t lttng_ust_read(int fd, void *buf, size_t len)
+{
+       ssize_t ret;
+       size_t copied = 0, to_copy = len;
+
+       do {
+               ret = read(fd, buf + copied, to_copy);
+               if (ret > 0) {
+                       copied += ret;
+                       to_copy -= ret;
+               }
+       } while ((ret > 0 && to_copy > 0)
+               || (ret < 0 && errno == EINTR));
+       if (ret > 0) {
+               ret = copied;
+       }
+       return ret;
+}
 /*
  * Returns the HOME directory path. Caller MUST NOT free(3) the returned
  * pointer.

diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c
index f5c4f1a1c4988e2e323981e491071e2572f5f527..0df70973fd7906f57d32e0289937bcbf861d7d1a 100644 (file)
--- a/liblttng-ust/lttng-ust-elf.c
+++ b/liblttng-ust/lttng-ust-elf.c
@@ -20,6 +20,13 @@
 #include <string.h>
 #include <lttng/align.h>
 #include <lttng/ust-elf.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include "lttng-tracer-core.h"
+
+#define BUF_LEN        4096
 
 /*
  * Retrieve the nth (where n is the `index` argument) phdr (program
@@ -48,14 +55,15 @@ struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf,
        }
 
        offset = elf->ehdr->e_phoff + index * elf->ehdr->e_phentsize;
-       if (fseek(elf->file, offset, SEEK_SET)) {
+       if (lseek(elf->fd, offset, SEEK_SET) < 0) {
                goto error;
        }
 
        if (is_elf_32_bit(elf)) {
                Elf32_Phdr elf_phdr;
 
-               if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) {
+               if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr))
+                               < sizeof(elf_phdr)) {
                        goto error;
                }
                if (!is_elf_native_endian(elf)) {
@@ -65,7 +73,8 @@ struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf,
        } else {
                Elf64_Phdr elf_phdr;
 
-               if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) {
+               if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr))
+                               < sizeof(elf_phdr)) {
                        goto error;
                }
                if (!is_elf_native_endian(elf)) {
@@ -108,14 +117,15 @@ struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf,
        }
 
        offset = elf->ehdr->e_shoff + index * elf->ehdr->e_shentsize;
-       if (fseek(elf->file, offset, SEEK_SET)) {
+       if (lseek(elf->fd, offset, SEEK_SET) < 0) {
                goto error;
        }
 
        if (is_elf_32_bit(elf)) {
                Elf32_Shdr elf_shdr;
 
-               if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) {
+               if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr))
+                               < sizeof(elf_shdr)) {
                        goto error;
                }
                if (!is_elf_native_endian(elf)) {
@@ -125,7 +135,8 @@ struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf,
        } else {
                Elf64_Shdr elf_shdr;
 
-               if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) {
+               if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr))
+                               < sizeof(elf_shdr)) {
                        goto error;
                }
                if (!is_elf_native_endian(elf)) {
@@ -152,7 +163,7 @@ static
 char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, uint32_t offset)
 {
        char *name = NULL;
-       size_t len;
+       size_t len = 0, to_read;        /* len does not include \0 */
 
        if (!elf) {
                goto error;
@@ -162,34 +173,45 @@ char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, uint32_t offset)
                goto error;
        }
 
-       if (fseek(elf->file, elf->section_names_offset + offset, SEEK_SET)) {
+       if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) {
                goto error;
        }
-       /* Note that len starts at 1, it is not an index. */
-       for (len = 1; offset + len <= elf->section_names_size; ++len) {
-               switch (fgetc(elf->file)) {
-               case EOF:
+
+       to_read = elf->section_names_size - offset;
+
+       /* Find first \0 after or at current location, remember len. */
+       for (;;) {
+               char buf[BUF_LEN];
+               ssize_t read_len;
+               size_t i;
+
+               if (!to_read) {
                        goto error;
-               case '\0':
-                       goto end;
-               default:
-                       break;
                }
+               read_len = lttng_ust_read(elf->fd, buf,
+                       min_t(size_t, BUF_LEN, to_read));
+               if (read_len <= 0) {
+                       goto error;
+               }
+               for (i = 0; i < read_len; i++) {
+                       if (buf[i] == '\0') {
+                               len += i;
+                               goto end;
+                       }
+               }
+               len += read_len;
+               to_read -= read_len;
        }
-
-       /* No name was found before the end of the table. */
-       goto error;
-
 end:
-       name = zmalloc(sizeof(char) * len);
+       name = zmalloc(sizeof(char) * (len + 1));       /* + 1 for \0 */
        if (!name) {
                goto error;
        }
-       if (fseek(elf->file, elf->section_names_offset + offset,
-               SEEK_SET)) {
+       if (lseek(elf->fd, elf->section_names_offset + offset,
+               SEEK_SET) < 0) {
                goto error;
        }
-       if (!fgets(name, len, elf->file)) {
+       if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) {
                goto error;
        }
 
@@ -210,7 +232,7 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
 {
        uint8_t e_ident[EI_NIDENT];
        struct lttng_ust_elf_shdr *section_names_shdr;
-       struct lttng_ust_elf *elf;
+       struct lttng_ust_elf *elf = NULL;
 
        elf = zmalloc(sizeof(struct lttng_ust_elf));
        if (!elf) {
@@ -222,17 +244,20 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
                goto error;
        }
 
-       elf->file = fopen(elf->path, "rb");
-       if (!elf->file) {
+       elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC);
+       if (elf->fd < 0) {
                goto error;
        }
 
-       if (!fread(e_ident, 1, EI_NIDENT, elf->file)) {
+       if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) {
                goto error;
        }
        elf->bitness = e_ident[EI_CLASS];
        elf->endianness = e_ident[EI_DATA];
-       rewind(elf->file);
+
+       if (lseek(elf->fd, 0, SEEK_SET) < 0) {
+               goto error;
+       }
 
        elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr));
        if (!elf->ehdr) {
@@ -242,7 +267,8 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
        if (is_elf_32_bit(elf)) {
                Elf32_Ehdr elf_ehdr;
 
-               if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) {
+               if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
+                               < sizeof(elf_ehdr)) {
                        goto error;
                }
                if (!is_elf_native_endian(elf)) {
@@ -252,7 +278,8 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
        } else {
                Elf64_Ehdr elf_ehdr;
 
-               if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) {
+               if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
+                               < sizeof(elf_ehdr)) {
                        goto error;
                }
                if (!is_elf_native_endian(elf)) {
@@ -270,16 +297,19 @@ struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
        elf->section_names_size = section_names_shdr->sh_size;
 
        free(section_names_shdr);
-
        return elf;
 
 error:
        if (elf) {
                free(elf->ehdr);
-               fclose(elf->file);
+               if (elf->fd >= 0) {
+                       if (close(elf->fd)) {
+                               abort();
+                       }
+               }
                free(elf->path);
+               free(elf);
        }
-       free(elf);
        return NULL;
 }
 
@@ -293,7 +323,9 @@ void lttng_ust_elf_destroy(struct lttng_ust_elf *elf)
        }
 
        free(elf->ehdr);
-       fclose(elf->file);
+       if (close(elf->fd)) {
+               abort();
+       }
        free(elf->path);
        free(elf);
 }
@@ -379,6 +411,7 @@ int lttng_ust_elf_get_build_id_from_segment(
 
        while (offset < segment_end) {
                struct lttng_ust_elf_nhdr nhdr;
+               size_t read_len;
 
                /* Align start of note entry */
                offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN);
@@ -390,10 +423,11 @@ int lttng_ust_elf_get_build_id_from_segment(
                 * build id the data following the header will not
                 * have been read.
                 */
-               if (fseek(elf->file, offset, SEEK_SET)) {
+               if (lseek(elf->fd, offset, SEEK_SET) < 0) {
                        goto error;
                }
-               if (!fread(&nhdr, sizeof(nhdr), 1, elf->file)) {
+               if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr))
+                               < sizeof(nhdr)) {
                        goto error;
                }
 
@@ -422,10 +456,11 @@ int lttng_ust_elf_get_build_id_from_segment(
                        goto error;
                }
 
-               if (fseek(elf->file, offset, SEEK_SET)) {
+               if (lseek(elf->fd, offset, SEEK_SET) < 0) {
                        goto error;
                }
-               if (!fread(_build_id, sizeof(*_build_id), _length, elf->file)) {
+               read_len = sizeof(*_build_id) * _length;
+               if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) {
                        goto error;
                }
 
@@ -520,7 +555,6 @@ error:
  *
  * Returns 0 on success, -1 if an error occurred.
  */
-static
 int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf,
                                        char **filename, uint32_t *crc,
                                        int *found,
@@ -528,6 +562,7 @@ int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf,
 {
        int _found = 0;
        char *_filename;
+       size_t filename_len;
        char *section_name = NULL;
        uint32_t _crc;
 
@@ -560,14 +595,14 @@ int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf,
        if (!_filename) {
                goto error;
        }
-       if (fseek(elf->file, shdr->sh_offset, SEEK_SET)) {
+       if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) {
                goto error;
        }
-       if (!fread(_filename, sizeof(*_filename), shdr->sh_size - ELF_CRC_SIZE,
-               elf->file)) {
+       filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE);
+       if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) {
                goto error;
        }
-       if (!fread(&_crc, sizeof(_crc), 1, elf->file)) {
+       if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) {
                goto error;
        }
        if (!is_elf_native_endian(elf)) {