src/common/index/index.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2016 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <assert.h>
  22 #include <sys/stat.h>
  23 #include <sys/types.h>
  24 #include <fcntl.h>
  25
  26 #include <lttng/constant.h>
  27 #include <common/common.h>
  28 #include <common/defaults.h>
  29 #include <common/compat/endian.h>
  30 #include <common/utils.h>
  31
  32 #include "index.h"
  33
  34 #define WRITE_FILE_FLAGS        (O_WRONLY | O_CREAT | O_TRUNC)
  35 #define READ_ONLY_FILE_FLAGS    O_RDONLY
  36
  37 static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
  38                 struct lttng_trace_chunk *chunk,
  39                 const char *channel_path, const char *stream_name,
  40                 uint64_t stream_file_size, uint64_t stream_file_index,
  41                 uint32_t index_major, uint32_t index_minor,
  42                 bool unlink_existing_file,
  43                 int flags)
  44 {
  45         struct lttng_index_file *index_file;
  46         enum lttng_trace_chunk_status chunk_status;
  47         int ret, fd = -1;
  48         ssize_t size_ret;
  49         struct ctf_packet_index_file_hdr hdr;
  50         char index_directory_path[LTTNG_PATH_MAX];
  51         char index_file_path[LTTNG_PATH_MAX];
  52         const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  53         const bool acquired_reference = lttng_trace_chunk_get(chunk);
  54         const char *separator;
  55
  56         assert(acquired_reference);
  57
  58         index_file = zmalloc(sizeof(*index_file));
  59         if (!index_file) {
  60                 PERROR("Failed to allocate lttng_index_file");
  61                 goto error;
  62         }
  63
  64         index_file->trace_chunk = chunk;
  65         if (channel_path[0] == '\0') {
  66                 separator = "";
  67         } else {
  68                 separator = "/";
  69         }
  70         ret = snprintf(index_directory_path, sizeof(index_directory_path),
  71                         "%s%s" DEFAULT_INDEX_DIR, channel_path, separator);
  72         if (ret < 0 || ret >= sizeof(index_directory_path)) {
  73                 ERR("Failed to format index directory path");
  74                 goto error;
  75         }
  76
  77         ret = utils_stream_file_path(index_directory_path, stream_name,
  78                         stream_file_size, stream_file_index,
  79                         DEFAULT_INDEX_FILE_SUFFIX,
  80                         index_file_path, sizeof(index_file_path));
  81         if (ret) {
  82                 goto error;
  83         }
  84
  85         if (unlink_existing_file) {
  86                 /*
  87                  * For tracefile rotation. We need to unlink the old
  88                  * file if present to synchronize with the tail of the
  89                  * live viewer which could be working on this same file.
  90                  * By doing so, any reference to the old index file
  91                  * stays valid even if we re-create a new file with the
  92                  * same name afterwards.
  93                  */
  94                 chunk_status = lttng_trace_chunk_unlink_file(
  95                                 chunk, index_file_path);
  96                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK &&
  97                                 !(chunk_status == LTTNG_TRACE_CHUNK_STATUS_ERROR &&
  98                                                 errno == ENOENT)) {
  99                         goto error;
 100                 }
 101         }
 102
 103         chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
 104                         flags, mode, &fd);
 105         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 106                 goto error;
 107         }
 108
 109         if (flags == WRITE_FILE_FLAGS) {
 110                 ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
 111                 size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 112                 if (size_ret < sizeof(hdr)) {
 113                         PERROR("Failed to write index header");
 114                         goto error;
 115                 }
 116                 index_file->element_len = ctf_packet_index_len(index_major, index_minor);
 117         } else {
 118                 uint32_t element_len;
 119
 120                 size_ret = lttng_read(fd, &hdr, sizeof(hdr));
 121                 if (size_ret < 0) {
 122                         PERROR("Failed to read index header");
 123                         goto error;
 124                 }
 125                 if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 126                         ERR("Invalid header magic");
 127                         goto error;
 128                 }
 129                 if (index_major != be32toh(hdr.index_major)) {
 130                         ERR("Index major number mismatch: %u, expect %u",
 131                                 be32toh(hdr.index_major), index_major);
 132                         goto error;
 133                 }
 134                 if (index_minor != be32toh(hdr.index_minor)) {
 135                         ERR("Index minor number mismatch: %u, expect %u",
 136                                 be32toh(hdr.index_minor), index_minor);
 137                         goto error;
 138                 }
 139                 element_len = be32toh(hdr.packet_index_len);
 140                 if (element_len > sizeof(struct ctf_packet_index)) {
 141                         ERR("Index element length too long");
 142                         goto error;
 143                 }
 144                 index_file->element_len = element_len;
 145         }
 146         index_file->fd = fd;
 147         index_file->major = index_major;
 148         index_file->minor = index_minor;
 149         urcu_ref_init(&index_file->ref);
 150
 151         return index_file;
 152
 153 error:
 154         if (fd >= 0) {
 155                 ret = close(fd);
 156                 if (ret < 0) {
 157                         PERROR("Failed to close file descriptor of index file");
 158                 }
 159         }
 160         lttng_trace_chunk_put(chunk);
 161         free(index_file);
 162         return NULL;
 163 }
 164
 165 struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
 166                 struct lttng_trace_chunk *chunk,
 167                 const char *channel_path, const char *stream_name,
 168                 uint64_t stream_file_size, uint64_t stream_file_index,
 169                 uint32_t index_major, uint32_t index_minor,
 170                 bool unlink_existing_file)
 171 {
 172         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 173                         stream_name, stream_file_size, stream_file_index,
 174                         index_major, index_minor, unlink_existing_file,
 175                         WRITE_FILE_FLAGS);
 176 }
 177
 178 struct lttng_index_file *lttng_index_file_create_from_trace_chunk_read_only(
 179                 struct lttng_trace_chunk *chunk,
 180                 const char *channel_path, const char *stream_name,
 181                 uint64_t stream_file_size, uint64_t stream_file_index,
 182                 uint32_t index_major, uint32_t index_minor)
 183 {
 184         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 185                         stream_name, stream_file_size, stream_file_index,
 186                         index_major, index_minor, false,
 187                         READ_ONLY_FILE_FLAGS);
 188 }
 189
 190 /*
 191  * Write index values to the given index file.
 192  *
 193  * Return 0 on success, -1 on error.
 194  */
 195 int lttng_index_file_write(const struct lttng_index_file *index_file,
 196                 const struct ctf_packet_index *element)
 197 {
 198         int fd;
 199         size_t len;
 200         ssize_t ret;
 201
 202         assert(index_file);
 203         assert(element);
 204
 205         fd = index_file->fd;
 206         len = index_file->element_len;
 207
 208         if (fd < 0) {
 209                 goto error;
 210         }
 211
 212         ret = lttng_write(fd, element, len);
 213         if (ret < len) {
 214                 PERROR("writing index file");
 215                 goto error;
 216         }
 217         return 0;
 218
 219 error:
 220         return -1;
 221 }
 222
 223 /*
 224  * Read index values from the given index file.
 225  *
 226  * Return 0 on success, -1 on error.
 227  */
 228 int lttng_index_file_read(const struct lttng_index_file *index_file,
 229                 struct ctf_packet_index *element)
 230 {
 231         ssize_t ret;
 232         int fd = index_file->fd;
 233         size_t len = index_file->element_len;
 234
 235         assert(element);
 236
 237         if (fd < 0) {
 238                 goto error;
 239         }
 240
 241         ret = lttng_read(fd, element, len);
 242         if (ret < 0) {
 243                 PERROR("read index file");
 244                 goto error;
 245         }
 246         if (ret < len) {
 247                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 248                 goto error;
 249         }
 250         return 0;
 251
 252 error:
 253         return -1;
 254 }
 255
 256 void lttng_index_file_get(struct lttng_index_file *index_file)
 257 {
 258         urcu_ref_get(&index_file->ref);
 259 }
 260
 261 static void lttng_index_file_release(struct urcu_ref *ref)
 262 {
 263         struct lttng_index_file *index_file = caa_container_of(ref,
 264                         struct lttng_index_file, ref);
 265
 266         if (close(index_file->fd)) {
 267                 PERROR("close index fd");
 268         }
 269         lttng_trace_chunk_put(index_file->trace_chunk);
 270         free(index_file);
 271 }
 272
 273 void lttng_index_file_put(struct lttng_index_file *index_file)
 274 {
 275         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 276 }