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 /*
  35  * Create the index file associated with a trace file.
  36  *
  37  * Return allocated struct lttng_index_file, NULL on error.
  38  */
  39 struct lttng_index_file *lttng_index_file_create(const char *path_name,
  40                 char *stream_name, int uid, int gid,
  41                 uint64_t size, uint64_t count, uint32_t major, uint32_t minor)
  42 {
  43         struct lttng_index_file *index_file;
  44         int ret, fd = -1;
  45         ssize_t size_ret;
  46         struct ctf_packet_index_file_hdr hdr;
  47         char fullpath[PATH_MAX];
  48         uint32_t element_len = ctf_packet_index_len(major, minor);
  49
  50         index_file = zmalloc(sizeof(*index_file));
  51         if (!index_file) {
  52                 PERROR("allocating lttng_index_file");
  53                 goto error;
  54         }
  55
  56         ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR,
  57                         path_name);
  58         if (ret < 0) {
  59                 PERROR("snprintf index path");
  60                 goto error;
  61         }
  62
  63         /* Create index directory if necessary. */
  64         ret = utils_mkdir(fullpath, S_IRWXU | S_IRWXG, uid, gid);
  65         if (ret < 0) {
  66                 if (errno != EEXIST) {
  67                         PERROR("Index trace directory creation error");
  68                         goto error;
  69                 }
  70         }
  71
  72         /*
  73          * For tracefile rotation. We need to unlink the old
  74          * file if present to synchronize with the tail of the
  75          * live viewer which could be working on this same file.
  76          * By doing so, any reference to the old index file
  77          * stays valid even if we re-create a new file with the
  78          * same name afterwards.
  79          */
  80         ret = utils_unlink_stream_file(fullpath, stream_name, size, count, uid,
  81                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  82         if (ret < 0 && errno != ENOENT) {
  83                 goto error;
  84         }
  85         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  86                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  87         if (ret < 0) {
  88                 goto error;
  89         }
  90         fd = ret;
  91
  92         ctf_packet_index_file_hdr_init(&hdr, major, minor);
  93         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
  94         if (size_ret < sizeof(hdr)) {
  95                 PERROR("write index header");
  96                 goto error;
  97         }
  98         index_file->fd = fd;
  99         index_file->major = major;
 100         index_file->minor = minor;
 101         index_file->element_len = element_len;
 102         urcu_ref_init(&index_file->ref);
 103
 104         return index_file;
 105
 106 error:
 107         if (fd >= 0) {
 108                 int close_ret;
 109
 110                 close_ret = close(fd);
 111                 if (close_ret < 0) {
 112                         PERROR("close index fd");
 113                 }
 114         }
 115         free(index_file);
 116         return NULL;
 117 }
 118
 119 struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
 120                 struct lttng_trace_chunk *chunk,
 121                 const char *channel_path, char *stream_name,
 122                 uint64_t stream_file_size, uint64_t stream_count,
 123                 uint32_t index_major, uint32_t index_minor,
 124                 bool unlink_existing_file)
 125 {
 126         struct lttng_index_file *index_file;
 127         enum lttng_trace_chunk_status chunk_status;
 128         int ret, fd = -1;
 129         ssize_t size_ret;
 130         struct ctf_packet_index_file_hdr hdr;
 131         char index_directory_path[LTTNG_PATH_MAX];
 132         char index_file_path[LTTNG_PATH_MAX];
 133         const uint32_t element_len = ctf_packet_index_len(index_major,
 134                         index_minor);
 135         const int flags = O_WRONLY | O_CREAT | O_TRUNC;
 136         const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
 137
 138         index_file = zmalloc(sizeof(*index_file));
 139         if (!index_file) {
 140                 PERROR("Failed to allocate lttng_index_file");
 141                 goto error;
 142         }
 143
 144         ret = snprintf(index_directory_path, sizeof(index_directory_path),
 145                         "%s/" DEFAULT_INDEX_DIR, channel_path);
 146         if (ret < 0 || ret >= sizeof(index_directory_path)) {
 147                 ERR("Failed to format index directory path");
 148                 goto error;
 149         }
 150
 151         ret = utils_stream_file_path(index_directory_path, stream_name,
 152                         stream_file_size, stream_count,
 153                         DEFAULT_INDEX_FILE_SUFFIX,
 154                         index_file_path, sizeof(index_file_path));
 155         if (ret) {
 156                 goto error;
 157         }
 158
 159         if (unlink_existing_file) {
 160                 /*
 161                  * For tracefile rotation. We need to unlink the old
 162                  * file if present to synchronize with the tail of the
 163                  * live viewer which could be working on this same file.
 164                  * By doing so, any reference to the old index file
 165                  * stays valid even if we re-create a new file with the
 166                  * same name afterwards.
 167                  */
 168                 chunk_status = lttng_trace_chunk_unlink_file(chunk,
 169                                 index_file_path);
 170                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 171                         goto error;
 172                 }
 173         }
 174
 175         chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
 176                         flags, mode, &fd);
 177         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 178                 goto error;
 179         }
 180
 181         ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
 182         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 183         if (size_ret < sizeof(hdr)) {
 184                 PERROR("Failed to write index header");
 185                 goto error;
 186         }
 187         index_file->fd = fd;
 188         index_file->major = index_major;
 189         index_file->minor = index_minor;
 190         index_file->element_len = element_len;
 191         urcu_ref_init(&index_file->ref);
 192
 193         return index_file;
 194
 195 error:
 196         if (fd >= 0) {
 197                 ret = close(fd);
 198                 if (ret < 0) {
 199                         PERROR("Failed to close file descriptor of index file");
 200                 }
 201         }
 202         free(index_file);
 203         return NULL;
 204 }
 205
 206 /*
 207  * Write index values to the given index file.
 208  *
 209  * Return 0 on success, -1 on error.
 210  */
 211 int lttng_index_file_write(const struct lttng_index_file *index_file,
 212                 const struct ctf_packet_index *element)
 213 {
 214         int fd;
 215         size_t len;
 216         ssize_t ret;
 217
 218         assert(index_file);
 219         assert(element);
 220
 221         fd = index_file->fd;
 222         len = index_file->element_len;
 223
 224         if (fd < 0) {
 225                 goto error;
 226         }
 227
 228         ret = lttng_write(fd, element, len);
 229         if (ret < len) {
 230                 PERROR("writing index file");
 231                 goto error;
 232         }
 233         return 0;
 234
 235 error:
 236         return -1;
 237 }
 238
 239 /*
 240  * Read index values from the given index file.
 241  *
 242  * Return 0 on success, -1 on error.
 243  */
 244 int lttng_index_file_read(const struct lttng_index_file *index_file,
 245                 struct ctf_packet_index *element)
 246 {
 247         ssize_t ret;
 248         int fd = index_file->fd;
 249         size_t len = index_file->element_len;
 250
 251         assert(element);
 252
 253         if (fd < 0) {
 254                 goto error;
 255         }
 256
 257         ret = lttng_read(fd, element, len);
 258         if (ret < 0) {
 259                 PERROR("read index file");
 260                 goto error;
 261         }
 262         if (ret < len) {
 263                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 264                 goto error;
 265         }
 266         return 0;
 267
 268 error:
 269         return -1;
 270 }
 271
 272 /*
 273  * Open index file using a given path, channel name and tracefile count.
 274  *
 275  * Return allocated struct lttng_index_file, NULL on error.
 276  */
 277 struct lttng_index_file *lttng_index_file_open(const char *path_name,
 278                 const char *channel_name, uint64_t tracefile_count,
 279                 uint64_t tracefile_count_current)
 280 {
 281         struct lttng_index_file *index_file;
 282         int ret, read_fd;
 283         ssize_t read_len;
 284         char fullpath[PATH_MAX];
 285         struct ctf_packet_index_file_hdr hdr;
 286         uint32_t major, minor, element_len;
 287
 288         assert(path_name);
 289         assert(channel_name);
 290
 291         index_file = zmalloc(sizeof(*index_file));
 292         if (!index_file) {
 293                 PERROR("allocating lttng_index_file");
 294                 goto error;
 295         }
 296
 297         if (tracefile_count > 0) {
 298                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 299                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 300                                 channel_name, tracefile_count_current);
 301         } else {
 302                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 303                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 304         }
 305         if (ret < 0) {
 306                 PERROR("snprintf index path");
 307                 goto error;
 308         }
 309
 310         DBG("Index opening file %s in read only", fullpath);
 311         read_fd = open(fullpath, O_RDONLY);
 312         if (read_fd < 0) {
 313                 PERROR("opening index in read-only");
 314                 goto error;
 315         }
 316
 317         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 318         if (read_len < 0) {
 319                 PERROR("Reading index header");
 320                 goto error_close;
 321         }
 322
 323         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 324                 ERR("Invalid header magic");
 325                 goto error_close;
 326         }
 327         major = be32toh(hdr.index_major);
 328         minor = be32toh(hdr.index_minor);
 329         element_len = be32toh(hdr.packet_index_len);
 330
 331         if (major != CTF_INDEX_MAJOR) {
 332                 ERR("Invalid header version");
 333                 goto error_close;
 334         }
 335         if (element_len > sizeof(struct ctf_packet_index)) {
 336                 ERR("Index element length too long");
 337                 goto error_close;
 338         }
 339
 340         index_file->fd = read_fd;
 341         index_file->major = major;
 342         index_file->minor = minor;
 343         index_file->element_len = element_len;
 344         urcu_ref_init(&index_file->ref);
 345
 346         return index_file;
 347
 348 error_close:
 349         if (read_fd >= 0) {
 350                 int close_ret;
 351
 352                 close_ret = close(read_fd);
 353                 if (close_ret < 0) {
 354                         PERROR("close read fd %d", read_fd);
 355                 }
 356         }
 357
 358 error:
 359         free(index_file);
 360         return NULL;
 361 }
 362
 363 void lttng_index_file_get(struct lttng_index_file *index_file)
 364 {
 365         urcu_ref_get(&index_file->ref);
 366 }
 367
 368 static void lttng_index_file_release(struct urcu_ref *ref)
 369 {
 370         struct lttng_index_file *index_file = caa_container_of(ref,
 371                         struct lttng_index_file, ref);
 372
 373         if (close(index_file->fd)) {
 374                 PERROR("close index fd");
 375         }
 376         free(index_file);
 377 }
 378
 379 void lttng_index_file_put(struct lttng_index_file *index_file)
 380 {
 381         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 382 }