src/bin/lttng-relayd/index-file.c

   1 /*
   2  * Copyright (C) 2018 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #include "index-file.h"
  19 #include "lttng-relayd.h"
  20
  21 #include <common/defaults.h>
  22 #include <common/error.h>
  23 #include <common/utils.h>
  24 #include <common/readwrite.h>
  25 #include <common/fd-tracker/fd-tracker.h>
  26 #include <common/fd-tracker/utils.h>
  27 #include <lttng/constant.h>
  28
  29 #include <inttypes.h>
  30 #include <stdbool.h>
  31 #include <urcu/ref.h>
  32 #include <sys/stat.h>
  33 #include <fcntl.h>
  34
  35 struct relay_index_file {
  36         bool suspendable;
  37         union {
  38                 /* Suspendable. */
  39                 struct fs_handle *handle;
  40                 /* Unsuspendable. */
  41                 int fd;
  42         } u;
  43         uint32_t major;
  44         uint32_t minor;
  45         uint32_t element_len;
  46         struct urcu_ref ref;
  47 };
  48
  49 /*
  50  * Create the index file associated with a trace file.
  51  *
  52  * Return allocated struct lttng_index_file, NULL on error.
  53  */
  54 struct relay_index_file *relay_index_file_create(const char *path_name,
  55                 const char *stream_name, uint64_t size, uint64_t count,
  56                 uint32_t idx_major, uint32_t idx_minor)
  57 {
  58         struct relay_index_file *index_file;
  59         struct fs_handle *fs_handle = NULL;
  60         int ret, fd = -1;
  61         ssize_t size_ret;
  62         struct ctf_packet_index_file_hdr hdr;
  63         char idx_dir_path[LTTNG_PATH_MAX];
  64         char idx_file_path[LTTNG_PATH_MAX];
  65         /*
  66          * With the session rotation feature on the relay, we might need to seek
  67          * and truncate a tracefile, so we need read and write access.
  68          */
  69         int flags = O_RDWR | O_CREAT | O_TRUNC;
  70         /* Open with 660 mode */
  71         mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  72
  73         index_file = zmalloc(sizeof(*index_file));
  74         if (!index_file) {
  75                 PERROR("allocating relay_index_file");
  76                 goto error;
  77         }
  78
  79         /*
  80          * The receiving end of the relay daemon is not expected to try
  81          * to append to an index file. It is thus safe to create it as
  82          * suspendable.
  83          */
  84         index_file->suspendable = true;
  85
  86         ret = snprintf(idx_dir_path, sizeof(idx_dir_path), "%s/" DEFAULT_INDEX_DIR,
  87                         path_name);
  88         if (ret < 0) {
  89                 PERROR("snprintf index path");
  90                 goto error;
  91         }
  92
  93         /* Create index directory if necessary. */
  94         ret = utils_mkdir(idx_dir_path, S_IRWXU | S_IRWXG, -1, -1);
  95         if (ret < 0) {
  96                 if (errno != EEXIST) {
  97                         PERROR("Index trace directory creation error");
  98                         goto error;
  99                 }
 100         }
 101
 102         ret = utils_stream_file_name(idx_file_path, idx_dir_path, stream_name,
 103                         size, count, DEFAULT_INDEX_FILE_SUFFIX);
 104         if (ret < 0) {
 105                 ERR("Could not build path of index file");
 106                 goto error;
 107         }
 108
 109         /*
 110          * For tracefile rotation. We need to unlink the old
 111          * file if present to synchronize with the tail of the
 112          * live viewer which could be working on this same file.
 113          * By doing so, any reference to the old index file
 114          * stays valid even if we re-create a new file with the
 115          * same name afterwards.
 116          */
 117         unlink(idx_file_path);
 118         if (ret < 0 && errno != ENOENT) {
 119                 PERROR("Failed to unlink index file");
 120                 goto error;
 121         }
 122
 123         fs_handle = fd_tracker_open_fs_handle(the_fd_tracker, idx_file_path,
 124                         flags, &mode);
 125         if (!fs_handle) {
 126                 goto error;
 127         }
 128         index_file->u.handle = fs_handle;
 129
 130         fd = fs_handle_get_fd(fs_handle);
 131         if (fd < 0) {
 132                 goto error;
 133         }
 134
 135         ctf_packet_index_file_hdr_init(&hdr, idx_major, idx_minor);
 136         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 137         if (size_ret < sizeof(hdr)) {
 138                 PERROR("write index header");
 139                 goto error;
 140         }
 141
 142         index_file->major = idx_major;
 143         index_file->minor = idx_minor;
 144         index_file->element_len = ctf_packet_index_len(idx_major, idx_minor);
 145         urcu_ref_init(&index_file->ref);
 146
 147         fs_handle_put_fd(fs_handle);
 148
 149         return index_file;
 150
 151 error:
 152         if (fd >= 0) {
 153                 fs_handle_put_fd(fs_handle);
 154         }
 155         if (fs_handle) {
 156                 int close_ret;
 157
 158                 close_ret = fs_handle_close(fs_handle);
 159                 if (close_ret < 0) {
 160                         PERROR("Failed to close index filesystem handle");
 161                 }
 162         }
 163         free(index_file);
 164         return NULL;
 165 }
 166
 167 static
 168 int open_file(void *data, int *out_fd)
 169 {
 170         int ret;
 171         const char *path = data;
 172
 173         ret = open(path, O_RDONLY);
 174         if (ret < 0) {
 175                 goto end;
 176         }
 177         *out_fd = ret;
 178         ret = 0;
 179 end:
 180         return ret;
 181 }
 182
 183 struct relay_index_file *relay_index_file_open(const char *path_name,
 184                 const char *channel_name, uint64_t tracefile_count,
 185                 uint64_t tracefile_count_current)
 186 {
 187         struct relay_index_file *index_file;
 188         int ret, fd;
 189         ssize_t read_len;
 190         char fullpath[PATH_MAX];
 191         char *path_param = fullpath;
 192         struct ctf_packet_index_file_hdr hdr;
 193         uint32_t major, minor, element_len;
 194
 195         assert(path_name);
 196         assert(channel_name);
 197
 198         index_file = zmalloc(sizeof(*index_file));
 199         if (!index_file) {
 200                 PERROR("Failed to allocate relay_index_file");
 201                 goto error;
 202         }
 203
 204         index_file->suspendable = false;
 205
 206         if (tracefile_count > 0) {
 207                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 208                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 209                                 channel_name, tracefile_count_current);
 210         } else {
 211                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 212                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 213         }
 214         if (ret < 0) {
 215                 PERROR("Failed to build index path");
 216                 goto error;
 217         }
 218
 219         DBG("Index opening file %s in read only", fullpath);
 220         ret = fd_tracker_open_unsuspendable_fd(the_fd_tracker, &fd,
 221                         (const char **) &path_param, 1,
 222                         open_file, (void *) fullpath);
 223         if (ret < 0) {
 224                 PERROR("Failed to open index file at %s", fullpath);
 225                 goto error;
 226         }
 227
 228         read_len = lttng_read(fd, &hdr, sizeof(hdr));
 229         if (read_len < 0) {
 230                 PERROR("Failed to read index header");
 231                 goto error_close;
 232         }
 233
 234         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 235                 ERR("Invalid header magic %#010x, expected %#010x",
 236                                 be32toh(hdr.magic), CTF_INDEX_MAGIC);
 237                 goto error_close;
 238         }
 239         major = be32toh(hdr.index_major);
 240         minor = be32toh(hdr.index_minor);
 241         element_len = be32toh(hdr.packet_index_len);
 242
 243         if (major != CTF_INDEX_MAJOR) {
 244                 ERR("Invalid header version, major = %" PRIu32 ", expected %i",
 245                                 major, CTF_INDEX_MAJOR);
 246                 goto error_close;
 247         }
 248         if (element_len > sizeof(struct ctf_packet_index)) {
 249                 ERR("Index element length too long (%" PRIu32 " bytes)",
 250                                 element_len);
 251                 goto error_close;
 252         }
 253
 254         index_file->u.fd = fd;
 255         index_file->major = major;
 256         index_file->minor = minor;
 257         index_file->element_len = element_len;
 258         urcu_ref_init(&index_file->ref);
 259
 260         return index_file;
 261
 262 error_close:
 263         ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker, &fd,
 264                         1, fd_tracker_util_close_fd, NULL);
 265         if (ret < 0) {
 266                 PERROR("Failed to close index fd %d", fd);
 267         }
 268
 269 error:
 270         free(index_file);
 271         return NULL;
 272 }
 273
 274 int relay_index_file_write(const struct relay_index_file *index_file,
 275                 const struct ctf_packet_index *element)
 276 {
 277         int fd, ret;
 278         ssize_t write_ret;
 279
 280         assert(index_file);
 281         assert(element);
 282
 283         fd = index_file->suspendable ?
 284                         fs_handle_get_fd(index_file->u.handle) :
 285                         index_file->u.fd;
 286         if (fd < 0) {
 287                 ret = fd;
 288                 goto end;
 289         }
 290
 291         write_ret = lttng_write(fd, element, index_file->element_len);
 292         if (write_ret < index_file->element_len) {
 293                 PERROR("Failed to write packet index to index file");
 294                 ret = -1;
 295         }
 296         ret = 0;
 297
 298         if (index_file->suspendable) {
 299                 fs_handle_put_fd(index_file->u.handle);
 300         }
 301 end:
 302         return ret;
 303 }
 304
 305 int relay_index_file_read(const struct relay_index_file *index_file,
 306                 struct ctf_packet_index *element)
 307 {
 308         int fd, ret;
 309         ssize_t read_ret;
 310
 311         assert(index_file);
 312         assert(element);
 313
 314         fd = index_file->suspendable ?
 315                         fs_handle_get_fd(index_file->u.handle) :
 316                         index_file->u.fd;
 317         if (fd < 0) {
 318                 ret = fd;
 319                 goto end;
 320         }
 321
 322         read_ret = lttng_read(fd, element, index_file->element_len);
 323         if (read_ret < index_file->element_len) {
 324                 PERROR("Failed to read packet index from file");
 325                 ret = -1;
 326         }
 327         ret = 0;
 328
 329         if (index_file->suspendable) {
 330                 fs_handle_put_fd(index_file->u.handle);
 331         }
 332 end:
 333         return ret;
 334 }
 335
 336 int relay_index_file_seek_end(struct relay_index_file *index_file)
 337 {
 338         int fd, ret = 0;
 339         off_t lseek_ret;
 340
 341         fd = index_file->suspendable ?
 342                         fs_handle_get_fd(index_file->u.handle) :
 343                         index_file->u.fd;
 344         if (fd < 0) {
 345                 ret = fd;
 346                 goto end;
 347         }
 348
 349         lseek_ret = lseek(fd, 0, SEEK_END);
 350         if (lseek_ret < 0) {
 351                 ret = lseek_ret;
 352         }
 353
 354         if (index_file->suspendable) {
 355                 fs_handle_put_fd(index_file->u.handle);
 356         }
 357 end:
 358         return ret;
 359 }
 360
 361 void relay_index_file_get(struct relay_index_file *index_file)
 362 {
 363         urcu_ref_get(&index_file->ref);
 364 }
 365
 366 static
 367 void relay_index_file_release(struct urcu_ref *ref)
 368 {
 369         int ret;
 370         struct relay_index_file *index_file = caa_container_of(ref,
 371                         struct relay_index_file, ref);
 372
 373         if (index_file->suspendable) {
 374                 ret = fs_handle_close(index_file->u.handle);
 375         } else {
 376                 ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker, &index_file->u.fd,
 377                                 1, fd_tracker_util_close_fd, NULL);
 378         }
 379         if (ret < 0) {
 380                 PERROR("Failed to close index file");
 381         }
 382         free(index_file);
 383 }
 384
 385 void relay_index_file_put(struct relay_index_file *index_file)
 386 {
 387         urcu_ref_put(&index_file->ref, relay_index_file_release);
 388 }