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 <common/common.h>
  27 #include <common/defaults.h>
  28 #include <common/compat/endian.h>
  29 #include <common/utils.h>
  30
  31 #include "index.h"
  32
  33 /*
  34  * Create the index file associated with a trace file.
  35  *
  36  * Return allocated struct lttng_index_file, NULL on error.
  37  */
  38 struct lttng_index_file *lttng_index_file_create(char *path_name,
  39                 char *stream_name, int uid, int gid,
  40                 uint64_t size, uint64_t count, uint32_t major, uint32_t minor)
  41 {
  42         struct lttng_index_file *index_file;
  43         int ret, fd = -1;
  44         ssize_t size_ret;
  45         struct ctf_packet_index_file_hdr hdr;
  46         char fullpath[PATH_MAX];
  47         uint32_t element_len = ctf_packet_index_len(major, minor);
  48
  49         index_file = zmalloc(sizeof(*index_file));
  50         if (!index_file) {
  51                 PERROR("allocating lttng_index_file");
  52                 goto error;
  53         }
  54
  55         ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR,
  56                         path_name);
  57         if (ret < 0) {
  58                 PERROR("snprintf index path");
  59                 goto error;
  60         }
  61
  62         /* Create index directory if necessary. */
  63         ret = utils_mkdir(fullpath, S_IRWXU | S_IRWXG, uid, gid);
  64         if (ret < 0) {
  65                 if (errno != EEXIST) {
  66                         PERROR("Index trace directory creation error");
  67                         goto error;
  68                 }
  69         }
  70
  71         /*
  72          * For tracefile rotation. We need to unlink the old
  73          * file if present to synchronize with the tail of the
  74          * live viewer which could be working on this same file.
  75          * By doing so, any reference to the old index file
  76          * stays valid even if we re-create a new file with the
  77          * same name afterwards.
  78          */
  79         ret = utils_unlink_stream_file(fullpath, stream_name, size, count, uid,
  80                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  81         DBG("utils_unlink_stream_file %s %s ret %d errno %d",
  82                         fullpath, stream_name, ret, errno);
  83         if (ret < 0 && errno != ENOENT) {
  84                 goto error;
  85         }
  86         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  87                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  88         DBG("utils_create_stream_file %s %s ret %d errno %d",
  89                         fullpath, stream_name, ret, errno);
  90         if (ret < 0) {
  91                 goto error;
  92         }
  93         fd = ret;
  94
  95         hdr.magic = htobe32(CTF_INDEX_MAGIC);
  96         hdr.index_major = htobe32(major);
  97         hdr.index_minor = htobe32(minor);
  98         hdr.packet_index_len = htobe32(element_len);
  99
 100         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 101         if (size_ret < sizeof(hdr)) {
 102                 PERROR("write index header");
 103                 goto error;
 104         }
 105         index_file->fd = fd;
 106         index_file->major = major;
 107         index_file->minor = minor;
 108         index_file->element_len = element_len;
 109         urcu_ref_init(&index_file->ref);
 110
 111         return index_file;
 112
 113 error:
 114         if (fd >= 0) {
 115                 int close_ret;
 116
 117                 close_ret = close(fd);
 118                 if (close_ret < 0) {
 119                         PERROR("close index fd");
 120                 }
 121         }
 122         free(index_file);
 123         return NULL;
 124 }
 125
 126 int lttng_index_file_unlink(char *path_name,
 127                 char *stream_name, int uid, int gid,
 128                 uint64_t tracefile_size,
 129                 uint64_t tracefile_count_current)
 130 {
 131         int ret;
 132         char fullpath[PATH_MAX];
 133
 134         ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR,
 135                         path_name);
 136         if (ret < 0) {
 137                 PERROR("snprintf index path");
 138                 goto error;
 139         }
 140
 141         ret = utils_unlink_stream_file(fullpath, stream_name,
 142                         tracefile_size, tracefile_count_current, uid,
 143                         gid, DEFAULT_INDEX_FILE_SUFFIX);
 144         if (ret < 0 && errno != ENOENT) {
 145                 goto error;
 146         }
 147
 148         return 0;
 149
 150 error:
 151         return -1;
 152 }
 153
 154 /*
 155  * Write index values to the given index file.
 156  *
 157  * Return 0 on success, -1 on error.
 158  */
 159 int lttng_index_file_write(const struct lttng_index_file *index_file,
 160                 const struct ctf_packet_index *element)
 161 {
 162         int fd;
 163         size_t len;
 164         ssize_t ret;
 165
 166         assert(index_file);
 167         assert(element);
 168
 169         fd = index_file->fd;
 170         len = index_file->element_len;
 171
 172         if (fd < 0) {
 173                 goto error;
 174         }
 175
 176         ret = lttng_write(fd, element, len);
 177         if (ret < len) {
 178                 PERROR("writing index file");
 179                 goto error;
 180         }
 181         return 0;
 182
 183 error:
 184         return -1;
 185 }
 186
 187 /*
 188  * Read index values from the given index file.
 189  *
 190  * Return 0 on success, -1 on error.
 191  */
 192 int lttng_index_file_read(const struct lttng_index_file *index_file,
 193                 struct ctf_packet_index *element)
 194 {
 195         ssize_t ret;
 196         int fd = index_file->fd;
 197         size_t len = index_file->element_len;
 198
 199         assert(element);
 200
 201         if (fd < 0) {
 202                 goto error;
 203         }
 204
 205         ret = lttng_read(fd, element, len);
 206         if (ret < 0) {
 207                 PERROR("read index file");
 208                 goto error;
 209         }
 210         if (ret < len) {
 211                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 212                 goto error;
 213         }
 214         return 0;
 215
 216 error:
 217         return -1;
 218 }
 219
 220 /*
 221  * Open index file using a given path, channel name and tracefile count.
 222  *
 223  * Return allocated struct lttng_index_file, NULL on error.
 224  */
 225 struct lttng_index_file *lttng_index_file_open(const char *path_name,
 226                 const char *channel_name, uint64_t tracefile_count,
 227                 uint64_t tracefile_count_current)
 228 {
 229         struct lttng_index_file *index_file;
 230         int ret, read_fd;
 231         ssize_t read_len;
 232         char fullpath[PATH_MAX];
 233         struct ctf_packet_index_file_hdr hdr;
 234         uint32_t major, minor, element_len;
 235
 236         assert(path_name);
 237         assert(channel_name);
 238
 239         index_file = zmalloc(sizeof(*index_file));
 240         if (!index_file) {
 241                 PERROR("allocating lttng_index_file");
 242                 goto error;
 243         }
 244
 245         if (tracefile_count > 0) {
 246                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 247                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 248                                 channel_name, tracefile_count_current);
 249         } else {
 250                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 251                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 252         }
 253         if (ret < 0) {
 254                 PERROR("snprintf index path");
 255                 goto error;
 256         }
 257
 258         DBG("Index opening file %s in read only", fullpath);
 259         read_fd = open(fullpath, O_RDONLY);
 260         if (read_fd < 0) {
 261                 PERROR("opening index in read-only");
 262                 goto error;
 263         }
 264
 265         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 266         if (read_len < 0) {
 267                 PERROR("Reading index header");
 268                 goto error_close;
 269         }
 270
 271         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 272                 ERR("Invalid header magic");
 273                 goto error_close;
 274         }
 275         major = be32toh(hdr.index_major);
 276         minor = be32toh(hdr.index_minor);
 277         element_len = be32toh(hdr.packet_index_len);
 278
 279         if (major != CTF_INDEX_MAJOR) {
 280                 ERR("Invalid header version");
 281                 goto error_close;
 282         }
 283         if (element_len > sizeof(struct ctf_packet_index)) {
 284                 ERR("Index element length too long");
 285                 goto error_close;
 286         }
 287
 288         index_file->fd = read_fd;
 289         index_file->major = major;
 290         index_file->minor = minor;
 291         index_file->element_len = element_len;
 292         urcu_ref_init(&index_file->ref);
 293
 294         return index_file;
 295
 296 error_close:
 297         if (read_fd >= 0) {
 298                 int close_ret;
 299
 300                 close_ret = close(read_fd);
 301                 if (close_ret < 0) {
 302                         PERROR("close read fd %d", read_fd);
 303                 }
 304         }
 305
 306 error:
 307         free(index_file);
 308         return NULL;
 309 }
 310
 311 void lttng_index_file_get(struct lttng_index_file *index_file)
 312 {
 313         urcu_ref_get(&index_file->ref);
 314 }
 315
 316 static void lttng_index_file_release(struct urcu_ref *ref)
 317 {
 318         struct lttng_index_file *index_file = caa_container_of(ref,
 319                         struct lttng_index_file, ref);
 320
 321         if (close(index_file->fd)) {
 322                 PERROR("close index fd");
 323         }
 324         free(index_file);
 325 }
 326
 327 void lttng_index_file_put(struct lttng_index_file *index_file)
 328 {
 329         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 330 }