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         if (ret < 0 && errno != ENOENT) {
  82                 goto error;
  83         }
  84         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  85                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  86         if (ret < 0) {
  87                 goto error;
  88         }
  89         fd = ret;
  90
  91         hdr.magic = htobe32(CTF_INDEX_MAGIC);
  92         hdr.index_major = htobe32(major);
  93         hdr.index_minor = htobe32(minor);
  94         hdr.packet_index_len = htobe32(element_len);
  95
  96         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
  97         if (size_ret < sizeof(hdr)) {
  98                 PERROR("write index header");
  99                 ret = -1;
 100                 goto error;
 101         }
 102         index_file->fd = fd;
 103         index_file->major = major;
 104         index_file->minor = minor;
 105         index_file->element_len = element_len;
 106         urcu_ref_init(&index_file->ref);
 107
 108         return index_file;
 109
 110 error:
 111         if (fd >= 0) {
 112                 int close_ret;
 113
 114                 close_ret = close(fd);
 115                 if (close_ret < 0) {
 116                         PERROR("close index fd");
 117                 }
 118         }
 119         free(index_file);
 120         return NULL;
 121 }
 122
 123 /*
 124  * Write index values to the given index file.
 125  *
 126  * Return 0 on success, -1 on error.
 127  */
 128 int lttng_index_file_write(const struct lttng_index_file *index_file,
 129                 const struct ctf_packet_index *element)
 130 {
 131         int fd;
 132         size_t len;
 133         ssize_t ret;
 134
 135         assert(index_file);
 136         assert(element);
 137
 138         fd = index_file->fd;
 139         len = index_file->element_len;
 140
 141         if (fd < 0) {
 142                 goto error;
 143         }
 144
 145         ret = lttng_write(fd, element, len);
 146         if (ret < len) {
 147                 PERROR("writing index file");
 148                 goto error;
 149         }
 150         return 0;
 151
 152 error:
 153         return -1;
 154 }
 155
 156 /*
 157  * Read index values from the given index file.
 158  *
 159  * Return 0 on success, -1 on error.
 160  */
 161 int lttng_index_file_read(const struct lttng_index_file *index_file,
 162                 struct ctf_packet_index *element)
 163 {
 164         ssize_t ret;
 165         int fd = index_file->fd;
 166         size_t len = index_file->element_len;
 167
 168         assert(element);
 169
 170         if (fd < 0) {
 171                 goto error;
 172         }
 173
 174         ret = lttng_read(fd, element, len);
 175         if (ret < 0) {
 176                 PERROR("read index file");
 177                 goto error;
 178         }
 179         if (ret < len) {
 180                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 181                 goto error;
 182         }
 183         return 0;
 184
 185 error:
 186         return -1;
 187 }
 188
 189 /*
 190  * Open index file using a given path, channel name and tracefile count.
 191  *
 192  * Return allocated struct lttng_index_file, NULL on error.
 193  */
 194 struct lttng_index_file *lttng_index_file_open(const char *path_name,
 195                 const char *channel_name, uint64_t tracefile_count,
 196                 uint64_t tracefile_count_current)
 197 {
 198         struct lttng_index_file *index_file;
 199         int ret, read_fd;
 200         ssize_t read_len;
 201         char fullpath[PATH_MAX];
 202         struct ctf_packet_index_file_hdr hdr;
 203         uint32_t major, minor, element_len;
 204
 205         assert(path_name);
 206         assert(channel_name);
 207
 208         index_file = zmalloc(sizeof(*index_file));
 209         if (!index_file) {
 210                 PERROR("allocating lttng_index_file");
 211                 goto error;
 212         }
 213
 214         if (tracefile_count > 0) {
 215                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 216                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 217                                 channel_name, tracefile_count_current);
 218         } else {
 219                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 220                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 221         }
 222         if (ret < 0) {
 223                 PERROR("snprintf index path");
 224                 goto error;
 225         }
 226
 227         DBG("Index opening file %s in read only", fullpath);
 228         read_fd = open(fullpath, O_RDONLY);
 229         if (read_fd < 0) {
 230                 if (errno == ENOENT) {
 231                         ret = -ENOENT;
 232                 } else {
 233                         PERROR("opening index in read-only");
 234                 }
 235                 goto error;
 236         }
 237
 238         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 239         if (read_len < 0) {
 240                 PERROR("Reading index header");
 241                 goto error_close;
 242         }
 243
 244         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 245                 ERR("Invalid header magic");
 246                 goto error_close;
 247         }
 248         major = be32toh(hdr.index_major);
 249         minor = be32toh(hdr.index_minor);
 250         element_len = be32toh(hdr.packet_index_len);
 251
 252         if (major != CTF_INDEX_MAJOR) {
 253                 ERR("Invalid header version");
 254                 goto error_close;
 255         }
 256         if (element_len > sizeof(struct ctf_packet_index)) {
 257                 ERR("Index element length too long");
 258                 goto error_close;
 259         }
 260
 261         index_file->fd = read_fd;
 262         index_file->major = major;
 263         index_file->minor = minor;
 264         index_file->element_len = element_len;
 265         urcu_ref_init(&index_file->ref);
 266
 267         return index_file;
 268
 269 error_close:
 270         if (read_fd >= 0) {
 271                 int close_ret;
 272
 273                 close_ret = close(read_fd);
 274                 if (close_ret < 0) {
 275                         PERROR("close read fd %d", read_fd);
 276                 }
 277         }
 278         ret = -1;
 279
 280 error:
 281         free(index_file);
 282         return NULL;
 283 }
 284
 285 void lttng_index_file_get(struct lttng_index_file *index_file)
 286 {
 287         urcu_ref_get(&index_file->ref);
 288 }
 289
 290 static void lttng_index_file_release(struct urcu_ref *ref)
 291 {
 292         struct lttng_index_file *index_file = caa_container_of(ref,
 293                         struct lttng_index_file, ref);
 294
 295         if (close(index_file->fd)) {
 296                 PERROR("close index fd");
 297         }
 298         free(index_file);
 299 }
 300
 301 void lttng_index_file_put(struct lttng_index_file *index_file)
 302 {
 303         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 304 }