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