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