src/common/index/index.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License, version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 51
  16  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _LGPL_SOURCE
  20 #include <assert.h>
  21 #include <sys/stat.h>
  22 #include <sys/types.h>
  23 #include <fcntl.h>
  24
  25 #include <common/common.h>
  26 #include <common/defaults.h>
  27 #include <common/compat/endian.h>
  28 #include <common/utils.h>
  29
  30 #include "index.h"
  31
  32 /*
  33  * Create the index file associated with a trace file.
  34  *
  35  * Return fd on success, a negative value on error.
  36  */
  37 int index_create_file(char *path_name, char *stream_name, int uid, int gid,
  38                 uint64_t size, uint64_t count)
  39 {
  40         int ret, fd = -1;
  41         ssize_t size_ret;
  42         struct ctf_packet_index_file_hdr hdr;
  43         char fullpath[PATH_MAX];
  44
  45         ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR,
  46                         path_name);
  47         if (ret < 0) {
  48                 PERROR("snprintf index path");
  49                 goto error;
  50         }
  51
  52         /* Create index directory if necessary. */
  53         ret = utils_mkdir(fullpath, S_IRWXU | S_IRWXG, uid, gid);
  54         if (ret < 0) {
  55                 if (errno != EEXIST) {
  56                         PERROR("Index trace directory creation error");
  57                         goto error;
  58                 }
  59         }
  60
  61         /*
  62          * For tracefile rotation. We need to unlink the old
  63          * file if present to synchronize with the tail of the
  64          * live viewer which could be working on this same file.
  65          * By doing so, any reference to the old index file
  66          * stays valid even if we re-create a new file with the
  67          * same name afterwards.
  68          */
  69         ret = utils_unlink_stream_file(fullpath, stream_name, size, count, uid,
  70                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  71         if (ret < 0 && errno != ENOENT) {
  72                 goto error;
  73         }
  74         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  75                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  76         if (ret < 0) {
  77                 goto error;
  78         }
  79         fd = ret;
  80
  81         hdr.magic = htobe32(CTF_INDEX_MAGIC);
  82         hdr.index_major = htobe32(CTF_INDEX_MAJOR);
  83         hdr.index_minor = htobe32(CTF_INDEX_MINOR);
  84         hdr.packet_index_len = htobe32(sizeof(struct ctf_packet_index));
  85
  86         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
  87         if (size_ret < sizeof(hdr)) {
  88                 PERROR("write index header");
  89                 ret = -1;
  90                 goto error;
  91         }
  92
  93         return fd;
  94
  95 error:
  96         if (fd >= 0) {
  97                 int close_ret;
  98
  99                 close_ret = close(fd);
 100                 if (close_ret < 0) {
 101                         PERROR("close index fd");
 102                 }
 103         }
 104         return ret;
 105 }
 106
 107 /*
 108  * Write index values to the given fd of size len.
 109  *
 110  * Return "len" on success or else < len on error. errno contains error
 111  * details.
 112  */
 113 ssize_t index_write(int fd, struct ctf_packet_index *index, size_t len)
 114 {
 115         ssize_t ret;
 116
 117         assert(index);
 118
 119         if (fd < 0) {
 120                 ret = -EINVAL;
 121                 goto error;
 122         }
 123
 124         ret = lttng_write(fd, index, len);
 125         if (ret < len) {
 126                 PERROR("writing index file");
 127         }
 128
 129 error:
 130         return ret;
 131 }
 132
 133 /*
 134  * Open index file using a given path, channel name and tracefile count.
 135  *
 136  * Return read only FD on success or else a negative value.
 137  */
 138 int index_open(const char *path_name, const char *channel_name,
 139                 uint64_t tracefile_count, uint64_t tracefile_count_current)
 140 {
 141         int ret, read_fd;
 142         ssize_t read_len;
 143         char fullpath[PATH_MAX];
 144         struct ctf_packet_index_file_hdr hdr;
 145
 146         assert(path_name);
 147         assert(channel_name);
 148
 149         if (tracefile_count > 0) {
 150                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 151                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 152                                 channel_name, tracefile_count_current);
 153         } else {
 154                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 155                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 156         }
 157         if (ret < 0) {
 158                 PERROR("snprintf index path");
 159                 goto error;
 160         }
 161
 162         DBG("Index opening file %s in read only", fullpath);
 163         read_fd = open(fullpath, O_RDONLY);
 164         if (read_fd < 0) {
 165                 if (errno == ENOENT) {
 166                         ret = -ENOENT;
 167                 } else {
 168                         PERROR("opening index in read-only");
 169                 }
 170                 goto error;
 171         }
 172
 173         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 174         if (read_len < 0) {
 175                 PERROR("Reading index header");
 176                 goto error_close;
 177         }
 178
 179         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 180                 ERR("Invalid header magic");
 181                 goto error_close;
 182         }
 183         if (be32toh(hdr.index_major) != CTF_INDEX_MAJOR ||
 184                         be32toh(hdr.index_minor) != CTF_INDEX_MINOR) {
 185                 ERR("Invalid header version");
 186                 goto error_close;
 187         }
 188
 189         return read_fd;
 190
 191 error_close:
 192         if (read_fd >= 0) {
 193                 int close_ret;
 194
 195                 close_ret = close(read_fd);
 196                 if (close_ret < 0) {
 197                         PERROR("close read fd %d", read_fd);
 198                 }
 199         }
 200         ret = -1;
 201
 202 error:
 203         return ret;
 204 }