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 _GNU_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 = run_as_mkdir(fullpath, S_IRWXU | S_IRWXG, uid, gid);
  54         if (ret < 0) {
  55                 if (ret != -EEXIST) {
  56                         PERROR("Index trace directory creation error");
  57                         goto error;
  58                 }
  59         }
  60
  61         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  62                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  63         if (ret < 0) {
  64                 goto error;
  65         }
  66         fd = ret;
  67
  68         hdr.magic = htobe32(CTF_INDEX_MAGIC);
  69         hdr.index_major = htobe32(CTF_INDEX_MAJOR);
  70         hdr.index_minor = htobe32(CTF_INDEX_MINOR);
  71         hdr.packet_index_len = htobe32(sizeof(struct ctf_packet_index));
  72
  73         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
  74         if (size_ret < sizeof(hdr)) {
  75                 PERROR("write index header");
  76                 ret = -1;
  77                 goto error;
  78         }
  79
  80         return fd;
  81
  82 error:
  83         if (fd >= 0) {
  84                 int close_ret;
  85
  86                 close_ret = close(fd);
  87                 if (close_ret < 0) {
  88                         PERROR("close index fd");
  89                 }
  90         }
  91         return ret;
  92 }
  93
  94 /*
  95  * Write index values to the given fd of size len.
  96  *
  97  * Return "len" on success or else < len on error. errno contains error
  98  * details.
  99  */
 100 ssize_t index_write(int fd, struct ctf_packet_index *index, size_t len)
 101 {
 102         ssize_t ret;
 103
 104         assert(index);
 105
 106         if (fd < 0) {
 107                 ret = -EINVAL;
 108                 goto error;
 109         }
 110
 111         ret = lttng_write(fd, index, len);
 112         if (ret < len) {
 113                 PERROR("writing index file");
 114         }
 115
 116 error:
 117         return ret;
 118 }
 119
 120 /*
 121  * Open index file using a given path, channel name and tracefile count.
 122  *
 123  * Return read only FD on success or else a negative value.
 124  */
 125 int index_open(const char *path_name, const char *channel_name,
 126                 uint64_t tracefile_count, uint64_t tracefile_count_current)
 127 {
 128         int ret, read_fd;
 129         ssize_t read_len;
 130         char fullpath[PATH_MAX];
 131         struct ctf_packet_index_file_hdr hdr;
 132
 133         assert(path_name);
 134         assert(channel_name);
 135
 136         if (tracefile_count > 0) {
 137                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 138                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 139                                 channel_name, tracefile_count_current);
 140         } else {
 141                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 142                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 143         }
 144         if (ret < 0) {
 145                 PERROR("snprintf index path");
 146                 goto error;
 147         }
 148
 149         DBG("Index opening file %s in read only", fullpath);
 150         read_fd = open(fullpath, O_RDONLY);
 151         if (read_fd < 0) {
 152                 if (errno == ENOENT) {
 153                         ret = -ENOENT;
 154                 } else {
 155                         PERROR("opening index in read-only");
 156                 }
 157                 goto error;
 158         }
 159
 160         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 161         if (read_len < 0) {
 162                 PERROR("Reading index header");
 163                 goto error_close;
 164         }
 165
 166         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 167                 ERR("Invalid header magic");
 168                 goto error_close;
 169         }
 170         if (be32toh(hdr.index_major) != CTF_INDEX_MAJOR ||
 171                         be32toh(hdr.index_minor) != CTF_INDEX_MINOR) {
 172                 ERR("Invalid header version");
 173                 goto error_close;
 174         }
 175
 176         return read_fd;
 177
 178 error_close:
 179         if (read_fd >= 0) {
 180                 int close_ret;
 181
 182                 close_ret = close(read_fd);
 183                 if (close_ret < 0) {
 184                         PERROR("close read fd %d", read_fd);
 185                 }
 186         }
 187         ret = -1;
 188
 189 error:
 190         return ret;
 191 }