| 1 | /* |
| 2 | * Copyright (C) 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 3 | * 2018 - Jérémie Galarneau <jeremie.galarneau@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 | |
| 21 | #include <urcu/ref.h> |
| 22 | #include <sys/stat.h> |
| 23 | #include <fcntl.h> |
| 24 | #include <common/common.h> |
| 25 | #include <common/fd-tracker/fd-tracker.h> |
| 26 | #include <common/fd-tracker/utils.h> |
| 27 | #include <common/utils.h> |
| 28 | |
| 29 | #include "stream-fd.h" |
| 30 | #include "lttng-relayd.h" |
| 31 | |
| 32 | struct stream_fd { |
| 33 | struct fs_handle *handle; |
| 34 | struct urcu_ref ref; |
| 35 | }; |
| 36 | |
| 37 | static struct stream_fd *_stream_fd_alloc(void) |
| 38 | { |
| 39 | struct stream_fd *sf; |
| 40 | |
| 41 | sf = zmalloc(sizeof(*sf)); |
| 42 | if (!sf) { |
| 43 | goto end; |
| 44 | } |
| 45 | urcu_ref_init(&sf->ref); |
| 46 | end: |
| 47 | return sf; |
| 48 | } |
| 49 | |
| 50 | static struct stream_fd *stream_fd_suspendable_create(struct fs_handle *handle) |
| 51 | { |
| 52 | struct stream_fd *stream_fd = _stream_fd_alloc(); |
| 53 | |
| 54 | if (!stream_fd) { |
| 55 | goto end; |
| 56 | } |
| 57 | |
| 58 | stream_fd->handle = handle; |
| 59 | end: |
| 60 | return stream_fd; |
| 61 | } |
| 62 | |
| 63 | struct stream_fd *stream_fd_open(const char *path) |
| 64 | { |
| 65 | struct stream_fd *stream_fd = NULL; |
| 66 | int flags = O_RDONLY; |
| 67 | struct fs_handle *handle; |
| 68 | |
| 69 | handle = fd_tracker_open_fs_handle(the_fd_tracker, path, |
| 70 | flags, NULL); |
| 71 | if (!handle) { |
| 72 | goto end; |
| 73 | } |
| 74 | |
| 75 | stream_fd = stream_fd_suspendable_create(handle); |
| 76 | if (!stream_fd) { |
| 77 | int close_ret; |
| 78 | |
| 79 | close_ret = fs_handle_close(handle); |
| 80 | if (close_ret) { |
| 81 | ERR("Failed to close filesystem handle of stream at %s", path); |
| 82 | } |
| 83 | } |
| 84 | end: |
| 85 | return stream_fd; |
| 86 | } |
| 87 | |
| 88 | static |
| 89 | struct fs_handle *create_write_fs_handle(const char *path) |
| 90 | { |
| 91 | struct fs_handle *handle; |
| 92 | /* |
| 93 | * With the session rotation feature on the relay, we might need to seek |
| 94 | * and truncate a tracefile, so we need read and write access. |
| 95 | */ |
| 96 | int flags = O_RDWR | O_CREAT | O_TRUNC; |
| 97 | /* Open with 660 mode */ |
| 98 | mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP; |
| 99 | |
| 100 | handle = fd_tracker_open_fs_handle(the_fd_tracker, path, flags, &mode); |
| 101 | if (!handle) { |
| 102 | ERR("Failed to open fs handle to %s", path); |
| 103 | } |
| 104 | |
| 105 | return handle; |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | * Stream file are created by on the consumerd/data-reception end. Those |
| 110 | * stream fds can be suspended as there is no expectation that the files |
| 111 | * will be unlinked and then need to be appended-to. |
| 112 | * |
| 113 | * Hence, the file descriptors are created as suspendable to allow the |
| 114 | * fd-tracker to reduce the number of active fds.. |
| 115 | */ |
| 116 | struct stream_fd *stream_fd_create(const char *path_name, const char *file_name, |
| 117 | uint64_t size, uint64_t count, const char *suffix) |
| 118 | { |
| 119 | struct stream_fd *stream_fd = NULL; |
| 120 | struct fs_handle *handle; |
| 121 | int ret; |
| 122 | char path[PATH_MAX]; |
| 123 | |
| 124 | ret = utils_stream_file_name(path, path_name, file_name, |
| 125 | size, count, suffix); |
| 126 | if (ret < 0) { |
| 127 | goto end; |
| 128 | } |
| 129 | |
| 130 | handle = create_write_fs_handle(path); |
| 131 | if (!handle) { |
| 132 | goto end; |
| 133 | } |
| 134 | |
| 135 | stream_fd = stream_fd_suspendable_create(handle); |
| 136 | if (!stream_fd) { |
| 137 | int close_ret; |
| 138 | |
| 139 | close_ret = fs_handle_close(handle); |
| 140 | if (close_ret) { |
| 141 | ERR("Failed to close filesystem handle of stream at %s", path); |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | end: |
| 146 | return stream_fd; |
| 147 | } |
| 148 | |
| 149 | /* |
| 150 | * This unlink wrapper allows the fd_tracker to check if any other |
| 151 | * fs_handle references the stream before unlinking it. If the relay holds |
| 152 | * this file open, it is essential to unlink it through an fs_handle as this |
| 153 | * will delay the actual unlink() until all handles have released this file. |
| 154 | * |
| 155 | * The file is renamed and unlinked once the last handle to its inode has been |
| 156 | * released. |
| 157 | */ |
| 158 | static |
| 159 | int unlink_through_handle(const char *path) |
| 160 | { |
| 161 | int ret = 0, close_ret; |
| 162 | struct fs_handle *handle; |
| 163 | /* |
| 164 | * Since this operation is only performed to perform the unlink |
| 165 | * through the fs_handle and fd-tracker system, the flag is opened |
| 166 | * without the O_CREAT. There is no need to perform the unlink if |
| 167 | * the file doesn't already exist. |
| 168 | */ |
| 169 | int flags = O_RDONLY; |
| 170 | |
| 171 | DBG("Unlinking stream at %s through a filesystem handle", path); |
| 172 | handle = fd_tracker_open_fs_handle(the_fd_tracker, path, flags, NULL); |
| 173 | if (!handle) { |
| 174 | /* There is nothing to do. */ |
| 175 | DBG("File %s does not exist, ignoring unlink", path); |
| 176 | goto end; |
| 177 | } |
| 178 | |
| 179 | ret = fs_handle_unlink(handle); |
| 180 | close_ret = fs_handle_close(handle); |
| 181 | if (close_ret) { |
| 182 | ERR("Failed to close handle after performing an unlink operation on a filesystem handle"); |
| 183 | } |
| 184 | end: |
| 185 | if (ret) { |
| 186 | DBG("Unlinking stream at %s failed with error code %i", path, ret); |
| 187 | } |
| 188 | return ret; |
| 189 | } |
| 190 | |
| 191 | int stream_fd_rotate(struct stream_fd *stream_fd, const char *path_name, |
| 192 | const char *file_name, uint64_t size, |
| 193 | uint64_t count, uint64_t *new_count) |
| 194 | { |
| 195 | int ret; |
| 196 | bool should_unlink; |
| 197 | char path[PATH_MAX]; |
| 198 | |
| 199 | assert(stream_fd); |
| 200 | |
| 201 | utils_stream_file_rotation_get_new_count(count, new_count, |
| 202 | &should_unlink); |
| 203 | |
| 204 | ret = utils_stream_file_name(path, path_name, file_name, |
| 205 | size, count, NULL); |
| 206 | if (ret < 0) { |
| 207 | goto error; |
| 208 | } |
| 209 | |
| 210 | ret = fs_handle_close(stream_fd->handle); |
| 211 | stream_fd->handle = NULL; |
| 212 | if (ret < 0) { |
| 213 | PERROR("Closing stream tracefile handle"); |
| 214 | goto error; |
| 215 | } |
| 216 | |
| 217 | if (should_unlink) { |
| 218 | ret = unlink_through_handle(path); |
| 219 | if (ret < 0) { |
| 220 | goto error; |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | ret = utils_stream_file_name(path, path_name, file_name, |
| 225 | size, new_count ? *new_count : 0, NULL); |
| 226 | if (ret < 0) { |
| 227 | goto error; |
| 228 | } |
| 229 | |
| 230 | stream_fd->handle = create_write_fs_handle(path); |
| 231 | if (!stream_fd->handle) { |
| 232 | ret = -1; |
| 233 | goto error; |
| 234 | } |
| 235 | |
| 236 | ret = 0; |
| 237 | |
| 238 | error: |
| 239 | return ret; |
| 240 | } |
| 241 | |
| 242 | void stream_fd_get(struct stream_fd *sf) |
| 243 | { |
| 244 | urcu_ref_get(&sf->ref); |
| 245 | } |
| 246 | |
| 247 | static void stream_fd_release(struct urcu_ref *ref) |
| 248 | { |
| 249 | struct stream_fd *sf = caa_container_of(ref, struct stream_fd, ref); |
| 250 | int ret; |
| 251 | |
| 252 | ret = fs_handle_close(sf->handle); |
| 253 | if (ret) { |
| 254 | PERROR("Error closing stream handle"); |
| 255 | } |
| 256 | free(sf); |
| 257 | } |
| 258 | |
| 259 | void stream_fd_put(struct stream_fd *sf) |
| 260 | { |
| 261 | urcu_ref_put(&sf->ref, stream_fd_release); |
| 262 | } |
| 263 | |
| 264 | int stream_fd_get_fd(struct stream_fd *sf) |
| 265 | { |
| 266 | return fs_handle_get_fd(sf->handle); |
| 267 | } |
| 268 | |
| 269 | void stream_fd_put_fd(struct stream_fd *sf) |
| 270 | { |
| 271 | fs_handle_put_fd(sf->handle); |
| 272 | } |