b2e36211aa4f8a7f5ce9d2be2784d91e3954310f
[lttng-tools.git] / 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 <lttng/constant.h>
27 #include <common/common.h>
28 #include <common/defaults.h>
29 #include <common/compat/endian.h>
30 #include <common/utils.h>
31
32 #include "index.h"
33
34 #define WRITE_FILE_FLAGS (O_WRONLY | O_CREAT | O_TRUNC)
35 #define READ_ONLY_FILE_FLAGS O_RDONLY
36
37 static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
38 struct lttng_trace_chunk *chunk,
39 const char *channel_path, const char *stream_name,
40 uint64_t stream_file_size, uint64_t stream_file_index,
41 uint32_t index_major, uint32_t index_minor,
42 bool unlink_existing_file,
43 int flags)
44 {
45 struct lttng_index_file *index_file;
46 enum lttng_trace_chunk_status chunk_status;
47 int ret, fd = -1;
48 ssize_t size_ret;
49 struct ctf_packet_index_file_hdr hdr;
50 char index_directory_path[LTTNG_PATH_MAX];
51 char index_file_path[LTTNG_PATH_MAX];
52 const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
53 const bool acquired_reference = lttng_trace_chunk_get(chunk);
54
55 assert(acquired_reference);
56
57 index_file = zmalloc(sizeof(*index_file));
58 if (!index_file) {
59 PERROR("Failed to allocate lttng_index_file");
60 goto error;
61 }
62
63 index_file->trace_chunk = chunk;
64 ret = snprintf(index_directory_path, sizeof(index_directory_path),
65 "%s/" DEFAULT_INDEX_DIR, channel_path);
66 if (ret < 0 || ret >= sizeof(index_directory_path)) {
67 ERR("Failed to format index directory path");
68 goto error;
69 }
70
71 ret = utils_stream_file_path(index_directory_path, stream_name,
72 stream_file_size, stream_file_index,
73 DEFAULT_INDEX_FILE_SUFFIX,
74 index_file_path, sizeof(index_file_path));
75 if (ret) {
76 goto error;
77 }
78
79 if (unlink_existing_file) {
80 /*
81 * For tracefile rotation. We need to unlink the old
82 * file if present to synchronize with the tail of the
83 * live viewer which could be working on this same file.
84 * By doing so, any reference to the old index file
85 * stays valid even if we re-create a new file with the
86 * same name afterwards.
87 */
88 chunk_status = lttng_trace_chunk_unlink_file(
89 chunk, index_file_path);
90 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK &&
91 !(chunk_status == LTTNG_TRACE_CHUNK_STATUS_ERROR &&
92 errno == ENOENT)) {
93 goto error;
94 }
95 }
96
97 chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
98 flags, mode, &fd);
99 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
100 goto error;
101 }
102
103 if (flags == WRITE_FILE_FLAGS) {
104 ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
105 size_ret = lttng_write(fd, &hdr, sizeof(hdr));
106 if (size_ret < sizeof(hdr)) {
107 PERROR("Failed to write index header");
108 goto error;
109 }
110 index_file->element_len = ctf_packet_index_len(index_major, index_minor);
111 } else {
112 uint32_t element_len;
113
114 size_ret = lttng_read(fd, &hdr, sizeof(hdr));
115 if (size_ret < 0) {
116 PERROR("Failed to read index header");
117 goto error;
118 }
119 if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
120 ERR("Invalid header magic");
121 goto error;
122 }
123 if (index_major != be32toh(hdr.index_major)) {
124 ERR("Index major number mismatch: %u, expect %u",
125 be32toh(hdr.index_major), index_major);
126 goto error;
127 }
128 if (index_minor != be32toh(hdr.index_minor)) {
129 ERR("Index minor number mismatch: %u, expect %u",
130 be32toh(hdr.index_minor), index_minor);
131 goto error;
132 }
133 element_len = be32toh(hdr.packet_index_len);
134 if (element_len > sizeof(struct ctf_packet_index)) {
135 ERR("Index element length too long");
136 goto error;
137 }
138 index_file->element_len = element_len;
139 }
140 index_file->fd = fd;
141 index_file->major = index_major;
142 index_file->minor = index_minor;
143 urcu_ref_init(&index_file->ref);
144
145 return index_file;
146
147 error:
148 if (fd >= 0) {
149 ret = close(fd);
150 if (ret < 0) {
151 PERROR("Failed to close file descriptor of index file");
152 }
153 }
154 lttng_trace_chunk_put(chunk);
155 free(index_file);
156 return NULL;
157 }
158
159 struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
160 struct lttng_trace_chunk *chunk,
161 const char *channel_path, const char *stream_name,
162 uint64_t stream_file_size, uint64_t stream_file_index,
163 uint32_t index_major, uint32_t index_minor,
164 bool unlink_existing_file)
165 {
166 return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
167 stream_name, stream_file_size, stream_file_index,
168 index_major, index_minor, unlink_existing_file,
169 WRITE_FILE_FLAGS);
170 }
171
172 struct lttng_index_file *lttng_index_file_create_from_trace_chunk_read_only(
173 struct lttng_trace_chunk *chunk,
174 const char *channel_path, const char *stream_name,
175 uint64_t stream_file_size, uint64_t stream_file_index,
176 uint32_t index_major, uint32_t index_minor)
177 {
178 return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
179 stream_name, stream_file_size, stream_file_index,
180 index_major, index_minor, false,
181 READ_ONLY_FILE_FLAGS);
182 }
183
184 /*
185 * Write index values to the given index file.
186 *
187 * Return 0 on success, -1 on error.
188 */
189 int lttng_index_file_write(const struct lttng_index_file *index_file,
190 const struct ctf_packet_index *element)
191 {
192 int fd;
193 size_t len;
194 ssize_t ret;
195
196 assert(index_file);
197 assert(element);
198
199 fd = index_file->fd;
200 len = index_file->element_len;
201
202 if (fd < 0) {
203 goto error;
204 }
205
206 ret = lttng_write(fd, element, len);
207 if (ret < len) {
208 PERROR("writing index file");
209 goto error;
210 }
211 return 0;
212
213 error:
214 return -1;
215 }
216
217 /*
218 * Read index values from the given index file.
219 *
220 * Return 0 on success, -1 on error.
221 */
222 int lttng_index_file_read(const struct lttng_index_file *index_file,
223 struct ctf_packet_index *element)
224 {
225 ssize_t ret;
226 int fd = index_file->fd;
227 size_t len = index_file->element_len;
228
229 assert(element);
230
231 if (fd < 0) {
232 goto error;
233 }
234
235 ret = lttng_read(fd, element, len);
236 if (ret < 0) {
237 PERROR("read index file");
238 goto error;
239 }
240 if (ret < len) {
241 ERR("lttng_read expected %zu, returned %zd", len, ret);
242 goto error;
243 }
244 return 0;
245
246 error:
247 return -1;
248 }
249
250 void lttng_index_file_get(struct lttng_index_file *index_file)
251 {
252 urcu_ref_get(&index_file->ref);
253 }
254
255 static void lttng_index_file_release(struct urcu_ref *ref)
256 {
257 struct lttng_index_file *index_file = caa_container_of(ref,
258 struct lttng_index_file, ref);
259
260 if (close(index_file->fd)) {
261 PERROR("close index fd");
262 }
263 lttng_trace_chunk_put(index_file->trace_chunk);
264 free(index_file);
265 }
266
267 void lttng_index_file_put(struct lttng_index_file *index_file)
268 {
269 urcu_ref_put(&index_file->ref, lttng_index_file_release);
270 }
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