Kernel-ctl: Expose kernel clear buffer operation
[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 <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(const 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 goto error;
100 }
101 index_file->fd = fd;
102 index_file->major = major;
103 index_file->minor = minor;
104 index_file->element_len = element_len;
105 urcu_ref_init(&index_file->ref);
106
107 return index_file;
108
109 error:
110 if (fd >= 0) {
111 int close_ret;
112
113 close_ret = close(fd);
114 if (close_ret < 0) {
115 PERROR("close index fd");
116 }
117 }
118 free(index_file);
119 return NULL;
120 }
121
122 /*
123 * Write index values to the given index file.
124 *
125 * Return 0 on success, -1 on error.
126 */
127 int lttng_index_file_write(const struct lttng_index_file *index_file,
128 const struct ctf_packet_index *element)
129 {
130 int fd;
131 size_t len;
132 ssize_t ret;
133
134 assert(index_file);
135 assert(element);
136
137 fd = index_file->fd;
138 len = index_file->element_len;
139
140 if (fd < 0) {
141 goto error;
142 }
143
144 ret = lttng_write(fd, element, len);
145 if (ret < len) {
146 PERROR("writing index file");
147 goto error;
148 }
149 return 0;
150
151 error:
152 return -1;
153 }
154
155 /*
156 * Read index values from the given index file.
157 *
158 * Return 0 on success, -1 on error.
159 */
160 int lttng_index_file_read(const struct lttng_index_file *index_file,
161 struct ctf_packet_index *element)
162 {
163 ssize_t ret;
164 int fd = index_file->fd;
165 size_t len = index_file->element_len;
166
167 assert(element);
168
169 if (fd < 0) {
170 goto error;
171 }
172
173 ret = lttng_read(fd, element, len);
174 if (ret < len) {
175 PERROR("read index file");
176 goto error;
177 }
178 return 0;
179
180 error:
181 return -1;
182 }
183
184 /*
185 * Open index file using a given path, channel name and tracefile count.
186 *
187 * Return allocated struct lttng_index_file, NULL on error.
188 */
189 struct lttng_index_file *lttng_index_file_open(const char *path_name,
190 const char *channel_name, uint64_t tracefile_count,
191 uint64_t tracefile_count_current)
192 {
193 struct lttng_index_file *index_file;
194 int ret, read_fd;
195 ssize_t read_len;
196 char fullpath[PATH_MAX];
197 struct ctf_packet_index_file_hdr hdr;
198 uint32_t major, minor, element_len;
199
200 assert(path_name);
201 assert(channel_name);
202
203 index_file = zmalloc(sizeof(*index_file));
204 if (!index_file) {
205 PERROR("allocating lttng_index_file");
206 goto error;
207 }
208
209 if (tracefile_count > 0) {
210 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
211 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
212 channel_name, tracefile_count_current);
213 } else {
214 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
215 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
216 }
217 if (ret < 0) {
218 PERROR("snprintf index path");
219 goto error;
220 }
221
222 DBG("Index opening file %s in read only", fullpath);
223 read_fd = open(fullpath, O_RDONLY);
224 if (read_fd < 0) {
225 PERROR("opening index in read-only");
226 goto error;
227 }
228
229 read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
230 if (read_len < 0) {
231 PERROR("Reading index header");
232 goto error_close;
233 }
234
235 if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
236 ERR("Invalid header magic");
237 goto error_close;
238 }
239 major = be32toh(hdr.index_major);
240 minor = be32toh(hdr.index_minor);
241 element_len = be32toh(hdr.packet_index_len);
242
243 if (major != CTF_INDEX_MAJOR) {
244 ERR("Invalid header version");
245 goto error_close;
246 }
247 if (element_len > sizeof(struct ctf_packet_index)) {
248 ERR("Index element length too long");
249 goto error_close;
250 }
251
252 index_file->fd = read_fd;
253 index_file->major = major;
254 index_file->minor = minor;
255 index_file->element_len = element_len;
256 urcu_ref_init(&index_file->ref);
257
258 return index_file;
259
260 error_close:
261 if (read_fd >= 0) {
262 int close_ret;
263
264 close_ret = close(read_fd);
265 if (close_ret < 0) {
266 PERROR("close read fd %d", read_fd);
267 }
268 }
269
270 error:
271 free(index_file);
272 return NULL;
273 }
274
275 void lttng_index_file_get(struct lttng_index_file *index_file)
276 {
277 urcu_ref_get(&index_file->ref);
278 }
279
280 static void lttng_index_file_release(struct urcu_ref *ref)
281 {
282 struct lttng_index_file *index_file = caa_container_of(ref,
283 struct lttng_index_file, ref);
284
285 if (close(index_file->fd)) {
286 PERROR("close index fd");
287 }
288 free(index_file);
289 }
290
291 void lttng_index_file_put(struct lttng_index_file *index_file)
292 {
293 urcu_ref_put(&index_file->ref, lttng_index_file_release);
294 }
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