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Commit | Line | Data |
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ee4512ed JH |
1 | #include "cache.h" |
2 | #include "trace2/tr2_dst.h" | |
a4d3a283 | 3 | #include "trace2/tr2_sid.h" |
bce9db6d | 4 | #include "trace2/tr2_sysenv.h" |
ee4512ed | 5 | |
a4d3a283 JS |
6 | /* |
7 | * How many attempts we will make at creating an automatically-named trace file. | |
8 | */ | |
9 | #define MAX_AUTO_ATTEMPTS 10 | |
10 | ||
83e57b04 JS |
11 | /* |
12 | * Sentinel file used to detect when we should discard new traces to avoid | |
13 | * writing too many trace files to a directory. | |
14 | */ | |
15 | #define DISCARD_SENTINEL_NAME "git-trace2-discard" | |
16 | ||
17 | /* | |
18 | * When set to zero, disables directory file count checks. Otherwise, controls | |
19 | * how many files we can write to a directory before entering discard mode. | |
20 | * This can be overridden via the TR2_SYSENV_MAX_FILES setting. | |
21 | */ | |
22 | static int tr2env_max_files = 0; | |
23 | ||
ee4512ed JH |
24 | static int tr2_dst_want_warning(void) |
25 | { | |
26 | static int tr2env_dst_debug = -1; | |
27 | ||
28 | if (tr2env_dst_debug == -1) { | |
bce9db6d | 29 | const char *env_value = tr2_sysenv_get(TR2_SYSENV_DST_DEBUG); |
ee4512ed JH |
30 | if (!env_value || !*env_value) |
31 | tr2env_dst_debug = 0; | |
32 | else | |
33 | tr2env_dst_debug = atoi(env_value) > 0; | |
34 | } | |
35 | ||
36 | return tr2env_dst_debug; | |
37 | } | |
38 | ||
39 | void tr2_dst_trace_disable(struct tr2_dst *dst) | |
40 | { | |
41 | if (dst->need_close) | |
42 | close(dst->fd); | |
43 | dst->fd = 0; | |
44 | dst->initialized = 1; | |
45 | dst->need_close = 0; | |
46 | } | |
47 | ||
83e57b04 JS |
48 | /* |
49 | * Check to make sure we're not overloading the target directory with too many | |
50 | * files. First get the threshold (if present) from the config or envvar. If | |
87db61a4 JS |
51 | * it's zero or unset, disable this check. Next check for the presence of a |
52 | * sentinel file, then check file count. | |
53 | * | |
54 | * Returns 0 if tracing should proceed as normal. Returns 1 if the sentinel file | |
55 | * already exists, which means tracing should be disabled. Returns -1 if there | |
56 | * are too many files but there was no sentinel file, which means we have | |
57 | * created and should write traces to the sentinel file. | |
83e57b04 JS |
58 | * |
59 | * We expect that some trace processing system is gradually collecting files | |
60 | * from the target directory; after it removes the sentinel file we'll start | |
61 | * writing traces again. | |
62 | */ | |
87db61a4 | 63 | static int tr2_dst_too_many_files(struct tr2_dst *dst, const char *tgt_prefix) |
83e57b04 JS |
64 | { |
65 | int file_count = 0, max_files = 0, ret = 0; | |
66 | const char *max_files_var; | |
67 | DIR *dirp; | |
68 | struct strbuf path = STRBUF_INIT, sentinel_path = STRBUF_INIT; | |
69 | struct stat statbuf; | |
70 | ||
71 | /* Get the config or envvar and decide if we should continue this check */ | |
72 | max_files_var = tr2_sysenv_get(TR2_SYSENV_MAX_FILES); | |
73 | if (max_files_var && *max_files_var && ((max_files = atoi(max_files_var)) >= 0)) | |
74 | tr2env_max_files = max_files; | |
75 | ||
76 | if (!tr2env_max_files) { | |
77 | ret = 0; | |
78 | goto cleanup; | |
79 | } | |
80 | ||
81 | strbuf_addstr(&path, tgt_prefix); | |
82 | if (!is_dir_sep(path.buf[path.len - 1])) { | |
83 | strbuf_addch(&path, '/'); | |
84 | } | |
85 | ||
86 | /* check sentinel */ | |
87 | strbuf_addbuf(&sentinel_path, &path); | |
88 | strbuf_addstr(&sentinel_path, DISCARD_SENTINEL_NAME); | |
89 | if (!stat(sentinel_path.buf, &statbuf)) { | |
90 | ret = 1; | |
91 | goto cleanup; | |
92 | } | |
93 | ||
94 | /* check file count */ | |
95 | dirp = opendir(path.buf); | |
96 | while (file_count < tr2env_max_files && dirp && readdir(dirp)) | |
97 | file_count++; | |
98 | if (dirp) | |
99 | closedir(dirp); | |
100 | ||
101 | if (file_count >= tr2env_max_files) { | |
87db61a4 JS |
102 | dst->too_many_files = 1; |
103 | dst->fd = open(sentinel_path.buf, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
104 | ret = -1; | |
83e57b04 JS |
105 | goto cleanup; |
106 | } | |
107 | ||
108 | cleanup: | |
109 | strbuf_release(&path); | |
110 | strbuf_release(&sentinel_path); | |
111 | return ret; | |
112 | } | |
113 | ||
a4d3a283 JS |
114 | static int tr2_dst_try_auto_path(struct tr2_dst *dst, const char *tgt_prefix) |
115 | { | |
87db61a4 | 116 | int too_many_files; |
a4d3a283 JS |
117 | const char *last_slash, *sid = tr2_sid_get(); |
118 | struct strbuf path = STRBUF_INIT; | |
119 | size_t base_path_len; | |
120 | unsigned attempt_count; | |
121 | ||
122 | last_slash = strrchr(sid, '/'); | |
123 | if (last_slash) | |
124 | sid = last_slash + 1; | |
125 | ||
126 | strbuf_addstr(&path, tgt_prefix); | |
127 | if (!is_dir_sep(path.buf[path.len - 1])) | |
128 | strbuf_addch(&path, '/'); | |
129 | strbuf_addstr(&path, sid); | |
130 | base_path_len = path.len; | |
131 | ||
87db61a4 JS |
132 | too_many_files = tr2_dst_too_many_files(dst, tgt_prefix); |
133 | if (!too_many_files) { | |
134 | for (attempt_count = 0; attempt_count < MAX_AUTO_ATTEMPTS; attempt_count++) { | |
135 | if (attempt_count > 0) { | |
136 | strbuf_setlen(&path, base_path_len); | |
137 | strbuf_addf(&path, ".%d", attempt_count); | |
138 | } | |
139 | ||
140 | dst->fd = open(path.buf, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
141 | if (dst->fd != -1) | |
142 | break; | |
143 | } | |
144 | } else if (too_many_files == 1) { | |
83e57b04 JS |
145 | strbuf_release(&path); |
146 | if (tr2_dst_want_warning()) | |
147 | warning("trace2: not opening %s trace file due to too " | |
148 | "many files in target directory %s", | |
149 | tr2_sysenv_display_name(dst->sysenv_var), | |
150 | tgt_prefix); | |
151 | return 0; | |
152 | } | |
153 | ||
87db61a4 | 154 | if (dst->fd == -1) { |
a4d3a283 JS |
155 | if (tr2_dst_want_warning()) |
156 | warning("trace2: could not open '%.*s' for '%s' tracing: %s", | |
157 | (int) base_path_len, path.buf, | |
5b2d1c0c JH |
158 | tr2_sysenv_display_name(dst->sysenv_var), |
159 | strerror(errno)); | |
a4d3a283 JS |
160 | |
161 | tr2_dst_trace_disable(dst); | |
162 | strbuf_release(&path); | |
163 | return 0; | |
164 | } | |
165 | ||
166 | strbuf_release(&path); | |
167 | ||
a4d3a283 JS |
168 | dst->need_close = 1; |
169 | dst->initialized = 1; | |
170 | ||
171 | return dst->fd; | |
172 | } | |
173 | ||
ee4512ed JH |
174 | static int tr2_dst_try_path(struct tr2_dst *dst, const char *tgt_value) |
175 | { | |
176 | int fd = open(tgt_value, O_WRONLY | O_APPEND | O_CREAT, 0666); | |
177 | if (fd == -1) { | |
178 | if (tr2_dst_want_warning()) | |
179 | warning("trace2: could not open '%s' for '%s' tracing: %s", | |
bce9db6d JH |
180 | tgt_value, |
181 | tr2_sysenv_display_name(dst->sysenv_var), | |
182 | strerror(errno)); | |
ee4512ed JH |
183 | |
184 | tr2_dst_trace_disable(dst); | |
185 | return 0; | |
186 | } | |
187 | ||
188 | dst->fd = fd; | |
189 | dst->need_close = 1; | |
190 | dst->initialized = 1; | |
191 | ||
192 | return dst->fd; | |
193 | } | |
194 | ||
195 | #ifndef NO_UNIX_SOCKETS | |
196 | #define PREFIX_AF_UNIX "af_unix:" | |
197 | #define PREFIX_AF_UNIX_STREAM "af_unix:stream:" | |
198 | #define PREFIX_AF_UNIX_DGRAM "af_unix:dgram:" | |
199 | ||
200 | static int tr2_dst_try_uds_connect(const char *path, int sock_type, int *out_fd) | |
201 | { | |
202 | int fd; | |
203 | struct sockaddr_un sa; | |
204 | ||
205 | fd = socket(AF_UNIX, sock_type, 0); | |
206 | if (fd == -1) | |
207 | return errno; | |
208 | ||
209 | sa.sun_family = AF_UNIX; | |
210 | strlcpy(sa.sun_path, path, sizeof(sa.sun_path)); | |
211 | ||
212 | if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) { | |
213 | int e = errno; | |
214 | close(fd); | |
215 | return e; | |
216 | } | |
217 | ||
218 | *out_fd = fd; | |
219 | return 0; | |
220 | } | |
221 | ||
222 | #define TR2_DST_UDS_TRY_STREAM (1 << 0) | |
223 | #define TR2_DST_UDS_TRY_DGRAM (1 << 1) | |
224 | ||
225 | static int tr2_dst_try_unix_domain_socket(struct tr2_dst *dst, | |
226 | const char *tgt_value) | |
227 | { | |
228 | unsigned int uds_try = 0; | |
229 | int fd; | |
230 | int e; | |
231 | const char *path = NULL; | |
232 | ||
233 | /* | |
234 | * Allow "af_unix:[<type>:]<absolute_path>" | |
235 | * | |
236 | * Trace2 always writes complete individual messages (without | |
237 | * chunking), so we can talk to either DGRAM or STREAM type sockets. | |
238 | * | |
239 | * Allow the user to explicitly request the socket type. | |
240 | * | |
241 | * If they omit the socket type, try one and then the other. | |
242 | */ | |
243 | ||
244 | if (skip_prefix(tgt_value, PREFIX_AF_UNIX_STREAM, &path)) | |
245 | uds_try |= TR2_DST_UDS_TRY_STREAM; | |
246 | ||
247 | else if (skip_prefix(tgt_value, PREFIX_AF_UNIX_DGRAM, &path)) | |
248 | uds_try |= TR2_DST_UDS_TRY_DGRAM; | |
249 | ||
250 | else if (skip_prefix(tgt_value, PREFIX_AF_UNIX, &path)) | |
251 | uds_try |= TR2_DST_UDS_TRY_STREAM | TR2_DST_UDS_TRY_DGRAM; | |
252 | ||
253 | if (!path || !*path) { | |
254 | if (tr2_dst_want_warning()) | |
255 | warning("trace2: invalid AF_UNIX value '%s' for '%s' tracing", | |
bce9db6d JH |
256 | tgt_value, |
257 | tr2_sysenv_display_name(dst->sysenv_var)); | |
ee4512ed JH |
258 | |
259 | tr2_dst_trace_disable(dst); | |
260 | return 0; | |
261 | } | |
262 | ||
263 | if (!is_absolute_path(path) || | |
264 | strlen(path) >= sizeof(((struct sockaddr_un *)0)->sun_path)) { | |
265 | if (tr2_dst_want_warning()) | |
266 | warning("trace2: invalid AF_UNIX path '%s' for '%s' tracing", | |
bce9db6d | 267 | path, tr2_sysenv_display_name(dst->sysenv_var)); |
ee4512ed JH |
268 | |
269 | tr2_dst_trace_disable(dst); | |
270 | return 0; | |
271 | } | |
272 | ||
273 | if (uds_try & TR2_DST_UDS_TRY_STREAM) { | |
274 | e = tr2_dst_try_uds_connect(path, SOCK_STREAM, &fd); | |
275 | if (!e) | |
276 | goto connected; | |
277 | if (e != EPROTOTYPE) | |
278 | goto error; | |
279 | } | |
280 | if (uds_try & TR2_DST_UDS_TRY_DGRAM) { | |
281 | e = tr2_dst_try_uds_connect(path, SOCK_DGRAM, &fd); | |
282 | if (!e) | |
283 | goto connected; | |
284 | } | |
285 | ||
286 | error: | |
287 | if (tr2_dst_want_warning()) | |
288 | warning("trace2: could not connect to socket '%s' for '%s' tracing: %s", | |
bce9db6d JH |
289 | path, tr2_sysenv_display_name(dst->sysenv_var), |
290 | strerror(e)); | |
ee4512ed JH |
291 | |
292 | tr2_dst_trace_disable(dst); | |
293 | return 0; | |
294 | ||
295 | connected: | |
296 | dst->fd = fd; | |
297 | dst->need_close = 1; | |
298 | dst->initialized = 1; | |
299 | ||
300 | return dst->fd; | |
301 | } | |
302 | #endif | |
303 | ||
304 | static void tr2_dst_malformed_warning(struct tr2_dst *dst, | |
305 | const char *tgt_value) | |
306 | { | |
1fd881d4 RS |
307 | warning("trace2: unknown value for '%s': '%s'", |
308 | tr2_sysenv_display_name(dst->sysenv_var), tgt_value); | |
ee4512ed JH |
309 | } |
310 | ||
311 | int tr2_dst_get_trace_fd(struct tr2_dst *dst) | |
312 | { | |
313 | const char *tgt_value; | |
314 | ||
315 | /* don't open twice */ | |
316 | if (dst->initialized) | |
317 | return dst->fd; | |
318 | ||
319 | dst->initialized = 1; | |
320 | ||
bce9db6d | 321 | tgt_value = tr2_sysenv_get(dst->sysenv_var); |
ee4512ed JH |
322 | |
323 | if (!tgt_value || !strcmp(tgt_value, "") || !strcmp(tgt_value, "0") || | |
324 | !strcasecmp(tgt_value, "false")) { | |
325 | dst->fd = 0; | |
326 | return dst->fd; | |
327 | } | |
328 | ||
329 | if (!strcmp(tgt_value, "1") || !strcasecmp(tgt_value, "true")) { | |
330 | dst->fd = STDERR_FILENO; | |
331 | return dst->fd; | |
332 | } | |
333 | ||
334 | if (strlen(tgt_value) == 1 && isdigit(*tgt_value)) { | |
335 | dst->fd = atoi(tgt_value); | |
336 | return dst->fd; | |
337 | } | |
338 | ||
a4d3a283 JS |
339 | if (is_absolute_path(tgt_value)) { |
340 | if (is_directory(tgt_value)) | |
341 | return tr2_dst_try_auto_path(dst, tgt_value); | |
342 | else | |
343 | return tr2_dst_try_path(dst, tgt_value); | |
344 | } | |
ee4512ed JH |
345 | |
346 | #ifndef NO_UNIX_SOCKETS | |
347 | if (starts_with(tgt_value, PREFIX_AF_UNIX)) | |
348 | return tr2_dst_try_unix_domain_socket(dst, tgt_value); | |
349 | #endif | |
350 | ||
351 | /* Always warn about malformed values. */ | |
352 | tr2_dst_malformed_warning(dst, tgt_value); | |
353 | tr2_dst_trace_disable(dst); | |
354 | return 0; | |
355 | } | |
356 | ||
357 | int tr2_dst_trace_want(struct tr2_dst *dst) | |
358 | { | |
359 | return !!tr2_dst_get_trace_fd(dst); | |
360 | } | |
361 | ||
362 | void tr2_dst_write_line(struct tr2_dst *dst, struct strbuf *buf_line) | |
363 | { | |
364 | int fd = tr2_dst_get_trace_fd(dst); | |
365 | ||
366 | strbuf_complete_line(buf_line); /* ensure final NL on buffer */ | |
367 | ||
368 | /* | |
369 | * We do not use write_in_full() because we do not want | |
370 | * a short-write to try again. We are using O_APPEND mode | |
371 | * files and the kernel handles the atomic seek+write. If | |
372 | * another thread or git process is concurrently writing to | |
373 | * this fd or file, our remainder-write may not be contiguous | |
374 | * with our initial write of this message. And that will | |
375 | * confuse readers. So just don't bother. | |
376 | * | |
377 | * It is assumed that TRACE2 messages are short enough that | |
378 | * the system can write them in 1 attempt and we won't see | |
379 | * a short-write. | |
380 | * | |
381 | * If we get an IO error, just close the trace dst. | |
382 | */ | |
383 | if (write(fd, buf_line->buf, buf_line->len) >= 0) | |
384 | return; | |
385 | ||
386 | if (tr2_dst_want_warning()) | |
bce9db6d JH |
387 | warning("unable to write trace to '%s': %s", |
388 | tr2_sysenv_display_name(dst->sysenv_var), | |
ee4512ed JH |
389 | strerror(errno)); |
390 | tr2_dst_trace_disable(dst); | |
391 | } |