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Commit | Line | Data |
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a64acf72 | 1 | #include "git-compat-util.h" |
0b027f6c | 2 | #include "abspath.h" |
538ac746 | 3 | #include "sigchain.h" |
a64acf72 | 4 | #include "strbuf.h" |
ee4512ed | 5 | #include "trace2/tr2_dst.h" |
a4d3a283 | 6 | #include "trace2/tr2_sid.h" |
bce9db6d | 7 | #include "trace2/tr2_sysenv.h" |
ee4512ed | 8 | |
a4d3a283 JS |
9 | /* |
10 | * How many attempts we will make at creating an automatically-named trace file. | |
11 | */ | |
12 | #define MAX_AUTO_ATTEMPTS 10 | |
13 | ||
83e57b04 JS |
14 | /* |
15 | * Sentinel file used to detect when we should discard new traces to avoid | |
16 | * writing too many trace files to a directory. | |
17 | */ | |
18 | #define DISCARD_SENTINEL_NAME "git-trace2-discard" | |
19 | ||
20 | /* | |
21 | * When set to zero, disables directory file count checks. Otherwise, controls | |
22 | * how many files we can write to a directory before entering discard mode. | |
23 | * This can be overridden via the TR2_SYSENV_MAX_FILES setting. | |
24 | */ | |
25 | static int tr2env_max_files = 0; | |
26 | ||
ee4512ed JH |
27 | static int tr2_dst_want_warning(void) |
28 | { | |
29 | static int tr2env_dst_debug = -1; | |
30 | ||
31 | if (tr2env_dst_debug == -1) { | |
bce9db6d | 32 | const char *env_value = tr2_sysenv_get(TR2_SYSENV_DST_DEBUG); |
ee4512ed JH |
33 | if (!env_value || !*env_value) |
34 | tr2env_dst_debug = 0; | |
35 | else | |
36 | tr2env_dst_debug = atoi(env_value) > 0; | |
37 | } | |
38 | ||
39 | return tr2env_dst_debug; | |
40 | } | |
41 | ||
42 | void tr2_dst_trace_disable(struct tr2_dst *dst) | |
43 | { | |
44 | if (dst->need_close) | |
45 | close(dst->fd); | |
46 | dst->fd = 0; | |
47 | dst->initialized = 1; | |
48 | dst->need_close = 0; | |
49 | } | |
50 | ||
83e57b04 JS |
51 | /* |
52 | * Check to make sure we're not overloading the target directory with too many | |
53 | * files. First get the threshold (if present) from the config or envvar. If | |
87db61a4 JS |
54 | * it's zero or unset, disable this check. Next check for the presence of a |
55 | * sentinel file, then check file count. | |
56 | * | |
57 | * Returns 0 if tracing should proceed as normal. Returns 1 if the sentinel file | |
58 | * already exists, which means tracing should be disabled. Returns -1 if there | |
59 | * are too many files but there was no sentinel file, which means we have | |
60 | * created and should write traces to the sentinel file. | |
83e57b04 JS |
61 | * |
62 | * We expect that some trace processing system is gradually collecting files | |
63 | * from the target directory; after it removes the sentinel file we'll start | |
64 | * writing traces again. | |
65 | */ | |
87db61a4 | 66 | static int tr2_dst_too_many_files(struct tr2_dst *dst, const char *tgt_prefix) |
83e57b04 JS |
67 | { |
68 | int file_count = 0, max_files = 0, ret = 0; | |
69 | const char *max_files_var; | |
70 | DIR *dirp; | |
71 | struct strbuf path = STRBUF_INIT, sentinel_path = STRBUF_INIT; | |
72 | struct stat statbuf; | |
73 | ||
74 | /* Get the config or envvar and decide if we should continue this check */ | |
75 | max_files_var = tr2_sysenv_get(TR2_SYSENV_MAX_FILES); | |
76 | if (max_files_var && *max_files_var && ((max_files = atoi(max_files_var)) >= 0)) | |
77 | tr2env_max_files = max_files; | |
78 | ||
79 | if (!tr2env_max_files) { | |
80 | ret = 0; | |
81 | goto cleanup; | |
82 | } | |
83 | ||
84 | strbuf_addstr(&path, tgt_prefix); | |
85 | if (!is_dir_sep(path.buf[path.len - 1])) { | |
86 | strbuf_addch(&path, '/'); | |
87 | } | |
88 | ||
89 | /* check sentinel */ | |
90 | strbuf_addbuf(&sentinel_path, &path); | |
91 | strbuf_addstr(&sentinel_path, DISCARD_SENTINEL_NAME); | |
92 | if (!stat(sentinel_path.buf, &statbuf)) { | |
93 | ret = 1; | |
94 | goto cleanup; | |
95 | } | |
96 | ||
97 | /* check file count */ | |
98 | dirp = opendir(path.buf); | |
99 | while (file_count < tr2env_max_files && dirp && readdir(dirp)) | |
100 | file_count++; | |
101 | if (dirp) | |
102 | closedir(dirp); | |
103 | ||
104 | if (file_count >= tr2env_max_files) { | |
87db61a4 JS |
105 | dst->too_many_files = 1; |
106 | dst->fd = open(sentinel_path.buf, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
107 | ret = -1; | |
83e57b04 JS |
108 | goto cleanup; |
109 | } | |
110 | ||
111 | cleanup: | |
112 | strbuf_release(&path); | |
113 | strbuf_release(&sentinel_path); | |
114 | return ret; | |
115 | } | |
116 | ||
a4d3a283 JS |
117 | static int tr2_dst_try_auto_path(struct tr2_dst *dst, const char *tgt_prefix) |
118 | { | |
87db61a4 | 119 | int too_many_files; |
a4d3a283 JS |
120 | const char *last_slash, *sid = tr2_sid_get(); |
121 | struct strbuf path = STRBUF_INIT; | |
122 | size_t base_path_len; | |
123 | unsigned attempt_count; | |
124 | ||
125 | last_slash = strrchr(sid, '/'); | |
126 | if (last_slash) | |
127 | sid = last_slash + 1; | |
128 | ||
129 | strbuf_addstr(&path, tgt_prefix); | |
130 | if (!is_dir_sep(path.buf[path.len - 1])) | |
131 | strbuf_addch(&path, '/'); | |
132 | strbuf_addstr(&path, sid); | |
133 | base_path_len = path.len; | |
134 | ||
87db61a4 JS |
135 | too_many_files = tr2_dst_too_many_files(dst, tgt_prefix); |
136 | if (!too_many_files) { | |
137 | for (attempt_count = 0; attempt_count < MAX_AUTO_ATTEMPTS; attempt_count++) { | |
138 | if (attempt_count > 0) { | |
139 | strbuf_setlen(&path, base_path_len); | |
140 | strbuf_addf(&path, ".%d", attempt_count); | |
141 | } | |
142 | ||
143 | dst->fd = open(path.buf, O_WRONLY | O_CREAT | O_EXCL, 0666); | |
144 | if (dst->fd != -1) | |
145 | break; | |
146 | } | |
147 | } else if (too_many_files == 1) { | |
83e57b04 JS |
148 | strbuf_release(&path); |
149 | if (tr2_dst_want_warning()) | |
150 | warning("trace2: not opening %s trace file due to too " | |
151 | "many files in target directory %s", | |
152 | tr2_sysenv_display_name(dst->sysenv_var), | |
153 | tgt_prefix); | |
154 | return 0; | |
155 | } | |
156 | ||
87db61a4 | 157 | if (dst->fd == -1) { |
a4d3a283 JS |
158 | if (tr2_dst_want_warning()) |
159 | warning("trace2: could not open '%.*s' for '%s' tracing: %s", | |
160 | (int) base_path_len, path.buf, | |
5b2d1c0c JH |
161 | tr2_sysenv_display_name(dst->sysenv_var), |
162 | strerror(errno)); | |
a4d3a283 JS |
163 | |
164 | tr2_dst_trace_disable(dst); | |
165 | strbuf_release(&path); | |
166 | return 0; | |
167 | } | |
168 | ||
169 | strbuf_release(&path); | |
170 | ||
a4d3a283 JS |
171 | dst->need_close = 1; |
172 | dst->initialized = 1; | |
173 | ||
174 | return dst->fd; | |
175 | } | |
176 | ||
ee4512ed JH |
177 | static int tr2_dst_try_path(struct tr2_dst *dst, const char *tgt_value) |
178 | { | |
179 | int fd = open(tgt_value, O_WRONLY | O_APPEND | O_CREAT, 0666); | |
180 | if (fd == -1) { | |
181 | if (tr2_dst_want_warning()) | |
182 | warning("trace2: could not open '%s' for '%s' tracing: %s", | |
bce9db6d JH |
183 | tgt_value, |
184 | tr2_sysenv_display_name(dst->sysenv_var), | |
185 | strerror(errno)); | |
ee4512ed JH |
186 | |
187 | tr2_dst_trace_disable(dst); | |
188 | return 0; | |
189 | } | |
190 | ||
191 | dst->fd = fd; | |
192 | dst->need_close = 1; | |
193 | dst->initialized = 1; | |
194 | ||
195 | return dst->fd; | |
196 | } | |
197 | ||
198 | #ifndef NO_UNIX_SOCKETS | |
199 | #define PREFIX_AF_UNIX "af_unix:" | |
200 | #define PREFIX_AF_UNIX_STREAM "af_unix:stream:" | |
201 | #define PREFIX_AF_UNIX_DGRAM "af_unix:dgram:" | |
202 | ||
203 | static int tr2_dst_try_uds_connect(const char *path, int sock_type, int *out_fd) | |
204 | { | |
205 | int fd; | |
206 | struct sockaddr_un sa; | |
207 | ||
208 | fd = socket(AF_UNIX, sock_type, 0); | |
209 | if (fd == -1) | |
4e0a64a7 | 210 | return -1; |
ee4512ed JH |
211 | |
212 | sa.sun_family = AF_UNIX; | |
213 | strlcpy(sa.sun_path, path, sizeof(sa.sun_path)); | |
214 | ||
215 | if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) { | |
4e0a64a7 | 216 | int saved_errno = errno; |
ee4512ed | 217 | close(fd); |
4e0a64a7 ÆAB |
218 | errno = saved_errno; |
219 | return -1; | |
ee4512ed JH |
220 | } |
221 | ||
222 | *out_fd = fd; | |
223 | return 0; | |
224 | } | |
225 | ||
226 | #define TR2_DST_UDS_TRY_STREAM (1 << 0) | |
227 | #define TR2_DST_UDS_TRY_DGRAM (1 << 1) | |
228 | ||
229 | static int tr2_dst_try_unix_domain_socket(struct tr2_dst *dst, | |
230 | const char *tgt_value) | |
231 | { | |
232 | unsigned int uds_try = 0; | |
233 | int fd; | |
ee4512ed JH |
234 | const char *path = NULL; |
235 | ||
236 | /* | |
237 | * Allow "af_unix:[<type>:]<absolute_path>" | |
238 | * | |
239 | * Trace2 always writes complete individual messages (without | |
240 | * chunking), so we can talk to either DGRAM or STREAM type sockets. | |
241 | * | |
242 | * Allow the user to explicitly request the socket type. | |
243 | * | |
244 | * If they omit the socket type, try one and then the other. | |
245 | */ | |
246 | ||
247 | if (skip_prefix(tgt_value, PREFIX_AF_UNIX_STREAM, &path)) | |
248 | uds_try |= TR2_DST_UDS_TRY_STREAM; | |
249 | ||
250 | else if (skip_prefix(tgt_value, PREFIX_AF_UNIX_DGRAM, &path)) | |
251 | uds_try |= TR2_DST_UDS_TRY_DGRAM; | |
252 | ||
253 | else if (skip_prefix(tgt_value, PREFIX_AF_UNIX, &path)) | |
254 | uds_try |= TR2_DST_UDS_TRY_STREAM | TR2_DST_UDS_TRY_DGRAM; | |
255 | ||
256 | if (!path || !*path) { | |
257 | if (tr2_dst_want_warning()) | |
258 | warning("trace2: invalid AF_UNIX value '%s' for '%s' tracing", | |
bce9db6d JH |
259 | tgt_value, |
260 | tr2_sysenv_display_name(dst->sysenv_var)); | |
ee4512ed JH |
261 | |
262 | tr2_dst_trace_disable(dst); | |
263 | return 0; | |
264 | } | |
265 | ||
266 | if (!is_absolute_path(path) || | |
267 | strlen(path) >= sizeof(((struct sockaddr_un *)0)->sun_path)) { | |
268 | if (tr2_dst_want_warning()) | |
269 | warning("trace2: invalid AF_UNIX path '%s' for '%s' tracing", | |
bce9db6d | 270 | path, tr2_sysenv_display_name(dst->sysenv_var)); |
ee4512ed JH |
271 | |
272 | tr2_dst_trace_disable(dst); | |
273 | return 0; | |
274 | } | |
275 | ||
276 | if (uds_try & TR2_DST_UDS_TRY_STREAM) { | |
4e0a64a7 | 277 | if (!tr2_dst_try_uds_connect(path, SOCK_STREAM, &fd)) |
ee4512ed | 278 | goto connected; |
4e0a64a7 | 279 | if (errno != EPROTOTYPE) |
ee4512ed JH |
280 | goto error; |
281 | } | |
282 | if (uds_try & TR2_DST_UDS_TRY_DGRAM) { | |
4e0a64a7 | 283 | if (!tr2_dst_try_uds_connect(path, SOCK_DGRAM, &fd)) |
ee4512ed JH |
284 | goto connected; |
285 | } | |
286 | ||
287 | error: | |
288 | if (tr2_dst_want_warning()) | |
289 | warning("trace2: could not connect to socket '%s' for '%s' tracing: %s", | |
bce9db6d | 290 | path, tr2_sysenv_display_name(dst->sysenv_var), |
4e0a64a7 | 291 | strerror(errno)); |
ee4512ed JH |
292 | |
293 | tr2_dst_trace_disable(dst); | |
294 | return 0; | |
295 | ||
296 | connected: | |
297 | dst->fd = fd; | |
298 | dst->need_close = 1; | |
299 | dst->initialized = 1; | |
300 | ||
301 | return dst->fd; | |
302 | } | |
303 | #endif | |
304 | ||
305 | static void tr2_dst_malformed_warning(struct tr2_dst *dst, | |
306 | const char *tgt_value) | |
307 | { | |
1fd881d4 RS |
308 | warning("trace2: unknown value for '%s': '%s'", |
309 | tr2_sysenv_display_name(dst->sysenv_var), tgt_value); | |
ee4512ed JH |
310 | } |
311 | ||
312 | int tr2_dst_get_trace_fd(struct tr2_dst *dst) | |
313 | { | |
314 | const char *tgt_value; | |
315 | ||
316 | /* don't open twice */ | |
317 | if (dst->initialized) | |
318 | return dst->fd; | |
319 | ||
320 | dst->initialized = 1; | |
321 | ||
bce9db6d | 322 | tgt_value = tr2_sysenv_get(dst->sysenv_var); |
ee4512ed JH |
323 | |
324 | if (!tgt_value || !strcmp(tgt_value, "") || !strcmp(tgt_value, "0") || | |
325 | !strcasecmp(tgt_value, "false")) { | |
326 | dst->fd = 0; | |
327 | return dst->fd; | |
328 | } | |
329 | ||
330 | if (!strcmp(tgt_value, "1") || !strcasecmp(tgt_value, "true")) { | |
331 | dst->fd = STDERR_FILENO; | |
332 | return dst->fd; | |
333 | } | |
334 | ||
335 | if (strlen(tgt_value) == 1 && isdigit(*tgt_value)) { | |
336 | dst->fd = atoi(tgt_value); | |
337 | return dst->fd; | |
338 | } | |
339 | ||
a4d3a283 JS |
340 | if (is_absolute_path(tgt_value)) { |
341 | if (is_directory(tgt_value)) | |
342 | return tr2_dst_try_auto_path(dst, tgt_value); | |
343 | else | |
344 | return tr2_dst_try_path(dst, tgt_value); | |
345 | } | |
ee4512ed JH |
346 | |
347 | #ifndef NO_UNIX_SOCKETS | |
348 | if (starts_with(tgt_value, PREFIX_AF_UNIX)) | |
349 | return tr2_dst_try_unix_domain_socket(dst, tgt_value); | |
350 | #endif | |
351 | ||
352 | /* Always warn about malformed values. */ | |
353 | tr2_dst_malformed_warning(dst, tgt_value); | |
354 | tr2_dst_trace_disable(dst); | |
355 | return 0; | |
356 | } | |
357 | ||
358 | int tr2_dst_trace_want(struct tr2_dst *dst) | |
359 | { | |
360 | return !!tr2_dst_get_trace_fd(dst); | |
361 | } | |
362 | ||
363 | void tr2_dst_write_line(struct tr2_dst *dst, struct strbuf *buf_line) | |
364 | { | |
365 | int fd = tr2_dst_get_trace_fd(dst); | |
538ac746 | 366 | ssize_t bytes; |
ee4512ed JH |
367 | |
368 | strbuf_complete_line(buf_line); /* ensure final NL on buffer */ | |
369 | ||
370 | /* | |
371 | * We do not use write_in_full() because we do not want | |
372 | * a short-write to try again. We are using O_APPEND mode | |
373 | * files and the kernel handles the atomic seek+write. If | |
374 | * another thread or git process is concurrently writing to | |
375 | * this fd or file, our remainder-write may not be contiguous | |
376 | * with our initial write of this message. And that will | |
377 | * confuse readers. So just don't bother. | |
378 | * | |
379 | * It is assumed that TRACE2 messages are short enough that | |
380 | * the system can write them in 1 attempt and we won't see | |
381 | * a short-write. | |
382 | * | |
383 | * If we get an IO error, just close the trace dst. | |
384 | */ | |
538ac746 JS |
385 | sigchain_push(SIGPIPE, SIG_IGN); |
386 | bytes = write(fd, buf_line->buf, buf_line->len); | |
387 | sigchain_pop(SIGPIPE); | |
388 | if (bytes >= 0) | |
ee4512ed JH |
389 | return; |
390 | ||
538ac746 | 391 | tr2_dst_trace_disable(dst); |
ee4512ed | 392 | if (tr2_dst_want_warning()) |
bce9db6d JH |
393 | warning("unable to write trace to '%s': %s", |
394 | tr2_sysenv_display_name(dst->sysenv_var), | |
ee4512ed | 395 | strerror(errno)); |
ee4512ed | 396 | } |