6cecb9cf |
1 | /* lttd |
2 | * |
3 | * Linux Trace Toolkit Daemon |
4 | * |
5 | * This is a simple daemon that reads a few relayfs channels and save them in a |
6 | * trace. |
7 | * |
8 | * |
9 | * Copyright 2005 - |
10 | * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
11 | */ |
12 | |
4e4d11b3 |
13 | #ifdef HAVE_CONFIG_H |
13474e75 |
14 | #include <config.h> |
4e4d11b3 |
15 | #endif |
16 | |
17 | #define _GNU_SOURCE |
6cecb9cf |
18 | #include <stdio.h> |
af4061b2 |
19 | #include <unistd.h> |
6cecb9cf |
20 | #include <errno.h> |
21 | #include <sys/types.h> |
22 | #include <sys/stat.h> |
6cecb9cf |
23 | #include <stdlib.h> |
24 | #include <dirent.h> |
25 | #include <string.h> |
9e7dbe44 |
26 | #include <fcntl.h> |
27 | #include <sys/poll.h> |
af4061b2 |
28 | #include <sys/mman.h> |
29 | #include <signal.h> |
30 | |
31 | /* Relayfs IOCTL */ |
32 | #include <asm/ioctl.h> |
33 | #include <asm/types.h> |
34 | |
35 | /* Get the next sub buffer that can be read. */ |
36 | #define RELAYFS_GET_SUBBUF _IOR(0xF4, 0x00,__u32) |
37 | /* Release the oldest reserved (by "get") sub buffer. */ |
38 | #define RELAYFS_PUT_SUBBUF _IO(0xF4, 0x01) |
39 | /* returns the number of sub buffers in the per cpu channel. */ |
40 | #define RELAYFS_GET_N_SUBBUFS _IOR(0xF4, 0x02,__u32) |
41 | /* returns the size of the sub buffers. */ |
42 | #define RELAYFS_GET_SUBBUF_SIZE _IOR(0xF4, 0x03,__u32) |
43 | |
44 | |
6cecb9cf |
45 | |
46 | enum { |
47 | GET_SUBBUF, |
48 | PUT_SUBBUF, |
49 | GET_N_BUBBUFS, |
50 | GET_SUBBUF_SIZE |
51 | }; |
52 | |
53 | struct fd_pair { |
54 | int channel; |
55 | int trace; |
af4061b2 |
56 | unsigned int n_subbufs; |
57 | unsigned int subbuf_size; |
58 | void *mmap; |
6cecb9cf |
59 | }; |
60 | |
61 | struct channel_trace_fd { |
62 | struct fd_pair *pair; |
63 | int num_pairs; |
64 | }; |
65 | |
66 | static char *trace_name = NULL; |
67 | static char *channel_name = NULL; |
68 | static int daemon_mode = 0; |
9e7dbe44 |
69 | static int append_mode = 0; |
af4061b2 |
70 | volatile static int quit_program = 0; /* For signal handler */ |
6cecb9cf |
71 | |
72 | /* Args : |
73 | * |
74 | * -t directory Directory name of the trace to write to. Will be created. |
75 | * -c directory Root directory of the relayfs trace channels. |
76 | * -d Run in background (daemon). |
9e7dbe44 |
77 | * -a Trace append mode. |
86a65fdb |
78 | * -s Send SIGUSR1 to parent when ready for IO. |
6cecb9cf |
79 | */ |
80 | void show_arguments(void) |
81 | { |
82 | printf("Please use the following arguments :\n"); |
83 | printf("\n"); |
84 | printf("-t directory Directory name of the trace to write to.\n" |
85 | " It will be created.\n"); |
86 | printf("-c directory Root directory of the relayfs trace channels.\n"); |
87 | printf("-d Run in background (daemon).\n"); |
9e7dbe44 |
88 | printf("-a Append to an possibly existing trace.\n"); |
6cecb9cf |
89 | printf("\n"); |
90 | } |
91 | |
92 | |
93 | /* parse_arguments |
94 | * |
95 | * Parses the command line arguments. |
96 | * |
97 | * Returns 1 if the arguments were correct, but doesn't ask for program |
98 | * continuation. Returns -1 if the arguments are incorrect, or 0 if OK. |
99 | */ |
100 | int parse_arguments(int argc, char **argv) |
101 | { |
102 | int ret = 0; |
103 | int argn = 1; |
104 | |
105 | if(argc == 2) { |
106 | if(strcmp(argv[1], "-h") == 0) { |
107 | return 1; |
108 | } |
109 | } |
110 | |
9e7dbe44 |
111 | while(argn < argc) { |
6cecb9cf |
112 | |
113 | switch(argv[argn][0]) { |
114 | case '-': |
115 | switch(argv[argn][1]) { |
116 | case 't': |
9e7dbe44 |
117 | if(argn+1 < argc) { |
118 | trace_name = argv[argn+1]; |
119 | argn++; |
120 | } |
6cecb9cf |
121 | break; |
122 | case 'c': |
9e7dbe44 |
123 | if(argn+1 < argc) { |
124 | channel_name = argv[argn+1]; |
125 | argn++; |
126 | } |
6cecb9cf |
127 | break; |
128 | case 'd': |
129 | daemon_mode = 1; |
130 | break; |
9e7dbe44 |
131 | case 'a': |
132 | append_mode = 1; |
133 | break; |
6cecb9cf |
134 | default: |
135 | printf("Invalid argument '%s'.\n", argv[argn]); |
136 | printf("\n"); |
137 | ret = -1; |
138 | } |
139 | break; |
140 | default: |
141 | printf("Invalid argument '%s'.\n", argv[argn]); |
142 | printf("\n"); |
143 | ret = -1; |
144 | } |
145 | argn++; |
146 | } |
147 | |
148 | if(trace_name == NULL) { |
149 | printf("Please specify a trace name.\n"); |
150 | printf("\n"); |
151 | ret = -1; |
152 | } |
153 | |
154 | if(channel_name == NULL) { |
155 | printf("Please specify a channel name.\n"); |
156 | printf("\n"); |
157 | ret = -1; |
158 | } |
159 | |
160 | return ret; |
161 | } |
162 | |
163 | void show_info(void) |
164 | { |
165 | printf("Linux Trace Toolkit Trace Daemon\n"); |
166 | printf("\n"); |
167 | printf("Reading from relayfs directory : %s\n", channel_name); |
168 | printf("Writing to trace directory : %s\n", trace_name); |
169 | printf("\n"); |
170 | } |
171 | |
172 | |
af4061b2 |
173 | /* signal handling */ |
174 | |
175 | static void handler(int signo) |
176 | { |
177 | printf("Signal %d received : exiting cleanly\n", signo); |
178 | quit_program = 1; |
179 | } |
180 | |
181 | |
182 | |
6cecb9cf |
183 | int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name, |
184 | struct channel_trace_fd *fd_pairs) |
185 | { |
186 | DIR *channel_dir = opendir(subchannel_name); |
187 | struct dirent *entry; |
188 | struct stat stat_buf; |
189 | int ret; |
190 | char path_channel[PATH_MAX]; |
191 | int path_channel_len; |
192 | char *path_channel_ptr; |
193 | char path_trace[PATH_MAX]; |
194 | int path_trace_len; |
195 | char *path_trace_ptr; |
02ba971e |
196 | int open_ret = 0; |
6cecb9cf |
197 | |
198 | if(channel_dir == NULL) { |
199 | perror(subchannel_name); |
02ba971e |
200 | open_ret = ENOENT; |
201 | goto end; |
6cecb9cf |
202 | } |
203 | |
6cecb9cf |
204 | printf("Creating trace subdirectory %s\n", subtrace_name); |
205 | ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO); |
206 | if(ret == -1) { |
3986d00b |
207 | if(errno != EEXIST) { |
9e7dbe44 |
208 | perror(subtrace_name); |
02ba971e |
209 | open_ret = -1; |
210 | goto end; |
9e7dbe44 |
211 | } |
6cecb9cf |
212 | } |
213 | |
214 | strncpy(path_channel, subchannel_name, PATH_MAX-1); |
215 | path_channel_len = strlen(path_channel); |
216 | path_channel[path_channel_len] = '/'; |
217 | path_channel_len++; |
218 | path_channel_ptr = path_channel + path_channel_len; |
219 | |
220 | strncpy(path_trace, subtrace_name, PATH_MAX-1); |
221 | path_trace_len = strlen(path_trace); |
222 | path_trace[path_trace_len] = '/'; |
223 | path_trace_len++; |
224 | path_trace_ptr = path_trace + path_trace_len; |
225 | |
226 | while((entry = readdir(channel_dir)) != NULL) { |
227 | |
228 | if(entry->d_name[0] == '.') continue; |
229 | |
230 | strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len); |
231 | strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len); |
232 | |
233 | ret = stat(path_channel, &stat_buf); |
234 | if(ret == -1) { |
235 | perror(path_channel); |
236 | continue; |
237 | } |
238 | |
239 | printf("Channel file : %s\n", path_channel); |
240 | |
241 | if(S_ISDIR(stat_buf.st_mode)) { |
242 | |
243 | printf("Entering channel subdirectory...\n"); |
244 | ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs); |
245 | if(ret < 0) continue; |
9e7dbe44 |
246 | } else if(S_ISREG(stat_buf.st_mode)) { |
247 | printf("Opening file.\n"); |
248 | |
249 | fd_pairs->pair = realloc(fd_pairs->pair, |
250 | ++fd_pairs->num_pairs * sizeof(struct fd_pair)); |
251 | |
252 | /* Open the channel in read mode */ |
253 | fd_pairs->pair[fd_pairs->num_pairs-1].channel = |
254 | open(path_channel, O_RDONLY | O_NONBLOCK); |
255 | if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) { |
256 | perror(path_channel); |
13474e75 |
257 | fd_pairs->num_pairs--; |
258 | continue; |
9e7dbe44 |
259 | } |
260 | /* Open the trace in write mode, only append if append_mode */ |
261 | ret = stat(path_trace, &stat_buf); |
262 | if(ret == 0) { |
263 | if(append_mode) { |
251b5c5e |
264 | printf("Appending to file %s as requested\n", path_trace); |
9e7dbe44 |
265 | |
266 | fd_pairs->pair[fd_pairs->num_pairs-1].trace = |
267 | open(path_trace, O_WRONLY|O_APPEND, |
268 | S_IRWXU|S_IRWXG|S_IRWXO); |
269 | |
270 | if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) { |
271 | perror(path_trace); |
272 | } |
273 | } else { |
274 | printf("File %s exists, cannot open. Try append mode.\n", path_trace); |
02ba971e |
275 | open_ret = -1; |
276 | goto end; |
9e7dbe44 |
277 | } |
278 | } else { |
279 | if(errno == ENOENT) { |
280 | fd_pairs->pair[fd_pairs->num_pairs-1].trace = |
281 | open(path_trace, O_WRONLY|O_CREAT|O_EXCL, |
282 | S_IRWXU|S_IRWXG|S_IRWXO); |
283 | if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) { |
284 | perror(path_trace); |
285 | } |
286 | } |
287 | } |
6cecb9cf |
288 | } |
6cecb9cf |
289 | } |
290 | |
02ba971e |
291 | end: |
6cecb9cf |
292 | closedir(channel_dir); |
293 | |
02ba971e |
294 | return open_ret; |
6cecb9cf |
295 | } |
296 | |
af4061b2 |
297 | |
298 | int read_subbuffer(struct fd_pair *pair) |
299 | { |
300 | unsigned int subbuf_index; |
13474e75 |
301 | int err, ret; |
af4061b2 |
302 | |
303 | |
13474e75 |
304 | err = ioctl(pair->channel, RELAYFS_GET_SUBBUF, |
af4061b2 |
305 | &subbuf_index); |
13474e75 |
306 | printf("index : %u\n", subbuf_index); |
307 | if(err != 0) { |
af4061b2 |
308 | perror("Error in reserving sub buffer"); |
13474e75 |
309 | ret = -EPERM; |
310 | goto get_error; |
af4061b2 |
311 | } |
13474e75 |
312 | |
313 | err = TEMP_FAILURE_RETRY(write(pair->trace, |
af4061b2 |
314 | pair->mmap + (subbuf_index * pair->subbuf_size), |
315 | pair->subbuf_size)); |
13474e75 |
316 | |
317 | if(err < 0) { |
af4061b2 |
318 | perror("Error in writing to file"); |
13474e75 |
319 | ret = err; |
320 | goto write_error; |
af4061b2 |
321 | } |
322 | |
323 | |
13474e75 |
324 | write_error: |
325 | err = ioctl(pair->channel, RELAYFS_PUT_SUBBUF); |
326 | if(err != 0) { |
af4061b2 |
327 | perror("Error in unreserving sub buffer"); |
13474e75 |
328 | ret = -EPERM; |
329 | goto get_error; |
af4061b2 |
330 | } |
331 | |
13474e75 |
332 | get_error: |
333 | return ret; |
af4061b2 |
334 | } |
335 | |
336 | |
9e7dbe44 |
337 | /* read_channels |
338 | * |
339 | * Read the realyfs channels and write them in the paired tracefiles. |
340 | * |
341 | * @fd_pairs : paired channels and trace files. |
342 | * |
343 | * returns 0 on success, -1 on error. |
344 | * |
345 | * Note that the high priority polled channels are consumed first. We then poll |
346 | * again to see if these channels are still in priority. Only when no |
347 | * high priority channel is left, we start reading low priority channels. |
348 | * |
349 | * Note that a channel is considered high priority when the buffer is almost |
350 | * full. |
351 | */ |
6cecb9cf |
352 | |
353 | int read_channels(struct channel_trace_fd *fd_pairs) |
354 | { |
9e7dbe44 |
355 | struct pollfd *pollfd; |
af4061b2 |
356 | int i,j; |
357 | int num_rdy, num_hup; |
68047576 |
358 | int high_prio; |
af4061b2 |
359 | int ret; |
360 | |
13474e75 |
361 | if(fd_pairs->num_pairs <= 0) { |
362 | printf("No channel to read\n"); |
363 | goto end; |
364 | } |
365 | |
af4061b2 |
366 | /* Get the subbuf sizes and number */ |
367 | |
368 | for(i=0;i<fd_pairs->num_pairs;i++) { |
369 | struct fd_pair *pair = &fd_pairs->pair[i]; |
9e7dbe44 |
370 | |
af4061b2 |
371 | ret = ioctl(pair->channel, RELAYFS_GET_N_SUBBUFS, |
372 | &pair->n_subbufs); |
373 | if(ret != 0) { |
374 | perror("Error in getting the number of subbuffers"); |
375 | goto end; |
376 | } |
377 | ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF_SIZE, |
378 | &pair->subbuf_size); |
379 | if(ret != 0) { |
380 | perror("Error in getting the size of the subbuffers"); |
381 | goto end; |
382 | } |
383 | } |
384 | |
385 | /* Mmap each FD */ |
386 | for(i=0;i<fd_pairs->num_pairs;i++) { |
387 | struct fd_pair *pair = &fd_pairs->pair[i]; |
388 | |
389 | pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ, |
390 | MAP_SHARED, pair->channel, 0); |
391 | if(pair->mmap == MAP_FAILED) { |
392 | perror("Mmap error"); |
393 | goto munmap; |
394 | } |
395 | } |
396 | |
397 | |
398 | /* Start polling the FD */ |
399 | |
9e7dbe44 |
400 | pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd)); |
401 | |
af4061b2 |
402 | /* Note : index in pollfd is the same index as fd_pair->pair */ |
9e7dbe44 |
403 | for(i=0;i<fd_pairs->num_pairs;i++) { |
404 | pollfd[i].fd = fd_pairs->pair[i].channel; |
405 | pollfd[i].events = POLLIN|POLLPRI; |
406 | } |
407 | |
408 | while(1) { |
68047576 |
409 | high_prio = 0; |
af4061b2 |
410 | num_hup = 0; |
411 | #ifdef DEBUG |
412 | printf("Press a key for next poll...\n"); |
413 | char buf[1]; |
414 | read(STDIN_FILENO, &buf, 1); |
13474e75 |
415 | printf("Next poll (polling %d fd) :\n", fd_pairs->num_pairs); |
af4061b2 |
416 | #endif //DEBUG |
417 | |
418 | /* Have we received a signal ? */ |
419 | if(quit_program) break; |
420 | |
9e7dbe44 |
421 | num_rdy = poll(pollfd, fd_pairs->num_pairs, -1); |
422 | if(num_rdy == -1) { |
423 | perror("Poll error"); |
af4061b2 |
424 | goto free_fd; |
9e7dbe44 |
425 | } |
426 | |
427 | printf("Data received\n"); |
428 | |
429 | for(i=0;i<fd_pairs->num_pairs;i++) { |
430 | switch(pollfd[i].revents) { |
431 | case POLLERR: |
432 | printf("Error returned in polling fd %d.\n", pollfd[i].fd); |
af4061b2 |
433 | num_hup++; |
9e7dbe44 |
434 | break; |
435 | case POLLHUP: |
436 | printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd); |
af4061b2 |
437 | num_hup++; |
9e7dbe44 |
438 | break; |
439 | case POLLNVAL: |
440 | printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd); |
af4061b2 |
441 | num_hup++; |
9e7dbe44 |
442 | break; |
443 | case POLLPRI: |
af4061b2 |
444 | printf("Urgent read on fd %d\n", pollfd[i].fd); |
9e7dbe44 |
445 | /* Take care of high priority channels first. */ |
68047576 |
446 | high_prio = 1; |
af4061b2 |
447 | ret |= read_subbuffer(&fd_pairs->pair[i]); |
9e7dbe44 |
448 | break; |
68047576 |
449 | } |
9e7dbe44 |
450 | } |
af4061b2 |
451 | /* If every FD has hung up, we end the read loop here */ |
452 | if(num_hup == fd_pairs->num_pairs) break; |
9e7dbe44 |
453 | |
68047576 |
454 | if(!high_prio) { |
455 | for(i=0;i<fd_pairs->num_pairs;i++) { |
456 | switch(pollfd[i].revents) { |
457 | case POLLIN: |
458 | /* Take care of low priority channels. */ |
af4061b2 |
459 | printf("Normal read on fd %d\n", pollfd[i].fd); |
460 | ret |= read_subbuffer(&fd_pairs->pair[i]); |
68047576 |
461 | break; |
462 | } |
463 | } |
9e7dbe44 |
464 | } |
465 | |
466 | } |
467 | |
af4061b2 |
468 | free_fd: |
9e7dbe44 |
469 | free(pollfd); |
470 | |
af4061b2 |
471 | /* munmap only the successfully mmapped indexes */ |
472 | i = fd_pairs->num_pairs; |
473 | munmap: |
474 | /* Munmap each FD */ |
475 | for(j=0;j<i;j++) { |
476 | struct fd_pair *pair = &fd_pairs->pair[j]; |
477 | int err_ret; |
478 | |
479 | err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs); |
480 | if(err_ret != 0) { |
481 | perror("Error in munmap"); |
482 | } |
483 | ret |= err_ret; |
484 | } |
485 | |
486 | end: |
487 | return ret; |
6cecb9cf |
488 | } |
489 | |
490 | |
491 | void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs) |
492 | { |
9e7dbe44 |
493 | int i; |
494 | int ret; |
6cecb9cf |
495 | |
9e7dbe44 |
496 | for(i=0;i<fd_pairs->num_pairs;i++) { |
497 | ret = close(fd_pairs->pair[i].channel); |
498 | if(ret == -1) perror("Close error on channel"); |
499 | ret = close(fd_pairs->pair[i].trace); |
500 | if(ret == -1) perror("Close error on trace"); |
501 | } |
502 | free(fd_pairs->pair); |
6cecb9cf |
503 | } |
504 | |
505 | int main(int argc, char ** argv) |
506 | { |
507 | int ret; |
6cecb9cf |
508 | struct channel_trace_fd fd_pairs = { NULL, 0 }; |
af4061b2 |
509 | struct sigaction act; |
6cecb9cf |
510 | |
511 | ret = parse_arguments(argc, argv); |
512 | |
513 | if(ret != 0) show_arguments(); |
514 | if(ret < 0) return EINVAL; |
515 | if(ret > 0) return 0; |
516 | |
517 | show_info(); |
518 | |
519 | if(daemon_mode) { |
4d20e474 |
520 | ret = daemon(0, 0); |
521 | |
522 | if(ret == -1) { |
523 | perror("An error occured while daemonizing."); |
524 | exit(-1); |
525 | } |
526 | } |
6cecb9cf |
527 | |
af4061b2 |
528 | /* Connect the signal handlers */ |
529 | act.sa_handler = handler; |
530 | act.sa_flags = 0; |
531 | sigemptyset(&(act.sa_mask)); |
532 | sigaddset(&(act.sa_mask), SIGTERM); |
533 | sigaddset(&(act.sa_mask), SIGQUIT); |
534 | sigaddset(&(act.sa_mask), SIGINT); |
535 | sigaction(SIGTERM, &act, NULL); |
536 | sigaction(SIGQUIT, &act, NULL); |
537 | sigaction(SIGINT, &act, NULL); |
538 | |
539 | //return 0; |
6cecb9cf |
540 | if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs)) |
9e7dbe44 |
541 | goto close_channel; |
6cecb9cf |
542 | |
543 | ret = read_channels(&fd_pairs); |
544 | |
9e7dbe44 |
545 | close_channel: |
6cecb9cf |
546 | close_channel_trace_pairs(&fd_pairs); |
547 | |
6cecb9cf |
548 | return ret; |
549 | } |