ustd/ustd.c

   1 /*
   2  * Copyright (C) 2009  Pierre-Marc Fournier
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #define _GNU_SOURCE
  19
  20 #include <sys/types.h>
  21 #include <sys/shm.h>
  22 #include <fcntl.h>
  23 #include <unistd.h>
  24 #include <pthread.h>
  25 #include <signal.h>
  26
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <errno.h>
  31 #include <assert.h>
  32
  33 #include "ustd.h"
  34 #include "localerr.h"
  35 #include "ustcomm.h"
  36
  37 /* return value: 0 = subbuffer is finished, it won't produce data anymore
  38  *               1 = got subbuffer successfully
  39  *               <0 = error
  40  */
  41
  42 #define GET_SUBBUF_OK 1
  43 #define GET_SUBBUF_DONE 0
  44 #define GET_SUBBUF_DIED 2
  45
  46 #define PUT_SUBBUF_OK 1
  47 #define PUT_SUBBUF_DIED 0
  48 #define PUT_SUBBUF_PUSHED 2
  49
  50 int test_sigpipe(void)
  51 {
  52         sigset_t sigset;
  53         int result;
  54
  55         result = sigemptyset(&sigset);
  56         if(result == -1) {
  57                 perror("sigemptyset");
  58                 return -1;
  59         }
  60         result = sigaddset(&sigset, SIGPIPE);
  61         if(result == -1) {
  62                 perror("sigaddset");
  63                 return -1;
  64         }
  65
  66         result = sigtimedwait(&sigset, NULL, &(struct timespec){0,0});
  67         if(result == -1 && errno == EAGAIN) {
  68                 /* no signal received */
  69                 return 0;
  70         }
  71         else if(result == -1) {
  72                 perror("sigtimedwait");
  73                 return -1;
  74         }
  75         else if(result == SIGPIPE) {
  76                 /* received sigpipe */
  77                 return 1;
  78         }
  79         else {
  80                 assert(0);
  81         }
  82 }
  83
  84 int get_subbuffer(struct buffer_info *buf)
  85 {
  86         char *send_msg;
  87         char *received_msg;
  88         char *rep_code;
  89         int retval;
  90         int result;
  91
  92         asprintf(&send_msg, "get_subbuffer %s", buf->name);
  93         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
  94         free(send_msg);
  95         if(test_sigpipe()) {
  96                 WARN("process %d destroyed before we could connect to it", buf->pid);
  97                 return GET_SUBBUF_DONE;
  98         }
  99         else if(result < 0) {
 100                 ERR("get_subbuffer: ustcomm_send_request failed");
 101                 return -1;
 102         }
 103         else if(result == 0) {
 104                 DBG("app died while being traced");
 105                 return GET_SUBBUF_DIED;
 106         }
 107
 108         result = sscanf(received_msg, "%as %ld", &rep_code, &buf->consumed_old);
 109         if(result != 2 && result != 1) {
 110                 ERR("unable to parse response to get_subbuffer");
 111                 return -1;
 112         }
 113
 114         DBG("received msg is %s", received_msg);
 115
 116         if(!strcmp(rep_code, "OK")) {
 117                 DBG("got subbuffer %s", buf->name);
 118                 retval = GET_SUBBUF_OK;
 119         }
 120         else if(nth_token_is(received_msg, "END", 0) == 1) {
 121                 return GET_SUBBUF_DONE;
 122         }
 123         else {
 124                 DBG("error getting subbuffer %s", buf->name);
 125                 retval = -1;
 126         }
 127
 128         /* FIMXE: free correctly the stuff */
 129         free(received_msg);
 130         free(rep_code);
 131         return retval;
 132 }
 133
 134 int put_subbuffer(struct buffer_info *buf)
 135 {
 136         char *send_msg;
 137         char *received_msg;
 138         char *rep_code;
 139         int retval;
 140         int result;
 141
 142         asprintf(&send_msg, "put_subbuffer %s %ld", buf->name, buf->consumed_old);
 143         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 144         if(result < 0) {
 145                 ERR("put_subbuffer: send_message failed");
 146                 return -1;
 147         }
 148         free(send_msg);
 149
 150         result = sscanf(received_msg, "%as", &rep_code);
 151         if(result != 1) {
 152                 ERR("unable to parse response to put_subbuffer");
 153                 return -1;
 154         }
 155         free(received_msg);
 156
 157         if(!strcmp(rep_code, "OK")) {
 158                 DBG("subbuffer put %s", buf->name);
 159                 retval = PUT_SUBBUF_OK;
 160         }
 161         else {
 162                 DBG("put_subbuffer: received error, we were pushed");
 163                 return PUT_SUBBUF_PUSHED;
 164         }
 165
 166         free(rep_code);
 167         return retval;
 168 }
 169
 170 /* This write is patient because it restarts if it was incomplete.
 171  */
 172
 173 ssize_t patient_write(int fd, const void *buf, size_t count)
 174 {
 175         const char *bufc = (const char *) buf;
 176         int result;
 177
 178         for(;;) {
 179                 result = write(fd, bufc, count);
 180                 if(result <= 0) {
 181                         return result;
 182                 }
 183                 count -= result;
 184                 bufc += result;
 185
 186                 if(count == 0) {
 187                         break;
 188                 }
 189         }
 190
 191         return bufc-(const char *)buf;
 192 }
 193
 194 void *consumer_thread(void *arg)
 195 {
 196         struct buffer_info *buf = (struct buffer_info *) arg;
 197         int result;
 198
 199         for(;;) {
 200                 /* get the subbuffer */
 201                 result = get_subbuffer(buf);
 202                 if(result == -1) {
 203                         ERR("error getting subbuffer");
 204                         continue;
 205                 }
 206                 else if(result == GET_SUBBUF_DONE) {
 207                         /* this is done */
 208                         break;
 209                 }
 210                 else if(result == GET_SUBBUF_DIED) {
 211                         finish_consuming_dead_subbuffer(buf);
 212                         break;
 213                 }
 214
 215                 /* write data to file */
 216                 result = patient_write(buf->file_fd, buf->mem + (buf->consumed_old & (buf->n_subbufs * buf->subbuf_size-1)), buf->subbuf_size);
 217                 if(result == -1) {
 218                         PERROR("write");
 219                         /* FIXME: maybe drop this trace */
 220                 }
 221
 222                 /* put the subbuffer */
 223                 result = put_subbuffer(buf);
 224                 if(result == -1) {
 225                         ERR("unknown error putting subbuffer (channel=%s)", buf->name);
 226                         break;
 227                 }
 228                 else if(result == PUT_SUBBUF_PUSHED) {
 229                         ERR("Buffer overflow (channel=%s), reader pushed. This channel will not be usable passed this point.", buf->name);
 230                         break;
 231                 }
 232                 else if(result == PUT_SUBBUF_DIED) {
 233                         WARN("application died while putting subbuffer");
 234                         /* FIXME: probably need to skip the first subbuffer in finish_consuming_dead_subbuffer */
 235                         finish_consuming_dead_subbuffer(buf);
 236                 }
 237                 else if(result == PUT_SUBBUF_OK) {
 238                 }
 239         }
 240
 241         DBG("thread for buffer %s is stopping", buf->name);
 242
 243         /* FIXME: destroy, unalloc... */
 244
 245         return NULL;
 246 }
 247
 248 int add_buffer(pid_t pid, char *bufname)
 249 {
 250         struct buffer_info *buf;
 251         char *send_msg;
 252         char *received_msg;
 253         int result;
 254         char *tmp;
 255         int fd;
 256         pthread_t thr;
 257         struct shmid_ds shmds;
 258
 259         buf = (struct buffer_info *) malloc(sizeof(struct buffer_info));
 260         if(buf == NULL) {
 261                 ERR("add_buffer: insufficient memory");
 262                 return -1;
 263         }
 264
 265         buf->name = bufname;
 266         buf->pid = pid;
 267
 268         /* connect to app */
 269         result = ustcomm_connect_app(buf->pid, &buf->conn);
 270         if(result) {
 271                 WARN("unable to connect to process, it probably died before we were able to connect");
 272                 return -1;
 273         }
 274
 275         /* get shmid */
 276         asprintf(&send_msg, "get_shmid %s", buf->name);
 277         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 278         free(send_msg);
 279         if(result == -1) {
 280                 ERR("problem in ustcomm_send_request(get_shmid)");
 281                 return -1;
 282         }
 283
 284         result = sscanf(received_msg, "%d %d", &buf->shmid, &buf->bufstruct_shmid);
 285         if(result != 2) {
 286                 ERR("unable to parse response to get_shmid");
 287                 return -1;
 288         }
 289         free(received_msg);
 290         DBG("got shmids %d %d", buf->shmid, buf->bufstruct_shmid);
 291
 292         /* get n_subbufs */
 293         asprintf(&send_msg, "get_n_subbufs %s", buf->name);
 294         result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 295         free(send_msg);
 296         if(result == -1) {
 297                 ERR("problem in ustcomm_send_request(g_n_subbufs)");
 298                 return -1;
 299         }
 300
 301         result = sscanf(received_msg, "%d", &buf->n_subbufs);
 302         if(result != 1) {
 303                 ERR("unable to parse response to get_n_subbufs");
 304                 return -1;
 305         }
 306         free(received_msg);
 307         DBG("got n_subbufs %d", buf->n_subbufs);
 308
 309         /* get subbuf size */
 310         asprintf(&send_msg, "get_subbuf_size %s", buf->name);
 311         ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 312         free(send_msg);
 313
 314         result = sscanf(received_msg, "%d", &buf->subbuf_size);
 315         if(result != 1) {
 316                 ERR("unable to parse response to get_subbuf_size");
 317                 return -1;
 318         }
 319         free(received_msg);
 320         DBG("got subbuf_size %d", buf->subbuf_size);
 321
 322         /* attach memory */
 323         buf->mem = shmat(buf->shmid, NULL, 0);
 324         if(buf->mem == (void *) 0) {
 325                 perror("shmat");
 326                 return -1;
 327         }
 328         DBG("successfully attached buffer memory");
 329
 330         buf->bufstruct_mem = shmat(buf->bufstruct_shmid, NULL, 0);
 331         if(buf->bufstruct_mem == (void *) 0) {
 332                 perror("shmat");
 333                 return -1;
 334         }
 335         DBG("successfully attached buffer bufstruct memory");
 336
 337         /* obtain info on the memory segment */
 338         result = shmctl(buf->shmid, IPC_STAT, &shmds);
 339         if(result == -1) {
 340                 perror("shmctl");
 341                 return -1;
 342         }
 343         buf->memlen = shmds.shm_segsz;
 344
 345         /* open file for output */
 346         asprintf(&tmp, "/tmp/trace/%s_0", buf->name);
 347         result = fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 00600);
 348         if(result == -1) {
 349                 PERROR("open");
 350                 ERR("failed opening trace file %s", tmp);
 351                 return -1;
 352         }
 353         buf->file_fd = fd;
 354         free(tmp);
 355
 356         pthread_create(&thr, NULL, consumer_thread, buf);
 357
 358         return 0;
 359 }
 360
 361 int main(int argc, char **argv)
 362 {
 363         struct ustcomm_ustd ustd;
 364         int result;
 365         sigset_t sigset;
 366
 367         result = ustcomm_init_ustd(&ustd);
 368         if(result == -1) {
 369                 ERR("failed to initialize socket");
 370                 return 1;
 371         }
 372
 373         result = sigemptyset(&sigset);
 374         if(result == -1) {
 375                 perror("sigemptyset");
 376                 return 1;
 377         }
 378         result = sigaddset(&sigset, SIGPIPE);
 379         if(result == -1) {
 380                 perror("sigaddset");
 381                 return 1;
 382         }
 383         result = sigprocmask(SIG_BLOCK, &sigset, NULL);
 384         if(result == -1) {
 385                 perror("sigprocmask");
 386                 return 1;
 387         }
 388
 389         /* app loop */
 390         for(;;) {
 391                 char *recvbuf;
 392
 393                 /* check for requests on our public socket */
 394                 result = ustcomm_ustd_recv_message(&ustd, &recvbuf, NULL, 100);
 395                 if(result == -1) {
 396                         ERR("error in ustcomm_ustd_recv_message");
 397                         continue;
 398                 }
 399                 if(result > 0) {
 400                         if(!strncmp(recvbuf, "collect", 7)) {
 401                                 pid_t pid;
 402                                 char *bufname;
 403                                 int result;
 404
 405                                 result = sscanf(recvbuf, "%*s %d %50as", &pid, &bufname);
 406                                 if(result != 2) {
 407                                         fprintf(stderr, "parsing error: %s\n", recvbuf);
 408                                 }
 409
 410                                 result = add_buffer(pid, bufname);
 411                                 if(result < 0) {
 412                                         ERR("error in add_buffer");
 413                                         continue;
 414                                 }
 415                         }
 416
 417                         free(recvbuf);
 418                 }
 419         }
 420
 421         return 0;
 422 }