libustcomm/ustcomm.c

   1 #define _GNU_SOURCE
   2 #include <sys/types.h>
   3 #include <signal.h>
   4 #include <errno.h>
   5 #include <sys/socket.h>
   6 #include <sys/un.h>
   7 #include <unistd.h>
   8 #include <poll.h>
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <execinfo.h>
  14
  15 #include "ustcomm.h"
  16 #include "localerr.h"
  17
  18 #define UNIX_PATH_MAX 108
  19 #define SOCK_DIR "/tmp/socks"
  20 #define UST_SIGNAL SIGIO
  21
  22 #define MSG_MAX 1000
  23
  24 /* FIXME: ustcomm blocks on message sending, which might be problematic in
  25  * some cases. Fix the poll() usage so sends are buffered until they don't
  26  * block.
  27  */
  28
  29 //static void bt(void)
  30 //{
  31 //      void *buffer[100];
  32 //      int result;
  33 //
  34 //      result = backtrace(&buffer, 100);
  35 //      backtrace_symbols_fd(buffer, result, STDERR_FILENO);
  36 //}
  37
  38 static void signal_process(pid_t pid)
  39 {
  40         int result;
  41
  42         result = kill(pid, UST_SIGNAL);
  43         if(result == -1) {
  44                 PERROR("kill");
  45                 return;
  46         }
  47
  48         sleep(1);
  49 }
  50
  51 int send_message_path(const char *path, const char *msg, char **reply, int signalpid)
  52 {
  53         int fd;
  54         int result;
  55         struct sockaddr_un addr;
  56
  57         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
  58         if(result == -1) {
  59                 PERROR("socket");
  60                 return -1;
  61         }
  62
  63         addr.sun_family = AF_UNIX;
  64
  65         result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
  66         if(result >= UNIX_PATH_MAX) {
  67                 ERR("string overflow allocating socket name");
  68                 return -1;
  69         }
  70
  71         if(signalpid >= 0)
  72                 signal_process(signalpid);
  73
  74         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
  75         if(result == -1) {
  76                 PERROR("connect");
  77                 return -1;
  78         }
  79
  80         result = send(fd, msg, strlen(msg), 0);
  81         if(result == -1) {
  82                 PERROR("send");
  83                 return -1;
  84         }
  85
  86         if(!reply)
  87                 return 0;
  88
  89         *reply = (char *) malloc(MSG_MAX+1);
  90         result = recvfrom(fd, *reply, MSG_MAX, 0, NULL, NULL);
  91         if(result == -1) {
  92                 PERROR("recvfrom");
  93                 return -1;
  94         }
  95
  96         (*reply)[result] = '\0';
  97
  98         return 0;
  99 }
 100
 101 /* pid: the pid of the trace process that must receive the msg
 102    msg: pointer to a null-terminated message to send
 103    reply: location where to put the null-terminated string of the reply;
 104           it must be free'd after usage
 105  */
 106
 107 int send_message(pid_t pid, const char *msg, char **reply)
 108 {
 109         int result;
 110         char path[UNIX_PATH_MAX];
 111
 112         result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
 113         if(result >= UNIX_PATH_MAX) {
 114                 fprintf(stderr, "string overflow allocating socket name");
 115                 return -1;
 116         }
 117
 118         send_message_path(path, msg, reply, pid);
 119
 120         return 0;
 121 }
 122
 123 /* Called by an app to ask the consumer daemon to connect to it. */
 124
 125 int ustcomm_request_consumer(pid_t pid, const char *channel)
 126 {
 127         char path[UNIX_PATH_MAX];
 128         int result;
 129         char *msg;
 130
 131         result = snprintf(path, UNIX_PATH_MAX, "%s/ustd", SOCK_DIR);
 132         if(result >= UNIX_PATH_MAX) {
 133                 fprintf(stderr, "string overflow allocating socket name");
 134                 return -1;
 135         }
 136
 137         asprintf(&msg, "collect %d %s", pid, channel);
 138
 139         send_message_path(path, msg, NULL, -1);
 140         free(msg);
 141
 142         return 0;
 143 }
 144
 145 static int recv_message_fd(int fd, char **msg, struct ustcomm_source *src)
 146 {
 147         int result;
 148
 149         *msg = (char *) malloc(MSG_MAX+1);
 150
 151         result = recv(fd, *msg, MSG_MAX, 0);
 152         if(result == -1) {
 153                 PERROR("recvfrom");
 154                 return -1;
 155         }
 156
 157         (*msg)[result] = '\0';
 158
 159         DBG("ustcomm_app_recv_message: result is %d, message is %s", result, (*msg));
 160
 161         return 0;
 162 }
 163
 164 int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char **msg, struct ustcomm_source *src)
 165 {
 166         struct pollfd *fds;
 167         struct ustcomm_connection *conn;
 168         int result;
 169         int retval;
 170
 171         for(;;) {
 172                 int idx = 0;
 173                 int n_fds = 1;
 174
 175                 list_for_each_entry(conn, &ustd->connections, list) {
 176                         n_fds++;
 177                 }
 178
 179                 fds = (struct pollfd *) malloc(n_fds * sizeof(struct pollfd));
 180                 if(fds == NULL) {
 181                         ERR("malloc returned NULL");
 182                         return -1;
 183                 }
 184
 185                 /* special idx 0 is for listening socket */
 186                 fds[idx].fd = ustd->listen_fd;
 187                 fds[idx].events = POLLIN;
 188                 idx++;
 189
 190                 list_for_each_entry(conn, &ustd->connections, list) {
 191                         fds[idx].fd = conn->fd;
 192                         fds[idx].events = POLLIN;
 193                         idx++;
 194                 }
 195
 196                 result = poll(fds, n_fds, -1);
 197                 if(result == -1) {
 198                         PERROR("poll");
 199                         return -1;
 200                 }
 201
 202                 if(fds[0].revents) {
 203                         struct ustcomm_connection *newconn;
 204                         int newfd;
 205
 206                         result = newfd = accept(ustd->listen_fd, NULL, NULL);
 207                         if(result == -1) {
 208                                 PERROR("accept");
 209                                 return -1;
 210                         }
 211
 212                         newconn = (struct ustcomm_connection *) malloc(sizeof(struct ustcomm_connection));
 213                         if(newconn == NULL) {
 214                                 ERR("malloc returned NULL");
 215                                 return -1;
 216                         }
 217
 218                         newconn->fd = newfd;
 219
 220                         list_add(&newconn->list, &ustd->connections);
 221                 }
 222
 223                 for(idx=1; idx<n_fds; idx++) {
 224                         if(fds[idx].revents) {
 225                                 retval = recv_message_fd(fds[idx].fd, msg, src);
 226                                 if(**msg == 0) {
 227                                         /* connection finished */
 228                                         close(fds[idx].fd);
 229
 230                                         list_for_each_entry(conn, &ustd->connections, list) {
 231                                                 if(conn->fd == fds[idx].fd) {
 232                                                         list_del(&conn->list);
 233                                                         break;
 234                                                 }
 235                                         }
 236                                 }
 237                                 else {
 238                                         goto free_fds_return;
 239                                 }
 240                         }
 241                 }
 242
 243                 free(fds);
 244         }
 245
 246 free_fds_return:
 247         free(fds);
 248         return retval;
 249 }
 250
 251 int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg, struct ustcomm_source *src)
 252 {
 253         return ustcomm_ustd_recv_message((struct ustcomm_ustd *)app, msg, src);
 254 }
 255
 256 static int init_named_socket(char *name, char **path_out)
 257 {
 258         int result;
 259         int fd;
 260
 261         struct sockaddr_un addr;
 262
 263         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 264         if(result == -1) {
 265                 PERROR("socket");
 266                 return -1;
 267         }
 268
 269         addr.sun_family = AF_UNIX;
 270
 271         strncpy(addr.sun_path, name, UNIX_PATH_MAX);
 272         addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 273
 274         result = access(name, F_OK);
 275         if(result == 0) {
 276                 /* file exists */
 277                 result = unlink(name);
 278                 if(result == -1) {
 279                         PERROR("unlink of socket file");
 280                         goto close_sock;
 281                 }
 282                 WARN("socket already exists; overwriting");
 283         }
 284
 285         result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
 286         if(result == -1) {
 287                 PERROR("bind");
 288                 goto close_sock;
 289         }
 290
 291         result = listen(fd, 1);
 292         if(result == -1) {
 293                 PERROR("listen");
 294                 goto close_sock;
 295         }
 296
 297         if(path_out) {
 298                 *path_out = "";
 299                 *path_out = strdupa(addr.sun_path);
 300         }
 301
 302         return fd;
 303
 304         close_sock:
 305         close(fd);
 306
 307         return -1;
 308 }
 309
 310 int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
 311 {
 312         int result;
 313         char *name;
 314
 315         result = asprintf(&name, "%s/%d", SOCK_DIR, (int)pid);
 316         if(result >= UNIX_PATH_MAX) {
 317                 ERR("string overflow allocating socket name");
 318                 return -1;
 319         }
 320
 321         handle->listen_fd = init_named_socket(name, &(handle->socketpath));
 322         if(handle->listen_fd < 0) {
 323                 ERR("error initializing named socket");
 324                 goto free_name;
 325         }
 326         free(name);
 327
 328         INIT_LIST_HEAD(&handle->connections);
 329
 330         return 0;
 331
 332 free_name:
 333         free(name);
 334         return -1;
 335 }
 336
 337 int ustcomm_init_ustd(struct ustcomm_ustd *handle)
 338 {
 339         int result;
 340         char *name;
 341
 342         result = asprintf(&name, "%s/%s", SOCK_DIR, "ustd");
 343         if(result >= UNIX_PATH_MAX) {
 344                 ERR("string overflow allocating socket name");
 345                 return -1;
 346         }
 347
 348         handle->listen_fd = init_named_socket(name, &handle->socketpath);
 349         if(handle->listen_fd < 0) {
 350                 ERR("error initializing named socket");
 351                 goto free_name;
 352         }
 353         free(name);
 354
 355         INIT_LIST_HEAD(&handle->connections);
 356
 357         return 0;
 358
 359 free_name:
 360         free(name);
 361         return -1;
 362 }
 363
 364 static char *find_tok(char *str)
 365 {
 366         while(*str == ' ') {
 367                 str++;
 368
 369                 if(*str == 0)
 370                         return NULL;
 371         }
 372
 373         return str;
 374 }
 375
 376 static char *find_sep(char *str)
 377 {
 378         while(*str != ' ') {
 379                 str++;
 380
 381                 if(*str == 0)
 382                         break;
 383         }
 384
 385         return str;
 386 }
 387
 388 int nth_token_is(char *str, char *token, int tok_no)
 389 {
 390         int i;
 391         char *start;
 392         char *end;
 393
 394         for(i=0; i<=tok_no; i++) {
 395                 str = find_tok(str);
 396                 if(str == NULL)
 397                         return -1;
 398
 399                 start = str;
 400
 401                 str = find_sep(str);
 402                 if(str == NULL)
 403                         return -1;
 404
 405                 end = str;
 406         }
 407
 408         if(end-start != strlen(token))
 409                 return 0;
 410
 411         if(strncmp(start, token, end-start))
 412                 return 0;
 413
 414         return 1;
 415 }
 416
 417 char *nth_token(char *str, int tok_no)
 418 {
 419         static char *retval = NULL;
 420         int i;
 421         char *start;
 422         char *end;
 423
 424         for(i=0; i<=tok_no; i++) {
 425                 str = find_tok(str);
 426                 if(str == NULL)
 427                         return NULL;
 428
 429                 start = str;
 430
 431                 str = find_sep(str);
 432                 if(str == NULL)
 433                         return NULL;
 434
 435                 end = str;
 436         }
 437
 438         if(retval) {
 439                 free(retval);
 440                 retval = NULL;
 441         }
 442
 443         asprintf(&retval, "%.*s", (int)(end-start), start);
 444
 445         return retval;
 446 }
 447