src/ipc.cc

   1 /*
   2  * DEBUG: section 54    Interprocess Communication
   3  * AUTHOR: Duane Wessels
   4  *
   5  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   6  * ----------------------------------------------------------
   7  *
   8  *  Squid is the result of efforts by numerous individuals from
   9  *  the Internet community; see the CONTRIBUTORS file for full
  10  *  details.   Many organizations have provided support for Squid's
  11  *  development; see the SPONSORS file for full details.  Squid is
  12  *  Copyrighted (C) 2001 by the Regents of the University of
  13  *  California; see the COPYRIGHT file for full details.  Squid
  14  *  incorporates software developed and/or copyrighted by other
  15  *  sources; see the CREDITS file for full details.
  16  *
  17  *  This program is free software; you can redistribute it and/or modify
  18  *  it under the terms of the GNU General Public License as published by
  19  *  the Free Software Foundation; either version 2 of the License, or
  20  *  (at your option) any later version.
  21  *
  22  *  This program is distributed in the hope that it will be useful,
  23  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  *  GNU General Public License for more details.
  26  *
  27  *  You should have received a copy of the GNU General Public License
  28  *  along with this program; if not, write to the Free Software
  29  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  30  *
  31  */
  32
  33 #include "squid.h"
  34 #include "comm/Connection.h"
  35 #include "fd.h"
  36 #include "fde.h"
  37 #include "globals.h"
  38 #include "ip/Address.h"
  39 #include "SquidConfig.h"
  40 #include "SquidIpc.h"
  41 #include "tools.h"
  42 #include "rfc1738.h"
  43
  44 static const char *hello_string = "hi there\n";
  45 #define HELLO_BUF_SZ 32
  46 static char hello_buf[HELLO_BUF_SZ];
  47
  48 static int
  49 ipcCloseAllFD(int prfd, int pwfd, int crfd, int cwfd)
  50 {
  51     if (prfd >= 0)
  52         comm_close(prfd);
  53
  54     if (prfd != pwfd)
  55         if (pwfd >= 0)
  56             comm_close(pwfd);
  57
  58     if (crfd >= 0)
  59         comm_close(crfd);
  60
  61     if (crfd != cwfd)
  62         if (cwfd >= 0)
  63             comm_close(cwfd);
  64
  65     return -1;
  66 }
  67
  68 static void
  69 PutEnvironment()
  70 {
  71 #if HAVE_PUTENV
  72     char *env_str;
  73     int tmp_s;
  74     env_str = (char *)xcalloc((tmp_s = strlen(Debug::debugOptions) + 32), 1);
  75     snprintf(env_str, tmp_s, "SQUID_DEBUG=%s", Debug::debugOptions);
  76     putenv(env_str);
  77 #endif
  78 }
  79
  80 pid_t
  81 ipcCreate(int type, const char *prog, const char *const args[], const char *name, Ip::Address &local_addr, int *rfd, int *wfd, void **hIpc)
  82 {
  83     pid_t pid;
  84     Ip::Address ChS;
  85     Ip::Address PaS;
  86     struct addrinfo *AI = NULL;
  87     int crfd = -1;
  88     int prfd = -1;
  89     int cwfd = -1;
  90     int pwfd = -1;
  91     int fd;
  92     int t1, t2, t3;
  93     int x;
  94
  95 #if USE_POLL && _SQUID_OSF_
  96     assert(type != IPC_FIFO);
  97 #endif
  98
  99     if (rfd)
 100         *rfd = -1;
 101
 102     if (wfd)
 103         *wfd = -1;
 104
 105     if (hIpc)
 106         *hIpc = NULL;
 107
 108 // NP: no wrapping around d and c usage since we *want* code expansion
 109 #define IPC_CHECK_FAIL(f,d,c) \
 110     if ((f) < 0) { \
 111         debugs(54, DBG_CRITICAL, "ERROR: Failed to create helper " d " FD: " << c); \
 112         return ipcCloseAllFD(prfd, pwfd, crfd, cwfd); \
 113     } else void(0)
 114
 115     if (type == IPC_TCP_SOCKET) {
 116         crfd = cwfd = comm_open(SOCK_STREAM,
 117                                 0,
 118                                 local_addr,
 119                                 COMM_NOCLOEXEC,
 120                                 name);
 121         prfd = pwfd = comm_open(SOCK_STREAM,
 122                                 0,                      /* protocol */
 123                                 local_addr,
 124                                 0,                      /* blocking */
 125                                 name);
 126         IPC_CHECK_FAIL(crfd, "child read", "TCP " << local_addr);
 127         IPC_CHECK_FAIL(prfd, "parent read", "TCP " << local_addr);
 128     } else if (type == IPC_UDP_SOCKET) {
 129         crfd = cwfd = comm_open(SOCK_DGRAM,
 130                                 0,
 131                                 local_addr,
 132                                 COMM_NOCLOEXEC,
 133                                 name);
 134         prfd = pwfd = comm_open(SOCK_DGRAM,
 135                                 0,
 136                                 local_addr,
 137                                 0,
 138                                 name);
 139         IPC_CHECK_FAIL(crfd, "child read", "UDP" << local_addr);
 140         IPC_CHECK_FAIL(prfd, "parent read", "UDP" << local_addr);
 141     } else if (type == IPC_FIFO) {
 142         int p2c[2];
 143         int c2p[2];
 144
 145         if (pipe(p2c) < 0) {
 146             debugs(54, DBG_CRITICAL, "ipcCreate: pipe: " << xstrerror());
 147             return -1; // maybe ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 148         }
 149         fd_open(prfd = p2c[0], FD_PIPE, "IPC FIFO Parent Read");
 150         fd_open(cwfd = p2c[1], FD_PIPE, "IPC FIFO Child Write");
 151
 152         if (pipe(c2p) < 0) {
 153             debugs(54, DBG_CRITICAL, "ipcCreate: pipe: " << xstrerror());
 154             return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 155         }
 156         fd_open(crfd = c2p[0], FD_PIPE, "IPC FIFO Child Read");
 157         fd_open(pwfd = c2p[1], FD_PIPE, "IPC FIFO Parent Write");
 158
 159         IPC_CHECK_FAIL(crfd, "child read", "FIFO pipe");
 160         IPC_CHECK_FAIL(prfd, "parent read", "FIFO pipe");
 161
 162 #if HAVE_SOCKETPAIR && defined(AF_UNIX)
 163
 164     } else if (type == IPC_UNIX_STREAM) {
 165         int fds[2];
 166         int buflen = 32768;
 167
 168         if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) < 0) {
 169             debugs(54, DBG_CRITICAL, "ipcCreate: socketpair: " << xstrerror());
 170             return -1;
 171         }
 172
 173         setsockopt(fds[0], SOL_SOCKET, SO_SNDBUF, (void *) &buflen, sizeof(buflen));
 174         setsockopt(fds[0], SOL_SOCKET, SO_RCVBUF, (void *) &buflen, sizeof(buflen));
 175         setsockopt(fds[1], SOL_SOCKET, SO_SNDBUF, (void *) &buflen, sizeof(buflen));
 176         setsockopt(fds[1], SOL_SOCKET, SO_RCVBUF, (void *) &buflen, sizeof(buflen));
 177         fd_open(prfd = pwfd = fds[0], FD_PIPE, "IPC UNIX STREAM Parent");
 178         fd_open(crfd = cwfd = fds[1], FD_PIPE, "IPC UNIX STREAM Parent");
 179         IPC_CHECK_FAIL(crfd, "child read", "UDS socket");
 180         IPC_CHECK_FAIL(prfd, "parent read", "UDS socket");
 181
 182     } else if (type == IPC_UNIX_DGRAM) {
 183         int fds[2];
 184
 185         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, fds) < 0) {
 186             debugs(54, DBG_CRITICAL, "ipcCreate: socketpair: " << xstrerror());
 187             return -1;
 188         }
 189
 190         fd_open(prfd = pwfd = fds[0], FD_PIPE, "IPC UNIX DGRAM Parent");
 191         fd_open(crfd = cwfd = fds[1], FD_PIPE, "IPC UNIX DGRAM Parent");
 192
 193         IPC_CHECK_FAIL(crfd, "child read", "UDS datagram");
 194         IPC_CHECK_FAIL(prfd, "parent read", "UDS datagram");
 195 #endif
 196
 197     } else {
 198         assert(IPC_NONE);
 199     }
 200
 201     debugs(54, 3, "ipcCreate: prfd FD " << prfd);
 202     debugs(54, 3, "ipcCreate: pwfd FD " << pwfd);
 203     debugs(54, 3, "ipcCreate: crfd FD " << crfd);
 204     debugs(54, 3, "ipcCreate: cwfd FD " << cwfd);
 205
 206     if (type == IPC_TCP_SOCKET || type == IPC_UDP_SOCKET) {
 207         PaS.InitAddrInfo(AI);
 208
 209         if (getsockname(pwfd, AI->ai_addr, &AI->ai_addrlen) < 0) {
 210             PaS.FreeAddrInfo(AI);
 211             debugs(54, DBG_CRITICAL, "ipcCreate: getsockname: " << xstrerror());
 212             return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 213         }
 214
 215         PaS = *AI;
 216
 217         debugs(54, 3, "ipcCreate: FD " << pwfd << " sockaddr " << PaS);
 218
 219         PaS.FreeAddrInfo(AI);
 220
 221         ChS.InitAddrInfo(AI);
 222
 223         if (getsockname(crfd, AI->ai_addr, &AI->ai_addrlen) < 0) {
 224             ChS.FreeAddrInfo(AI);
 225             debugs(54, DBG_CRITICAL, "ipcCreate: getsockname: " << xstrerror());
 226             return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 227         }
 228
 229         ChS = *AI;
 230
 231         ChS.FreeAddrInfo(AI);
 232
 233         debugs(54, 3, "ipcCreate: FD " << crfd << " sockaddr " << ChS );
 234
 235     }
 236
 237     if (type == IPC_TCP_SOCKET) {
 238         if (listen(crfd, 1) < 0) {
 239             debugs(54, DBG_IMPORTANT, "ipcCreate: listen FD " << crfd << ": " << xstrerror());
 240             return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 241         }
 242
 243         debugs(54, 3, "ipcCreate: FD " << crfd << " listening...");
 244     }
 245
 246     /* flush or else we get dup data if unbuffered_logs is set */
 247     logsFlush();
 248
 249     if ((pid = fork()) < 0) {
 250         debugs(54, DBG_IMPORTANT, "ipcCreate: fork: " << xstrerror());
 251         return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 252     }
 253
 254     if (pid > 0) {              /* parent */
 255         /* close shared socket with child */
 256         comm_close(crfd);
 257
 258         if (cwfd != crfd)
 259             comm_close(cwfd);
 260
 261         cwfd = crfd = -1;
 262
 263         if (type == IPC_TCP_SOCKET || type == IPC_UDP_SOCKET) {
 264             if (comm_connect_addr(pwfd, ChS) == COMM_ERROR)
 265                 return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 266         }
 267
 268         memset(hello_buf, '\0', HELLO_BUF_SZ);
 269
 270         if (type == IPC_UDP_SOCKET)
 271             x = comm_udp_recv(prfd, hello_buf, HELLO_BUF_SZ - 1, 0);
 272         else
 273             x = read(prfd, hello_buf, HELLO_BUF_SZ - 1);
 274
 275         if (x < 0) {
 276             debugs(54, DBG_CRITICAL, "ipcCreate: PARENT: hello read test failed");
 277             debugs(54, DBG_CRITICAL, "--> read: " << xstrerror());
 278             return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 279         } else if (strcmp(hello_buf, hello_string)) {
 280             debugs(54, DBG_CRITICAL, "ipcCreate: PARENT: hello read test failed");
 281             debugs(54, DBG_CRITICAL, "--> read returned " << x);
 282             debugs(54, DBG_CRITICAL, "--> got '" << rfc1738_escape(hello_buf) << "'");
 283             return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 284         }
 285
 286         commUnsetFdTimeout(prfd);
 287         commSetNonBlocking(prfd);
 288         commSetNonBlocking(pwfd);
 289
 290         if (rfd)
 291             *rfd = prfd;
 292
 293         if (wfd)
 294             *wfd = pwfd;
 295
 296         fd_table[prfd].flags.ipc = 1;
 297
 298         fd_table[pwfd].flags.ipc = 1;
 299
 300         if (Config.sleep_after_fork) {
 301             /* XXX emulation of usleep() */
 302
 303             struct timeval sl;
 304             sl.tv_sec = Config.sleep_after_fork / 1000000;
 305             sl.tv_usec = Config.sleep_after_fork % 1000000;
 306             select(0, NULL, NULL, NULL, &sl);
 307         }
 308
 309         return pid;
 310     }
 311
 312     /* child */
 313     no_suid();                  /* give up extra priviliges */
 314
 315     /* close shared socket with parent */
 316     close(prfd);
 317
 318     if (pwfd != prfd)
 319         close(pwfd);
 320
 321     pwfd = prfd = -1;
 322
 323     if (type == IPC_TCP_SOCKET) {
 324         debugs(54, 3, "ipcCreate: calling accept on FD " << crfd);
 325
 326         if ((fd = accept(crfd, NULL, NULL)) < 0) {
 327             debugs(54, DBG_CRITICAL, "ipcCreate: FD " << crfd << " accept: " << xstrerror());
 328             _exit(1);
 329         }
 330
 331         debugs(54, 3, "ipcCreate: CHILD accepted new FD " << fd);
 332         close(crfd);
 333         cwfd = crfd = fd;
 334     } else if (type == IPC_UDP_SOCKET) {
 335         if (comm_connect_addr(crfd, PaS) == COMM_ERROR)
 336             return ipcCloseAllFD(prfd, pwfd, crfd, cwfd);
 337     }
 338
 339     if (type == IPC_UDP_SOCKET) {
 340         x = comm_udp_send(cwfd, hello_string, strlen(hello_string) + 1, 0);
 341
 342         if (x < 0) {
 343             debugs(54, DBG_CRITICAL, "sendto FD " << cwfd << ": " << xstrerror());
 344             debugs(54, DBG_CRITICAL, "ipcCreate: CHILD: hello write test failed");
 345             _exit(1);
 346         }
 347     } else {
 348         if (write(cwfd, hello_string, strlen(hello_string) + 1) < 0) {
 349             debugs(54, DBG_CRITICAL, "write FD " << cwfd << ": " << xstrerror());
 350             debugs(54, DBG_CRITICAL, "ipcCreate: CHILD: hello write test failed");
 351             _exit(1);
 352         }
 353     }
 354
 355     PutEnvironment();
 356     /*
 357      * This double-dup stuff avoids problems when one of
 358      *  crfd, cwfd, or debug_log are in the rage 0-2.
 359      */
 360
 361     do {
 362         /* First make sure 0-2 is occupied by something. Gets cleaned up later */
 363         x = dup(crfd);
 364         assert(x > -1);
 365     } while (x < 3 && x > -1);
 366
 367     close(x);
 368
 369     t1 = dup(crfd);
 370
 371     t2 = dup(cwfd);
 372
 373     t3 = dup(fileno(debug_log));
 374
 375     assert(t1 > 2 && t2 > 2 && t3 > 2);
 376
 377     close(crfd);
 378
 379     close(cwfd);
 380
 381     close(fileno(debug_log));
 382
 383     dup2(t1, 0);
 384
 385     dup2(t2, 1);
 386
 387     dup2(t3, 2);
 388
 389     close(t1);
 390
 391     close(t2);
 392
 393     close(t3);
 394
 395     /* Make sure all other filedescriptors are closed */
 396     for (x = 3; x < SQUID_MAXFD; ++x)
 397         close(x);
 398
 399 #if HAVE_SETSID
 400     if (opt_no_daemon)
 401         setsid();
 402 #endif
 403
 404     execvp(prog, (char *const *) args);
 405
 406     debug_log = fdopen(2, "a+");
 407
 408     debugs(54, DBG_CRITICAL, "ipcCreate: " << prog << ": " << xstrerror());
 409
 410     _exit(1);
 411
 412     return 0;
 413 }