usr.sbin/ppp/exec.c

   1 /*-
   2  * Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/usr.sbin/ppp/exec.c,v 1.18.2.6 2002/09/01 02:12:26 brian Exp $
  27  * $DragonFly: src/usr.sbin/ppp/exec.c,v 1.2 2003/06/17 04:30:00 dillon Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/socket.h>
  32 #include <sys/un.h>
  33
  34 #include <errno.h>
  35 #include <fcntl.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <sys/wait.h>
  40 #include <sys/uio.h>
  41 #include <termios.h>
  42 #include <unistd.h>
  43
  44 #include "layer.h"
  45 #include "defs.h"
  46 #include "mbuf.h"
  47 #include "log.h"
  48 #include "timer.h"
  49 #include "lqr.h"
  50 #include "hdlc.h"
  51 #include "throughput.h"
  52 #include "fsm.h"
  53 #include "lcp.h"
  54 #include "ccp.h"
  55 #include "link.h"
  56 #include "async.h"
  57 #include "descriptor.h"
  58 #include "physical.h"
  59 #include "mp.h"
  60 #include "chat.h"
  61 #include "command.h"
  62 #include "auth.h"
  63 #include "chap.h"
  64 #include "cbcp.h"
  65 #include "datalink.h"
  66 #include "id.h"
  67 #include "exec.h"
  68
  69 static struct device execdevice = {
  70   EXEC_DEVICE,
  71   "exec",
  72   0,
  73   { CD_NOTREQUIRED, 0 },
  74   NULL,
  75   NULL,
  76   NULL,
  77   NULL,
  78   NULL,
  79   NULL,
  80   NULL,
  81   NULL,
  82   NULL,
  83   NULL,
  84   NULL,
  85   NULL,
  86   NULL,
  87   NULL
  88 };
  89
  90 struct device *
  91 exec_iov2device(int type, struct physical *p, struct iovec *iov,
  92                 int *niov, int maxiov __unused, int *auxfd __unused,
  93                 int *nauxfd __unused)
  94 {
  95   if (type == EXEC_DEVICE) {
  96     free(iov[(*niov)++].iov_base);
  97     physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE);
  98     return &execdevice;
  99   }
 100
 101   return NULL;
 102 }
 103
 104 struct device *
 105 exec_Create(struct physical *p)
 106 {
 107   if (p->fd < 0 && *p->name.full == '!') {
 108     int fids[2], type;
 109
 110     p->fd--;    /* We own the device but maybe can't use it - change fd */
 111     type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM;
 112
 113     if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0)
 114       log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n",
 115                  strerror(errno));
 116     else {
 117       static int child_status;          /* This variable is abused ! */
 118       int stat, argc, i, ret, wret, pidpipe[2];
 119       pid_t pid, realpid;
 120       char *argv[MAXARGS];
 121
 122       stat = fcntl(fids[0], F_GETFL, 0);
 123       if (stat > 0) {
 124         stat |= O_NONBLOCK;
 125         fcntl(fids[0], F_SETFL, stat);
 126       }
 127       realpid = getpid();
 128       if (pipe(pidpipe) == -1) {
 129         log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n",
 130                    strerror(errno));
 131         close(fids[1]);
 132       } else switch ((pid = fork())) {
 133         case -1:
 134           log_Printf(LogPHASE, "Unable to fork for line exec: %s\n",
 135                      strerror(errno));
 136           close(pidpipe[0]);
 137           close(pidpipe[1]);
 138           close(fids[1]);
 139           break;
 140
 141         case  0:
 142           close(pidpipe[0]);
 143           close(fids[0]);
 144           timer_TermService();
 145 #ifndef NOSUID
 146           setuid(ID0realuid());
 147 #endif
 148
 149           child_status = 0;
 150           switch ((pid = vfork())) {
 151             case 0:
 152               close(pidpipe[1]);
 153               break;
 154
 155             case -1:
 156               ret = errno;
 157               log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n",
 158                          strerror(errno));
 159               close(pidpipe[1]);
 160               _exit(ret);
 161
 162             default:
 163               write(pidpipe[1], &pid, sizeof pid);
 164               close(pidpipe[1]);
 165               _exit(child_status);      /* The error from exec() ! */
 166           }
 167
 168           log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base);
 169
 170           if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv),
 171                                PARSE_REDUCE|PARSE_NOHASH)) < 0) {
 172             log_Printf(LogWARN, "Syntax error in exec command\n");
 173             _exit(ESRCH);
 174           }
 175
 176           command_Expand(argv, argc, (char const *const *)argv,
 177                          p->dl->bundle, 0, realpid);
 178
 179           dup2(fids[1], STDIN_FILENO);
 180           dup2(fids[1], STDOUT_FILENO);
 181           dup2(fids[1], STDERR_FILENO);
 182           for (i = getdtablesize(); i > STDERR_FILENO; i--)
 183             fcntl(i, F_SETFD, 1);
 184
 185           execvp(*argv, argv);
 186           child_status = errno;         /* Only works for vfork() */
 187           printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status));
 188           _exit(child_status);
 189           break;
 190
 191         default:
 192           close(pidpipe[1]);
 193           close(fids[1]);
 194           if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) !=
 195               sizeof p->session_owner)
 196             p->session_owner = (pid_t)-1;
 197           close(pidpipe[0]);
 198           while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR)
 199             ;
 200           if (wret == -1) {
 201             log_Printf(LogWARN, "Waiting for child process: %s\n",
 202                        strerror(errno));
 203             close(fids[0]);
 204             p->session_owner = (pid_t)-1;
 205             break;
 206           } else if (WIFSIGNALED(stat)) {
 207             log_Printf(LogWARN, "Child process received sig %d !\n",
 208                        WTERMSIG(stat));
 209             close(fids[0]);
 210             p->session_owner = (pid_t)-1;
 211             break;
 212           } else if (WIFSTOPPED(stat)) {
 213             log_Printf(LogWARN, "Child process received stop sig %d !\n",
 214                        WSTOPSIG(stat));
 215             /* I guess that's ok.... */
 216           } else if ((ret = WEXITSTATUS(stat))) {
 217             log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base,
 218                        strerror(ret));
 219             close(fids[0]);
 220             p->session_owner = (pid_t)-1;
 221             break;
 222           }
 223           p->fd = fids[0];
 224           log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd);
 225           physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE);
 226           if (p->cfg.cd.necessity != CD_DEFAULT)
 227             log_Printf(LogWARN, "Carrier settings ignored\n");
 228           return &execdevice;
 229       }
 230       close(fids[0]);
 231     }
 232   }
 233
 234   return NULL;
 235 }