exec.c revision 61973 
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: head/usr.sbin/ppp/exec.c 61973 2000-06-22 20:51:03Z brian $
27 */
28
29#include <sys/param.h>
30#include <sys/socket.h>
31#include <sys/un.h>
32
33#include <errno.h>
34#include <fcntl.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38#include <sys/wait.h>
39#include <sys/uio.h>
40#include <termios.h>
41#include <unistd.h>
42
43#include "layer.h"
44#include "defs.h"
45#include "mbuf.h"
46#include "log.h"
47#include "timer.h"
48#include "lqr.h"
49#include "hdlc.h"
50#include "throughput.h"
51#include "fsm.h"
52#include "lcp.h"
53#include "ccp.h"
54#include "link.h"
55#include "async.h"
56#include "descriptor.h"
57#include "physical.h"
58#include "mp.h"
59#include "chat.h"
60#include "command.h"
61#include "auth.h"
62#include "chap.h"
63#include "cbcp.h"
64#include "datalink.h"
65#include "id.h"
66#include "exec.h"
67
68static struct device execdevice = {
69  EXEC_DEVICE,
70  "exec",
71  { CD_NOTREQUIRED, 0 },
72  NULL,
73  NULL,
74  NULL,
75  NULL,
76  NULL,
77  NULL,
78  NULL,
79  NULL,
80  NULL,
81  NULL,
82  NULL,
83  NULL
84};
85
86struct device *
87exec_iov2device(int type, struct physical *p, struct iovec *iov,
88                int *niov, int maxiov, int *auxfd, int *nauxfd)
89{
90  if (type == EXEC_DEVICE) {
91    free(iov[(*niov)++].iov_base);
92    physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE);
93    return &execdevice;
94  }
95
96  return NULL;
97}
98
99struct device *
100exec_Create(struct physical *p)
101{
102  if (p->fd < 0 && *p->name.full == '!') {
103    int fids[2], type;
104
105    p->fd--;	/* We own the device but maybe can't use it - change fd */
106    type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM;
107
108    if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0)
109      log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n",
110                 strerror(errno));
111    else {
112      static int child_status;		/* This variable is abused ! */
113      int stat, argc, i, ret, wret, pidpipe[2];
114      pid_t pid, realpid;
115      char *argv[MAXARGS];
116
117      stat = fcntl(fids[0], F_GETFL, 0);
118      if (stat > 0) {
119        stat |= O_NONBLOCK;
120        fcntl(fids[0], F_SETFL, stat);
121      }
122      realpid = getpid();
123      if (pipe(pidpipe) == -1) {
124        log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n",
125                   strerror(errno));
126        close(fids[1]);
127      } else switch ((pid = fork())) {
128        case -1:
129          log_Printf(LogPHASE, "Unable to fork for line exec: %s\n",
130                     strerror(errno));
131          close(pidpipe[0]);
132          close(pidpipe[1]);
133          close(fids[1]);
134          break;
135
136        case  0:
137          close(pidpipe[0]);
138          close(fids[0]);
139          timer_TermService();
140          setuid(ID0realuid());
141
142          child_status = 0;
143          switch ((pid = vfork())) {
144            case 0:
145              close(pidpipe[1]);
146              break;
147
148            case -1:
149              ret = errno;
150              log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n",
151                         strerror(errno));
152              close(pidpipe[1]);
153              _exit(ret);
154
155            default:
156              write(pidpipe[1], &pid, sizeof pid);
157              close(pidpipe[1]);
158              _exit(child_status);	/* The error from exec() ! */
159          }
160
161          log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base);
162
163          if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv),
164                               PARSE_REDUCE|PARSE_NOHASH)) < 0) {
165            log_Printf(LogWARN, "Syntax error in exec command\n");
166            _exit(ESRCH);
167          }
168
169          command_Expand(argv, argc, (char const *const *)argv,
170                         p->dl->bundle, 0, realpid);
171
172          dup2(fids[1], STDIN_FILENO);
173          dup2(fids[1], STDOUT_FILENO);
174          dup2(fids[1], STDERR_FILENO);
175          for (i = getdtablesize(); i > STDERR_FILENO; i--)
176            fcntl(i, F_SETFD, 1);
177
178          execvp(*argv, argv);
179          child_status = errno;		/* Only works for vfork() */
180          printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status));
181          _exit(child_status);
182          break;
183
184        default:
185          close(pidpipe[1]);
186          close(fids[1]);
187          if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) !=
188              sizeof p->session_owner)
189            p->session_owner = (pid_t)-1;
190          close(pidpipe[0]);
191          while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR)
192            ;
193          if (wret == -1) {
194            log_Printf(LogWARN, "Waiting for child process: %s\n",
195                       strerror(errno));
196            close(fids[0]);
197            p->session_owner = (pid_t)-1;
198            break;
199          } else if (WIFSIGNALED(stat)) {
200            log_Printf(LogWARN, "Child process received sig %d !\n",
201                       WTERMSIG(stat));
202            close(fids[0]);
203            p->session_owner = (pid_t)-1;
204            break;
205          } else if (WIFSTOPPED(stat)) {
206            log_Printf(LogWARN, "Child process received stop sig %d !\n",
207                       WSTOPSIG(stat));
208            /* I guess that's ok.... */
209          } else if ((ret = WEXITSTATUS(stat))) {
210            log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base,
211                       strerror(ret));
212            close(fids[0]);
213            p->session_owner = (pid_t)-1;
214            break;
215          }
216          p->fd = fids[0];
217          log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd);
218          physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE);
219          if (p->cfg.cd.necessity != CD_DEFAULT)
220            log_Printf(LogWARN, "Carrier settings ignored\n");
221          return &execdevice;
222      }
223      close(fids[0]);
224    }
225  }
226
227  return NULL;
228}
229