exec.c revision 58454 
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 58454 2000-03-22 03:01:53Z 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_FORCE_ASYNC);
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];
104
105    p->fd--;	/* We own the device but maybe can't use it - change fd */
106
107    if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, fids) < 0)
108      log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n",
109	         strerror(errno));
110    else {
111      static int child_status;
112      int stat, argc, i, ret, wret;
113      pid_t pid, realpid;
114      char *argv[MAXARGS];
115
116      stat = fcntl(fids[0], F_GETFL, 0);
117      if (stat > 0) {
118        stat |= O_NONBLOCK;
119        fcntl(fids[0], F_SETFL, stat);
120      }
121      realpid = getpid();
122      switch ((pid = fork())) {
123        case -1:
124          log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n",
125	             strerror(errno));
126          close(fids[1]);
127          break;
128
129        case  0:
130          close(fids[0]);
131          timer_TermService();
132          setuid(ID0realuid());
133
134          child_status = 0;
135          switch (vfork()) {
136            case 0:
137              break;
138
139            case -1:
140              ret = errno;
141              log_Printf(LogPHASE, "Unable to fork to drop parent: %s\n",
142	                 strerror(errno));
143              _exit(ret);
144              break;
145
146            default:
147              _exit(child_status);	/* The error from exec() ! */
148          }
149
150          log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base);
151
152          if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv),
153                               PARSE_REDUCE|PARSE_NOHASH)) < 0) {
154            log_Printf(LogWARN, "Syntax error in exec command\n");
155            _exit(ESRCH);
156          }
157
158          command_Expand(argv, argc, (char const *const *)argv,
159                         p->dl->bundle, 0, realpid);
160
161          dup2(fids[1], STDIN_FILENO);
162          dup2(fids[1], STDOUT_FILENO);
163          dup2(fids[1], STDERR_FILENO);
164          for (i = getdtablesize(); i > STDERR_FILENO; i--)
165            fcntl(i, F_SETFD, 1);
166
167          execvp(*argv, argv);
168          child_status = errno;		/* Only works for vfork() */
169          printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status));
170          _exit(child_status);
171          break;
172
173        default:
174          close(fids[1]);
175          while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR)
176            ;
177          if (wret == -1) {
178            log_Printf(LogWARN, "Waiting for child process: %s\n",
179                       strerror(errno));
180            close(fids[0]);
181            break;
182          } else if (WIFSIGNALED(stat)) {
183            log_Printf(LogWARN, "Child process received sig %d !\n",
184                       WTERMSIG(stat));
185            close(fids[0]);
186            break;
187          } else if (WIFSTOPPED(stat)) {
188            log_Printf(LogWARN, "Child process received stop sig %d !\n",
189                       WSTOPSIG(stat));
190            /* I guess that's ok.... */
191          } else if ((ret = WEXITSTATUS(stat))) {
192            log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base,
193                       strerror(ret));
194            close(fids[0]);
195            break;
196          }
197          p->fd = fids[0];
198          log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd);
199          physical_SetupStack(p, execdevice.name, PHYSICAL_FORCE_ASYNC);
200          if (p->cfg.cd.necessity != CD_DEFAULT)
201            log_Printf(LogWARN, "Carrier settings ignored\n");
202          return &execdevice;
203      }
204      close(fids[0]);
205    }
206  }
207
208  return NULL;
209}
210