summaryrefslogtreecommitdiff
path: root/mit-pthreads/pthreads/process.c
blob: 9b3abb3384bdc57d1030b64729b1055815e117ea (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
/* ==== process.c ============================================================
 * Copyright (c) 1994 by Chris Provenzano, proven@mit.edu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by Chris Provenzano.
 * 4. The name of Chris Provenzano may not be used to endorse or promote 
 *	  products derived from this software without specific prior written
 *	  permission.
 *
 * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL CHRIS PROVENZANO BE LIABLE FOR ANY 
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE.
 *
 * Description : Process functions (fork, exec, ...).
 *
 *  1.23 94/04/18 proven
 *      -Started coding this file.
 */

#include <pthread.h>
#include <sys/types.h>
#include <pthread.h>
#include <stdarg.h>
#include <unistd.h>
#ifdef HAVE_ALLOC_H
#include <alloc.h>
#endif

extern void *alloca();

#ifndef lint
static const char rcsid[] = "$Id$";
#endif

/* ==========================================================================
 * fork()
 *
 * This function requires a sig_prevent()/sig_check_and_resume() for the
 * parent. The child never unlocks.
 */
pid_t fork()
{
	pid_t ret;

	pthread_sched_prevent();

	fd_kern_fork();
	if (ret = machdep_sys_fork()) { /* Parent or error */
		pthread_sched_resume();
	} else { /* Child */
		machdep_unset_thread_timer(NULL);
		machdep_stop_timer(NULL);
		fork_lock++;
                pthread_kernel_lock--;
	}
	return(ret);
}

#ifdef HAVE_VFORK
/* The semantics of vfork probably won't mix well with the pthread
   library code.  Don't even try.  */
pid_t vfork ()
{
	return fork ();
}
#endif

/* ==========================================================================
 * execve()
 *
 * This function requires a sig_prevent()/sig_check_and_resume() if one
 * hasn't been done in the fork routine. Normally machdep_sys_execve()
 * should never return.
 */
int execve(const char *name, char * const *argv, char * const *envp) 
{
	int ret;

	if (!fork_lock) {
		pthread_sched_prevent();
		fd_kern_exec(0);
		ret = machdep_sys_execve(name, argv, envp);
		pthread_sched_resume();
	} else {
		fd_kern_exec(1);
		ret = machdep_sys_execve(name, argv, envp);
	}
	return(ret);
}

/* Variants of execve.  Define them here so that the system versions
   don't get used and drag in the system version of execve.  */
#include <sys/stat.h>
#include <string.h>
#include <sys/param.h>
extern char **environ;

static const char *find (const char *name, char *buf)
{
	char *p1, *p2;
	extern char *getenv ();
	struct stat sb;

	if (strchr (name, '/'))
		return name;
	p1 = getenv ("PATH");
	if (p1 == 0)
		p1 = "/bin:/usr/bin:";
	while (*p1) {
		memset (buf, 0, MAXPATHLEN);
		p2 = strchr (p1, ':');
		if (p2 == 0)
			p2 = p1 + strlen (p1);
		strncpy (buf, p1, p2 - p1);
		buf[p2 - p1] = 0;
		strcat (buf, "/");
		strcat (buf, name);
		if (lstat (buf, &sb) == 0)
			return buf;

		if (*p2 == ':')
			p2++;
		p1 = p2;
	}
	return name;
}

int execl (const char *path, const char *arg, ...)
{
#ifdef SCO_3_5
  return execve (path, (char *const *) &arg, environ);
#else
  char ** argv;
  va_list ap;
  int i;

  va_start(ap, arg);
  for (i = 1; va_arg(ap, char *) != NULL; i++);
  va_end(ap);

  argv = alloca (i * sizeof (char *));

  va_start(ap, arg);
  argv[0] = (char *) arg;
  for (i = 1; (argv[i] = (char *) va_arg(ap, char *)) != NULL; i++);
  va_end(ap);

  return execve (path, argv, environ);
#endif
}

int execlp (const char *name, const char *arg, ...)
{
#ifdef SCO_3_5
  char buf[MAXPATHLEN];
  return execve (find (name, buf), (char *const *) &arg, environ);
#else
  char buf[MAXPATHLEN];
  char ** argv;
  va_list ap;
  int i;
 
  va_start(ap, arg);
  for (i = 1; va_arg(ap, char *) != NULL; i++);
  va_end(ap);
 
  argv = alloca (i * sizeof (char *));

  va_start(ap, arg);
  argv[0] = (char *) arg;
  for (i = 1; (argv[i] = (char *) va_arg(ap, char *)) != NULL; i++);
  va_end(ap);

  return execve (find (name, buf), argv, environ);
#endif
}

int execle (const char *name, const char *arg, ... /* , char *const envp[] */);

/* This one turns on ptrace-style tracing?  */
int exect (const char *path, char *const argv[], char *const envp[]);

int execv (const char *path, char *const argv[]) {
	return execve (path, argv, environ);
}

int execvp (const char *name, char *const argv[]) {
	char buf[MAXPATHLEN];
	return execve (find (name, buf), argv, environ);
}