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[binutils.git] / libiberty / pex-unix.c
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1 /* Utilities to execute a program in a subprocess (possibly linked by pipes
2 with other subprocesses), and wait for it. Generic Unix version
3 (also used for UWIN and VMS).
4 Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003
5 Free Software Foundation, Inc.
7 This file is part of the libiberty library.
8 Libiberty is free software; you can redistribute it and/or
9 modify it under the terms of the GNU Library General Public
10 License as published by the Free Software Foundation; either
11 version 2 of the License, or (at your option) any later version.
13 Libiberty is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Library General Public License for more details.
18 You should have received a copy of the GNU Library General Public
19 License along with libiberty; see the file COPYING.LIB. If not,
20 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
23 #include "pex-common.h"
25 #include <stdio.h>
26 #include <errno.h>
27 #ifdef NEED_DECLARATION_ERRNO
28 extern int errno;
29 #endif
30 #ifdef HAVE_STRING_H
31 #include <string.h>
32 #endif
33 #ifdef HAVE_UNISTD_H
34 #include <unistd.h>
35 #endif
36 #ifdef HAVE_STDLIB_H
37 #include <stdlib.h>
38 #endif
39 #ifdef HAVE_SYS_WAIT_H
40 #include <sys/wait.h>
41 #endif
43 #ifndef HAVE_WAITPID
44 #define waitpid(pid, status, flags) wait(status)
45 #endif
47 extern int execv ();
48 extern int execvp ();
50 int
51 pexecute (program, argv, this_pname, temp_base, errmsg_fmt, errmsg_arg, flags)
52 const char *program;
53 char * const *argv;
54 const char *this_pname;
55 const char *temp_base ATTRIBUTE_UNUSED;
56 char **errmsg_fmt, **errmsg_arg;
57 int flags;
59 int (*func)() = (flags & PEXECUTE_SEARCH ? execvp : execv);
60 int pid;
61 int pdes[2];
62 int input_desc, output_desc;
63 int retries, sleep_interval;
64 /* Pipe waiting from last process, to be used as input for the next one.
65 Value is STDIN_FILE_NO if no pipe is waiting
66 (i.e. the next command is the first of a group). */
67 static int last_pipe_input;
69 /* If this is the first process, initialize. */
70 if (flags & PEXECUTE_FIRST)
71 last_pipe_input = STDIN_FILE_NO;
73 input_desc = last_pipe_input;
75 /* If this isn't the last process, make a pipe for its output,
76 and record it as waiting to be the input to the next process. */
77 if (! (flags & PEXECUTE_LAST))
79 if (pipe (pdes) < 0)
81 *errmsg_fmt = "pipe";
82 *errmsg_arg = NULL;
83 return -1;
85 output_desc = pdes[WRITE_PORT];
86 last_pipe_input = pdes[READ_PORT];
88 else
90 /* Last process. */
91 output_desc = STDOUT_FILE_NO;
92 last_pipe_input = STDIN_FILE_NO;
95 /* Fork a subprocess; wait and retry if it fails. */
96 sleep_interval = 1;
97 pid = -1;
98 for (retries = 0; retries < 4; retries++)
100 pid = fork ();
101 if (pid >= 0)
102 break;
103 sleep (sleep_interval);
104 sleep_interval *= 2;
107 switch (pid)
109 case -1:
110 *errmsg_fmt = "fork";
111 *errmsg_arg = NULL;
112 return -1;
114 case 0: /* child */
115 /* Move the input and output pipes into place, if necessary. */
116 if (input_desc != STDIN_FILE_NO)
118 close (STDIN_FILE_NO);
119 dup (input_desc);
120 close (input_desc);
122 if (output_desc != STDOUT_FILE_NO)
124 close (STDOUT_FILE_NO);
125 dup (output_desc);
126 close (output_desc);
129 /* Close the parent's descs that aren't wanted here. */
130 if (last_pipe_input != STDIN_FILE_NO)
131 close (last_pipe_input);
133 /* Exec the program. */
134 (*func) (program, argv);
136 fprintf (stderr, "%s: ", this_pname);
137 fprintf (stderr, install_error_msg, program);
138 fprintf (stderr, ": %s\n", xstrerror (errno));
139 exit (-1);
140 /* NOTREACHED */
141 return 0;
143 default:
144 /* In the parent, after forking.
145 Close the descriptors that we made for this child. */
146 if (input_desc != STDIN_FILE_NO)
147 close (input_desc);
148 if (output_desc != STDOUT_FILE_NO)
149 close (output_desc);
151 /* Return child's process number. */
152 return pid;
157 pwait (pid, status, flags)
158 int pid;
159 int *status;
160 int flags ATTRIBUTE_UNUSED;
162 /* ??? Here's an opportunity to canonicalize the values in STATUS.
163 Needed? */
164 pid = waitpid (pid, status, 0);
165 return pid;