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5a17353c DD |
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. | |
6 | ||
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. | |
12 | ||
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. | |
17 | ||
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. */ | |
22 | ||
23 | #include "pex-common.h" | |
24 | ||
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 | |
42 | ||
43 | #ifndef HAVE_WAITPID | |
44 | #define waitpid(pid, status, flags) wait(status) | |
45 | #endif | |
46 | ||
47 | extern int execv (); | |
48 | extern int execvp (); | |
49 | ||
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; | |
58 | { | |
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; | |
68 | ||
69 | /* If this is the first process, initialize. */ | |
70 | if (flags & PEXECUTE_FIRST) | |
71 | last_pipe_input = STDIN_FILE_NO; | |
72 | ||
73 | input_desc = last_pipe_input; | |
74 | ||
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)) | |
78 | { | |
79 | if (pipe (pdes) < 0) | |
80 | { | |
81 | *errmsg_fmt = "pipe"; | |
82 | *errmsg_arg = NULL; | |
83 | return -1; | |
84 | } | |
85 | output_desc = pdes[WRITE_PORT]; | |
86 | last_pipe_input = pdes[READ_PORT]; | |
87 | } | |
88 | else | |
89 | { | |
90 | /* Last process. */ | |
91 | output_desc = STDOUT_FILE_NO; | |
92 | last_pipe_input = STDIN_FILE_NO; | |
93 | } | |
94 | ||
95 | /* Fork a subprocess; wait and retry if it fails. */ | |
96 | sleep_interval = 1; | |
97 | pid = -1; | |
98 | for (retries = 0; retries < 4; retries++) | |
99 | { | |
100 | pid = fork (); | |
101 | if (pid >= 0) | |
102 | break; | |
103 | sleep (sleep_interval); | |
104 | sleep_interval *= 2; | |
105 | } | |
106 | ||
107 | switch (pid) | |
108 | { | |
109 | case -1: | |
110 | *errmsg_fmt = "fork"; | |
111 | *errmsg_arg = NULL; | |
112 | return -1; | |
113 | ||
114 | case 0: /* child */ | |
115 | /* Move the input and output pipes into place, if necessary. */ | |
116 | if (input_desc != STDIN_FILE_NO) | |
117 | { | |
118 | close (STDIN_FILE_NO); | |
119 | dup (input_desc); | |
120 | close (input_desc); | |
121 | } | |
122 | if (output_desc != STDOUT_FILE_NO) | |
123 | { | |
124 | close (STDOUT_FILE_NO); | |
125 | dup (output_desc); | |
126 | close (output_desc); | |
127 | } | |
128 | ||
129 | /* Close the parent's descs that aren't wanted here. */ | |
130 | if (last_pipe_input != STDIN_FILE_NO) | |
131 | close (last_pipe_input); | |
132 | ||
133 | /* Exec the program. */ | |
134 | (*func) (program, argv); | |
135 | ||
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; | |
142 | ||
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); | |
150 | ||
151 | /* Return child's process number. */ | |
152 | return pid; | |
153 | } | |
154 | } | |
155 | ||
156 | int | |
157 | pwait (pid, status, flags) | |
158 | int pid; | |
159 | int *status; | |
160 | int flags ATTRIBUTE_UNUSED; | |
161 | { | |
162 | /* ??? Here's an opportunity to canonicalize the values in STATUS. | |
163 | Needed? */ | |
164 | pid = waitpid (pid, status, 0); | |
165 | return pid; | |
166 | } |