1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * Utility functions for buffering output to stdout, stderr while
31  * process is grabbed.  Prevents infamous deadlocks due to pfiles `pgrep xterm`
32  * and other varients.
33  */
34 
35 #include "libproc.h"
36 #include <stdio.h>
37 
38 static int cached_stdout_fd = -1;
39 static int cached_stderr_fd = -1;
40 static int initialized = 0;
41 
42 static char stdout_name[] = "/tmp/.stdoutXXXXXX";
43 static char stderr_name[] = "/tmp/.stderrXXXXXX";
44 
45 int
proc_initstdio(void)46 proc_initstdio(void)
47 {
48 	int fd;
49 
50 	(void) fflush(stdout);
51 	(void) fflush(stderr);
52 
53 	if ((cached_stdout_fd = dup(1)) < 0) {
54 		return (-1);
55 	}
56 
57 	if ((cached_stderr_fd = dup(2)) < 0) {
58 		(void) close(cached_stdout_fd);
59 		return (-1);
60 	}
61 
62 	if ((fd = mkstemp(stdout_name)) < 0) {
63 		(void) close(cached_stdout_fd);
64 		(void) close(cached_stderr_fd);
65 		return (-1);
66 	}
67 
68 	(void) unlink(stdout_name);
69 
70 	if (dup2(fd, 1) < 0) {
71 		(void) close(fd);
72 		(void) close(cached_stdout_fd);
73 		(void) close(cached_stderr_fd);
74 		return (-1);
75 	}
76 
77 	(void) close(fd);
78 
79 
80 	if ((fd = mkstemp(stderr_name)) < 0) {
81 		(void) dup2(cached_stdout_fd, 1);
82 		(void) close(cached_stdout_fd);
83 		(void) close(cached_stderr_fd);
84 		return (-1);
85 	}
86 
87 	(void) unlink(stderr_name);
88 
89 	if (dup2(fd, 2) < 0) {
90 		(void) close(fd);
91 		(void) dup2(cached_stdout_fd, 1);
92 		(void) close(cached_stdout_fd);
93 		(void) dup2(cached_stderr_fd, 2);
94 		(void) close(cached_stderr_fd);
95 		(void) close(fd);
96 		return (-1);
97 	}
98 
99 	(void) close(fd);
100 
101 	initialized = 1;
102 
103 	return (0);
104 }
105 
106 static int
copy_fd(int out,FILE * in,size_t len)107 copy_fd(int out, FILE *in, size_t len)
108 {
109 	char buffer[8192];
110 	int rlen, alen;
111 	int errors = 0;
112 
113 	rewind(in);
114 	while (len > 0 && !errors) {
115 		rlen = (len > sizeof (buffer)) ? sizeof (buffer) : len;
116 		alen = read(fileno(in), buffer, rlen);
117 		if (alen == rlen) {
118 			if (write(out, buffer, alen) < alen)
119 				errors++;
120 			else
121 				len -= alen;
122 		}
123 		else
124 			errors++;
125 	}
126 	rewind(in);
127 	return (errors);
128 }
129 
130 int
proc_flushstdio(void)131 proc_flushstdio(void)
132 {
133 	size_t len;
134 	int errors = 0;
135 
136 	/*
137 	 * flush any pending IO
138 	 */
139 
140 	if (!initialized)
141 		return (-1);
142 
143 	(void) fflush(stdout);
144 	(void) fflush(stderr);
145 
146 	if ((len = ftell(stdout)) > 0)
147 		errors += copy_fd(cached_stdout_fd, stdout, len);
148 
149 
150 	if ((len = ftell(stderr)) > 0)
151 		errors += copy_fd(cached_stderr_fd, stderr, len);
152 
153 	return (errors?-1:0);
154 }
155 
156 int
proc_finistdio(void)157 proc_finistdio(void)
158 {
159 	if (!initialized)
160 		return (-1);
161 
162 	if (proc_flushstdio() != 0)
163 		return (-1);
164 
165 	(void) dup2(cached_stdout_fd, 1);
166 	(void) close(cached_stdout_fd);
167 	(void) dup2(cached_stderr_fd, 2);
168 	(void) close(cached_stderr_fd);
169 
170 	return (0);
171 }
172