usr/src/lib/libproc/common/proc_stdio.c

   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
  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
 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
 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
 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 }