usr.bin/mail/mime_child.c

   1 /*      $NetBSD: mime_child.c,v 1.6 2007/10/29 23:20:38 christos Exp $  */
   2
   3 /*-
   4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Anon Ymous.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32
  33 #ifdef MIME_SUPPORT
  34
  35 #include <sys/cdefs.h>
  36 #ifndef __lint__
  37 __RCSID("$NetBSD: mime_child.c,v 1.6 2007/10/29 23:20:38 christos Exp $");
  38 #endif /* not __lint__ */
  39
  40 #include <assert.h>
  41 #include <fcntl.h>
  42 #include <signal.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <unistd.h>
  46
  47 #include "def.h"
  48 #include "extern.h"
  49
  50 #ifdef MIME_SUPPORT
  51 #include "mime.h"
  52 #include "mime_child.h"
  53 #endif
  54
  55 /*
  56  * This module contains the core routines used by mime modules that
  57  * need to fork children.  Nothing else in the mime modules should be
  58  * doing a pipe(), fork(), or a call to any popen functions that do.
  59  * These routines are tied to the file registry in popen.c and hence
  60  * share much of popen code.
  61  */
  62
  63 #define READ 0
  64 #define WRITE 1
  65
  66 static int
  67 get_cmd_flags(const char *cmd, const char **cmd_start)
  68 {
  69         const char *cp;
  70         int flags;
  71
  72         flags = 0;
  73         for (cp = cmd; cp && *cp; cp++)
  74                 switch (*cp) {
  75                 case '+':
  76                         flags |= CMD_FLAG_ALTERNATIVE;
  77                         break;
  78                 case '-':
  79                         flags |= CMD_FLAG_NO_DECODE;
  80                         break;
  81                 case '!':
  82                         flags |= CMD_FLAG_SHELLCMD;
  83                         break;
  84                 default:
  85                         goto done;
  86                 }
  87  done:
  88         if (cmd_start)
  89                 *cmd_start = cp;
  90
  91         return flags;
  92 }
  93
  94
  95 static int
  96 prepare_pipe(sigset_t *nset, int p[2])
  97 {
  98         if (pipe(p) == -1)
  99                 return -1;
 100
 101         (void)fcntl(p[READ],  F_SETFD, FD_CLOEXEC);
 102         (void)fcntl(p[WRITE], F_SETFD, FD_CLOEXEC);
 103         /*
 104          * We _must_ ignore SIGINT and SIGPIPE or the child
 105          * will end up in our earlier handlers.
 106          */
 107         (void)sigemptyset(nset);
 108         (void)sigaddset(nset, SIGINT);
 109         (void)sigaddset(nset, SIGPIPE);
 110         (void)sigaddset(nset, SIGHUP);
 111         (void)sigaddset(nset, SIGTSTP);
 112         (void)sigaddset(nset, SIGTTOU);
 113         (void)sigaddset(nset, SIGTTIN);
 114
 115         return 0;
 116 }
 117
 118
 119 PUBLIC int
 120 mime_run_command(const char *cmd, FILE *fo)
 121 {
 122         sigset_t nset;
 123         FILE *nfo;
 124         pid_t pid;
 125         int p[2];
 126         int flags;
 127
 128         if (cmd == NULL)
 129                 return 0;
 130
 131         flags = get_cmd_flags(cmd, &cmd);
 132         if (fo == NULL)         /* no output file, just return the flags! */
 133                 return flags;
 134
 135         if ((flags & CMD_FLAG_SHELLCMD) != 0) { /* run command under the shell */
 136                 char *cp;
 137                 char *shellcmd;
 138                 if ((shellcmd = value(ENAME_SHELL)) == NULL)
 139                         shellcmd = __UNCONST(_PATH_CSHELL);
 140                 (void)sasprintf(&cp, "%s -c '%s'", shellcmd, cmd);
 141                 cmd = cp;
 142         }
 143         if (prepare_pipe(&nset, p) != 0) {
 144                 warn("mime_run_command: prepare_pipe");
 145                 return flags;   /* XXX - this or -1? */
 146         }
 147         flush_files(fo, 0); /* flush fo, all registered files, and stdout */
 148
 149         switch (pid = start_command(cmd, &nset, p[READ], fileno(fo), NULL)) {
 150         case -1:        /* error */
 151                 /* start_command already did a warn(). */
 152                 warnx("mime_run_command: %s", cmd); /* tell a bit more */
 153                 (void)close(p[READ]);
 154                 (void)close(p[WRITE]);
 155                 return flags;                   /* XXX - this or -1? */
 156
 157         case 0:         /* child */
 158                 assert(/*CONSTCOND*/ 0);        /* a real coding error! */
 159                 /* NOTREACHED */
 160
 161         default:        /* parent */
 162                 (void)close(p[READ]);
 163
 164                 nfo = fdopen(p[WRITE], "w");
 165                 if (nfo == NULL) {
 166                         warn("mime_run_command: fdopen");
 167                         (void)close(p[WRITE]);
 168                         warn("fdopen");
 169                         return flags;
 170                 }
 171                 register_file(nfo, 1, pid);
 172                 return flags;
 173         }
 174 }
 175
 176
 177 PUBLIC void
 178 mime_run_function(void (*fn)(FILE *, FILE *, void *), FILE *fo, void *cookie)
 179 {
 180         sigset_t nset;
 181         FILE *nfo;
 182         pid_t pid;
 183         int p[2];
 184
 185         if (prepare_pipe(&nset, p) != 0) {
 186                 warn("mime_run_function: pipe");
 187                 return;
 188         }
 189         flush_files(fo, 0); /* flush fo, all registered files, and stdout */
 190
 191         switch (pid = fork()) {
 192         case -1:        /* error */
 193                 warn("mime_run_function: fork");
 194                 (void)close(p[READ]);
 195                 (void)close(p[WRITE]);
 196                 return;
 197
 198         case 0:         /* child */
 199                 (void)close(p[WRITE]);
 200                 prepare_child(&nset, p[READ], fileno(fo));
 201                 fn(stdin, stdout, cookie);
 202                 (void)fflush(stdout);
 203                 _exit(0);
 204                 /* NOTREACHED */
 205
 206         default:        /* parent */
 207                 (void)close(p[READ]);
 208                 nfo = fdopen(p[WRITE], "w");
 209                 if (nfo == NULL) {
 210                         warn("run_function: fdopen");
 211                         (void)close(p[WRITE]);
 212                         return;
 213                 }
 214                 register_file(nfo, 1, pid);
 215                 return;
 216         }
 217 }
 218
 219 #endif /* MIME_SUPPORT */