usr.bin/make/proc.c

   1 /*-
   2  * Copyright (C) 2005 Max Okumoto.
   3  *      All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $DragonFly: src/usr.bin/make/proc.c,v 1.6 2005/07/19 18:14:15 okumoto Exp $
  27  */
  28
  29 #include <unistd.h>
  30 #include <errno.h>
  31 #include <string.h>
  32 #include <fcntl.h>
  33 #include <stdlib.h>
  34
  35 #include "proc.h"
  36 #include "shell.h"
  37 #include "util.h"
  38
  39 /**
  40  * Replace the current process.
  41  */
  42 void
  43 Proc_Exec(const ProcStuff *ps, struct Shell *shell)
  44 {
  45
  46         if (ps->in != STDIN_FILENO) {
  47                 /*
  48                  * Redirect the child's stdin to the input fd
  49                  * and reset it to the beginning (again).
  50                  */
  51                 if (dup2(ps->in, STDIN_FILENO) == -1)
  52                         Punt("Cannot dup2: %s", strerror(errno));
  53                 lseek(STDIN_FILENO, (off_t)0, SEEK_SET);
  54         }
  55
  56         if (ps->out != STDOUT_FILENO) {
  57                 /*
  58                  * Redirect the child's stdout to the output fd.
  59                  */
  60                 if (dup2(ps->out, STDOUT_FILENO) == -1)
  61                         Punt("Cannot dup2: %s", strerror(errno));
  62                 close(ps->out);
  63         }
  64
  65         if (ps->err != STDERR_FILENO) {
  66                 /*
  67                  * Redirect the child's stderr to the err fd.
  68                  */
  69                 if (dup2(ps->err, STDERR_FILENO) == -1)
  70                         Punt("Cannot dup2: %s", strerror(errno));
  71                 close(ps->err);
  72         }
  73
  74         if (ps->merge_errors) {
  75                 /*
  76                  * Send stderr to parent process too.
  77                  */
  78                 if (dup2(STDOUT_FILENO, STDERR_FILENO) == -1)
  79                         Punt("Cannot dup2: %s", strerror(errno));
  80         }
  81
  82         if (shell->unsetenv) {
  83                 /* for the benfit of ksh */
  84                 unsetenv("ENV");
  85         }
  86
  87         /*
  88          * The file descriptors for stdin, stdout, or stderr might
  89          * have been marked close-on-exec.  Clear the flag on all
  90          * of them.
  91          */
  92         fcntl(STDIN_FILENO, F_SETFD,
  93             fcntl(STDIN_FILENO, F_GETFD) & (~FD_CLOEXEC));
  94         fcntl(STDOUT_FILENO, F_SETFD,
  95             fcntl(STDOUT_FILENO, F_GETFD) & (~FD_CLOEXEC));
  96         fcntl(STDERR_FILENO, F_SETFD,
  97             fcntl(STDERR_FILENO, F_GETFD) & (~FD_CLOEXEC));
  98
  99         if (ps->pgroup) {
 100 #if defined(USE_PGRP)
 101                 /*
 102                  * Become a process group leader, so we can kill it and all
 103                  * its descendants in one fell swoop, by killing its process
 104                  * family, but not commit suicide.
 105                  */
 106 #if defined(SYSV)
 107                 setsid();
 108 #else
 109                 setpgid(0, getpid());
 110 #endif
 111 #endif /* USE_PGRP */
 112         }
 113
 114         if (ps->searchpath) {
 115                 execvp(ps->argv[0], ps->argv);
 116
 117                 write(STDERR_FILENO, ps->argv[0], strlen(ps->argv[0]));
 118                 write(STDERR_FILENO, ":", 1);
 119                 write(STDERR_FILENO, strerror(errno), strlen(strerror(errno)));
 120                 write(STDERR_FILENO, "\n", 1);
 121         } else {
 122                 execv(shell->path, ps->argv);
 123
 124                 write(STDERR_FILENO,
 125                     "Could not execute shell\n",
 126                     sizeof("Could not execute shell"));
 127         }
 128
 129         /*
 130          * Since we are the child process, exit without flushing buffers.
 131          */
 132         _exit(1);
 133 }