exec/exec_fork_pipe.c

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00001 // Copyright 2006 Benedikt Böhm <hollow@gentoo.org>
00002 //
00003 // This program is free software; you can redistribute it and/or modify
00004 // it under the terms of the GNU General Public License as published by
00005 // the Free Software Foundation; either version 2 of the License, or
00006 // (at your option) any later version.
00007 //
00008 // This program is distributed in the hope that it will be useful,
00009 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00010 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00011 // GNU General Public License for more details.
00012 //
00013 // You should have received a copy of the GNU General Public License
00014 // along with this program; if not, write to the
00015 // Free Software Foundation, Inc.,
00016 // 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
00017 
00018 #include <unistd.h>
00019 #include <stdlib.h>
00020 #include <stdarg.h>
00021 #include <errno.h>
00022 #include <sys/wait.h>
00023 
00024 #include "argv.h"
00025 #include "exec.h"
00026 #include "io.h"
00027 #include "printf.h"
00028 
00029 int exec_fork_pipe(char **out, const char *fmt, ...)
00030 {
00031         va_list ap;
00032         va_start(ap, fmt);
00033         
00034         char *cmd;
00035         _lucid_vasprintf(&cmd, fmt, ap);
00036         
00037         va_end(ap);
00038         
00039         int argc;
00040         char *argv[EXEC_MAX_ARGV];
00041         
00042         argc = argv_from_str(cmd, argv, EXEC_MAX_ARGV);
00043         
00044         if (argc < 1) {
00045                 free(cmd);
00046                 return errno = EINVAL, -1;
00047         }
00048         
00049         int outfds[2];
00050         
00051         if (pipe(outfds) == -1)
00052                 return -1;
00053         
00054         pid_t pid;
00055         int status;
00056         
00057         switch ((pid = fork())) {
00058         case -1:
00059                 free(cmd);
00060                 return -1;
00061         
00062         case 0:
00063                 usleep(200);
00064                 
00065                 close(outfds[0]);
00066                 
00067                 dup2(outfds[1], STDOUT_FILENO);
00068                 dup2(outfds[1], STDERR_FILENO);
00069                 
00070                 execvp(argv[0], argv);
00071                 
00072                 /* never get here */
00073                 exit(errno);
00074         
00075         default:
00076                 free(cmd);
00077                 
00078                 close(outfds[1]);
00079                 
00080                 if (out && io_read_eof(outfds[0], out) == -1)
00081                         return -1;
00082                 
00083                 close(outfds[0]);
00084                 
00085                 if (waitpid(pid, &status, 0) == -1)
00086                         return -1;
00087         }
00088         
00089         return status;
00090 }

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