source: trunk/third/transcript/src/milan/system.c @ 9090

Revision 9090, 1.1 KB checked in by ghudson, 28 years ago (diff)
This commit was generated by cvs2svn to compensate for changes in r9089, which included commits to RCS files with non-trunk default branches.
Line 
1/* Copyright Milan Technology, 1991 1992 */
2/* @(#)system.c 2.0 10/9/92 */
3
4#include <signal.h>
5#include "dp.h"
6#include "errors.h"
7
8#ifdef BSD
9#include <sys/wait.h>
10#endif
11
12
13#ifdef BSD
14void sig_child()
15{
16   int pid;
17   union wait status;
18   while ((pid = wait3(&status,WNOHANG,(struct rusage*)0))>0);
19}
20#endif
21
22/* Makes a pipe, forks, makes the stdin in child come from
23 * the read end of the pipe.  Returns the write end of the
24 * pipe to the parent.
25 */
26
27#ifdef ANSI
28int initPipes(char *cmd)
29#else
30int initPipes(cmd)
31char* cmd;
32#endif
33{
34   int pipe_fd[2], pid;
35
36   if (pipe(pipe_fd) < 0)
37      error_protect(ERR_PIPE);
38   if ((pid = fork()) < 0)
39      error_protect(ERR_FORK);
40   else if (pid > 0) {
41      /* parent */
42      close(pipe_fd[readEnd]);
43      return(pipe_fd[writeEnd]);
44   }
45   else {
46      /* child */
47      /* make childs stdin come from read end of pipe */
48      if (pipe_fd[readEnd] != STDIN_FILENO) {
49         dup2(pipe_fd[readEnd], STDIN_FILENO);
50         close(pipe_fd[readEnd]);
51      }
52      close(pipe_fd[writeEnd]);
53      execl("/bin/sh", "sh", "-c", cmd, (char*)0);
54   }   
55}
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