src/common/unix_process.c

#ifndef lint
static const char       RCSid[] = "$Id: unix_process.c,v 3.3 2003/11/10 16:41:52 greg Exp $";
#endif
/*
 * Routines to communicate with separate process via dual pipes
 * Unix version
 *
 * External symbols declared in standard.h
 */

#include "copyright.h"

#include <sys/types.h>
#include <sys/wait.h>

#include "rtprocess.h"


int
open_process(           /* open communication to separate process */
SUBPROC *pd,
char    *av[]
)
{
        extern char     *getpath(), *getenv();
        char    *compath;
        int     p0[2], p1[2];

        pd->running = 0; /* not yet */
                                        /* find executable */
        compath = getpath(av[0], getenv("PATH"), 1);
        if (compath == 0)
                return(0);
        if (pipe(p0) < 0 || pipe(p1) < 0)
                return(-1);
        if ((pd->pid = fork()) == 0) {          /* if child */
                close(p0[1]);
                close(p1[0]);
                if (p0[0] != 0) {       /* connect p0 to stdin */
                        dup2(p0[0], 0);
                        close(p0[0]);
                }
                if (p1[1] != 1) {       /* connect p1 to stdout */
                        dup2(p1[1], 1);
                        close(p1[1]);
                }
                execv(compath, av);     /* exec command */
                perror(compath);
                _exit(127);
        }
        if (pd->pid == -1)
                return(-1);
        close(p0[0]);
        close(p1[1]);
        pd->r = p1[0];
        pd->w = p0[1];
        pd->running = 1;
        return(PIPE_BUF);
}


int
close_process(          /* close pipes and wait for process */
SUBPROC *pd
)
{
        int     pid, status;

        close(pd->r);
        close(pd->w);
        pd->running = 0;
        while ((pid = wait(&status)) != -1)
                if (pid == pd->pid)
                        return(status>>8 & 0xff);
        return(-1);             /* ? unknown status */
}


Revision:	3.4
Committed:	Tue Nov 11 16:24:06 2003 UTC (20 years, 5 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 3.3:	+2 -2 lines
Log Message:	Replaced all calls to vfork() with regular fork() calls
#	User	Rev	Content
1	schorsch	3.1	#ifndef lint
2	greg	3.4	static const char RCSid[] = "$Id: unix_process.c,v 3.3 2003/11/10 16:41:52 greg Exp $";
3	schorsch	3.1	#endif
4			/*
5			* Routines to communicate with separate process via dual pipes
6			* Unix version
7			*
8			* External symbols declared in standard.h
9			*/
10
11			#include "copyright.h"
12	schorsch	3.2
13			#include <sys/types.h>
14			#include <sys/wait.h>
15	schorsch	3.1
16			#include "rtprocess.h"
17
18
19			int
20			open_process( /* open communication to separate process */
21			SUBPROC *pd,
22			char *av[]
23			)
24			{
25			extern char getpath(), getenv();
26			char *compath;
27			int p0[2], p1[2];
28
29			pd->running = 0; /* not yet */
30			/* find executable */
31			compath = getpath(av[0], getenv("PATH"), 1);
32			if (compath == 0)
33			return(0);
34			if (pipe(p0) < 0 \|\| pipe(p1) < 0)
35			return(-1);
36	greg	3.4	if ((pd->pid = fork()) == 0) { /* if child */
37	schorsch	3.1	close(p0[1]);
38			close(p1[0]);
39			if (p0[0] != 0) { /* connect p0 to stdin */
40			dup2(p0[0], 0);
41			close(p0[0]);
42			}
43			if (p1[1] != 1) { /* connect p1 to stdout */
44			dup2(p1[1], 1);
45			close(p1[1]);
46			}
47			execv(compath, av); /* exec command */
48			perror(compath);
49			_exit(127);
50			}
51			if (pd->pid == -1)
52			return(-1);
53			close(p0[0]);
54			close(p1[1]);
55			pd->r = p1[0];
56			pd->w = p0[1];
57			pd->running = 1;
58			return(PIPE_BUF);
59			}
60
61
62
63			int
64			close_process( /* close pipes and wait for process */
65			SUBPROC *pd
66			)
67			{
68			int pid, status;
69
70			close(pd->r);
71			close(pd->w);
72			pd->running = 0;
73			while ((pid = wait(&status)) != -1)
74			if (pid == pd->pid)
75			return(status>>8 & 0xff);
76			return(-1); /* ? unknown status */
77			}
78
79