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root/radiance/ray/src/common/unix_process.c
Revision: 3.9
Committed: Sat Dec 12 23:08:13 2009 UTC (14 years, 3 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad4R1, rad4R0
Changes since 3.8: +4 -3 lines
Log Message:
Bug fixes and performance improvements to rtrace -n option

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: unix_process.c,v 3.8 2006/06/07 17:52:03 schorsch Exp $";
3 #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
13 #include <sys/types.h>
14 #include <sys/wait.h>
15 #include <fcntl.h>
16 #include <stdlib.h>
17
18 #include "rtprocess.h"
19 #include "rtio.h"
20
21
22 int
23 open_process( /* open communication to separate process */
24 SUBPROC *pd,
25 char *av[]
26 )
27 {
28 char *compath;
29 int p0[2], p1[2];
30
31 pd->running = 0; /* not yet */
32 /* find executable */
33 compath = getpath(av[0], getenv("PATH"), 1);
34 if (compath == 0)
35 return(0);
36 if (pipe(p0) < 0 || pipe(p1) < 0)
37 return(-1);
38 if ((pd->pid = fork()) == 0) { /* if child */
39 close(p0[1]);
40 close(p1[0]);
41 if (p0[0] != 0) { /* connect p0 to stdin */
42 dup2(p0[0], 0);
43 close(p0[0]);
44 }
45 if (p1[1] != 1) { /* connect p1 to stdout */
46 dup2(p1[1], 1);
47 close(p1[1]);
48 }
49 execv(compath, av); /* exec command */
50 perror(compath);
51 _exit(127);
52 }
53 if (pd->pid == -1)
54 return(-1);
55 close(p0[0]);
56 close(p1[1]);
57 pd->r = p1[0];
58 pd->w = p0[1];
59 /*
60 * Close write stream on exec to avoid multiprocessing deadlock.
61 * No use in read stream without it, so set flag there as well.
62 * GW: This bug took me two days to figure out!!
63 */
64 fcntl(pd->r, F_SETFD, FD_CLOEXEC);
65 fcntl(pd->w, F_SETFD, FD_CLOEXEC);
66 pd->running = 1;
67 return(PIPE_BUF);
68 }
69
70
71
72 int
73 close_process( /* close pipes and wait for process */
74 SUBPROC *pd
75 )
76 {
77 int status;
78
79 if (!pd->running)
80 return(0);
81 close(pd->w);
82 pd->running = 0;
83 if (waitpid(pd->pid, &status, 0) == pd->pid) {
84 close(pd->r);
85 return(status>>8 & 0xff);
86 }
87 return(-1); /* ? unknown status */
88 }
89
90