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root/radiance/ray/src/common/unix_process.c
Revision: 3.6
Committed: Sun Sep 19 08:42:22 2004 UTC (19 years, 6 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad3R6, rad3R6P1
Changes since 3.5: +9 -1 lines
Log Message:
Fixed deadlock upon termination of mkillum with -n option

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: unix_process.c,v 3.5 2004/09/17 21:43:49 greg 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
17 #include "rtprocess.h"
18
19
20 int
21 open_process( /* open communication to separate process */
22 SUBPROC *pd,
23 char *av[]
24 )
25 {
26 extern char *getpath(), *getenv();
27 char *compath;
28 int p0[2], p1[2];
29
30 pd->running = 0; /* not yet */
31 /* find executable */
32 compath = getpath(av[0], getenv("PATH"), 1);
33 if (compath == 0)
34 return(0);
35 if (pipe(p0) < 0 || pipe(p1) < 0)
36 return(-1);
37 if ((pd->pid = fork()) == 0) { /* if child */
38 close(p0[1]);
39 close(p1[0]);
40 if (p0[0] != 0) { /* connect p0 to stdin */
41 dup2(p0[0], 0);
42 close(p0[0]);
43 }
44 if (p1[1] != 1) { /* connect p1 to stdout */
45 dup2(p1[1], 1);
46 close(p1[1]);
47 }
48 execv(compath, av); /* exec command */
49 perror(compath);
50 _exit(127);
51 }
52 if (pd->pid == -1)
53 return(-1);
54 close(p0[0]);
55 close(p1[1]);
56 pd->r = p1[0];
57 pd->w = p0[1];
58 /*
59 * Close write stream on exec to avoid multiprocessing deadlock.
60 * No use in read stream without it, so set flag there as well.
61 * GW: This bug took me two days to figure out!!
62 */
63 fcntl(pd->r, F_SETFD, FD_CLOEXEC);
64 fcntl(pd->w, F_SETFD, FD_CLOEXEC);
65 pd->running = 1;
66 return(PIPE_BUF);
67 }
68
69
70
71 int
72 close_process( /* close pipes and wait for process */
73 SUBPROC *pd
74 )
75 {
76 int pid, status;
77
78 if (!pd->running)
79 return(0);
80 close(pd->r);
81 close(pd->w);
82 pd->running = 0;
83 if (waitpid(pd->pid, &status, 0) == pd->pid)
84 return(status>>8 & 0xff);
85 return(-1); /* ? unknown status */
86 }
87
88