| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: unix_process.c,v 3.13 2017/03/24 12:56:12 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 |
#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->pid = -1; |
| 32 |
pd->running = 0; /* not going yet */ |
| 33 |
|
| 34 |
if (av == NULL) /* cloning operation? */ |
| 35 |
compath = NULL; |
| 36 |
else if ((compath = getpath(av[0], getenv("PATH"), X_OK)) == NULL) |
| 37 |
return(0); |
| 38 |
if (pipe(p0) < 0 || pipe(p1) < 0) |
| 39 |
return(-1); |
| 40 |
#ifdef BSD |
| 41 |
if (compath != NULL) |
| 42 |
pd->pid = vfork(); /* more efficient with exec() */ |
| 43 |
else |
| 44 |
#endif |
| 45 |
pd->pid = fork(); |
| 46 |
if (pd->pid == 0) { /* if child... */ |
| 47 |
close(p0[1]); |
| 48 |
close(p1[0]); |
| 49 |
if (p0[0] != 0) { /* connect p0 to stdin */ |
| 50 |
dup2(p0[0], 0); |
| 51 |
close(p0[0]); |
| 52 |
} |
| 53 |
if (p1[1] != 1) { /* connect p1 to stdout */ |
| 54 |
dup2(p1[1], 1); |
| 55 |
close(p1[1]); |
| 56 |
} |
| 57 |
if (compath == NULL) /* just cloning? */ |
| 58 |
return(0); |
| 59 |
execv(compath, av); /* else exec command */ |
| 60 |
perror(compath); |
| 61 |
_exit(127); |
| 62 |
} |
| 63 |
if (pd->pid == -1) |
| 64 |
return(-1); |
| 65 |
close(p0[0]); |
| 66 |
close(p1[1]); |
| 67 |
pd->r = p1[0]; |
| 68 |
pd->w = p0[1]; |
| 69 |
/* |
| 70 |
* Close write stream on exec to avoid multiprocessing deadlock. |
| 71 |
* No use in read stream without it, so set flag there as well. |
| 72 |
* GW: This bug took me two days to figure out!! |
| 73 |
*/ |
| 74 |
fcntl(pd->r, F_SETFD, FD_CLOEXEC); |
| 75 |
fcntl(pd->w, F_SETFD, FD_CLOEXEC); |
| 76 |
pd->running = 1; |
| 77 |
return(PIPE_BUF); |
| 78 |
} |
| 79 |
|
| 80 |
|
| 81 |
int |
| 82 |
close_processes( /* close pipes and wait for processes to finish */ |
| 83 |
SUBPROC pd[], |
| 84 |
int nproc |
| 85 |
) |
| 86 |
{ |
| 87 |
int togo = nproc; |
| 88 |
int status, rtn_status = 0; |
| 89 |
RT_PID pid; |
| 90 |
int i; |
| 91 |
|
| 92 |
for (i = 0; i < nproc; i++) /* close pipes, first */ |
| 93 |
if (pd[i].running) { |
| 94 |
close(pd[i].w); |
| 95 |
close(pd[i].r); |
| 96 |
pd[i].running = 0; |
| 97 |
} else |
| 98 |
togo -= (pd[i].pid < 0); |
| 99 |
if (nproc == 1) { /* await specific process? */ |
| 100 |
if (waitpid(pd->pid, &status, 0) != pd->pid) |
| 101 |
return(-1); |
| 102 |
pd->pid = -1; |
| 103 |
return(status>>8 & 0xff); |
| 104 |
} |
| 105 |
/* else unordered wait */ |
| 106 |
while (togo > 0 && (pid = wait(&status)) >= 0) { |
| 107 |
for (i = nproc; i-- > 0; ) |
| 108 |
if (pd[i].pid == pid) { |
| 109 |
pd[i].pid = -1; |
| 110 |
--togo; |
| 111 |
break; |
| 112 |
} |
| 113 |
if (i < 0) |
| 114 |
continue; /* child we don't know? */ |
| 115 |
status = status>>8 & 0xff; |
| 116 |
if (status) /* record non-zero status */ |
| 117 |
rtn_status = status; |
| 118 |
} |
| 119 |
if (togo) /* child went missing? */ |
| 120 |
return(-1); |
| 121 |
return(rtn_status); |
| 122 |
} |
