1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
#include "u.h"
#include <errno.h>
#include "libc.h"
#include "thread.h"
#include "threadimpl.h"
static Lock thewaitlock;
static Channel *thewaitchan;
static Channel *dowaitchan;
/* BUG - start waitproc on first exec, not when threadwaitchan is called */
static void
waitproc(void *v)
{
Channel *c;
Waitmsg *w;
_threadsetsysproc();
for(;;){
while((w = wait()) == nil){
if(errno == ECHILD)
recvul(dowaitchan);
}
if((c = thewaitchan) != nil)
sendp(c, w);
else
free(w);
}
}
Channel*
threadwaitchan(void)
{
if(thewaitchan)
return thewaitchan;
lock(&thewaitlock);
if(thewaitchan){
unlock(&thewaitlock);
return thewaitchan;
}
thewaitchan = chancreate(sizeof(Waitmsg*), 4);
chansetname(thewaitchan, "threadwaitchan");
dowaitchan = chancreate(sizeof(ulong), 1);
chansetname(dowaitchan, "dowaitchan");
proccreate(waitproc, nil, STACK);
unlock(&thewaitlock);
return thewaitchan;
}
int
threadspawn(int fd[3], char *cmd, char *argv[])
{
int i, n, p[2], pid;
char exitstr[100];
if(pipe(p) < 0)
return -1;
if(fcntl(p[0], F_SETFD, 1) < 0 || fcntl(p[1], F_SETFD, 1) < 0){
close(p[0]);
close(p[1]);
return -1;
}
switch(pid = fork()){
case -1:
close(p[0]);
close(p[1]);
return -1;
case 0:
dup2(fd[0], 0);
dup2(fd[1], 1);
dup2(fd[2], 2);
for(i=3; i<100; i++)
if(i != p[1])
close(i);
execvp(cmd, argv);
fprint(p[1], "%d", errno);
close(p[1]);
_exit(0);
}
close(p[1]);
n = read(p[0], exitstr, sizeof exitstr-1);
close(p[0]);
if(n > 0){ /* exec failed */
exitstr[n] = 0;
errno = atoi(exitstr);
return -1;
}
close(fd[0]);
if(fd[1] != fd[0])
close(fd[1]);
if(fd[2] != fd[1] && fd[2] != fd[0])
close(fd[2]);
channbsendul(dowaitchan, 1);
return pid;
}
int
_threadexec(Channel *cpid, int fd[3], char *cmd, char *argv[])
{
int pid;
pid = threadspawn(fd, cmd, argv);
if(cpid){
if(pid < 0)
chansendul(cpid, ~0);
else
chansendul(cpid, pid);
}
return pid;
}
void
threadexec(Channel *cpid, int fd[3], char *cmd, char *argv[])
{
if(_threadexec(cpid, fd, cmd, argv) >= 0)
threadexits("threadexec");
}
void
threadexecl(Channel *cpid, int fd[3], char *cmd, ...)
{
char **argv, *s;
int n, pid;
va_list arg;
va_start(arg, cmd);
for(n=0; va_arg(arg, char*) != nil; n++)
;
n++;
va_end(arg);
argv = malloc(n*sizeof(argv[0]));
if(argv == nil){
if(cpid)
chansendul(cpid, ~0);
return;
}
va_start(arg, cmd);
for(n=0; (s=va_arg(arg, char*)) != nil; n++)
argv[n] = s;
argv[n] = 0;
va_end(arg);
pid = _threadexec(cpid, fd, cmd, argv);
free(argv);
if(pid >= 0)
threadexits("threadexecl");
}
|