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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
#include <u.h>
#include <signal.h>
#include "rc.h"
#include "getflags.h"
#include "exec.h"
#include "io.h"
#include "fns.h"
int havefork = 1;
void
Xasync(void)
{
int null = open("/dev/null", 0);
int pid;
int tcpgrp, pgrp;
char npid[10];
if(null<0){
Xerror("Can't open /dev/null\n");
return;
}
switch(pid = rfork(RFFDG|RFPROC|RFNOTEG)){
case -1:
close(null);
Xerror("try again");
break;
case 0:
/*
* Should make reads of tty fail, writes succeed.
*/
signal(SIGTTIN, SIG_IGN);
signal(SIGTTOU, SIG_IGN);
pushredir(ROPEN, null, 0);
start(runq->code, runq->pc+1, runq->local);
runq->ret = 0;
break;
default:
close(null);
runq->pc = runq->code[runq->pc].i;
inttoascii(npid, pid);
setvar("apid", newword(npid, (word *)0));
break;
}
}
void
Xpipe(void)
{
struct thread *p = runq;
int pc = p->pc, forkid;
int lfd = p->code[pc++].i;
int rfd = p->code[pc++].i;
int pfd[2];
if(pipe(pfd)<0){
Xerror("can't get pipe");
return;
}
switch(forkid = fork()){
case -1:
Xerror("try again");
break;
case 0:
start(p->code, pc+2, runq->local);
runq->ret = 0;
close(pfd[PRD]);
pushredir(ROPEN, pfd[PWR], lfd);
break;
default:
start(p->code, p->code[pc].i, runq->local);
close(pfd[PWR]);
pushredir(ROPEN, pfd[PRD], rfd);
p->pc = p->code[pc+1].i;
p->pid = forkid;
break;
}
}
/*
* Who should wait for the exit from the fork?
*/
void
Xbackq(void)
{
char wd[8193];
int c;
char *s, *ewd=&wd[8192], *stop;
struct io *f;
var *ifs = vlook("ifs");
word *v, *nextv;
int pfd[2];
int pid;
stop = ifs->val?ifs->val->word:"";
if(pipe(pfd)<0){
Xerror("can't make pipe");
return;
}
switch(pid = fork()){
case -1:
Xerror("try again");
close(pfd[PRD]);
close(pfd[PWR]);
return;
case 0:
close(pfd[PRD]);
start(runq->code, runq->pc+1, runq->local);
pushredir(ROPEN, pfd[PWR], 1);
return;
default:
close(pfd[PWR]);
f = openfd(pfd[PRD]);
s = wd;
v = 0;
while((c = rchr(f))!=EOF){
if(strchr(stop, c) || s==ewd){
if(s!=wd){
*s='\0';
v = newword(wd, v);
s = wd;
}
}
else *s++=c;
}
if(s!=wd){
*s='\0';
v = newword(wd, v);
}
closeio(f);
Waitfor(pid, 0);
/* v points to reversed arglist -- reverse it onto argv */
while(v){
nextv = v->next;
v->next = runq->argv->words;
runq->argv->words = v;
v = nextv;
}
runq->pc = runq->code[runq->pc].i;
return;
}
}
void
Xpipefd(void)
{
struct thread *p = runq;
int pc = p->pc;
char name[40];
int pfd[2];
int sidefd, mainfd;
if(pipe(pfd)<0){
Xerror("can't get pipe");
return;
}
if(p->code[pc].i==READ){
sidefd = pfd[PWR];
mainfd = pfd[PRD];
}
else{
sidefd = pfd[PRD];
mainfd = pfd[PWR];
}
switch(fork()){
case -1:
Xerror("try again");
break;
case 0:
start(p->code, pc+2, runq->local);
close(mainfd);
pushredir(ROPEN, sidefd, p->code[pc].i==READ?1:0);
runq->ret = 0;
break;
default:
close(sidefd);
pushredir(ROPEN, mainfd, mainfd); /* isn't this a noop? */
strcpy(name, Fdprefix);
inttoascii(name+strlen(name), mainfd);
pushword(name);
p->pc = p->code[pc+1].i;
break;
}
}
void
Xsubshell(void)
{
int pid;
switch(pid = fork()){
case -1:
Xerror("try again");
break;
case 0:
start(runq->code, runq->pc+1, runq->local);
runq->ret = 0;
break;
default:
Waitfor(pid, 1);
runq->pc = runq->code[runq->pc].i;
break;
}
}
int
execforkexec(void)
{
int pid;
int n;
char buf[ERRMAX];
switch(pid = fork()){
case -1:
return -1;
case 0:
pushword("exec");
execexec();
strcpy(buf, "can't exec: ");
n = strlen(buf);
errstr(buf+n, ERRMAX-n);
Exit(buf);
}
return pid;
}
|
