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
|
/* ISC license. */
/* MT-unsafe */
#include <skalibs/sysdeps.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#ifdef SKALIBS_HASPOSIXSPAWN
#include <stdlib.h>
#include <spawn.h>
#include <skalibs/config.h>
#else
#include <skalibs/sig.h>
#include <skalibs/strerr2.h>
#include <skalibs/exec.h>
#endif
#include <skalibs/types.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/env.h>
#include <skalibs/djbunix.h>
/*
If n = 0 : child's stdin and stdout are the same as the parent's
If n >= 1 : pipes between parent and child.
Parent reads on even ones, writes on odd ones.
*/
pid_t child_spawn (char const *prog, char const *const *argv, char const *const *envp, int *fds, unsigned int n)
{
pid_t pid ;
#ifdef SKALIBS_HASPOSIXSPAWN
posix_spawn_file_actions_t actions ;
posix_spawnattr_t attr ;
int e ;
#else
int syncpipe[2] ;
#endif
int p[n ? n : 1][2] ;
size_t m = sizeof(SKALIBS_CHILD_SPAWN_FDS_ENVVAR) ;
unsigned int i = 0 ;
char modifs[m + 1 + n * UINT_FMT] ;
memcpy(modifs, SKALIBS_CHILD_SPAWN_FDS_ENVVAR "=", sizeof(SKALIBS_CHILD_SPAWN_FDS_ENVVAR)) ;
for (; i < n ; i++)
{
if (pipe(p[i]) < 0) goto errpi ;
if ((ndelay_on(p[i][i & 1]) < 0) || (coe(p[i][i & 1]) < 0))
{
i++ ; goto errpi ;
}
}
for (i = 2 ; i < n ; i++)
{
m += uint_fmt(modifs + m, p[i][!(i & 1)]) ;
if (i+1 < n) modifs[m++] = ',' ;
}
modifs[m++] = 0 ;
#ifdef SKALIBS_HASPOSIXSPAWN
e = posix_spawnattr_init(&attr) ;
if (e) goto erre ;
{
sigset_t set ;
sigemptyset(&set) ;
e = posix_spawnattr_setsigmask(&attr, &set) ;
if (e) goto errattr ;
e = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK) ;
if (e) goto errattr ;
}
e = posix_spawn_file_actions_init(&actions) ;
if (e) goto errattr ;
if (n >= 2 && p[1][0])
{
e = posix_spawn_file_actions_adddup2(&actions, p[1][0], 0) ;
if (e) goto erractions ;
e = posix_spawn_file_actions_addclose(&actions, p[1][0]) ;
if (e) goto erractions ;
}
if (n && p[0][1] != 1)
{
e = posix_spawn_file_actions_adddup2(&actions, p[0][1], 1) ;
if (e) goto erractions ;
e = posix_spawn_file_actions_addclose(&actions, p[0][1]) ;
if (e) goto erractions ;
}
{
int nopath = !getenv("PATH") ;
size_t envlen = env_len(envp) ;
char const *newenv[envlen + 2] ;
if (!env_mergen(newenv, envlen+2, envp, envlen, modifs, m, 1)) goto erractions ;
if (nopath && (setenv("PATH", SKALIBS_DEFAULTPATH, 0) < 0))
{
e = errno ; goto erractions ;
}
e = posix_spawnp(&pid, prog, &actions, &attr, (char *const *)argv, (char *const *)newenv) ;
if (nopath) unsetenv("PATH") ;
if (e) goto erractions ;
}
posix_spawn_file_actions_destroy(&actions) ;
posix_spawnattr_destroy(&attr) ;
#else
if (pipecoe(syncpipe) < 0) goto errp ;
pid = fork() ;
if (pid < 0) goto errsp ;
else if (!pid)
{
size_t len = strlen(PROG) ;
char name[len + 9] ;
memcpy(name, PROG, len) ;
memcpy(name + len, " (child)", 9) ;
PROG = name ;
if (n >= 2)
{
if (fd_move2(0, p[1][0], 1, p[0][1]) < 0) goto syncdie ;
}
else if (n)
{
if (fd_move(1, p[0][1]) < 0) goto syncdie ;
}
sig_blocknone() ;
mexec_aen(prog, argv, envp, modifs, m, 1) ;
syncdie:
{
char c = errno ;
fd_write(syncpipe[1], &c, 1) ;
}
_exit(127) ;
}
fd_close(syncpipe[1]) ;
{
char c ;
syncpipe[1] = fd_read(syncpipe[0], &c, 1) ;
if (syncpipe[1])
{
int e = c ;
if (syncpipe[1] < 0) e = errno ;
if (wait_pid(pid, &syncpipe[1]) < 0) e = errno ;
errno = e ;
goto errsp0 ;
}
}
fd_close(syncpipe[0]) ;
#endif
for (i = n ; i ; i--)
{
fd_close(p[i-1][i & 1]) ;
fds[i-1] = p[i-1][!(i & 1)] ;
}
return pid ;
#ifdef SKALIBS_HASPOSIXSPAWN
erractions:
posix_spawn_file_actions_destroy(&actions) ;
errattr:
posix_spawnattr_destroy(&attr) ;
erre:
errno = e ;
#endif
#ifndef SKALIBS_HASPOSIXSPAWN
errsp:
fd_close(syncpipe[1]) ;
errsp0:
fd_close(syncpipe[0]) ;
errp:
#endif
i = n ;
errpi:
while (i--)
{
fd_close(p[i][1]) ;
fd_close(p[i][0]) ;
}
return 0 ;
}
|
