xref: /plan9-contrib/sys/src/ape/lib/ap/plan9/execve.c (revision 781103c4074deb8af160e8a0da2742ba6b29dc2b)
1 #include "lib.h"
2 #include <unistd.h>
3 #include <errno.h>
4 #include <string.h>
5 #include <signal.h>
6 #include "sys9.h"
7 
8 extern char **environ;
9 
10 int
execve(const char * name,const char * argv[],const char * envp[])11 execve(const char *name, const char *argv[], const char *envp[])
12 {
13 	int n, f, i;
14 	char **e, *ss, *se;
15 	Fdinfo *fi;
16 	unsigned long flags;
17 	char nam[256+5];
18 	char buf[1000];
19 
20 	_RFORK(RFCENVG);
21 	/*
22 	 * To pass _fdinfo[] across exec, put lines like
23 	 *   fd flags oflags
24 	 * in $_fdinfo (for open fd's)
25 	 */
26 
27 	f = _CREATE("#e/_fdinfo", OWRITE, 0666);
28 	ss = buf;
29 	for(n = 0; n<OPEN_MAX; n++){
30 		fi = &_fdinfo[n];
31 		flags = fi->flags;
32 		if(flags&FD_CLOEXEC){
33 			_CLOSE(n);
34 			fi->flags = 0;
35 			fi->oflags = 0;
36 		}else if(flags&FD_ISOPEN){
37 			ss = _ultoa(ss, n);
38 			*ss++ = ' ';
39 			ss = _ultoa(ss, flags);
40 			*ss++ = ' ';
41 			ss = _ultoa(ss, fi->oflags);
42 			*ss++ = '\n';
43 			if(ss-buf < sizeof(buf)-50){
44 				_WRITE(f, buf, ss-buf);
45 				ss = buf;
46 			}
47 		}
48 	}
49 	if(ss > buf)
50 		_WRITE(f, buf, ss-buf);
51 	_CLOSE(f);
52 	/*
53 	 * To pass _sighdlr[] across exec, set $_sighdlr
54 	 * to list of blank separated fd's that have
55 	 * SIG_IGN (the rest will be SIG_DFL).
56 	 * We write the variable, even if no signals
57 	 * are ignored, in case the current value of the
58 	 * variable ignored some.
59 	 */
60 	f = _CREATE("#e/_sighdlr", OWRITE, 0666);
61 	if(f >= 0){
62 		ss = buf;
63 		for(i = 0; i <=MAXSIG && ss < &buf[sizeof(buf)]-5; i++) {
64 			if(_sighdlr[i] == SIG_IGN) {
65 				ss = _ultoa(ss, i);
66 				*ss++ = ' ';
67 			}
68 		}
69 		_WRITE(f, buf, ss-buf);
70 		_CLOSE(f);
71 	}
72 	if(envp){
73 		strcpy(nam, "#e/");
74 		for(e = (char **)envp; (ss = *e); e++) {
75 			se = strchr(ss, '=');
76 			if(!se || ss==se)
77 				continue;	/* what is name? value? */
78 			n = se-ss;
79 			if(n >= sizeof(nam)-3)
80 				n = sizeof(nam)-3-1;
81 			memcpy(nam+3, ss, n);
82 			nam[3+n] = 0;
83 			f = _CREATE(nam, OWRITE, 0666);
84 			if(f < 0)
85 				continue;
86 			se++; /* past = */
87 			n = strlen(se);
88 			/* temporarily decode nulls (see _envsetup()) */
89 			for(i=0; i < n; i++)
90 				if(se[i] == 1)
91 					se[i] = 0;
92 			_WRITE(f, se, n);
93 			/* put nulls back */
94 			for(i=0; i < n; i++)
95 				if(se[i] == 0)
96 					se[i] = 1;
97 			_CLOSE(f);
98 		}
99 	}
100 	n = _EXEC(name, argv);
101 	_syserrno();
102 	return n;
103 }
104