/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include "lib.h"#include <unistd.h>#include <errno.h>#include <string.h>#include <signal.h>#include "sys9.h" extern char **environ; intexecve(const char *name, const char *argv[], const char *envp[]){	int n, f, i;	char **e, *ss, *se;	Fdinfo *fi;	unsigned long flags;	char nam[256+5];	char buf[1000]; 	_RFORK(RFCENVG);	/*	 * To pass _fdinfo[] across exec, put lines like	 *   fd flags oflags	 * in $_fdinfo (for open fd's)	 */ 	f = _CREATE("#e/_fdinfo", OWRITE, 0666);	ss = buf;	for(n = 0; n<OPEN_MAX; n++){		fi = &_fdinfo[n];		flags = fi->flags;		if(flags&FD_CLOEXEC){			_CLOSE(n);			fi->flags = 0;			fi->oflags = 0;		}else if(flags&FD_ISOPEN){			ss = _ultoa(ss, n);			*ss++ = ' ';			ss = _ultoa(ss, flags);			*ss++ = ' ';			ss = _ultoa(ss, fi->oflags);			*ss++ = '\n';			if(ss-buf < sizeof(buf)-50){				_WRITE(f, buf, ss-buf);				ss = buf;			}		}	}	if(ss > buf)		_WRITE(f, buf, ss-buf);	_CLOSE(f);	/*	 * To pass _sighdlr[] across exec, set $_sighdlr	 * to list of blank separated fd's that have	 * SIG_IGN (the rest will be SIG_DFL).	 * We write the variable, even if no signals	 * are ignored, in case the current value of the	 * variable ignored some.	 */	f = _CREATE("#e/_sighdlr", OWRITE, 0666);	if(f >= 0){		ss = buf;		for(i = 0; i <=MAXSIG && ss < &buf[sizeof(buf)]-5; i++) {			if(_sighdlr[i] == SIG_IGN) {				ss = _ultoa(ss, i);				*ss++ = ' ';			}		}		_WRITE(f, buf, ss-buf);		_CLOSE(f);	}	if(envp){		strcpy(nam, "#e/");		for(e = (char **)envp; (ss = *e); e++) {			se = strchr(ss, '=');			if(!se || ss==se)				continue;	/* what is name? value? */			n = se-ss;			if(n >= sizeof(nam)-3)				n = sizeof(nam)-3-1;			memcpy(nam+3, ss, n);			nam[3+n] = 0;			f = _CREATE(nam, OWRITE, 0666);			if(f < 0)				continue;			se++; /* past = */			n = strlen(se);			/* temporarily decode nulls (see _envsetup()) */			for(i=0; i < n; i++)				if(se[i] == 1)					se[i] = 0;			_WRITE(f, se, n);			/* put nulls back */			for(i=0; i < n; i++)				if(se[i] == 0)					se[i] = 1;			_CLOSE(f);		}	}	n = _EXEC(name, argv);	_syserrno();	return n;}