/*  * 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 "defs.h"#include <sys/wait.h>#include <sys/stat.h>#include <fcntl.h>#include <errno.h> static int	metas(char *);static int	waitproc(int *);static int	doshell(char *, int);static int	doexec(char *); intdosys(char *comstring, int nohalt, int nowait, char *prefix){int status;struct process *procp; /* make sure there is room in the process stack */if(nproc >= MAXPROC)	waitstack(MAXPROC-1); /* make sure fewer than proclimit processes are running */while(proclive >= proclimit)	{	enbint(SIG_IGN);	waitproc(&status);	enbint(intrupt);	} if(prefix)	{	fputs(prefix, stdout);	fputs(comstring, stdout);	} procp = procstack + nproc;procp->pid = (forceshell || metas(comstring) ) ?	doshell(comstring,nohalt) : doexec(comstring);if(procp->pid == -1)	fatal("fork failed");procstack[nproc].nohalt = nohalt;procstack[nproc].nowait = nowait;procstack[nproc].done = NO;++proclive;++nproc; if(nowait)	{	printf(" &%d\n", procp->pid);	fflush(stdout);	return 0;	}if(prefix)	{	putchar('\n');	fflush(stdout);	}return waitstack(nproc-1);} static intmetas(char *s)   /* Are there are any  Shell meta-characters? */{char c; while( (funny[c = *s++] & META) == 0 )	;return( c );} static voiddoclose(void)	/* Close open directory files before exec'ing */{struct dirhd *od; for (od = firstod; od; od = od->nxtdirhd)	if(od->dirfc)		closedir(od->dirfc);} /*  wait till none of the processes in the stack starting at k is live */intwaitstack(int k){int npending, status, totstatus;int i; totstatus = 0;npending = 0;for(i=k ; i<nproc; ++i)	if(! procstack[i].done)		++npending;enbint(SIG_IGN);if(dbgflag > 1)	printf("waitstack(%d)\n", k); while(npending>0 && proclive>0)	{	if(waitproc(&status) >= k)		--npending;	totstatus |= status;	} if(nproc > k)	nproc = k;enbint(intrupt);return totstatus;} static intwaitproc(int *statp){pid_t pid;int status;int i;struct process *procp;char junk[50];static int inwait = NO; if(inwait)	/* avoid infinite recursions on errors */	return MAXPROC;inwait = YES; pid = wait(&status);if(dbgflag > 1)	fprintf(stderr, "process %d done, status = %d\n", pid, status);if(pid == -1)	{	if(errno == ECHILD)	/* multiple deaths, no problem */		{		if(proclive)			{			for(i=0, procp=procstack; i<nproc; ++i, ++procp)				procp->done = YES;			proclive = nproc = 0;			}		return MAXPROC;		}	fatal("bad wait code");	}for(i=0, procp=procstack; i<nproc; ++i, ++procp)	if(procp->pid == pid)		{		--proclive;		procp->done = YES; 		if(status)			{			if(procp->nowait)				printf("%d: ", pid);			if( WEXITSTATUS(status) )				printf("*** Error code %d", WEXITSTATUS(status) );			else	printf("*** Termination code %d", WTERMSIG(status));					printf(procp->nohalt ? "(ignored)\n" : "\n");			fflush(stdout);			if(!keepgoing && !procp->nohalt)				fatal(CHNULL);			}		*statp = status;		inwait = NO;		return i;		} sprintf(junk, "spurious return from process %d", pid);fatal(junk);/*NOTREACHED*/return -1;} static intdoshell(char *comstring, int nohalt){pid_t pid; if((pid = fork()) == 0)	{	enbint(SIG_DFL);	doclose(); 	execl(SHELLCOM, "sh", (nohalt ? "-c" : "-ce"), comstring, NULL);	fatal("Couldn't load Shell");	} return pid;} static intdoexec(char *str){char *t, *tend;char **argv;char **p;int nargs;pid_t pid; while( *str==' ' || *str=='\t' )	++str;if( *str == '\0' )	return(-1);	/* no command */ nargs = 1;for(t = str ; *t ; )	{	++nargs;	while(*t!=' ' && *t!='\t' && *t!='\0')		++t;	if(*t)	/* replace first white space with \0, skip rest */		for( *t++ = '\0' ; *t==' ' || *t=='\t'  ; ++t)			;	} /* now allocate args array, copy pointer to start of each string,   then terminate array with a null*/p = argv = (char **) ckalloc(nargs*sizeof(char *));tend = t;for(t = str ; t<tend ; )	{	*p++ = t;	while( *t )		++t;	do	{		++t;		} while(t<tend && (*t==' ' || *t=='\t') );	}*p = NULL;/*TEMP  for(p=argv; *p; ++p)printf("arg=%s\n", *p);*/ if((pid = fork()) == 0)	{	enbint(SIG_DFL);	doclose();	enbint(intrupt);	execvp(str, argv);	printf("\n");	fatal1("Cannot load %s",str);	} free( (char *) argv);return pid;} voidtouch(int force, char *name){struct stat stbuff;char junk[1];int fd; if( stat(name,&stbuff) < 0)	if(force)		goto create;	else		{		fprintf(stderr, "touch: file %s does not exist.\n", name);		return;		} if(stbuff.st_size == 0)	goto create; if( (fd = open(name, O_RDWR)) < 0)	goto bad; if( read(fd, junk, 1) < 1)	{	close(fd);	goto bad;	}lseek(fd, 0L, SEEK_SET);if( write(fd, junk, 1) < 1 )	{	close(fd);	goto bad;	}close(fd);return; bad:	fprintf(stderr, "Cannot touch %s\n", name);	return; create:	if( (fd = creat(name, 0666)) < 0)		goto bad;	close(fd);}