rc: terminate rc when exec fails, cleanup

The execexec() function should never return, as it irreversably changes
the filedescriptor table for the new program. This means rc's internal
filedesciptors for reading the script get implicitely closed and we cannot
continue the rc interpreter when Execute() fails. So Execute() now sets the
error status, and execexec() runs Xexit() in case Execute() returns.

sys/src/cmd/rc/glob.c

@@ -101,7 +101,7 @@ glob(void *ap)
 		return;
 	}
 	globname = emalloc(globlen);
-	globname[0]='\0';
+	memset(globname, 0, globlen);
 	globdir(p, (uchar *)globname);
 	efree(globname);
 	if(svglobv==globv){

sys/src/cmd/rc/haventfork.c

@@ -189,32 +189,29 @@ execforkexec(void)
 {
 	char **argv;
 	char file[1024];
-	int nc;
+	int nc, mc;
 	word *path;
 	int pid;
 
 	if(runq->argv->words==0)
 		return -1;
 	argv = mkargv(runq->argv->words);
-
+	mc = strlen(argv[1])+1;
 	for(path = searchpath(runq->argv->words->word);path;path = path->next){
 		nc = strlen(path->word);
-		if(nc < sizeof file - 1){	/* 1 for / */
+		if(nc + mc >= sizeof file - 1)	/* 1 for / */
-			strcpy(file, path->word);
+			continue;
-			if(file[0]){
+		if(nc > 0){
-				strcat(file, "/");
+			memmove(file, path->word, nc);
-				nc++;
+			file[nc++] = '/';
 		}
-			if(nc+strlen(argv[1])<sizeof(file)){
+		memmove(file+nc, argv[1], mc);
-				strcat(file, argv[1]);
 		pid = ForkExecute(file, argv+1, mapfd(0), mapfd(1), mapfd(2));
 		if(pid >= 0){
 			free(argv);
 			return pid;
 		}
 	}
-		}
-	}
 	free(argv);
 	return -1;
 }

sys/src/cmd/rc/plan9.c

@@ -305,72 +305,36 @@ Updenv(void)
 
 /* not used on plan 9 */
 int
-ForkExecute(char *file, char **argv, int sin, int sout, int serr)
+ForkExecute(char *, char **, int, int, int)
 {
-	int pid;
-
-	if(access(file, 1) != 0)
 	return -1;
-	switch(pid = fork()){
-	case -1:
-		return -1;
-	case 0:
-		if(sin >= 0)
-			dup(sin, 0);
-		else
-			close(0);
-		if(sout >= 0)
-			dup(sout, 1);
-		else
-			close(1);
-		if(serr >= 0)
-			dup(serr, 2);
-		else
-			close(2);
-		exec(file, argv);
-		exits(file);
-	}
-	return pid;
 }
 
 void
 Execute(word *args, word *path)
 {
 	char **argv = mkargv(args);
-	char file[1024], errstr[1024];
+	char file[1024];
-	int nc;
+	int nc, mc;
 
 	Updenv();
-	errstr[0] = '\0';
+	mc = strlen(argv[1])+1;
 	for(;path;path = path->next){
 		nc = strlen(path->word);
-		if(nc < sizeof file - 1){	/* 1 for / */
+		if(nc + mc >= sizeof file - 1){	/* 1 for / */
-			strcpy(file, path->word);
+			werrstr("command path name too long");
-			if(file[0]){
+			continue;
-				strcat(file, "/");
-				nc++;
 		}
-			if(nc + strlen(argv[1]) < sizeof file){
+		if(nc > 0){
-				strcat(file, argv[1]);
+			memmove(file, path->word, nc);
+			file[nc++] = '/';
+		}
+		memmove(file+nc, argv[1], mc);
 		exec(file, argv+1);
-				rerrstr(errstr, sizeof errstr);
-				/*
-				 * if file exists and is executable, exec should
-				 * have worked, unless it's a directory or an
-				 * executable for another architecture.  in
-				 * particular, if it failed due to lack of
-				 * swap/vm (e.g., arg. list too long) or other
-				 * allocation failure, stop searching and print
-				 * the reason for failure.
-				 */
-				if (strstr(errstr, " allocat") != nil ||
-				    strstr(errstr, " full") != nil)
-					break;
 	}
-			else werrstr("command name too long");
+	rerrstr(file, sizeof file);
-		}
+	setstatus(file);
-	}
+	pfmt(err, "%s: %s\n", argv[1], file);
-	pfmt(err, "%s: %s\n", argv[1], errstr);
 	efree((char *)argv);
 }
 #define	NDIR	256		/* shoud be a better way */
@@ -464,7 +428,7 @@ Again:
 	}
 	if(dir[f].i == dir[f].n)
 		return 0;
-	strcpy(p, dir[f].dbuf[dir[f].i].name);
+	strncpy((char*)p, dir[f].dbuf[dir[f].i].name, NDIR);
 	dir[f].i++;
 	return 1;
 }

sys/src/cmd/rc/simple.c

@@ -55,7 +55,6 @@ Xsimple(void)
 			/* fork and wait is redundant */
 			pushword("exec");
 			execexec();
-			Xexit();
 		}
 		else{
 			flush(err);
@@ -120,6 +119,7 @@ execexec(void)
 	doredir(runq->redir);
 	Execute(runq->argv->words, searchpath(runq->argv->words->word));
 	poplist();
+	Xexit();
 }
 
 void

sys/src/cmd/rc/subr.c

@@ -9,15 +9,14 @@ emalloc(long n)
 	void *p = Malloc(n);
 	if(p==0)
 		panic("Can't malloc %d bytes", n);
-/*	if(err){ pfmt(err, "malloc %d->%p\n", n, p); flush(err); } /**/
 	return p;
 }
 
 void*
 erealloc(void *p, long n)
 {
-	p = Realloc(p, n);		/* botch, should be Realloc */
+	p = Realloc(p, n);
-	if(p==0)
+	if(p==0 && n!=0)
 		panic("Can't realloc %d bytes\n", n);
 	return p;
 }
@@ -25,7 +24,6 @@ erealloc(void *p, long n)
 void
 efree(void *p)
 {
-/*	pfmt(err, "free %p\n", p); flush(err); /**/
 	if(p)
 		free(p);
 	else pfmt(err, "free 0\n");

sys/src/cmd/rc/unix.c

@@ -275,6 +275,7 @@ register struct word *args, *path;
 		}
 	}
 Bad:
+	setstatus(msg);
 	pfmt(err, "%s: %s\n", argv[1], msg);
 	efree((char *)env);
 	efree((char *)argv);
@@ -319,7 +320,7 @@ int onlydirs;		/* ignored, just advisory */
 	struct direct *dp = readdir(dirlist[f]);
 	if(dp==0)
 		return 0;
-	strcpy(p, dp->d_name);
+	strncpy(p, dp->d_name, NDIR);
 	return 1;
 }
 Closedir(f){

sys/src/cmd/rc/win32.c

@@ -299,6 +299,7 @@ Execute(word *args, word *path)
 		}
 	}
 	rerrstr(file, sizeof file);
+	setstatus(file);
 	pfmt(err, "%s: %s\n", argv[1], file);
 	efree((char *)argv);
 }
@@ -393,7 +394,7 @@ Again:
 	}
 	if(dir[f].i == dir[f].n)
 		return 0;
-	strcpy(p, dir[f].dbuf[dir[f].i].name);
+	strncpy(p, dir[f].dbuf[dir[f].i].name, NDIR);
 	dir[f].i++;
 	return 1;
 }