ape: fix _grpmems(), access(), getppid(), cleanup

_grpmems() was broken tokenizing group list in place.
we have to copy it to status buffer before tokenizing.

dynamically alloc path for test file to check write
permission on directory and add pid to the name to
prevent races.

use _OPEN instead of ape open to read /dev/ppid in
getppid().

use mode enums instead of numeric constants for _OPEN()
and _CREATE().

sys/src/ape/lib/ap/plan9/_envsetup.c

@@ -44,7 +44,7 @@ _envsetup(void)
 	nohandle = 0;
 	fdinited = 0;
 	cnt = 0;
-	dfd = _OPEN("/env", 0);
+	dfd = _OPEN("/env", OREAD);
 	if(dfd < 0)
 		goto done;
 	psize = Envhunk;
@@ -63,7 +63,7 @@ _envsetup(void)
 		}
 		strcpy(p, "/env/");
 		memcpy(p+5, d9->name, n+1);
-		f = _OPEN(p, 0);
+		f = _OPEN(p, OREAD);
 		memset(p, 0, n+6);
 		memcpy(p, d9->name, n);
 		p[n] = '=';

sys/src/ape/lib/ap/plan9/_fdinfo.c

@@ -41,7 +41,7 @@ readprocfdinit(void)
 	strcpy(buf, "/proc/");
 	_ultoa(buf+6, getpid());
 	strcat(buf, "/fd");
-	pfd = _OPEN(buf, 0);
+	pfd = _OPEN(buf, OREAD);
 	if(pfd < 0)
 		return -1;
 	memset(buf, 0, sizeof buf);

sys/src/ape/lib/ap/plan9/_getpw.c

@@ -153,20 +153,19 @@ _grpmems(char *list)
 	char **v;
 	char *p;
 	static char *holdvec[200];
-	static char holdlist[1000];
+	static char holdlist[1024];
 
-	p = list;
 	v = holdvec;
-	if(p) {
-		strncpy(holdlist, list, sizeof(holdlist));
+	if(list != 0){
+		memset(holdlist, 0, sizeof(holdlist));
+		strncpy(holdlist, list, sizeof(holdlist)-1);
+		p = holdlist;
 		while(v< &holdvec[sizeof(holdvec)]-1 && *p){
 			*v++ = p;
 			p = strchr(p, ',');
-			if(p){
-				p++;
-				*p = 0;
-			}else
+			if(p == 0)
 				break;
+			*p++ = 0;
 		}
 	}
 	*v = 0;

sys/src/ape/lib/ap/plan9/access.c

@@ -24,8 +24,6 @@ access(const char *name, int mode)
 		2,
 		2
 	};
-	char tname[1024];
-
 	if(mode == 0){
 		db = _dirstat(name);
 		if(db == nil){
@@ -48,13 +46,23 @@ access(const char *name, int mode)
 			close(fd);
 		}
 		if(mode & W_OK){
-			strncpy(tname, name, sizeof(tname)-9);
-			strcat(tname, "/_AcChAcK");
-			fd = creat(tname, 0666);
-			if(fd < 0)
+			char *tname;
+			int nname;
+			nname = strlen(name);
+			tname = malloc(nname+32);
+			if(tname == 0)
 				return -1;
-			close(fd);
-			_REMOVE(tname);
+			memset(tname, 0, nname+32);
+			memcpy(tname, name, n);
+			memcpy(tname+nname, "/_AcChAcK", 9);
+			_ultoa(tname+nname+9, getpid());
+			fd = _CREATE(tname, ORCLOSE, 0666);
+			if(fd < 0){
+				free(tname);
+				return -1;
+			}
+			_CLOSE(fd);
+			free(tname);
 		}
 		return 0;
 	}

sys/src/ape/lib/ap/plan9/getppid.c

@@ -3,7 +3,7 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <errno.h>
+#include <string.h>
 #include "sys9.h"
 
 pid_t
@@ -13,10 +13,10 @@ getppid(void)
 	int f;
 
 	memset(b, 0, sizeof(b));
-	f = open("/dev/ppid", 0);
+	f = _OPEN("/dev/ppid", OREAD);
 	if(f >= 0) {
-		read(f, b, sizeof(b));
-		close(f);
+		_PREAD(f, b, sizeof(b), 0);
+		_CLOSE(f);
 	}
 	return atol(b);
 }

sys/src/ape/lib/ap/plan9/rename.c

@@ -49,13 +49,13 @@ rename(const char *from, const char *to)
 		int ffd, tfd;
 		char buf[8192];
 
-		if((ffd = _OPEN(from, 0)) < 0 ||
-		   (tfd = _CREATE(to, 1, d->mode)) < 0){
+		if((ffd = _OPEN(from, OREAD)) < 0 ||
+		   (tfd = _CREATE(to, OWRITE, d->mode)) < 0){
 			_CLOSE(ffd);
 			_syserrno();
 			n = -1;
 		}
-		while(n>=0 && (n = _READ(ffd, buf, 8192)) > 0)
+		while(n>=0 && (n = _READ(ffd, buf, sizeof(buf))) > 0)
 			if(_WRITE(tfd, buf, n) != n){
 				_syserrno();
 				n = -1;

sys/src/ape/lib/ap/plan9/time.c

@@ -15,7 +15,7 @@ time(time_t *tp)
 	time_t t;
 
 	memset(b, 0, sizeof(b));
-	f = _OPEN("/dev/time", 0);
+	f = _OPEN("/dev/time", OREAD);
 	if(f >= 0) {
 		_PREAD(f, b, sizeof(b), 0);
 		_CLOSE(f);