lib9: use opendir/readdir to read directories

getdirentries(2) has been deprecated on macOS since 10.5 (ten releases ago).
Using it requires disabling 64-bit inodes, but that in turn makes binaries
incompatible with some dynamic libraries, most notably ASAN.

At some point getdirentries(2) will actually be removed.

For both these reasons, switch to opendir/readdir.
A little clunky since we have to keep the DIR* hidden away
to preserve the int fd interfaces, but it lets us remove a bunch
of OS-specific code too.

include/u.h

@@ -39,9 +39,6 @@ extern "C" {
 #	define _ALL_SOURCE
 #	undef HAS_SYS_TERMIOS
 #endif
-#if defined(__APPLE__)
-#	define _DARWIN_NO_64_BIT_INODE	/* Snow Leopard */
-#endif
 #define _LARGEFILE64_SOURCE 1
 #define _FILE_OFFSET_BITS 64
 

src/lib9/open.c

@@ -1,15 +1,76 @@
 #define _GNU_SOURCE	/* for Linux O_DIRECT */
 #include <u.h>
-#define NOPLAN9DEFINES
-#include <sys/file.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <libc.h>
-#include <sys/stat.h>
 #include <dirent.h>
-#ifndef O_DIRECT
+#include <errno.h>
-#define O_DIRECT 0
+#include <sys/file.h>
-#endif
+#include <sys/stat.h>
+#define NOPLAN9DEFINES
+#include <libc.h>
+
+static struct {
+	Lock lk;
+	DIR **d;
+	int nd;
+} dirs;
+
+static int
+dirput(int fd, DIR *d)
+{
+	int i, nd;
+	DIR **dp;
+
+	if(fd < 0) {
+		werrstr("invalid fd");
+		return -1;
+	}
+	lock(&dirs.lk);
+	if(fd >= dirs.nd) {
+		nd = dirs.nd*2;
+		if(nd <= fd)
+			nd = fd+1;
+		dp = realloc(dirs.d, nd*sizeof dirs.d[0]);
+		if(dp == nil) {
+			werrstr("out of memory");
+			unlock(&dirs.lk);
+			return -1;
+		}
+		for(i=dirs.nd; i<nd; i++)
+			dp[i] = nil;
+		dirs.d = dp;
+		dirs.nd = nd;
+	}
+	dirs.d[fd] = d;
+	unlock(&dirs.lk);
+	return 0;
+}
+
+static DIR*
+dirget(int fd)
+{
+	DIR *d;
+
+	lock(&dirs.lk);
+	d = nil;
+	if(0 <= fd && fd < dirs.nd)
+		d = dirs.d[fd];
+	unlock(&dirs.lk);
+	return d;
+}
+
+static DIR*
+dirdel(int fd)
+{
+	DIR *d;
+
+	lock(&dirs.lk);
+	d = nil;
+	if(0 <= fd && fd < dirs.nd) {
+		d = dirs.d[fd];
+		dirs.d[fd] = nil;
+	}
+	unlock(&dirs.lk);
+	return d;
+}
 
 int
 p9create(char *path, int mode, ulong perm)
@@ -81,6 +142,8 @@ p9open(char *name, int mode)
 	int cexec, rclose;
 	int fd, umode, lock, rdwr;
 	struct flock fl;
+	struct stat st;
+	DIR *d;
 
 	rdwr = mode&3;
 	umode = rdwr;
@@ -123,6 +186,17 @@ p9open(char *name, int mode)
 		}
 		if(cexec)
 			fcntl(fd, F_SETFL, FD_CLOEXEC);
+		if(fstat(fd, &st) >= 0 && S_ISDIR(st.st_mode)) {
+			d = fdopendir(fd);
+			if(d == nil) {
+				close(fd);
+				return -1;
+			}
+			if(dirput(fd, d) < 0) {
+				closedir(d);
+				return -1;
+			}
+		}
 		if(rclose)
 			remove(name);
 	}
@@ -132,213 +206,143 @@ p9open(char *name, int mode)
 vlong
 p9seek(int fd, vlong offset, int whence)
 {
+	DIR *d;
+
+	if((d = dirget(fd)) != nil) {
+		if(whence == 1 && offset == 0)
+			return telldir(d);
+		if(whence == 0) {
+			seekdir(d, offset);
+			return 0;
+		}
+		werrstr("bad seek in directory");
+		return -1;
+	}
+
 	return lseek(fd, offset, whence);
 }
 
 int
 p9close(int fd)
 {
+	DIR *d;
+
+	if((d = dirdel(fd)) != nil)
+		return closedir(d);
 	return close(fd);
 }
 
+typedef struct DirBuild DirBuild;
+struct DirBuild {
+	Dir *d;
+	int nd;
+	int md;
+	char *str;
+	char *estr;
+};
+
 extern int _p9dir(struct stat*, struct stat*, char*, Dir*, char**, char*);
 
-#if defined(__linux__)
 static int
-mygetdents(int fd, struct dirent *buf, int n)
+dirbuild1(DirBuild *b, struct stat *lst, struct stat *st, char *name)
 {
-	off_t off;
+	int i, nstr;
-	int nn;
+	Dir *d;
+	int md, mstr;
+	char *lo, *hi, *newlo;
 
-	/* This doesn't match the man page, but it works in Debian with a 2.2 kernel */
+	nstr = _p9dir(lst, st, name, nil, nil, nil);
-	off = p9seek(fd, 0, 1);
+	if(b->md-b->nd < 1 || b->estr-b->str < nstr) {
-	nn = getdirentries(fd, (void*)buf, n, &off);
+		// expand either d space or str space or both.
-	return nn;
+		md = b->md;
-}
+		if(b->md-b->nd < 1) {
-#elif defined(__APPLE__)
+			md *= 2;
-static int
+			if(md < 16)
-mygetdents(int fd, struct dirent *buf, int n)
+				md = 16;
-{
+		}
-	long off;
+		mstr = b->estr-(char*)&b->d[b->md];
-	return getdirentries(fd, (void*)buf, n, &off);
+		if(b->estr-b->str < nstr) {
-}
+			mstr += nstr;
-#elif defined(__FreeBSD__) || defined(__DragonFly__)
+			mstr += mstr/2;
-static int
+		}
-mygetdents(int fd, struct dirent *buf, int n)
+		if(mstr < 512)
-{
+			mstr = 512;
-	off_t off;
+		d = realloc(b->d, md*sizeof d[0] + mstr);
-	return getdirentries(fd, (void*)buf, n, &off);
+		if(d == nil)
-}
+			return -1;
-#elif defined(__sun__) || defined(__NetBSD__) || defined(__OpenBSD__)
+		// move strings and update pointers in Dirs
-static int
+		lo = (char*)&b->d[b->md];
-mygetdents(int fd, struct dirent *buf, int n)
+		newlo = (char*)&d[md];
-{
+		hi = b->str;
-	return getdents(fd, (void*)buf, n);
+		memmove(newlo, lo+((char*)d-(char*)b->d), hi-lo);
-}
+		for(i=0; i<b->nd; i++) {
-#elif defined(__AIX__)
+			if(lo <= d[i].name && d[i].name < hi)
-static int
+				d[i].name += newlo - lo;
-mygetdents(int fd, struct dirent *buf, int n)
+			if(lo <= d[i].uid && d[i].uid < hi)
-{
+				d[i].uid += newlo - lo;
-	return getdirent(fd, (void*)buf, n);
+			if(lo <= d[i].gid && d[i].gid < hi)
-}
+				d[i].gid += newlo - lo;
-#endif
+			if(lo <= d[i].muid && d[i].muid < hi)
-
+				d[i].muid += newlo - lo;
-#if defined(__DragonFly__)
+		}
-static inline int d_reclen(struct dirent *de) { return _DIRENT_DIRSIZ(de); }
+		b->d = d;
-#else
+		b->md = md;
-static inline int d_reclen(struct dirent *de) { return de->d_reclen; }
+		b->str += newlo - lo;
-#endif
+		b->estr = newlo + mstr;
-
-static int
-countde(char *p, int n)
-{
-	char *e;
-	int m;
-	struct dirent *de;
-
-	e = p+n;
-	m = 0;
-	while(p < e){
-		de = (struct dirent*)p;
-		if(d_reclen(de) <= 4+2+2+1 || p+d_reclen(de) > e)
-			break;
-		if(de->d_name[0]=='.' && de->d_name[1]==0)
-			de->d_name[0] = 0;
-		else if(de->d_name[0]=='.' && de->d_name[1]=='.' && de->d_name[2]==0)
-			de->d_name[0] = 0;
-		m++;
-		p += d_reclen(de);
 	}
-	return m;
+	_p9dir(lst, st, name, &b->d[b->nd], &b->str, b->estr);
+	b->nd++;
+	return 0;
 }
 
-static int
+static long
-dirpackage(int fd, char *buf, int n, Dir **dp)
+dirreadmax(int fd, Dir **dp, int max)
 {
-	int oldwd;
+	int i;
-	char *p, *str, *estr;
+	DIR *dir;
-	int i, nstr, m;
+	DirBuild b;
 	struct dirent *de;
 	struct stat st, lst;
-	Dir *d;
 
-	n = countde(buf, n);
+	if((dir = dirget(fd)) == nil) {
-	if(n <= 0)
+		werrstr("not a directory");
-		return n;
-
-	if((oldwd = open(".", O_RDONLY)) < 0)
-		return -1;
-	if(fchdir(fd) < 0)
 		return -1;
+	}
 
-	p = buf;
+	memset(&b, 0, sizeof b);
-	nstr = 0;
+	for(i=0; max == -1 || i<max; i++) { // max = not too many, not too few
-
+		errno = 0;
-	for(i=0; i<n; i++){
+		de = readdir(dir);
-		de = (struct dirent*)p;
+		if(de == nil) {
-		memset(&lst, 0, sizeof lst);
+			if(b.nd == 0 && errno != 0)
-		if(de->d_name[0] == 0)
+				return -1;
-			/* nothing */ {}
+			break;
-		else if(lstat(de->d_name, &lst) < 0)
-			de->d_name[0] = 0;
-		else{
-			st = lst;
-			if(S_ISLNK(lst.st_mode))
-				stat(de->d_name, &st);
-			nstr += _p9dir(&lst, &st, de->d_name, nil, nil, nil);
 		}
-		p += d_reclen(de);
+		if(de->d_name[de->d_namlen] != 0)
+			sysfatal("bad readdir");
+		if(de->d_name[0]=='.' && de->d_name[1]==0)
+			continue;
+		if(de->d_name[0]=='.' && de->d_name[1]=='.' && de->d_name[2]==0)
+			continue;
+		if(fstatat(fd, de->d_name, &lst, AT_SYMLINK_NOFOLLOW) < 0)
+			continue;
+		st = lst;
+		if(S_ISLNK(lst.st_mode))
+			fstatat(fd, de->d_name, &st, 0);
+		dirbuild1(&b, &lst, &st, de->d_name);
 	}
-
+	*dp = b.d;
-	d = malloc(sizeof(Dir)*n+nstr);
+	return b.nd;
-	if(d == nil){
-		fchdir(oldwd);
-		close(oldwd);
-		return -1;
-	}
-	str = (char*)&d[n];
-	estr = str+nstr;
-
-	p = buf;
-	m = 0;
-	for(i=0; i<n; i++){
-		de = (struct dirent*)p;
-		if(de->d_name[0] != 0 && lstat(de->d_name, &lst) >= 0){
-			st = lst;
-			if((lst.st_mode&S_IFMT) == S_IFLNK)
-				stat(de->d_name, &st);
-			_p9dir(&lst, &st, de->d_name, &d[m++], &str, estr);
-		}
-		p += d_reclen(de);
-	}
-
-	fchdir(oldwd);
-	close(oldwd);
-	*dp = d;
-	return m;
 }
 
 long
 dirread(int fd, Dir **dp)
 {
-	char *buf;
+	return dirreadmax(fd, dp, 10);
-	struct stat st;
-	int n;
-
-	*dp = 0;
-
-	if(fstat(fd, &st) < 0)
-		return -1;
-
-	if(st.st_blksize < 8192)
-		st.st_blksize = 8192;
-
-	buf = malloc(st.st_blksize);
-	if(buf == nil)
-		return -1;
-
-	n = mygetdents(fd, (void*)buf, st.st_blksize);
-	if(n < 0){
-		free(buf);
-		return -1;
-	}
-	n = dirpackage(fd, buf, n, dp);
-	free(buf);
-	return n;
 }
 
-
 long
-dirreadall(int fd, Dir **d)
+dirreadall(int fd, Dir **dp)
 {
-	uchar *buf, *nbuf;
+	return dirreadmax(fd, dp, -1);
-	long n, ts;
-	struct stat st;
-
-	if(fstat(fd, &st) < 0)
-		return -1;
-
-	if(st.st_blksize < 8192)
-		st.st_blksize = 8192;
-
-	buf = nil;
-	ts = 0;
-	for(;;){
-		nbuf = realloc(buf, ts+st.st_blksize);
-		if(nbuf == nil){
-			free(buf);
-			return -1;
-		}
-		buf = nbuf;
-		n = mygetdents(fd, (void*)(buf+ts), st.st_blksize);
-		if(n <= 0)
-			break;
-		ts += n;
-	}
-	if(ts >= 0)
-		ts = dirpackage(fd, (char*)buf, ts, d);
-	free(buf);
-	if(ts == 0 && n < 0)
-		return -1;
-	return ts;
 }