Implement readdir_r. Audit for proper thread safety and locking.

 -Erik

libc/misc/dirent/Makefile

@@ -25,7 +25,7 @@ TOPDIR=../../../
 include $(TOPDIR)Rules.mak
 
 CSRC=alphasort.c closedir.c dirfd.c opendir.c readdir.c rewinddir.c scandir.c \
-     	seekdir.c telldir.c readdir64.c alphasort64.c scandir64.c
+     	seekdir.c telldir.c readdir64.c alphasort64.c scandir64.c readdir_r.c
 COBJS=$(patsubst %.c,%.o, $(CSRC))
 OBJS=$(COBJS)
 

libc/misc/dirent/closedir.c

@@ -19,8 +19,14 @@ int closedir(DIR * dir)
 		__set_errno(EBADF);
 		return -1;
 	}
+#ifdef _POSIX_THREADS
+	pthread_mutex_lock(dir->dd_lock);
+#endif
 	fd = dir->dd_fd;
 	dir->dd_fd = -1;
+#ifdef _POSIX_THREADS
+	pthread_mutex_unlock(dir->dd_lock);
+#endif
 	free(dir->dd_buf);
 	free(dir);
 	return close(fd);

libc/misc/dirent/dirstream.h

@@ -30,17 +30,6 @@ Cambridge, MA 02139, USA.  */
 #include <pthread.h>
 #endif
 
-
-#ifdef __UCLIBC_HAVE_LFS__
-#ifndef __USE_LARGEFILE64
-# define __USE_LARGEFILE64
-#endif
-# define stuff_t    __off64_t
-#else
-# define stuff_t    __off_t
-#endif
-
-
 /* For now, syscall readdir () only supports one entry at a time. It
  * will be changed in the future.
 #define NUMENT		3
@@ -59,22 +48,20 @@ struct __dirstream {
   int dd_fd;
 
   /* offset of the next dir entry in buffer */
-  stuff_t dd_nextloc;
+  size_t dd_nextloc;
 
   /* bytes of valid entries in buffer */
-  stuff_t dd_size;
+  size_t dd_size;
 
   /* -> directory buffer */
   void *dd_buf;
 
   /* offset of the next dir entry in directory. */
-  stuff_t dd_nextoff;
+  off_t dd_nextoff;
 
   /* total size of buffer */
-  stuff_t dd_max;
+  size_t dd_max;
  
-  enum {unknown, have_getdents, no_getdents} dd_getdents;
-
   /* lock */
 #ifdef _POSIX_THREADS
   pthread_mutex_t *dd_lock;

libc/misc/dirent/opendir.c

@@ -39,7 +39,6 @@ DIR *opendir(const char *name)
 
 	ptr->dd_fd = fd;
 	ptr->dd_nextloc = ptr->dd_size = ptr->dd_nextoff = 0;
-	ptr->dd_getdents = unknown;
 
 	ptr->dd_max = statbuf.st_blksize;
 	if (ptr->dd_max < 512)
@@ -52,5 +51,8 @@ DIR *opendir(const char *name)
 		return NULL;
 	}
 	ptr->dd_buf = buf;
+#ifdef _POSIX_THREADS
+	pthread_mutex_init(ptr->dd_lock, NULL);
+#endif
 	return ptr;
 }

libc/misc/dirent/readdir.c

@@ -10,7 +10,7 @@ extern int getdents __P ((unsigned int fd, struct dirent *dirp, unsigned int cou
 
 struct dirent *readdir(DIR * dir)
 {
-	int result;
+	ssize_t bytes;
 	struct dirent *de;
 
 	if (!dir) {
@@ -18,42 +18,36 @@ struct dirent *readdir(DIR * dir)
 		return NULL;
 	}
 
-	/* Are we running an old kernel? */
-	if (dir->dd_getdents == no_getdents) {
-		abort();
-	}
+#ifdef _POSIX_THREADS
+	pthread_mutex_lock(dir->dd_lock);
+#endif
 
-	if (dir->dd_size <= dir->dd_nextloc) {
+	do {
+	    if (dir->dd_size <= dir->dd_nextloc) {
 		/* read dir->dd_max bytes of directory entries. */
-		result = getdents(dir->dd_fd, dir->dd_buf, dir->dd_max);
-
-		/* We assume we have getdents (). */
-		dir->dd_getdents = have_getdents;
-		if (result <= 0) {
-			result = -result;
-			if (result > 0) {
-				/* Are we right? */
-				if (result == ENOSYS) {
-					dir->dd_getdents = no_getdents;
-					abort();
-				}
-				__set_errno(result);
-			}
-
-			return NULL;
+		bytes = getdents(dir->dd_fd, dir->dd_buf, dir->dd_max);
+		if (bytes <= 0) {
+		    de = NULL;
+		    goto all_done;
 		}
-
-		dir->dd_size = result;
+		dir->dd_size = bytes;
 		dir->dd_nextloc = 0;
-	}
+	    }
+
+	    de = (struct dirent *) (((char *) dir->dd_buf) + dir->dd_nextloc);
 
-	de = (struct dirent *) (((char *) dir->dd_buf) + dir->dd_nextloc);
+	    /* Am I right? H.J. */
+	    dir->dd_nextloc += de->d_reclen;
 
-	/* Am I right? H.J. */
-	dir->dd_nextloc += de->d_reclen;
+	    /* We have to save the next offset here. */
+	    dir->dd_nextoff = de->d_off;
 
-	/* We have to save the next offset here. */
-	dir->dd_nextoff = de->d_off;
+	    /* Skip deleted files.  */
+	} while (de->d_ino == 0);
 
+all_done:
+#ifdef _POSIX_THREADS
+	pthread_mutex_unlock(dir->dd_lock);
+#endif
 	return de;
 }

libc/misc/dirent/readdir64.c

@@ -25,7 +25,7 @@ extern int getdents64 __P ((unsigned int fd, struct dirent64 *dirp, unsigned int
 
 struct dirent64 *readdir64(DIR * dir)
 {
-	int result;
+	ssize_t bytes;
 	struct dirent64 *de;
 
 	if (!dir) {
@@ -33,42 +33,37 @@ struct dirent64 *readdir64(DIR * dir)
 		return NULL;
 	}
 
-	/* Are we running an old kernel? */
-	if (dir->dd_getdents == no_getdents) {
-		abort();
-	}
+#ifdef _POSIX_THREADS
+	pthread_mutex_lock(dir->dd_lock);
+#endif
 
-	if (dir->dd_size <= dir->dd_nextloc) {
+	do {
+	    if (dir->dd_size <= dir->dd_nextloc) {
 		/* read dir->dd_max bytes of directory entries. */
-		result = getdents64(dir->dd_fd, dir->dd_buf, dir->dd_max);
-
-		/* We assume we have getdents64 (). */
-		dir->dd_getdents = have_getdents;
-		if (result <= 0) {
-			result = -result;
-			if (result > 0) {
-				/* Are we right? */
-				if (result == ENOSYS) {
-					dir->dd_getdents = no_getdents;
-					abort();
-				}
-				__set_errno(result);
-			}
-
-			return NULL;
+		bytes = getdents64(dir->dd_fd, dir->dd_buf, dir->dd_max);
+		if (bytes <= 0) {
+		    de = NULL;
+		    goto all_done;
 		}
-
-		dir->dd_size = result;
+		dir->dd_size = bytes;
 		dir->dd_nextloc = 0;
-	}
+	    }
+
+	    de = (struct dirent64 *) (((char *) dir->dd_buf) + dir->dd_nextloc);
 
-	de = (struct dirent64 *) (((char *) dir->dd_buf) + dir->dd_nextloc);
+	    /* Am I right? H.J. */
+	    dir->dd_nextloc += de->d_reclen;
 
-	/* Am I right? H.J. */
-	dir->dd_nextloc += de->d_reclen;
+	    /* We have to save the next offset here. */
+	    dir->dd_nextoff = de->d_off;
 
-	/* We have to save the next offset here. */
-	dir->dd_nextoff = de->d_off;
+	    /* Skip deleted files.  */
+	} while (dir->d_ino == 0);
+
+all_done:
+#ifdef _POSIX_THREADS
+	pthread_mutex_unlock(dir->dd_lock);
+#endif
 
 	return de;
 }

libc/misc/dirent/readdir_r.c

@@ -0,0 +1,63 @@
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <dirent.h>
+#include "dirstream.h"
+
+extern int getdents __P ((unsigned int fd, struct dirent *dirp, unsigned int count));
+
+
+int readdir_r(DIR *dir, struct dirent *entry, struct dirent **result)
+{
+	int ret;
+	ssize_t bytes;
+	struct dirent *de;
+
+	if (!dir) {
+	    __set_errno(EBADF);
+	    return(EBADF);
+	}
+	de = NULL;
+
+#ifdef _POSIX_THREADS
+	pthread_mutex_lock(dir->dd_lock);
+#endif
+
+	do {
+	    if (dir->dd_size <= dir->dd_nextloc) {
+		/* read dir->dd_max bytes of directory entries. */
+		bytes = getdents(dir->dd_fd, dir->dd_buf, dir->dd_max);
+		if (bytes <= 0) {
+		    *result = NULL;
+		    ret = errno;
+		    goto all_done;
+		}
+		dir->dd_size = bytes;
+		dir->dd_nextloc = 0;
+	    }
+
+	    de = (struct dirent *) (((char *) dir->dd_buf) + dir->dd_nextloc);
+
+	    /* Am I right? H.J. */
+	    dir->dd_nextloc += de->d_reclen;
+
+	    /* We have to save the next offset here. */
+	    dir->dd_nextoff = de->d_off;
+	    /* Skip deleted files.  */
+	} while (de->d_ino == 0);
+
+	if (de == NULL) {
+	    *result = NULL;
+	} else {
+	    *result = memcpy (entry, de, de->d_reclen);
+	}
+	ret = 0;
+
+all_done:
+
+#ifdef _POSIX_THREADS
+	pthread_mutex_unlock(dir->dd_lock);
+#endif
+        return((de != NULL)? 0 : ret);
+}

libc/misc/dirent/rewinddir.c

@@ -11,6 +11,12 @@ void rewinddir(DIR * dir)
 		__set_errno(EBADF);
 		return;
 	}
+#ifdef _POSIX_THREADS
+	pthread_mutex_lock(dir->dd_lock);
+#endif
 	lseek(dir->dd_fd, 0, SEEK_SET);
 	dir->dd_nextoff = dir->dd_nextloc = dir->dd_size = 0;
+#ifdef _POSIX_THREADS
+	pthread_mutex_unlock(dir->dd_lock);
+#endif
 }

libc/misc/dirent/seekdir.c

@@ -10,6 +10,12 @@ void seekdir(DIR * dir, long int offset)
 		__set_errno(EBADF);
 		return;
 	}
+#ifdef _POSIX_THREADS
+	pthread_mutex_lock(dir->dd_lock);
+#endif
 	dir->dd_nextoff = lseek(dir->dd_fd, offset, SEEK_SET);
 	dir->dd_size = dir->dd_nextloc = 0;
+#ifdef _POSIX_THREADS
+	pthread_mutex_unlock(dir->dd_lock);
+#endif
 }

libc/misc/dirent/telldir.c

@@ -6,31 +6,11 @@
 
 long int telldir(DIR * dir)
 {
-	off_t offset;
-
 	if (!dir) {
 		__set_errno(EBADF);
 		return -1;
 	}
 
-	switch (dir->dd_getdents) {
-	case no_getdents:
-		/* We are running the old kernel. This is the starting offset
-		   of the next readdir(). */
-		offset = lseek(dir->dd_fd, 0, SEEK_CUR);
-		break;
-
-	case unknown:
-		/* readdir () is not called yet. but seekdir () may be called. */
-	case have_getdents:
-		/* The next entry. */
-		offset = dir->dd_nextoff;
-		break;
-
-	default:
-		__set_errno(EBADF);
-		offset = -1;
-	}
-
-	return offset;
+	/* The next entry. */
+	return dir->dd_nextoff;
 }