1 files changed, 458 insertions, 0 deletions

diff --git a/contrib/spd_readdir.c b/contrib/spd_readdir.c
new file mode 100644
index 0000000..8345fa1
--- /dev/null
+++ b/contrib/spd_readdir.c
@@ -0,0 +1,458 @@
+/*
+ * readdir accelerator
+ *
+ * (C) Copyright 2003, 2004, 2008 by Theodore Ts'o.
+ *
+ * 2008-06-08 Modified by Ross Boylan <RossBoylan stanfordalumni org>
+ *    Added support for readdir_r and readdir64_r calls.  Note
+ *     this has not been tested on anything other than GNU/Linux i386,
+ *     and that the regular readdir wrapper will take slightly more
+ *     space than Ted's original since it now includes a lock.
+ *
+ * Compile using the command:
+ *
+ * gcc -o spd_readdir.so -shared -fpic spd_readdir.c -ldl
+ *
+ * Use it by setting the LD_PRELOAD environment variable:
+ * 
+ * export LD_PRELOAD=/usr/local/sbin/spd_readdir.so
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ * 
+ */
+
+#define ALLOC_STEPSIZE	100
+#define MAX_DIRSIZE	0
+
+#define DEBUG
+/* Util we autoconfiscate spd_readdir... */
+#define HAVE___SECURE_GETENV	1
+#define HAVE_PRCTL		1
+#define HAVE_SYS_PRCTL_H	1
+
+#ifdef DEBUG
+#define DEBUG_DIR(x)	{if (do_debug) { x; }}
+#else
+#define DEBUG_DIR(x)
+#endif
+
+#define _GNU_SOURCE
+#define __USE_LARGEFILE64
+
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dirent.h>
+#include <errno.h>
+#include <dlfcn.h>
+#ifdef HAVE_SYS_PRCTL_H
+#include <sys/prctl.h>
+#else
+#define PR_GET_DUMPABLE 3
+#endif
+#include <pthread.h>
+
+struct dirent_s {
+	unsigned long long d_ino;
+	long long d_off;
+	unsigned short int d_reclen;
+	unsigned char d_type;
+	char *d_name;
+};
+
+struct dir_s {
+	DIR	*dir;
+	pthread_mutex_t lock; /* Mutex lock for this structure.  */
+	int	num;
+	int	max;
+	struct dirent_s *dp;
+	int	pos;
+	int	direct;
+	struct dirent ret_dir;
+	struct dirent64 ret_dir64;
+};
+
+static int (*real_closedir)(DIR *dir) = 0;
+static DIR *(*real_opendir)(const char *name) = 0;
+static DIR *(*real_fdopendir)(int fd) = 0;
+static void *(*real_rewinddir)(DIR *dirp) = 0;
+static struct dirent *(*real_readdir)(DIR *dir) = 0;
+static int (*real_readdir_r)(DIR *dir, struct dirent *entry,
+			     struct dirent **result) = 0;
+static struct dirent64 *(*real_readdir64)(DIR *dir) = 0;
+static int (*real_readdir64_r)(DIR *dir, struct dirent64 *entry,
+			       struct dirent64 **result) = 0;
+static off_t (*real_telldir)(DIR *dir) = 0;
+static void (*real_seekdir)(DIR *dir, off_t offset) = 0;
+static int (*real_dirfd)(DIR *dir) = 0;
+static unsigned long max_dirsize = MAX_DIRSIZE;
+static int num_open = 0;
+#ifdef DEBUG
+static int do_debug = 0;
+#endif
+
+static char *safe_getenv(const char *arg)
+{
+	if ((getuid() != geteuid()) || (getgid() != getegid()))
+		return NULL;
+#if HAVE_PRCTL
+	if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
+		return NULL;
+#else
+#if (defined(linux) && defined(SYS_prctl))
+	if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
+		return NULL;
+#endif
+#endif
+
+#if HAVE___SECURE_GETENV
+	return __secure_getenv(arg);
+#else
+	return getenv(arg);
+#endif
+}
+
+static void setup_ptr()
+{
+	char *cp;
+
+	real_opendir = dlsym(RTLD_NEXT, "opendir");
+	real_fdopendir = dlsym(RTLD_NEXT, "fdopendir");
+	real_closedir = dlsym(RTLD_NEXT, "closedir");
+	real_rewinddir = dlsym(RTLD_NEXT, "rewinddir");
+	real_readdir = dlsym(RTLD_NEXT, "readdir");
+	real_readdir_r = dlsym(RTLD_NEXT, "readdir_r");
+	real_readdir64 = dlsym(RTLD_NEXT, "readdir64");
+	real_readdir64_r = dlsym(RTLD_NEXT, "readdir64_r");
+	real_telldir = dlsym(RTLD_NEXT, "telldir");
+	real_seekdir = dlsym(RTLD_NEXT, "seekdir");
+	real_dirfd = dlsym(RTLD_NEXT, "dirfd");
+	if ((cp = safe_getenv("SPD_READDIR_MAX_SIZE")) != NULL) {
+		max_dirsize = atol(cp);
+	}
+#ifdef DEBUG
+	if (safe_getenv("SPD_READDIR_DEBUG")) {
+		printf("initialized!\n");
+		do_debug++;
+	}
+#endif
+}
+
+static void free_cached_dir(struct dir_s *dirstruct)
+{
+	int i;
+
+	pthread_mutex_destroy(&(dirstruct->lock));
+
+	if (!dirstruct->dp)
+		return;
+
+	for (i=0; i < dirstruct->num; i++) {
+		free(dirstruct->dp[i].d_name);
+	}
+	free(dirstruct->dp);
+	dirstruct->dp = 0;
+	dirstruct->max = dirstruct->num = 0;
+}	
+
+static int ino_cmp(const void *a, const void *b)
+{
+	const struct dirent_s *ds_a = (const struct dirent_s *) a;
+	const struct dirent_s *ds_b = (const struct dirent_s *) b;
+	ino_t i_a, i_b;
+	
+	i_a = ds_a->d_ino;
+	i_b = ds_b->d_ino;
+
+	if (ds_a->d_name[0] == '.') {
+		if (ds_a->d_name[1] == 0)
+			i_a = 0;
+		else if ((ds_a->d_name[1] == '.') && (ds_a->d_name[2] == 0))
+			i_a = 1;
+	}
+	if (ds_b->d_name[0] == '.') {
+		if (ds_b->d_name[1] == 0)
+			i_b = 0;
+		else if ((ds_b->d_name[1] == '.') && (ds_b->d_name[2] == 0))
+			i_b = 1;
+	}
+
+	return (i_a - i_b);
+}
+
+static struct dir_s *alloc_dirstruct(DIR *dir)
+{
+	struct dir_s	*dirstruct;
+	static pthread_mutexattr_t mutexattr;
+	mutexattr.__align = PTHREAD_MUTEX_RECURSIVE;
+
+	dirstruct = malloc(sizeof(struct dir_s));
+	if (dirstruct)
+		memset(dirstruct, 0, sizeof(struct dir_s));
+	dirstruct->dir = dir;
+	pthread_mutex_init(&(dirstruct->lock), &mutexattr);
+	return dirstruct;
+}
+
+static void cache_dirstruct(struct dir_s *dirstruct)
+{
+	struct dirent_s *ds, *dnew;
+	struct dirent64 *d;
+
+	while ((d = (*real_readdir64)(dirstruct->dir)) != NULL) {
+		if (dirstruct->num >= dirstruct->max) {
+			dirstruct->max += ALLOC_STEPSIZE;
+			DEBUG_DIR(printf("Reallocating to size %d\n", 
+					 dirstruct->max));
+			dnew = realloc(dirstruct->dp, 
+				       dirstruct->max * sizeof(struct dir_s));
+			if (!dnew)
+				goto nomem;
+			dirstruct->dp = dnew;
+		}
+		ds = &dirstruct->dp[dirstruct->num++];
+		ds->d_ino = d->d_ino;
+		ds->d_off = d->d_off;
+		ds->d_reclen = d->d_reclen;
+		ds->d_type = d->d_type;
+		if ((ds->d_name = malloc(strlen(d->d_name)+1)) == NULL) {
+			dirstruct->num--;
+			goto nomem;
+		}
+		strcpy(ds->d_name, d->d_name);
+		DEBUG_DIR(printf("readdir: %lu %s\n", 
+				 (unsigned long) d->d_ino, d->d_name));
+	}
+	qsort(dirstruct->dp, dirstruct->num, sizeof(struct dirent_s), ino_cmp);
+	return;
+nomem:
+	DEBUG_DIR(printf("No memory, backing off to direct readdir\n"));
+	free_cached_dir(dirstruct);
+	dirstruct->direct = 1;
+}
+
+DIR *opendir(const char *name)
+{
+	DIR *dir;
+	struct dir_s	*dirstruct;
+	struct stat st;
+
+	if (!real_opendir)
+		setup_ptr();
+
+	DEBUG_DIR(printf("Opendir(%s) (%d open)\n", name, num_open++));
+	dir = (*real_opendir)(name);
+	if (!dir)
+		return NULL;
+
+	dirstruct = alloc_dirstruct(dir);
+	if (!dirstruct) {
+		(*real_closedir)(dir);
+		errno = -ENOMEM;
+		return NULL;
+	}
+
+	if (max_dirsize && (stat(name, &st) == 0) && 
+	    (st.st_size > max_dirsize)) {
+		DEBUG_DIR(printf("Directory size %ld, using direct readdir\n",
+				 st.st_size));
+		dirstruct->direct = 1;
+		return (DIR *) dirstruct;
+	}
+
+	cache_dirstruct(dirstruct);
+	return ((DIR *) dirstruct);
+}
+
+DIR *fdopendir(int fd)
+{
+	DIR *dir;
+	struct dir_s	*dirstruct;
+	struct stat st;
+
+	if (!real_fdopendir)
+		setup_ptr();
+
+	DEBUG_DIR(printf("fdopendir(%d) (%d open)\n", fd, num_open++));
+	dir = (*real_fdopendir)(fd);
+	if (!dir)
+		return NULL;
+
+	dirstruct = alloc_dirstruct(dir);
+	if (!dirstruct) {
+		(*real_closedir)(dir);
+		errno = -ENOMEM;
+		return NULL;
+	}
+
+	if (max_dirsize && (fstat(fd, &st) == 0) && 
+	    (st.st_size > max_dirsize)) {
+		DEBUG_DIR(printf("Directory size %ld, using direct readdir\n",
+				 st.st_size));
+		dirstruct->dir = dir;
+		dirstruct->direct = 1;
+		return (DIR *) dirstruct;
+	}
+
+	cache_dirstruct(dirstruct);
+	return ((DIR *) dirstruct);
+}
+
+int closedir(DIR *dir)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+
+	DEBUG_DIR(printf("Closedir (%d open)\n", --num_open));
+	if (dirstruct->dir)
+		(*real_closedir)(dirstruct->dir);
+
+	free_cached_dir(dirstruct);
+	free(dirstruct);
+	return 0;
+}
+
+struct dirent *readdir(DIR *dir)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+	struct dirent_s *ds;
+
+	if (dirstruct->direct)
+		return (*real_readdir)(dirstruct->dir);
+
+	if (dirstruct->pos >= dirstruct->num)
+		return NULL;
+
+	ds = &dirstruct->dp[dirstruct->pos++];
+	dirstruct->ret_dir.d_ino = ds->d_ino;
+	dirstruct->ret_dir.d_off = ds->d_off;
+	dirstruct->ret_dir.d_reclen = ds->d_reclen;
+	dirstruct->ret_dir.d_type = ds->d_type;
+	strncpy(dirstruct->ret_dir.d_name, ds->d_name,
+		sizeof(dirstruct->ret_dir.d_name));
+
+	return (&dirstruct->ret_dir);
+}
+
+int readdir_r(DIR *dir, struct dirent *entry, struct dirent **result)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+	struct dirent_s *ds;
+
+	if (dirstruct->direct)
+		return (*real_readdir_r)(dirstruct->dir, entry, result);
+
+	pthread_mutex_lock(&(dirstruct->lock));
+	if (dirstruct->pos >= dirstruct->num) {
+		*result = NULL;
+	} else {
+		ds = &dirstruct->dp[dirstruct->pos++];
+		entry->d_ino = ds->d_ino;
+		entry->d_off = ds->d_off;
+		entry->d_reclen = ds->d_reclen;
+		entry->d_type = ds->d_type;
+		strncpy(entry->d_name, ds->d_name, sizeof(entry->d_name));
+		*result = entry;
+	}
+	pthread_mutex_unlock(&(dirstruct->lock));
+	return 0;
+}
+
+struct dirent64 *readdir64(DIR *dir)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+	struct dirent_s *ds;
+
+	if (dirstruct->direct)
+		return (*real_readdir64)(dirstruct->dir);
+
+	if (dirstruct->pos >= dirstruct->num)
+		return NULL;
+
+	ds = &dirstruct->dp[dirstruct->pos++];
+	dirstruct->ret_dir64.d_ino = ds->d_ino;
+	dirstruct->ret_dir64.d_off = ds->d_off;
+	dirstruct->ret_dir64.d_reclen = ds->d_reclen;
+	dirstruct->ret_dir64.d_type = ds->d_type;
+	strncpy(dirstruct->ret_dir64.d_name, ds->d_name,
+		sizeof(dirstruct->ret_dir64.d_name));
+
+	return (&dirstruct->ret_dir64);
+}
+
+int readdir64_r (DIR *__restrict dir,
+		 struct dirent64 *__restrict entry,
+		 struct dirent64 **__restrict result)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+	struct dirent_s *ds;
+
+	if (dirstruct->direct)
+		return (*real_readdir64_r)(dir, entry, result);
+	pthread_mutex_lock(&(dirstruct->lock));
+	if (dirstruct->pos >= dirstruct->num) {
+		*result = NULL;
+	} else {
+		ds = &dirstruct->dp[dirstruct->pos++];
+		entry->d_ino = ds->d_ino;
+		entry->d_off = ds->d_off;
+		entry->d_reclen = ds->d_reclen;
+		entry->d_type = ds->d_type;
+		strncpy(entry->d_name, ds->d_name,
+			sizeof(entry->d_name));
+		*result = entry;
+	}
+	pthread_mutex_unlock(&(dirstruct->lock));
+	return 0;
+}
+
+off_t telldir(DIR *dir)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+
+	if (dirstruct->direct)
+		return (*real_telldir)(dirstruct->dir);
+
+	return ((off_t) dirstruct->pos);
+}
+
+void seekdir(DIR *dir, off_t offset)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+
+	if (dirstruct->direct) {
+		(*real_seekdir)(dirstruct->dir, offset);
+		return;
+	}
+
+	dirstruct->pos = offset;
+}
+
+void rewinddir(DIR *dir)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+
+	(*real_rewinddir)(dirstruct->dir);
+	if (dirstruct->direct)
+		return;
+	
+	pthread_mutex_lock(&(dirstruct->lock));
+	dirstruct->pos = 0;
+	free_cached_dir(dirstruct);
+	cache_dirstruct(dirstruct);
+	pthread_mutex_unlock(&(dirstruct->lock));
+}
+
+int dirfd(DIR *dir)
+{
+	struct dir_s	*dirstruct = (struct dir_s *) dir;
+	int fd = (*real_dirfd)(dirstruct->dir);
+
+	DEBUG_DIR(printf("dirfd %d, %p\n", fd, real_dirfd));
+	return fd;
+}