diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7d435f3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+*.o
+*.so
+cachedel
+cachestats
+nocache
diff --git a/Makefile b/Makefile
index 88aa8e2..4f8b4bf 100644
--- a/Makefile
+++ b/Makefile
@@ -10,11 +10,11 @@ bindir  = $(DESTDIR)$(PREFIX)$(BINDIR)
 libdir  = $(DESTDIR)$(PREFIX)$(LIBDIR)
 
 CACHE_BINS=cachedel cachestats
-NOCACHE_BINS=nocache.o fcntl_helpers.o pageinfo.o
+NOCACHE_BINS=nocache.o fcntl_helpers.o pageinfo.o wrappers.o
 MANPAGES=$(wildcard man/*.1)
 
 CC ?= gcc
-CFLAGS+= -Wall
+CFLAGS+= -Wall -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64
 COMPILE = $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS)
 
 .PHONY: all
diff --git a/nocache.c b/nocache.c
index ae2699b..fccb3f3 100644
--- a/nocache.c
+++ b/nocache.c
@@ -3,6 +3,7 @@
 #include <sys/stat.h>
 #include <sys/mman.h>
 #include <unistd.h>
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -15,8 +16,10 @@
 #include <assert.h>
 #include <signal.h>
 
+#include "wrappers.h"
 #include "pageinfo.h"
 #include "fcntl_helpers.h"
+#include "nocache.h"
 
 static void init(void) __attribute__((constructor));
 static void destroy(void) __attribute__((destructor));
@@ -24,38 +27,6 @@ static void init_mutexes(void);
 static void init_debugging(void);
 static void handle_stdout(void);
 
-static void store_pageinfo(int fd);
-static void free_unclaimed_pages(int fd, bool block_signals);
-
-int open(const char *pathname, int flags, mode_t mode);
-int open64(const char *pathname, int flags, mode_t mode);
-int creat(const char *pathname, int flags, mode_t mode);
-int creat64(const char *pathname, int flags, mode_t mode);
-int openat(int dirfd, const char *pathname, int flags, mode_t mode);
-int openat64(int dirfd, const char *pathname, int flags, mode_t mode);
-int __openat_2(int dirfd, const char *pathname, int flags, mode_t mode)
-    __attribute__ ((alias ("openat")));
-int dup(int oldfd);
-int dup2(int oldfd, int newfd);
-int close(int fd);
-FILE *fopen(const char *path, const char *mode);
-FILE *fopen64(const char *path, const char *mode);
-int fclose(FILE *fp);
-
-int (*_original_open)(const char *pathname, int flags, mode_t mode);
-int (*_original_open64)(const char *pathname, int flags, mode_t mode);
-int (*_original_creat)(const char *pathname, int flags, mode_t mode);
-int (*_original_creat64)(const char *pathname, int flags, mode_t mode);
-int (*_original_openat)(int dirfd, const char *pathname, int flags, mode_t mode);
-int (*_original_openat64)(int dirfd, const char *pathname, int flags, mode_t mode);
-int (*_original_dup)(int fd);
-int (*_original_dup2)(int newfd, int oldfd);
-int (*_original_close)(int fd);
-FILE *(*_original_fopen)(const char *path, const char *mode);
-FILE *(*_original_fopen64)(const char *path, const char *mode);
-int (*_original_fclose)(FILE *fp);
-
-
 /* Info about a file descriptor 'fd' is stored in fds[fd]. Before accessing an
  * element, callers MUST both check fds_lock != NULL and then acquire
  * fds_lock[fd] while holding the fds_iter_lock. While any mutex in fds_lock is
@@ -70,9 +41,11 @@ static size_t PAGESIZE;
 static char *env_nr_fadvise = "NOCACHE_NR_FADVISE";
 static int nr_fadvise;
 
+int nocache_EOF;
+
 static char *env_debugfd = "NOCACHE_DEBUGFD";
-int debugfd = -1;
-FILE *debugfp;
+static int debugfd = -1;
+static FILE *debugfp;
 
 static char *env_flushall = "NOCACHE_FLUSHALL";
 static char flushall;
@@ -80,12 +53,21 @@ static char flushall;
 static char *env_max_fds = "NOCACHE_MAX_FDS";
 static rlim_t max_fd_limit = 1 << 20;
 
-#define DEBUG(...) \
-    do { \
-        if(debugfp != NULL) { \
-            fprintf(debugfp, "[nocache] DEBUG: " __VA_ARGS__); \
-        } \
-    } while(0)
+int nocache_fileno(FILE *fp)
+{
+    return fileno(fp);
+}
+
+void debug(const char *fmt, ...)
+{
+    if(debugfp != NULL) {
+        va_list args;
+
+        va_start(args, fmt);
+        vfprintf(debugfp, fmt, args);
+        va_end(args);
+    }
+}
 
 static void init(void)
 {
@@ -141,6 +123,7 @@ static void init(void)
     }
 
     PAGESIZE = getpagesize();
+    nocache_EOF = EOF;
     pthread_mutex_lock(&fds_iter_lock);
     for(i = 0; i < max_fds; i++) {
         pthread_mutex_lock(&fds_lock[i]);
@@ -232,198 +215,7 @@ static void destroy(void)
     pthread_mutex_unlock(&fds_iter_lock);
 }
 
-int open(const char *pathname, int flags, mode_t mode)
-{
-    int fd;
-
-    if(!_original_open)
-        _original_open = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "open");
-    assert(_original_open != NULL);
-
-    if((fd = _original_open(pathname, flags, mode)) != -1) {
-        DEBUG("open(pathname=%s, flags=0x%x, mode=0%o) = %d\n",
-            pathname, flags, mode, fd);
-        store_pageinfo(fd);
-    }
-    return fd;
-}
-
-int open64(const char *pathname, int flags, mode_t mode)
-{
-    int fd;
-
-    if(!_original_open64)
-        _original_open64 = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "open64");
-    assert(_original_open64 != NULL);
-
-    DEBUG("open64(pathname=%s, flags=0x%x, mode=0%o)\n", pathname, flags, mode);
-
-    if((fd = _original_open64(pathname, flags, mode)) != -1)
-        store_pageinfo(fd);
-    return fd;
-}
-
-int creat(const char *pathname, int flags, mode_t mode)
-{
-    int fd;
-
-    if(!_original_creat)
-        _original_creat = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "creat");
-    assert(_original_creat != NULL);
-
-    DEBUG("creat(pathname=%s, flags=0x%x, mode=0%o)\n", pathname, flags, mode);
-
-    if((fd = _original_creat(pathname, flags, mode)) != -1)
-        store_pageinfo(fd);
-    return fd;
-}
-
-int creat64(const char *pathname, int flags, mode_t mode)
-{
-    int fd;
-
-    if(!_original_creat64)
-        _original_creat64 = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "creat64");
-    assert(_original_creat64 != NULL);
-
-    DEBUG("creat64(pathname=%s, flags=0x%x, mode=0%o)\n", pathname, flags, mode);
-
-    if((fd = _original_creat64(pathname, flags, mode)) != -1)
-        store_pageinfo(fd);
-    return fd;
-}
-
-int openat(int dirfd, const char *pathname, int flags, mode_t mode)
-{
-    int fd;
-
-    if(!_original_openat)
-        _original_openat = (int (*)(int, const char *, int, mode_t)) dlsym(RTLD_NEXT, "openat");
-    assert(_original_openat != NULL);
-
-    DEBUG("openat(dirfd=%d, pathname=%s, flags=0x%x, mode=0%o)\n", dirfd, pathname, flags, mode);
-
-    if((fd = _original_openat(dirfd, pathname, flags, mode)) != -1)
-        store_pageinfo(fd);
-    return fd;
-}
-
-int openat64(int dirfd, const char *pathname, int flags, mode_t mode)
-{
-    int fd;
-
-    if(!_original_openat64)
-        _original_openat64 = (int (*)(int, const char *, int, mode_t)) dlsym(RTLD_NEXT, "openat64");
-    assert(_original_openat64 != NULL);
-
-    DEBUG("openat64(dirfd=%d, pathname=%s, flags=0x%x, mode=0%o)\n", dirfd, pathname, flags, mode);
-
-    if((fd = _original_openat64(dirfd, pathname, flags, mode)) != -1)
-        store_pageinfo(fd);
-    return fd;
-}
-
-int dup(int oldfd)
-{
-    int fd;
-
-    if(!_original_dup)
-        _original_dup = (int (*)(int)) dlsym(RTLD_NEXT, "dup");
-    assert(_original_dup != NULL);
-
-    DEBUG("dup(oldfd=%d)\n", oldfd);
-
-    if((fd = _original_dup(oldfd)) != -1)
-        store_pageinfo(fd);
-    return fd;
-}
-
-int dup2(int oldfd, int newfd)
-{
-    int ret;
-
-    /* if newfd is already opened, the kernel will close it directly
-     * once dup2 is invoked. So now is the last chance to mark the
-     * pages as "DONTNEED" */
-    if(valid_fd(newfd))
-        free_unclaimed_pages(newfd, true);
-
-    if(!_original_dup2)
-        _original_dup2 = (int (*)(int, int)) dlsym(RTLD_NEXT, "dup2");
-    assert(_original_dup2 != NULL);
-
-    DEBUG("dup2(oldfd=%d, newfd=%d)\n", oldfd, newfd);
-
-    if((ret = _original_dup2(oldfd, newfd)) != -1)
-        store_pageinfo(newfd);
-    return ret;
-}
-
-int close(int fd)
-{
-    if(!_original_close)
-        _original_close = (int (*)(int)) dlsym(RTLD_NEXT, "close");
-    assert(_original_close != NULL);
-
-    free_unclaimed_pages(fd, true);
-
-    DEBUG("close(%d)\n", fd);
-    return _original_close(fd);
-}
-
-FILE *fopen(const char *path, const char *mode)
-{
-    int fd;
-    FILE *fp = NULL;
-
-    if(!_original_fopen)
-       _original_fopen = (FILE *(*)(const char *, const char *)) dlsym(RTLD_NEXT, "fopen");
-    assert(_original_fopen != NULL);
-
-    DEBUG("fopen(path=%s, mode=%s)\n", path, mode);
-
-    if((fp = _original_fopen(path, mode)) != NULL)
-        if((fd = fileno(fp)) != -1)
-            store_pageinfo(fd);
-
-    return fp;
-}
-
-FILE *fopen64(const char *path, const char *mode)
-{
-    int fd;
-    FILE *fp;
-    fp = NULL;
-
-    if(!_original_fopen64)
-        _original_fopen64 = (FILE *(*)(const char *, const char *)) dlsym(RTLD_NEXT, "fopen64");
-    assert(_original_fopen64 != NULL);
-
-    DEBUG("fopen64(path=%s, mode=%s)\n", path, mode);
-
-    if((fp = _original_fopen64(path, mode)) != NULL)
-        if((fd = fileno(fp)) != -1)
-            store_pageinfo(fd);
-
-    return fp;
-}
-
-int fclose(FILE *fp)
-{
-    if(!_original_fclose)
-        _original_fclose = (int (*)(FILE *)) dlsym(RTLD_NEXT, "fclose");
-    assert(_original_fclose != NULL);
-
-    if(_original_fclose) {
-        free_unclaimed_pages(fileno(fp), true);
-        return _original_fclose(fp);
-    }
-
-    errno = EFAULT;
-    return EOF;
-}
-
-static void store_pageinfo(int fd)
+void store_pageinfo(int fd)
 {
     sigset_t mask, old_mask;
 
@@ -472,7 +264,7 @@ static void store_pageinfo(int fd)
     return;
 }
 
-static void free_unclaimed_pages(int fd, bool block_signals)
+void free_unclaimed_pages(int fd, bool block_signals)
 {
     struct stat st;
     sigset_t mask, old_mask;
diff --git a/nocache.h b/nocache.h
new file mode 100644
index 0000000..6853367
--- /dev/null
+++ b/nocache.h
@@ -0,0 +1,17 @@
+#ifndef NOCACHE_H
+#define NOCACHE_H
+
+#include <stdbool.h>
+
+#define DEBUG(...) \
+    debug("[nocache] DEBUG: " __VA_ARGS__)
+
+void debug(const char *fmt, ...);
+
+extern int nocache_EOF;
+int nocache_fileno(FILE *fp);
+
+void store_pageinfo(int fd);
+void free_unclaimed_pages(int fd, bool block_signals);
+
+#endif
diff --git a/pageinfo.c b/pageinfo.c
index 12f8b0d..c0de511 100644
--- a/pageinfo.c
+++ b/pageinfo.c
@@ -9,14 +9,7 @@
 #include <string.h>
 
 #include "pageinfo.h"
-
-extern FILE *debugfp;
-#define DEBUG(...) \
-    do { \
-        if(debugfp != NULL) { \
-            fprintf(debugfp, "[nocache] DEBUG: " __VA_ARGS__); \
-        } \
-    } while(0)
+#include "nocache.h"
 
 static int insert_into_br_list(struct file_pageinfo *pi,
     struct byterange **brtail, size_t pos, size_t len);
diff --git a/wrappers.c b/wrappers.c
new file mode 100644
index 0000000..638c588
--- /dev/null
+++ b/wrappers.c
@@ -0,0 +1,232 @@
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <stddef.h>
+#include <assert.h>
+#include <errno.h>
+#include <dlfcn.h>
+
+typedef struct FILE FILE;
+
+#include "wrappers.h"
+#include "pageinfo.h"
+#include "fcntl_helpers.h"
+#include "nocache.h"
+
+int open(const char *pathname, int flags, mode_t mode);
+int open64(const char *pathname, int flags, mode_t mode);
+int creat(const char *pathname, int flags, mode_t mode);
+int creat64(const char *pathname, int flags, mode_t mode);
+int openat(int dirfd, const char *pathname, int flags, mode_t mode);
+int openat64(int dirfd, const char *pathname, int flags, mode_t mode);
+int dup(int oldfd);
+int dup2(int oldfd, int newfd);
+int close(int fd);
+FILE *fopen(const char *path, const char *mode);
+FILE *fopen64(const char *path, const char *mode);
+int fclose(FILE *fp);
+
+int (*_original_open)(const char *pathname, int flags, mode_t mode);
+int (*_original_open64)(const char *pathname, int flags, mode_t mode);
+int (*_original_creat)(const char *pathname, int flags, mode_t mode);
+int (*_original_creat64)(const char *pathname, int flags, mode_t mode);
+int (*_original_openat)(int dirfd, const char *pathname, int flags, mode_t mode);
+int (*_original_openat64)(int dirfd, const char *pathname, int flags, mode_t mode);
+int (*_original_dup)(int fd);
+int (*_original_dup2)(int newfd, int oldfd);
+int (*_original_close)(int fd);
+FILE *(*_original_fopen)(const char *path, const char *mode);
+FILE *(*_original_fopen64)(const char *path, const char *mode);
+int (*_original_fclose)(FILE *fp);
+
+int open(const char *pathname, int flags, mode_t mode)
+{
+    int fd;
+
+    if(!_original_open)
+        _original_open = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "open");
+    assert(_original_open != NULL);
+
+    if((fd = _original_open(pathname, flags, mode)) != -1) {
+        DEBUG("open(pathname=%s, flags=0x%x, mode=0%o) = %d\n",
+            pathname, flags, mode, fd);
+        store_pageinfo(fd);
+    }
+    return fd;
+}
+
+int open64(const char *pathname, int flags, mode_t mode)
+{
+    int fd;
+
+    if(!_original_open64)
+        _original_open64 = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "open64");
+    assert(_original_open64 != NULL);
+
+    DEBUG("open64(pathname=%s, flags=0x%x, mode=0%o)\n", pathname, flags, mode);
+
+    if((fd = _original_open64(pathname, flags, mode)) != -1)
+        store_pageinfo(fd);
+    return fd;
+}
+
+int creat(const char *pathname, int flags, mode_t mode)
+{
+    int fd;
+
+    if(!_original_creat)
+        _original_creat = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "creat");
+    assert(_original_creat != NULL);
+
+    DEBUG("creat(pathname=%s, flags=0x%x, mode=0%o)\n", pathname, flags, mode);
+
+    if((fd = _original_creat(pathname, flags, mode)) != -1)
+        store_pageinfo(fd);
+    return fd;
+}
+
+int creat64(const char *pathname, int flags, mode_t mode)
+{
+    int fd;
+
+    if(!_original_creat64)
+        _original_creat64 = (int (*)(const char *, int, mode_t)) dlsym(RTLD_NEXT, "creat64");
+    assert(_original_creat64 != NULL);
+
+    DEBUG("creat64(pathname=%s, flags=0x%x, mode=0%o)\n", pathname, flags, mode);
+
+    if((fd = _original_creat64(pathname, flags, mode)) != -1)
+        store_pageinfo(fd);
+    return fd;
+}
+
+int openat(int dirfd, const char *pathname, int flags, mode_t mode)
+{
+    int fd;
+
+    if(!_original_openat)
+        _original_openat = (int (*)(int, const char *, int, mode_t)) dlsym(RTLD_NEXT, "openat");
+    assert(_original_openat != NULL);
+
+    DEBUG("openat(dirfd=%d, pathname=%s, flags=0x%x, mode=0%o)\n", dirfd, pathname, flags, mode);
+
+    if((fd = _original_openat(dirfd, pathname, flags, mode)) != -1)
+        store_pageinfo(fd);
+    return fd;
+}
+
+int openat64(int dirfd, const char *pathname, int flags, mode_t mode)
+{
+    int fd;
+
+    if(!_original_openat64)
+        _original_openat64 = (int (*)(int, const char *, int, mode_t)) dlsym(RTLD_NEXT, "openat64");
+    assert(_original_openat64 != NULL);
+
+    DEBUG("openat64(dirfd=%d, pathname=%s, flags=0x%x, mode=0%o)\n", dirfd, pathname, flags, mode);
+
+    if((fd = _original_openat64(dirfd, pathname, flags, mode)) != -1)
+        store_pageinfo(fd);
+    return fd;
+}
+
+int dup(int oldfd)
+{
+    int fd;
+
+    if(!_original_dup)
+        _original_dup = (int (*)(int)) dlsym(RTLD_NEXT, "dup");
+    assert(_original_dup != NULL);
+
+    DEBUG("dup(oldfd=%d)\n", oldfd);
+
+    if((fd = _original_dup(oldfd)) != -1)
+        store_pageinfo(fd);
+    return fd;
+}
+
+int dup2(int oldfd, int newfd)
+{
+    int ret;
+
+    /* if newfd is already opened, the kernel will close it directly
+     * once dup2 is invoked. So now is the last chance to mark the
+     * pages as "DONTNEED" */
+    if(valid_fd(newfd))
+        free_unclaimed_pages(newfd, true);
+
+    if(!_original_dup2)
+        _original_dup2 = (int (*)(int, int)) dlsym(RTLD_NEXT, "dup2");
+    assert(_original_dup2 != NULL);
+
+    DEBUG("dup2(oldfd=%d, newfd=%d)\n", oldfd, newfd);
+
+    if((ret = _original_dup2(oldfd, newfd)) != -1)
+        store_pageinfo(newfd);
+    return ret;
+}
+
+int close(int fd)
+{
+    if(!_original_close)
+        _original_close = (int (*)(int)) dlsym(RTLD_NEXT, "close");
+    assert(_original_close != NULL);
+
+    free_unclaimed_pages(fd, true);
+
+    DEBUG("close(%d)\n", fd);
+    return _original_close(fd);
+}
+
+FILE *fopen(const char *path, const char *mode)
+{
+    int fd;
+    FILE *fp = NULL;
+
+    if(!_original_fopen)
+       _original_fopen = (FILE *(*)(const char *, const char *)) dlsym(RTLD_NEXT, "fopen");
+    assert(_original_fopen != NULL);
+
+    DEBUG("fopen(path=%s, mode=%s)\n", path, mode);
+
+    if((fp = _original_fopen(path, mode)) != NULL)
+        if((fd = nocache_fileno(fp)) != -1)
+            store_pageinfo(fd);
+
+    return fp;
+}
+
+FILE *fopen64(const char *path, const char *mode)
+{
+    int fd;
+    FILE *fp;
+    fp = NULL;
+
+    if(!_original_fopen64)
+        _original_fopen64 = (FILE *(*)(const char *, const char *)) dlsym(RTLD_NEXT, "fopen64");
+    assert(_original_fopen64 != NULL);
+
+    DEBUG("fopen64(path=%s, mode=%s)\n", path, mode);
+
+    if((fp = _original_fopen64(path, mode)) != NULL)
+        if((fd = nocache_fileno(fp)) != -1)
+            store_pageinfo(fd);
+
+    return fp;
+}
+
+int fclose(FILE *fp)
+{
+    if(!_original_fclose)
+        _original_fclose = (int (*)(FILE *)) dlsym(RTLD_NEXT, "fclose");
+    assert(_original_fclose != NULL);
+
+    if(_original_fclose) {
+        free_unclaimed_pages(nocache_fileno(fp), true);
+        return _original_fclose(fp);
+    }
+
+    errno = EFAULT;
+    return nocache_EOF;
+}
+
+/* vim:set et sw=4 ts=4: */
diff --git a/wrappers.h b/wrappers.h
new file mode 100644
index 0000000..dc66bfd
--- /dev/null
+++ b/wrappers.h
@@ -0,0 +1,17 @@
+#ifndef NOCACHE_WRAPPERS_H
+#define NOCACHE_WRAPPERS_H
+
+extern int (*_original_open)(const char *pathname, int flags, mode_t mode);
+extern int (*_original_open64)(const char *pathname, int flags, mode_t mode);
+extern int (*_original_creat)(const char *pathname, int flags, mode_t mode);
+extern int (*_original_creat64)(const char *pathname, int flags, mode_t mode);
+extern int (*_original_openat)(int dirfd, const char *pathname, int flags, mode_t mode);
+extern int (*_original_openat64)(int dirfd, const char *pathname, int flags, mode_t mode);
+extern int (*_original_dup)(int fd);
+extern int (*_original_dup2)(int newfd, int oldfd);
+extern int (*_original_close)(int fd);
+extern FILE *(*_original_fopen)(const char *path, const char *mode);
+extern FILE *(*_original_fopen64)(const char *path, const char *mode);
+extern int (*_original_fclose)(FILE *fp);
+
+#endif