1 files changed, 410 insertions, 0 deletions
diff --git a/example/fusexmp.c b/example/fusexmp.c
new file mode 100644
index 0000000..b00039d
--- /dev/null
+++ b/example/fusexmp.c
@@ -0,0 +1,410 @@
+#ifdef linux
+/* For pread()/pwrite() */
+#define _XOPEN_SOURCE 500
+#endif
+
+/* For setgroups() */
+#define _BSD_SOURCE
+
+#include <fuse.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <errno.h>
+#include <signal.h>
+#include <utime.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <sys/fsuid.h>
+
+static struct fuse *xmp_fuse;
+
+static int set_creds(struct fuse_cred *cred)
+{
+    int res;
+
+    res = setfsuid(cred->uid);
+    if(res == -1)
+        return -errno;
+
+    res = setfsgid(cred->gid);
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static void restore_creds()
+{
+    setfsuid(getuid());
+    setfsgid(getgid());
+}
+
+static int xmp_getattr(struct fuse_cred *cred, const char *path,
+                       struct stat *stbuf)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = lstat(path, stbuf);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_readlink(struct fuse_cred *cred, const char *path, char *buf,
+                        size_t size)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = readlink(path, buf, size - 1);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    buf[res] = '\0';
+    return 0;
+}
+
+
+static int xmp_getdir(struct fuse_cred *cred, const char *path, fuse_dirh_t h,
+                      fuse_dirfil_t filler)
+{
+    DIR *dp;
+    struct dirent *de;
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    dp = opendir(path);
+    restore_creds();
+    if(dp == NULL)
+        return -errno;
+
+    while((de = readdir(dp)) != NULL) {
+        res = filler(h, de->d_name, de->d_type);
+        if(res != 0)
+            break;
+    }
+
+    closedir(dp);
+    return res;
+}
+
+static int xmp_mknod(struct fuse_cred *cred, const char *path, mode_t mode,
+                     dev_t rdev)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = mknod(path, mode, rdev);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_mkdir(struct fuse_cred *cred, const char *path, mode_t mode)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = mkdir(path, mode);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_unlink(struct fuse_cred *cred, const char *path)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = unlink(path);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_rmdir(struct fuse_cred *cred, const char *path)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = rmdir(path);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_symlink(struct fuse_cred *cred, const char *from,
+                       const char *to)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = symlink(from, to);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_rename(struct fuse_cred *cred, const char *from, const char *to)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = rename(from, to);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_link(struct fuse_cred *cred, const char *from, const char *to)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = link(from, to);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_chmod(struct fuse_cred *cred, const char *path, mode_t mode)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = chmod(path, mode);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+    
+    return 0;
+}
+
+static int xmp_chown(struct fuse_cred *cred, const char *path, uid_t uid,
+                     gid_t gid)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = lchown(path, uid, gid);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_truncate(struct fuse_cred *cred, const char *path, off_t size)
+{
+    int res;
+    
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = truncate(path, size);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+static int xmp_utime(struct fuse_cred *cred, const char *path,
+                     struct utimbuf *buf)
+{
+    int res;
+    
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = utime(path, buf);
+    restore_creds();
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
+
+static int xmp_open(struct fuse_cred *cred, const char *path, int flags)
+{
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    res = open(path, flags);
+    restore_creds();
+    if(res == -1) 
+        return -errno;
+
+    close(res);
+    return 0;
+}
+
+static int xmp_read(struct fuse_cred *cred, const char *path, char *buf,
+                    size_t size, off_t offset)
+{
+    int fd;
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    fd = open(path, O_RDONLY);
+    restore_creds();
+    if(fd == -1)
+        return -errno;
+
+    res = pread(fd, buf, size, offset);
+    if(res == -1)
+        res = -errno;
+    
+    close(fd);
+    return res;
+}
+
+static int xmp_write(struct fuse_cred *cred, const char *path, const char *buf,
+                     size_t size, off_t offset)
+{
+    int fd;
+    int res;
+
+    res = set_creds(cred);
+    if(res)
+        return res;
+    fd = open(path, O_WRONLY);
+    restore_creds();
+    if(fd == -1)
+        return -errno;
+
+    res = pwrite(fd, buf, size, offset);
+    if(res == -1)
+        res = -errno;
+    
+    close(fd);
+    return res;
+}
+
+static void exit_handler()
+{
+    exit(0);
+}
+
+static void set_signal_handlers()
+{
+    struct sigaction sa;
+
+    sa.sa_handler = exit_handler;
+    sigemptyset(&(sa.sa_mask));
+    sa.sa_flags = 0;
+
+    if (sigaction(SIGHUP, &sa, NULL) == -1 || 
+	sigaction(SIGINT, &sa, NULL) == -1 || 
+	sigaction(SIGTERM, &sa, NULL) == -1) {
+	
+	perror("Cannot set exit signal handlers");
+        exit(1);
+    }
+
+    sa.sa_handler = SIG_IGN;
+    
+    if(sigaction(SIGPIPE, &sa, NULL) == -1) {
+	perror("Cannot set ignored signals");
+        exit(1);
+    }
+}
+
+static void cleanup()
+{
+    fuse_unmount(xmp_fuse);
+    fuse_destroy(xmp_fuse);
+}
+
+static struct fuse_operations xmp_oper = {
+    getattr:	xmp_getattr,
+    readlink:	xmp_readlink,
+    getdir:     xmp_getdir,
+    mknod:	xmp_mknod,
+    mkdir:	xmp_mkdir,
+    symlink:	xmp_symlink,
+    unlink:	xmp_unlink,
+    rmdir:	xmp_rmdir,
+    rename:     xmp_rename,
+    link:	xmp_link,
+    chmod:	xmp_chmod,
+    chown:	xmp_chown,
+    truncate:	xmp_truncate,
+    utime:	xmp_utime,
+    open:	xmp_open,
+    read:	xmp_read,
+    write:	xmp_write,
+};
+
+int main(int argc, char *argv[])
+{
+    int res;
+    if(argc != 2) {
+        fprintf(stderr, "usage: %s mount_dir\n", argv[0]);
+        exit(1);
+    }
+
+    set_signal_handlers();
+    atexit(cleanup);
+    setgroups(0, NULL);
+
+    xmp_fuse = fuse_new(0,0);
+    res = fuse_mount(xmp_fuse, argv[1]);
+    if(res == -1)
+        exit(1);
+        
+    fuse_set_operations(xmp_fuse, &xmp_oper);
+
+    fuse_loop(xmp_fuse);
+
+    return 0;
+}