From 463189cd121ce9a9f79d24c207e7c6c31898ea06 Mon Sep 17 00:00:00 2001 From: Nikolaus Rath Date: Sun, 9 Oct 2016 19:22:57 -0700 Subject: Renamed some examples to make their function more obvious Also, added more comments for the same purpose. --- example/passthrough.c | 432 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 432 insertions(+) create mode 100644 example/passthrough.c (limited to 'example/passthrough.c') diff --git a/example/passthrough.c b/example/passthrough.c new file mode 100644 index 0000000..cf72cb2 --- /dev/null +++ b/example/passthrough.c @@ -0,0 +1,432 @@ +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2007 Miklos Szeredi + Copyright (C) 2011 Sebastian Pipping + + This program can be distributed under the terms of the GNU GPL. + See the file COPYING. +*/ + +/** @file + * @tableofcontents + * + * This file system mirrors the existing file system hierarchy of the + * system, starting at the root file system. This is implemented by + * just "passing through" all requests to the corresponding user-space + * libc functions. It's performance is terrible. + * + * \section section_compile compiling this example + * + * gcc -Wall passthrough.c `pkg-config fuse3 --cflags --libs` -o passthrough + * + * \section section_source the complete source + * \include passthrough.c + */ + + +#define FUSE_USE_VERSION 30 + +#ifdef HAVE_CONFIG_H +#include +#endif + +#ifdef linux +/* For pread()/pwrite()/utimensat() */ +#define _XOPEN_SOURCE 700 +#endif + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#ifdef HAVE_SETXATTR +#include +#endif + +static int xmp_getattr(const char *path, struct stat *stbuf) +{ + int res; + + res = lstat(path, stbuf); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_access(const char *path, int mask) +{ + int res; + + res = access(path, mask); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_readlink(const char *path, char *buf, size_t size) +{ + int res; + + res = readlink(path, buf, size - 1); + if (res == -1) + return -errno; + + buf[res] = '\0'; + return 0; +} + + +static int xmp_readdir(const char *path, void *buf, fuse_fill_dir_t filler, + off_t offset, struct fuse_file_info *fi, + enum fuse_readdir_flags flags) +{ + DIR *dp; + struct dirent *de; + + (void) offset; + (void) fi; + (void) flags; + + dp = opendir(path); + if (dp == NULL) + return -errno; + + while ((de = readdir(dp)) != NULL) { + struct stat st; + memset(&st, 0, sizeof(st)); + st.st_ino = de->d_ino; + st.st_mode = de->d_type << 12; + if (filler(buf, de->d_name, &st, 0, 0)) + break; + } + + closedir(dp); + return 0; +} + +static int xmp_mknod(const char *path, mode_t mode, dev_t rdev) +{ + int res; + + /* On Linux this could just be 'mknod(path, mode, rdev)' but this + is more portable */ + if (S_ISREG(mode)) { + res = open(path, O_CREAT | O_EXCL | O_WRONLY, mode); + if (res >= 0) + res = close(res); + } else if (S_ISFIFO(mode)) + res = mkfifo(path, mode); + else + res = mknod(path, mode, rdev); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_mkdir(const char *path, mode_t mode) +{ + int res; + + res = mkdir(path, mode); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_unlink(const char *path) +{ + int res; + + res = unlink(path); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_rmdir(const char *path) +{ + int res; + + res = rmdir(path); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_symlink(const char *from, const char *to) +{ + int res; + + res = symlink(from, to); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_rename(const char *from, const char *to, unsigned int flags) +{ + int res; + + if (flags) + return -EINVAL; + + res = rename(from, to); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_link(const char *from, const char *to) +{ + int res; + + res = link(from, to); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_chmod(const char *path, mode_t mode) +{ + int res; + + res = chmod(path, mode); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_chown(const char *path, uid_t uid, gid_t gid) +{ + int res; + + res = lchown(path, uid, gid); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_truncate(const char *path, off_t size) +{ + int res; + + res = truncate(path, size); + if (res == -1) + return -errno; + + return 0; +} + +#ifdef HAVE_UTIMENSAT +static int xmp_utimens(const char *path, const struct timespec ts[2]) +{ + int res; + + /* don't use utime/utimes since they follow symlinks */ + res = utimensat(0, path, ts, AT_SYMLINK_NOFOLLOW); + if (res == -1) + return -errno; + + return 0; +} +#endif + +static int xmp_open(const char *path, struct fuse_file_info *fi) +{ + int res; + + res = open(path, fi->flags); + if (res == -1) + return -errno; + + close(res); + return 0; +} + +static int xmp_read(const char *path, char *buf, size_t size, off_t offset, + struct fuse_file_info *fi) +{ + int fd; + int res; + + (void) fi; + fd = open(path, O_RDONLY); + if (fd == -1) + return -errno; + + res = pread(fd, buf, size, offset); + if (res == -1) + res = -errno; + + close(fd); + return res; +} + +static int xmp_write(const char *path, const char *buf, size_t size, + off_t offset, struct fuse_file_info *fi) +{ + int fd; + int res; + + (void) fi; + fd = open(path, O_WRONLY); + if (fd == -1) + return -errno; + + res = pwrite(fd, buf, size, offset); + if (res == -1) + res = -errno; + + close(fd); + return res; +} + +static int xmp_statfs(const char *path, struct statvfs *stbuf) +{ + int res; + + res = statvfs(path, stbuf); + if (res == -1) + return -errno; + + return 0; +} + +static int xmp_release(const char *path, struct fuse_file_info *fi) +{ + /* Just a stub. This method is optional and can safely be left + unimplemented */ + + (void) path; + (void) fi; + return 0; +} + +static int xmp_fsync(const char *path, int isdatasync, + struct fuse_file_info *fi) +{ + /* Just a stub. This method is optional and can safely be left + unimplemented */ + + (void) path; + (void) isdatasync; + (void) fi; + return 0; +} + +#ifdef HAVE_POSIX_FALLOCATE +static int xmp_fallocate(const char *path, int mode, + off_t offset, off_t length, struct fuse_file_info *fi) +{ + int fd; + int res; + + (void) fi; + + if (mode) + return -EOPNOTSUPP; + + fd = open(path, O_WRONLY); + if (fd == -1) + return -errno; + + res = -posix_fallocate(fd, offset, length); + + close(fd); + return res; +} +#endif + +#ifdef HAVE_SETXATTR +/* xattr operations are optional and can safely be left unimplemented */ +static int xmp_setxattr(const char *path, const char *name, const char *value, + size_t size, int flags) +{ + int res = lsetxattr(path, name, value, size, flags); + if (res == -1) + return -errno; + return 0; +} + +static int xmp_getxattr(const char *path, const char *name, char *value, + size_t size) +{ + int res = lgetxattr(path, name, value, size); + if (res == -1) + return -errno; + return res; +} + +static int xmp_listxattr(const char *path, char *list, size_t size) +{ + int res = llistxattr(path, list, size); + if (res == -1) + return -errno; + return res; +} + +static int xmp_removexattr(const char *path, const char *name) +{ + int res = lremovexattr(path, name); + if (res == -1) + return -errno; + return 0; +} +#endif /* HAVE_SETXATTR */ + +static struct fuse_operations xmp_oper = { + .getattr = xmp_getattr, + .access = xmp_access, + .readlink = xmp_readlink, + .readdir = xmp_readdir, + .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, +#ifdef HAVE_UTIMENSAT + .utimens = xmp_utimens, +#endif + .open = xmp_open, + .read = xmp_read, + .write = xmp_write, + .statfs = xmp_statfs, + .release = xmp_release, + .fsync = xmp_fsync, +#ifdef HAVE_POSIX_FALLOCATE + .fallocate = xmp_fallocate, +#endif +#ifdef HAVE_SETXATTR + .setxattr = xmp_setxattr, + .getxattr = xmp_getxattr, + .listxattr = xmp_listxattr, + .removexattr = xmp_removexattr, +#endif +}; + +int main(int argc, char *argv[]) +{ + umask(0); + return fuse_main(argc, argv, &xmp_oper, NULL); +} -- cgit v1.2.3