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FUSE_MAIN(3) Library Functions Manual FUSE_MAIN(3)

fuse_main — FUSE helper function

#include <fuse.h>

int
fuse_main(int argc, char **argv, const struct fuse_operations *ops, void *data);

There are two ways of implementing a FUSE filesystem: by calling only () and passing this function the argument containing all the callbacks of the filesystem, or by using the other functions, as detailed in fuse_loop(3)

argv is the list of arguments supplied to the program's main method and must at a minimum specify the directory on which the file system is to be mounted. The other arguments can be custom arguments specific to the file system or those supported by fuse_parse_cmdline(3), fuse_new(3) and fuse_mount(3).

Here is a simple example of a FUSE implementation:

#include <errno.h>
#include <fuse.h>
#include <string.h>

static int
fs_readdir(const char *path, void *data, fuse_fill_dir_t filler,
           off_t off, struct fuse_file_info *ffi)
{
	if (strcmp(path, "/") != 0)
		return -ENOENT;

	filler(data, ".", NULL, 0);
	filler(data, "..", NULL, 0);
	filler(data, "file", NULL, 0);
	return 0;
}

static int
fs_read(const char *path, char *buf, size_t size, off_t off,
        struct fuse_file_info *ffi)
{
	size_t len;
	const char *file_contents = "fuse filesystem example\n";

	len = strlen(file_contents);

	if (off < len) {
		if (off + size > len)
			size = len - off;
		memcpy(buf, file_contents + off, size);
	} else
		size = 0;

	return size;
}

static int
fs_open(const char *path, struct fuse_file_info *ffi)
{
	if (strncmp(path, "/file", 10) != 0)
		return -ENOENT;

	if ((ffi->flags & 3) != O_RDONLY)
		return -EACCES;

	return 0;
}

static int
fs_getattr(const char *path, struct stat *st)
{
	if (strcmp(path, "/") == 0) {
		st->st_blksize = 512;
		st->st_mode = 0755;
		st->st_nlink = 2;
	} else if (strcmp(path, "/file") == 0) {
		st->st_mode = 0644;
		st->st_blksize = 512;
		st->st_nlink = 1;
		st->st_size = 5;
	} else {
		return -ENOENT;
	}

	return 0;
}

struct fuse_operations fsops = {
	.readdir = fs_readdir,
	.read = fs_read,
	.open = fs_open,
	.getattr = fs_getattr,
};

int
main(int argc, char **argv)
{
	return (fuse_main(argc, argv, &fsops, NULL));
}

fuse_loop(3), fuse_mount(3), fuse_new(3), fuse_parse_cmdline(3), fuse_setup(3), fuse(4)

The fuse_main() function conforms to FUSE 2.6.

The fuse_main() function first appeared in OpenBSD 5.4.

Sylvestre Gallon <ccna.syl@gmail.com>
Helg Bredow <helg@openbsd.org>

May 25, 2020 openbsd