Astral/kernel-src/sys/syscalls/stat.c

#include <kernel/syscalls.h>
#include <kernel/abi.h>
#include <kernel/vfs.h>
#include <arch/cpu.h>
#include <errno.h>
#include <kernel/file.h>
#include <kernel/alloc.h>

// vnode should be locked
static int dostat(vnode_t *vnode, stat_t *stat) {
	vattr_t attr;
	int e = VOP_GETATTR(vnode, &attr, &current_thread()->proc->cred);
	if (e)
		return e;

	stat->dev = TODEV(attr.devmajor, attr.devminor);
	stat->rdev = TODEV(attr.rdevmajor, attr.rdevminor);
	stat->ino = attr.inode;
	stat->nlink = attr.nlinks;
	stat->mode = attr.mode | MAKETYPE(vfs_getposixtype(attr.type));
	stat->uid = attr.uid;
	stat->gid = attr.gid;
	stat->size = attr.size;
	stat->blksize = attr.fsblocksize;
	stat->blocks = attr.blocksused;
	stat->atim = attr.atime;
	stat->mtim = attr.mtime;
	stat->ctim = attr.ctime;

	return 0;
}

syscallret_t syscall_fstat(context_t *ctx, int fd, stat_t *ustat) {
	syscallret_t ret = {
		.ret = -1
	};
	file_t *file = fd_get(fd);
	if (file == NULL) {
		ret.errno = EBADF;
		return ret;
	}

	stat_t buf;
	VOP_LOCK(file->vnode);
	ret.errno = dostat(file->vnode, &buf);
	VOP_UNLOCK(file->vnode);
	if (ret.errno)
		goto cleanup;

	ret.errno = usercopy_touser(ustat, &buf, sizeof(stat_t));
	ret.ret = ret.errno ? -1 : 0;

	cleanup:
	fd_release(file);
	return ret;
}

syscallret_t syscall_fstatat(context_t *ctx, int dirfd, char *upath, stat_t *ustat, int flags) {
	syscallret_t ret = {
		.ret = -1
	};

	size_t pathlen;
	ret.errno = usercopy_strlen(upath, &pathlen);
	if (ret.errno)
		return ret;

	vnode_t *node = NULL;
	vnode_t *dirnode = NULL;
	file_t *file = NULL;
	char *path = NULL;
	if (pathlen == 0 && (flags & AT_EMPTY_PATH)) {
		file = fd_get(dirfd);
		if (file == NULL) {
			ret.errno = EBADF;
			goto cleanup;
		}

		node = file->vnode;
		VOP_HOLD(node);
		fd_release(file);
		VOP_LOCK(node);
		file = NULL;
	} else {
		path = alloc(pathlen + 1);
		if (path == NULL) {
			ret.errno = ENOMEM;
			return ret;
		}

		ret.errno = usercopy_fromuser(path, upath, pathlen);
		if (ret.errno) {
			free(path);
			return ret;
		}

		ret.errno = dirfd_enter(path, dirfd, &file, &dirnode);
		if (ret.errno)
			goto cleanup;

		ret.errno = vfs_lookup(&node, dirnode, path, NULL, flags & AT_SYMLINK_NOFOLLOW ? VFS_LOOKUP_NOLINK : 0);
		if (ret.errno)
			goto cleanup;
	}

	stat_t buf;
	ret.errno = dostat(node, &buf);
	VOP_UNLOCK(node);
	if (ret.errno)
		goto cleanup;

	ret.errno = usercopy_touser(ustat, &buf, sizeof(stat_t));
	ret.ret = ret.errno ? -1 : 0;

	cleanup:
	if (node)
		VOP_RELEASE(node);

	if (dirnode)
		dirfd_leave(dirnode, file);

	if (path)
		free(path);

	return ret;
}