util-lib: split stat()/statfs()/stavfs() related calls into stat-util.[ch]

src/basic/stat-util.c

@@ -0,0 +1,216 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010-2012 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <fcntl.h>
+#include <linux/magic.h>
+#include <sys/statvfs.h>
+#include <unistd.h>
+
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "macro.h"
+#include "missing.h"
+#include "stat-util.h"
+#include "string-util.h"
+
+int is_symlink(const char *path) {
+        struct stat info;
+
+        assert(path);
+
+        if (lstat(path, &info) < 0)
+                return -errno;
+
+        return !!S_ISLNK(info.st_mode);
+}
+
+int is_dir(const char* path, bool follow) {
+        struct stat st;
+        int r;
+
+        assert(path);
+
+        if (follow)
+                r = stat(path, &st);
+        else
+                r = lstat(path, &st);
+        if (r < 0)
+                return -errno;
+
+        return !!S_ISDIR(st.st_mode);
+}
+
+int is_device_node(const char *path) {
+        struct stat info;
+
+        assert(path);
+
+        if (lstat(path, &info) < 0)
+                return -errno;
+
+        return !!(S_ISBLK(info.st_mode) || S_ISCHR(info.st_mode));
+}
+
+int dir_is_empty(const char *path) {
+        _cleanup_closedir_ DIR *d;
+        struct dirent *de;
+
+        d = opendir(path);
+        if (!d)
+                return -errno;
+
+        FOREACH_DIRENT(de, d, return -errno)
+                return 0;
+
+        return 1;
+}
+
+bool null_or_empty(struct stat *st) {
+        assert(st);
+
+        if (S_ISREG(st->st_mode) && st->st_size <= 0)
+                return true;
+
+        /* We don't want to hardcode the major/minor of /dev/null,
+         * hence we do a simpler "is this a device node?" check. */
+
+        if (S_ISCHR(st->st_mode) || S_ISBLK(st->st_mode))
+                return true;
+
+        return false;
+}
+
+int null_or_empty_path(const char *fn) {
+        struct stat st;
+
+        assert(fn);
+
+        if (stat(fn, &st) < 0)
+                return -errno;
+
+        return null_or_empty(&st);
+}
+
+int null_or_empty_fd(int fd) {
+        struct stat st;
+
+        assert(fd >= 0);
+
+        if (fstat(fd, &st) < 0)
+                return -errno;
+
+        return null_or_empty(&st);
+}
+
+int path_is_read_only_fs(const char *path) {
+        struct statvfs st;
+
+        assert(path);
+
+        if (statvfs(path, &st) < 0)
+                return -errno;
+
+        if (st.f_flag & ST_RDONLY)
+                return true;
+
+        /* On NFS, statvfs() might not reflect whether we can actually
+         * write to the remote share. Let's try again with
+         * access(W_OK) which is more reliable, at least sometimes. */
+        if (access(path, W_OK) < 0 && errno == EROFS)
+                return true;
+
+        return false;
+}
+
+int path_is_os_tree(const char *path) {
+        char *p;
+        int r;
+
+        assert(path);
+
+        /* We use /usr/lib/os-release as flag file if something is an OS */
+        p = strjoina(path, "/usr/lib/os-release");
+        r = access(p, F_OK);
+        if (r >= 0)
+                return 1;
+
+        /* Also check for the old location in /etc, just in case. */
+        p = strjoina(path, "/etc/os-release");
+        r = access(p, F_OK);
+
+        return r >= 0;
+}
+
+int files_same(const char *filea, const char *fileb) {
+        struct stat a, b;
+
+        assert(filea);
+        assert(fileb);
+
+        if (stat(filea, &a) < 0)
+                return -errno;
+
+        if (stat(fileb, &b) < 0)
+                return -errno;
+
+        return a.st_dev == b.st_dev &&
+               a.st_ino == b.st_ino;
+}
+
+bool is_fs_type(const struct statfs *s, statfs_f_type_t magic_value) {
+        assert(s);
+        assert_cc(sizeof(statfs_f_type_t) >= sizeof(s->f_type));
+
+        return F_TYPE_EQUAL(s->f_type, magic_value);
+}
+
+int fd_check_fstype(int fd, statfs_f_type_t magic_value) {
+        struct statfs s;
+
+        if (fstatfs(fd, &s) < 0)
+                return -errno;
+
+        return is_fs_type(&s, magic_value);
+}
+
+int path_check_fstype(const char *path, statfs_f_type_t magic_value) {
+        _cleanup_close_ int fd = -1;
+
+        fd = open(path, O_RDONLY);
+        if (fd < 0)
+                return -errno;
+
+        return fd_check_fstype(fd, magic_value);
+}
+
+bool is_temporary_fs(const struct statfs *s) {
+    return is_fs_type(s, TMPFS_MAGIC) ||
+           is_fs_type(s, RAMFS_MAGIC);
+}
+
+int fd_is_temporary_fs(int fd) {
+        struct statfs s;
+
+        if (fstatfs(fd, &s) < 0)
+                return -errno;
+
+        return is_temporary_fs(&s);
+}