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-rw-r--r--src/shared/path-util.c364
1 files changed, 364 insertions, 0 deletions
diff --git a/src/shared/path-util.c b/src/shared/path-util.c
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+++ b/src/shared/path-util.c
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+/*-*- 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 <assert.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <sys/statvfs.h>
+
+#include "macro.h"
+#include "util.h"
+#include "log.h"
+#include "strv.h"
+#include "path-util.h"
+#include "missing.h"
+
+bool path_is_absolute(const char *p) {
+ return p[0] == '/';
+}
+
+char *path_get_file_name(const char *p) {
+ char *r;
+
+ assert(p);
+
+ r = strrchr(p, '/');
+ if (r)
+ return r + 1;
+
+ return (char*) p;
+}
+
+int path_get_parent(const char *path, char **_r) {
+ const char *e, *a = NULL, *b = NULL, *p;
+ char *r;
+ bool slash = false;
+
+ assert(path);
+ assert(_r);
+
+ if (!*path)
+ return -EINVAL;
+
+ for (e = path; *e; e++) {
+
+ if (!slash && *e == '/') {
+ a = b;
+ b = e;
+ slash = true;
+ } else if (slash && *e != '/')
+ slash = false;
+ }
+
+ if (*(e-1) == '/')
+ p = a;
+ else
+ p = b;
+
+ if (!p)
+ return -EINVAL;
+
+ if (p == path)
+ r = strdup("/");
+ else
+ r = strndup(path, p-path);
+
+ if (!r)
+ return -ENOMEM;
+
+ *_r = r;
+ return 0;
+}
+
+char *path_make_absolute(const char *p, const char *prefix) {
+ assert(p);
+
+ /* Makes every item in the list an absolute path by prepending
+ * the prefix, if specified and necessary */
+
+ if (path_is_absolute(p) || !prefix)
+ return strdup(p);
+
+ return strjoin(prefix, "/", p, NULL);
+}
+
+char *path_make_absolute_cwd(const char *p) {
+ _cleanup_free_ char *cwd = NULL;
+
+ assert(p);
+
+ /* Similar to path_make_absolute(), but prefixes with the
+ * current working directory. */
+
+ if (path_is_absolute(p))
+ return strdup(p);
+
+ cwd = get_current_dir_name();
+ if (!cwd)
+ return NULL;
+
+ return path_make_absolute(p, cwd);
+}
+
+char **path_strv_canonicalize(char **l) {
+ char **s;
+ unsigned k = 0;
+ bool enomem = false;
+
+ if (strv_isempty(l))
+ return l;
+
+ /* Goes through every item in the string list and canonicalize
+ * the path. This works in place and won't rollback any
+ * changes on failure. */
+
+ STRV_FOREACH(s, l) {
+ char *t, *u;
+
+ t = path_make_absolute_cwd(*s);
+ free(*s);
+ *s = NULL;
+
+ if (!t) {
+ enomem = true;
+ continue;
+ }
+
+ errno = 0;
+ u = realpath(t, 0);
+ if (!u) {
+ if (errno == ENOENT)
+ u = t;
+ else {
+ free(t);
+ if (errno == ENOMEM || !errno)
+ enomem = true;
+
+ continue;
+ }
+ } else
+ free(t);
+
+ l[k++] = u;
+ }
+
+ l[k] = NULL;
+
+ if (enomem)
+ return NULL;
+
+ return l;
+}
+
+char **path_strv_canonicalize_uniq(char **l) {
+ if (strv_isempty(l))
+ return l;
+
+ if (!path_strv_canonicalize(l))
+ return NULL;
+
+ return strv_uniq(l);
+}
+
+char *path_kill_slashes(char *path) {
+ char *f, *t;
+ bool slash = false;
+
+ /* Removes redundant inner and trailing slashes. Modifies the
+ * passed string in-place.
+ *
+ * ///foo///bar/ becomes /foo/bar
+ */
+
+ for (f = path, t = path; *f; f++) {
+
+ if (*f == '/') {
+ slash = true;
+ continue;
+ }
+
+ if (slash) {
+ slash = false;
+ *(t++) = '/';
+ }
+
+ *(t++) = *f;
+ }
+
+ /* Special rule, if we are talking of the root directory, a
+ trailing slash is good */
+
+ if (t == path && slash)
+ *(t++) = '/';
+
+ *t = 0;
+ return path;
+}
+
+bool path_equal(const char *a, const char *b) {
+ assert(a);
+ assert(b);
+
+ if ((a[0] == '/') != (b[0] == '/'))
+ return false;
+
+ for (;;) {
+ size_t j, k;
+
+ a += strspn(a, "/");
+ b += strspn(b, "/");
+
+ if (*a == 0 && *b == 0)
+ return true;
+
+ if (*a == 0 || *b == 0)
+ return false;
+
+ j = strcspn(a, "/");
+ k = strcspn(b, "/");
+
+ if (j != k)
+ return false;
+
+ if (memcmp(a, b, j) != 0)
+ return false;
+
+ a += j;
+ b += k;
+ }
+}
+
+int path_is_mount_point(const char *t, bool allow_symlink) {
+
+ union file_handle_union h = {
+ .handle.handle_bytes = MAX_HANDLE_SZ
+ };
+
+ int mount_id, mount_id_parent;
+ char *parent;
+ struct stat a, b;
+ int r;
+
+ /* We are not actually interested in the file handles, but
+ * name_to_handle_at() also passes us the mount ID, hence use
+ * it but throw the handle away */
+
+ if (path_equal(t, "/"))
+ return 1;
+
+ r = name_to_handle_at(AT_FDCWD, t, &h.handle, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0);
+ if (r < 0) {
+ if (errno == ENOSYS || errno == ENOTSUP)
+ /* This kernel or file system does not support
+ * name_to_handle_at(), hence fallback to the
+ * traditional stat() logic */
+ goto fallback;
+
+ if (errno == ENOENT)
+ return 0;
+
+ return -errno;
+ }
+
+ r = path_get_parent(t, &parent);
+ if (r < 0)
+ return r;
+
+ h.handle.handle_bytes = MAX_HANDLE_SZ;
+ r = name_to_handle_at(AT_FDCWD, parent, &h.handle, &mount_id_parent, 0);
+ free(parent);
+ if (r < 0) {
+ /* The parent can't do name_to_handle_at() but the
+ * directory we are interested in can? If so, it must
+ * be a mount point */
+ if (errno == EOPNOTSUPP)
+ return 1;
+
+ return -errno;
+ }
+
+ return mount_id != mount_id_parent;
+
+fallback:
+ if (allow_symlink)
+ r = stat(t, &a);
+ else
+ r = lstat(t, &a);
+
+ if (r < 0) {
+ if (errno == ENOENT)
+ return 0;
+
+ return -errno;
+ }
+
+ r = path_get_parent(t, &parent);
+ if (r < 0)
+ return r;
+
+ r = lstat(parent, &b);
+ free(parent);
+ if (r < 0)
+ return -errno;
+
+ return a.st_dev != b.st_dev;
+}
+
+bool paths_check_timestamp(const char* const* paths, usec_t *timestamp, bool update) {
+ bool changed = false;
+ const char* const* i;
+
+ assert(timestamp);
+
+ if (paths == NULL)
+ return false;
+
+ STRV_FOREACH(i, paths) {
+ struct stat stats;
+ usec_t u;
+
+ if (stat(*i, &stats) < 0)
+ continue;
+
+ u = timespec_load(&stats.st_mtim);
+
+ /* first check */
+ if (*timestamp >= u)
+ continue;
+
+ log_debug("timestamp of '%s' changed", *i);
+
+ /* update timestamp */
+ if (update) {
+ *timestamp = u;
+ changed = true;
+ } else
+ return true;
+ }
+
+ return changed;
+}
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