+++ /dev/null
-/*-*- 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 <string.h>
-#include <unistd.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <fcntl.h>
-#include <sys/statvfs.h>
-
-#include "macro.h"
-#include "util.h"
-#include "log.h"
-#include "strv.h"
-#include "path-util.h"
-#include "missing.h"
-#include "fileio.h"
-
-bool path_is_absolute(const char *p) {
- return p[0] == '/';
-}
-
-bool is_path(const char *p) {
- return !!strchr(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_split_and_make_absolute(const char *p) {
- char **l;
- assert(p);
-
- l = strv_split(p, ":");
- if (!l)
- return NULL;
-
- if (!path_strv_make_absolute_cwd(l)) {
- strv_free(l);
- return NULL;
- }
-
- return l;
-}
-
-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 strjoin(cwd, "/", p, NULL);
-}
-
-int path_make_relative(const char *from_dir, const char *to_path, char **_r) {
- char *r, *p;
- unsigned n_parents;
-
- assert(from_dir);
- assert(to_path);
- assert(_r);
-
- /* Strips the common part, and adds ".." elements as necessary. */
-
- if (!path_is_absolute(from_dir))
- return -EINVAL;
-
- if (!path_is_absolute(to_path))
- return -EINVAL;
-
- /* Skip the common part. */
- for (;;) {
- size_t a;
- size_t b;
-
- from_dir += strspn(from_dir, "/");
- to_path += strspn(to_path, "/");
-
- if (!*from_dir) {
- if (!*to_path)
- /* from_dir equals to_path. */
- r = strdup(".");
- else
- /* from_dir is a parent directory of to_path. */
- r = strdup(to_path);
-
- if (!r)
- return -ENOMEM;
-
- path_kill_slashes(r);
-
- *_r = r;
- return 0;
- }
-
- if (!*to_path)
- break;
-
- a = strcspn(from_dir, "/");
- b = strcspn(to_path, "/");
-
- if (a != b)
- break;
-
- if (memcmp(from_dir, to_path, a) != 0)
- break;
-
- from_dir += a;
- to_path += b;
- }
-
- /* If we're here, then "from_dir" has one or more elements that need to
- * be replaced with "..". */
-
- /* Count the number of necessary ".." elements. */
- for (n_parents = 0;;) {
- from_dir += strspn(from_dir, "/");
-
- if (!*from_dir)
- break;
-
- from_dir += strcspn(from_dir, "/");
- n_parents++;
- }
-
- r = malloc(n_parents * 3 + strlen(to_path) + 1);
- if (!r)
- return -ENOMEM;
-
- for (p = r; n_parents > 0; n_parents--, p += 3)
- memcpy(p, "../", 3);
-
- strcpy(p, to_path);
- path_kill_slashes(r);
-
- *_r = r;
- return 0;
-}
-
-char **path_strv_make_absolute_cwd(char **l) {
- char **s;
-
- /* Goes through every item in the string list and makes it
- * absolute. This works in place and won't rollback any
- * changes on failure. */
-
- STRV_FOREACH(s, l) {
- char *t;
-
- t = path_make_absolute_cwd(*s);
- if (!t)
- return NULL;
-
- free(*s);
- *s = t;
- }
-
- return l;
-}
-
-char **path_strv_resolve(char **l, const char *prefix) {
- 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;
- _cleanup_free_ char *orig = NULL;
-
- if (!path_is_absolute(*s)) {
- free(*s);
- continue;
- }
-
- if (prefix) {
- orig = *s;
- t = strappend(prefix, orig);
- if (!t) {
- enomem = true;
- continue;
- }
- } else
- t = *s;
-
- errno = 0;
- u = canonicalize_file_name(t);
- if (!u) {
- if (errno == ENOENT) {
- if (prefix) {
- u = orig;
- orig = NULL;
- free(t);
- } else
- u = t;
- } else {
- free(t);
- if (errno == ENOMEM || errno == 0)
- enomem = true;
-
- continue;
- }
- } else if (prefix) {
- char *x;
-
- free(t);
- x = path_startswith(u, prefix);
- if (x) {
- /* restore the slash if it was lost */
- if (!startswith(x, "/"))
- *(--x) = '/';
-
- t = strdup(x);
- free(u);
- if (!t) {
- enomem = true;
- continue;
- }
- u = t;
- } else {
- /* canonicalized path goes outside of
- * prefix, keep the original path instead */
- free(u);
- u = orig;
- orig = NULL;
- }
- } else
- free(t);
-
- l[k++] = u;
- }
-
- l[k] = NULL;
-
- if (enomem)
- return NULL;
-
- return l;
-}
-
-char **path_strv_resolve_uniq(char **l, const char *prefix) {
-
- if (strv_isempty(l))
- return l;
-
- if (!path_strv_resolve(l, prefix))
- 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;
-}
-
-char* path_startswith(const char *path, const char *prefix) {
- assert(path);
- assert(prefix);
-
- if ((path[0] == '/') != (prefix[0] == '/'))
- return NULL;
-
- for (;;) {
- size_t a, b;
-
- path += strspn(path, "/");
- prefix += strspn(prefix, "/");
-
- if (*prefix == 0)
- return (char*) path;
-
- if (*path == 0)
- return NULL;
-
- a = strcspn(path, "/");
- b = strcspn(prefix, "/");
-
- if (a != b)
- return NULL;
-
- if (memcmp(path, prefix, a) != 0)
- return NULL;
-
- path += a;
- prefix += b;
- }
-}
-
-int path_compare(const char *a, const char *b) {
- int d;
-
- assert(a);
- assert(b);
-
- /* A relative path and an abolute path must not compare as equal.
- * Which one is sorted before the other does not really matter.
- * Here a relative path is ordered before an absolute path. */
- d = (a[0] == '/') - (b[0] == '/');
- if (d)
- return d;
-
- for (;;) {
- size_t j, k;
-
- a += strspn(a, "/");
- b += strspn(b, "/");
-
- if (*a == 0 && *b == 0)
- return 0;
-
- /* Order prefixes first: "/foo" before "/foo/bar" */
- if (*a == 0)
- return -1;
- if (*b == 0)
- return 1;
-
- j = strcspn(a, "/");
- k = strcspn(b, "/");
-
- /* Alphabetical sort: "/foo/aaa" before "/foo/b" */
- d = memcmp(a, b, MIN(j, k));
- if (d)
- return (d > 0) - (d < 0); /* sign of d */
-
- /* Sort "/foo/a" before "/foo/aaa" */
- d = (j > k) - (j < k); /* sign of (j - k) */
- if (d)
- return d;
-
- a += j;
- b += k;
- }
-}
-
-bool path_equal(const char *a, const char *b) {
- return path_compare(a, b) == 0;
-}
-
-bool path_equal_or_files_same(const char *a, const char *b) {
- return path_equal(a, b) || files_same(a, b) > 0;
-}
-
-char* path_join(const char *root, const char *path, const char *rest) {
- assert(path);
-
- if (!isempty(root))
- return strjoin(root, endswith(root, "/") ? "" : "/",
- path[0] == '/' ? path+1 : path,
- rest ? (endswith(path, "/") ? "" : "/") : NULL,
- rest && rest[0] == '/' ? rest+1 : rest,
- NULL);
- else
- return strjoin(path,
- rest ? (endswith(path, "/") ? "" : "/") : NULL,
- rest && rest[0] == '/' ? rest+1 : rest,
- NULL);
-}
-
-static int fd_fdinfo_mnt_id(int fd, const char *filename, int flags, int *mnt_id) {
- char path[strlen("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
- _cleanup_free_ char *fdinfo = NULL;
- _cleanup_close_ int subfd = -1;
- char *p;
- int r;
-
- if ((flags & AT_EMPTY_PATH) && isempty(filename))
- xsprintf(path, "/proc/self/fdinfo/%i", fd);
- else {
- subfd = openat(fd, filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH);
- if (subfd < 0)
- return -errno;
-
- xsprintf(path, "/proc/self/fdinfo/%i", subfd);
- }
-
- r = read_full_file(path, &fdinfo, NULL);
- if (r == -ENOENT) /* The fdinfo directory is a relatively new addition */
- return -EOPNOTSUPP;
- if (r < 0)
- return -errno;
-
- p = startswith(fdinfo, "mnt_id:");
- if (!p) {
- p = strstr(fdinfo, "\nmnt_id:");
- if (!p) /* The mnt_id field is a relatively new addition */
- return -EOPNOTSUPP;
-
- p += 8;
- }
-
- p += strspn(p, WHITESPACE);
- p[strcspn(p, WHITESPACE)] = 0;
-
- return safe_atoi(p, mnt_id);
-}
-
-int fd_is_mount_point(int fd, const char *filename, int flags) {
- union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT;
- int mount_id = -1, mount_id_parent = -1;
- bool nosupp = false, check_st_dev = true;
- struct stat a, b;
- int r;
-
- assert(fd >= 0);
- assert(filename);
-
- /* First we will try the name_to_handle_at() syscall, which
- * tells us the mount id and an opaque file "handle". It is
- * not supported everywhere though (kernel compile-time
- * option, not all file systems are hooked up). If it works
- * the mount id is usually good enough to tell us whether
- * something is a mount point.
- *
- * If that didn't work we will try to read the mount id from
- * /proc/self/fdinfo/<fd>. This is almost as good as
- * name_to_handle_at(), however, does not return the
- * opaque file handle. The opaque file handle is pretty useful
- * to detect the root directory, which we should always
- * consider a mount point. Hence we use this only as
- * fallback. Exporting the mnt_id in fdinfo is a pretty recent
- * kernel addition.
- *
- * As last fallback we do traditional fstat() based st_dev
- * comparisons. This is how things were traditionally done,
- * but unionfs breaks breaks this since it exposes file
- * systems with a variety of st_dev reported. Also, btrfs
- * subvolumes have different st_dev, even though they aren't
- * real mounts of their own. */
-
- r = name_to_handle_at(fd, filename, &h.handle, &mount_id, flags);
- if (r < 0) {
- if (errno == ENOSYS)
- /* This kernel does not support name_to_handle_at()
- * fall back to simpler logic. */
- goto fallback_fdinfo;
- else if (errno == EOPNOTSUPP)
- /* This kernel or file system does not support
- * name_to_handle_at(), hence let's see if the
- * upper fs supports it (in which case it is a
- * mount point), otherwise fallback to the
- * traditional stat() logic */
- nosupp = true;
- else
- return -errno;
- }
-
- r = name_to_handle_at(fd, "", &h_parent.handle, &mount_id_parent, AT_EMPTY_PATH);
- if (r < 0) {
- if (errno == EOPNOTSUPP) {
- if (nosupp)
- /* Neither parent nor child do name_to_handle_at()?
- We have no choice but to fall back. */
- goto fallback_fdinfo;
- else
- /* 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. */
- return 1;
- } else
- return -errno;
- }
-
- /* The parent can do name_to_handle_at() but the
- * directory we are interested in can't? If so, it
- * must be a mount point. */
- if (nosupp)
- return 1;
-
- /* If the file handle for the directory we are
- * interested in and its parent are identical, we
- * assume this is the root directory, which is a mount
- * point. */
-
- if (h.handle.handle_bytes == h_parent.handle.handle_bytes &&
- h.handle.handle_type == h_parent.handle.handle_type &&
- memcmp(h.handle.f_handle, h_parent.handle.f_handle, h.handle.handle_bytes) == 0)
- return 1;
-
- return mount_id != mount_id_parent;
-
-fallback_fdinfo:
- r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id);
- if (r == -EOPNOTSUPP)
- goto fallback_fstat;
- if (r < 0)
- return r;
-
- r = fd_fdinfo_mnt_id(fd, "", AT_EMPTY_PATH, &mount_id_parent);
- if (r < 0)
- return r;
-
- if (mount_id != mount_id_parent)
- return 1;
-
- /* Hmm, so, the mount ids are the same. This leaves one
- * special case though for the root file system. For that,
- * let's see if the parent directory has the same inode as we
- * are interested in. Hence, let's also do fstat() checks now,
- * too, but avoid the st_dev comparisons, since they aren't
- * that useful on unionfs mounts. */
- check_st_dev = false;
-
-fallback_fstat:
- /* yay for fstatat() taking a different set of flags than the other
- * _at() above */
- if (flags & AT_SYMLINK_FOLLOW)
- flags &= ~AT_SYMLINK_FOLLOW;
- else
- flags |= AT_SYMLINK_NOFOLLOW;
- if (fstatat(fd, filename, &a, flags) < 0)
- return -errno;
-
- if (fstatat(fd, "", &b, AT_EMPTY_PATH) < 0)
- return -errno;
-
- /* A directory with same device and inode as its parent? Must
- * be the root directory */
- if (a.st_dev == b.st_dev &&
- a.st_ino == b.st_ino)
- return 1;
-
- return check_st_dev && (a.st_dev != b.st_dev);
-}
-
-/* flags can be AT_SYMLINK_FOLLOW or 0 */
-int path_is_mount_point(const char *t, int flags) {
- _cleanup_close_ int fd = -1;
- _cleanup_free_ char *canonical = NULL, *parent = NULL;
- int r;
-
- assert(t);
-
- if (path_equal(t, "/"))
- return 1;
-
- /* we need to resolve symlinks manually, we can't just rely on
- * fd_is_mount_point() to do that for us; if we have a structure like
- * /bin -> /usr/bin/ and /usr is a mount point, then the parent that we
- * look at needs to be /usr, not /. */
- if (flags & AT_SYMLINK_FOLLOW) {
- canonical = canonicalize_file_name(t);
- if (!canonical)
- return -errno;
- }
-
- r = path_get_parent(canonical ?: t, &parent);
- if (r < 0)
- return r;
-
- fd = openat(AT_FDCWD, parent, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_PATH);
- if (fd < 0)
- return -errno;
-
- return fd_is_mount_point(fd, basename(canonical ?: t), flags);
-}
-
-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;
-
- /* 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 find_binary(const char *name, bool local, char **filename) {
- assert(name);
-
- if (is_path(name)) {
- if (local && access(name, X_OK) < 0)
- return -errno;
-
- if (filename) {
- char *p;
-
- p = path_make_absolute_cwd(name);
- if (!p)
- return -ENOMEM;
-
- *filename = p;
- }
-
- return 0;
- } else {
- const char *path;
- const char *word, *state;
- size_t l;
-
- /**
- * Plain getenv, not secure_getenv, because we want
- * to actually allow the user to pick the binary.
- */
- path = getenv("PATH");
- if (!path)
- path = DEFAULT_PATH;
-
- FOREACH_WORD_SEPARATOR(word, l, path, ":", state) {
- _cleanup_free_ char *p = NULL;
-
- if (asprintf(&p, "%.*s/%s", (int) l, word, name) < 0)
- return -ENOMEM;
-
- if (access(p, X_OK) < 0)
- continue;
-
- if (filename) {
- *filename = path_kill_slashes(p);
- p = NULL;
- }
-
- return 0;
- }
-
- return -ENOENT;
- }
-}
-
-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;
-}
-
-int fsck_exists(const char *fstype) {
- _cleanup_free_ char *p = NULL, *d = NULL;
- const char *checker;
- int r;
-
- checker = strjoina("fsck.", fstype);
-
- r = find_binary(checker, true, &p);
- if (r < 0)
- return r;
-
- /* An fsck that is linked to /bin/true is a non-existent
- * fsck */
-
- r = readlink_malloc(p, &d);
- if (r >= 0 &&
- (path_equal(d, "/bin/true") ||
- path_equal(d, "/usr/bin/true") ||
- path_equal(d, "/dev/null")))
- return -ENOENT;
-
- return 0;
-}
-
-char *prefix_root(const char *root, const char *path) {
- char *n, *p;
- size_t l;
-
- /* If root is passed, prefixes path with it. Otherwise returns
- * it as is. */
-
- assert(path);
-
- /* First, drop duplicate prefixing slashes from the path */
- while (path[0] == '/' && path[1] == '/')
- path++;
-
- if (isempty(root) || path_equal(root, "/"))
- return strdup(path);
-
- l = strlen(root) + 1 + strlen(path) + 1;
-
- n = new(char, l);
- if (!n)
- return NULL;
-
- p = stpcpy(n, root);
-
- while (p > n && p[-1] == '/')
- p--;
-
- if (path[0] != '/')
- *(p++) = '/';
-
- strcpy(p, path);
- return n;
-}
~ianmdlvl / elogind.git / blobdiff