| /*-*- 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] == '/'; |
| } |
| |
| 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 path_make_absolute(p, cwd); |
| } |
| |
| 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 */ |
| 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; |
| } |
| } |
| |
| 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; |
| } |
| } |
| |
| char* path_join(const char *root, const char *path, const char *rest) { |
| assert(path); |
| |
| if (!isempty(root)) |
| return strjoin(root, "/", |
| path[0] == '/' ? path+1 : path, |
| rest ? "/" : NULL, |
| rest && rest[0] == '/' ? rest+1 : rest, |
| NULL); |
| else |
| return strjoin(path, |
| rest ? "/" : NULL, |
| rest && rest[0] == '/' ? rest+1 : rest, |
| NULL); |
| } |
| |
| 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; |
| _cleanup_free_ char *parent = NULL; |
| 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 (IN_SET(errno, ENOSYS, EOPNOTSUPP)) |
| /* 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); |
| 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); |
| if (r < 0) |
| return -errno; |
| |
| return a.st_dev != b.st_dev; |
| } |
| |
| 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 = strappenda(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 = strappenda(path, "/etc/os-release"); |
| r = access(p, F_OK); |
| |
| return r >= 0; |
| } |
| |
| int find_binary(const char *name, char **filename) { |
| assert(name); |
| |
| if (is_path(name)) { |
| if (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 = strappenda("fsck.", fstype); |
| |
| r = find_binary(checker, &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; |
| } |