diff options
author | Kay Sievers <kay@vrfy.org> | 2015-06-09 14:27:33 +0200 |
---|---|---|
committer | Kay Sievers <kay@vrfy.org> | 2015-06-11 10:52:46 +0200 |
commit | a095315b3c31f7a419baceac82c26c3c5ac0cd12 (patch) | |
tree | a5a70cf5b5430c0a6873311437b8345d7071f249 /src/shared/path-util.c | |
parent | 37c47e5e5b8e47dd886ed6e8355b1203082b4a3e (diff) |
build-sys: split internal basic/ library from shared/
basic/ can be used by everything
cannot use anything outside of basic/
libsystemd/ can use basic/
cannot use shared/
shared/ can use libsystemd/
Diffstat (limited to 'src/shared/path-util.c')
-rw-r--r-- | src/shared/path-util.c | 853 |
1 files changed, 0 insertions, 853 deletions
diff --git a/src/shared/path-util.c b/src/shared/path-util.c deleted file mode 100644 index 537705446a..0000000000 --- a/src/shared/path-util.c +++ /dev/null @@ -1,853 +0,0 @@ -/*-*- 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 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; -} |