X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fshared%2Fpath-util.c;h=7090989fcba21015b4638e49eeac894702a4b338;hp=4857971b33002f29b496f6292a380d742c069b28;hb=f734154b8de9da6624d94c08aed86e5716dc631e;hpb=874310b7b68c4c0d36ff07397db30a959bb7dae5
diff --git a/src/shared/path-util.c b/src/shared/path-util.c
index 4857971b3..7090989fc 100644
--- a/src/shared/path-util.c
+++ b/src/shared/path-util.c
@@ -19,15 +19,12 @@
along with systemd; If not, see .
***/
-#include
#include
#include
#include
#include
-#include
#include
#include
-#include
#include
#include "macro.h"
@@ -36,6 +33,7 @@
#include "strv.h"
#include "path-util.h"
#include "missing.h"
+#include "fileio.h"
bool path_is_absolute(const char *p) {
return p[0] == '/';
@@ -45,17 +43,6 @@ bool is_path(const char *p) {
return !!strchr(p, '/');
}
-char *path_get_file_name(const char *p) {
- char *r;
-
- assert(p);
-
- if ((r = strrchr(p, '/')))
- 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;
@@ -101,7 +88,8 @@ char **path_split_and_make_absolute(const char *p) {
char **l;
assert(p);
- if (!(l = strv_split(p, ":")))
+ l = strv_split(p, ":");
+ if (!l)
return NULL;
if (!path_strv_make_absolute_cwd(l)) {
@@ -125,7 +113,7 @@ char *path_make_absolute(const char *p, const char *prefix) {
}
char *path_make_absolute_cwd(const char *p) {
- char *cwd, *r;
+ _cleanup_free_ char *cwd = NULL;
assert(p);
@@ -135,13 +123,96 @@ char *path_make_absolute_cwd(const char *p) {
if (path_is_absolute(p))
return strdup(p);
- if (!(cwd = get_current_dir_name()))
+ cwd = get_current_dir_name();
+ if (!cwd)
return NULL;
- r = path_make_absolute(p, cwd);
- free(cwd);
+ 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;
- return r;
+ 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) {
@@ -154,7 +225,8 @@ char **path_strv_make_absolute_cwd(char **l) {
STRV_FOREACH(s, l) {
char *t;
- if (!(t = path_make_absolute_cwd(*s)))
+ t = path_make_absolute_cwd(*s);
+ if (!t)
return NULL;
free(*s);
@@ -164,7 +236,7 @@ char **path_strv_make_absolute_cwd(char **l) {
return l;
}
-char **path_strv_canonicalize(char **l) {
+char **path_strv_resolve(char **l, const char *prefix) {
char **s;
unsigned k = 0;
bool enomem = false;
@@ -178,30 +250,66 @@ char **path_strv_canonicalize(char **l) {
STRV_FOREACH(s, l) {
char *t, *u;
+ _cleanup_free_ char *orig = NULL;
- t = path_make_absolute_cwd(*s);
- free(*s);
- *s = NULL;
-
- if (!t) {
- enomem = true;
+ 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)
- u = t;
- else {
+ if (errno == ENOENT) {
+ if (prefix) {
+ u = orig;
+ orig = NULL;
+ free(t);
+ } else
+ u = t;
+ } else {
free(t);
- if (errno == ENOMEM || !errno)
+ 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;
}
@@ -214,24 +322,15 @@ char **path_strv_canonicalize(char **l) {
return l;
}
-char **path_strv_remove_empty(char **l) {
- char **f, **t;
+char **path_strv_resolve_uniq(char **l, const char *prefix) {
- if (!l)
- return NULL;
-
- for (f = t = l; *f; f++) {
-
- if (dir_is_empty(*f) > 0) {
- free(*f);
- continue;
- }
+ if (strv_isempty(l))
+ return l;
- *(t++) = *f;
- }
+ if (!path_strv_resolve(l, prefix))
+ return NULL;
- *t = NULL;
- return l;
+ return strv_uniq(l);
}
char *path_kill_slashes(char *path) {
@@ -302,12 +401,18 @@ char* path_startswith(const char *path, const char *prefix) {
}
}
-bool path_equal(const char *a, const char *b) {
+int path_compare(const char *a, const char *b) {
+ int d;
+
assert(a);
assert(b);
- if ((a[0] == '/') != (b[0] == '/'))
- return false;
+ /* 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;
@@ -316,100 +421,228 @@ bool path_equal(const char *a, const char *b) {
b += strspn(b, "/");
if (*a == 0 && *b == 0)
- return true;
+ return 0;
- if (*a == 0 || *b == 0)
- return false;
+ /* Order prefixes first: "/foo" before "/foo/bar" */
+ if (*a == 0)
+ return -1;
+ if (*b == 0)
+ return 1;
j = strcspn(a, "/");
k = strcspn(b, "/");
- if (j != k)
- return false;
+ /* Alphabetical sort: "/foo/aaa" before "/foo/b" */
+ d = memcmp(a, b, MIN(j, k));
+ if (d)
+ return (d > 0) - (d < 0); /* sign of d */
- if (memcmp(a, b, j) != 0)
- return false;
+ /* Sort "/foo/a" before "/foo/aaa" */
+ d = (j > k) - (j < k); /* sign of (j - k) */
+ if (d)
+ return d;
a += j;
b += k;
}
}
-int path_is_mount_point(const char *t, bool allow_symlink) {
- char *parent;
+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;
- struct file_handle *h;
- int mount_id, mount_id_parent;
- struct stat a, b;
- /* 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 ((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;
- if (path_equal(t, "/"))
- return 1;
+ 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;
- h = alloca(MAX_HANDLE_SZ);
- h->handle_bytes = MAX_HANDLE_SZ;
+ 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);
+}
- r = name_to_handle_at(AT_FDCWD, t, h, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0);
+int fd_is_mount_point(int fd) {
+ 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);
+
+ /* 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/. 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, "", &h.handle, &mount_id, AT_EMPTY_PATH);
if (r < 0) {
- if (errno == ENOSYS || errno == ENOTSUP)
+ 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 fallback to the
+ * 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 */
- goto fallback;
-
- if (errno == ENOENT)
- return 0;
+ nosupp = true;
+ else
+ return -errno;
+ }
- return -errno;
+ r = name_to_handle_at(fd, "..", &h_parent.handle, &mount_id_parent, 0);
+ 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;
}
- r = path_get_parent(t, &parent);
+ /* 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, "", AT_EMPTY_PATH, &mount_id);
+ if (r == -EOPNOTSUPP)
+ goto fallback_fstat;
if (r < 0)
return r;
- h->handle_bytes = MAX_HANDLE_SZ;
- r = name_to_handle_at(AT_FDCWD, parent, h, &mount_id_parent, 0);
- free(parent);
+ r = fd_fdinfo_mnt_id(fd, "..", 0, &mount_id_parent);
+ if (r < 0)
+ return r;
- 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 == ENOTSUP)
- return 1;
+ 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:
+ if (fstatat(fd, "", &a, AT_EMPTY_PATH) < 0)
return -errno;
- }
- return mount_id != mount_id_parent;
+ if (fstatat(fd, "..", &b, 0) < 0)
+ return -errno;
-fallback:
- if (allow_symlink)
- r = stat(t, &a);
- else
- r = lstat(t, &a);
+ /* 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;
- if (r < 0) {
- if (errno == ENOENT)
- return 0;
+ return check_st_dev && (a.st_dev != b.st_dev);
+}
- return -errno;
- }
+int path_is_mount_point(const char *t, bool allow_symlink) {
+ _cleanup_close_ int fd = -1;
- r = path_get_parent(t, &parent);
- if (r < 0)
- return r;
+ assert(t);
- r = lstat(parent, &b);
- free(parent);
+ if (path_equal(t, "/"))
+ return 1;
- if (r < 0)
+ fd = openat(AT_FDCWD, t, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|(allow_symlink ? 0 : O_PATH));
+ if (fd < 0)
return -errno;
- return a.st_dev != b.st_dev;
+ return fd_is_mount_point(fd);
}
int path_is_read_only_fs(const char *path) {
@@ -420,5 +653,177 @@ int path_is_read_only_fs(const char *path) {
if (statvfs(path, &st) < 0)
return -errno;
- return !!(st.f_flag & ST_RDONLY);
+ 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;
}