X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fshared%2Fpath-util.c;h=b3fe0b81791f618949b4cbac1b183f3ba3e0b858;hp=97a200504ba80f61e9e745b5aab6390bf4996070;hb=db594aef549b1376ea80030bd0966ed872eac01e;hpb=8ac7549330c774b8ca04034c1303165fe6a920b0

diff --git a/src/shared/path-util.c b/src/shared/path-util.c
index 97a200504..b3fe0b817 100644
--- a/src/shared/path-util.c
+++ b/src/shared/path-util.c
@@ -45,17 +45,6 @@ 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 +90,8 @@ 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 +115,7 @@ 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 +125,96 @@ 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;
+
+                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;
 
-        return r;
+                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 +227,8 @@ 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 +238,7 @@ 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;
@@ -178,25 +252,65 @@ 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);
-
-                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);
-                free(t);
-
                 if (!u) {
-                        if (errno == ENOMEM || !errno)
-                                enomem = true;
-
-                        continue;
-                }
+                        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;
         }
@@ -209,24 +323,15 @@ char **path_strv_canonicalize(char **l) {
         return l;
 }
 
-char **path_strv_remove_empty(char **l) {
-        char **f, **t;
-
-        if (!l)
-                return NULL;
+char **path_strv_resolve_uniq(char **l, const char *prefix) {
 
-        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) {
@@ -264,12 +369,12 @@ char *path_kill_slashes(char *path) {
         return path;
 }
 
-bool path_startswith(const char *path, const char *prefix) {
+char* path_startswith(const char *path, const char *prefix) {
         assert(path);
         assert(prefix);
 
         if ((path[0] == '/') != (prefix[0] == '/'))
-                return false;
+                return NULL;
 
         for (;;) {
                 size_t a, b;
@@ -278,19 +383,19 @@ bool path_startswith(const char *path, const char *prefix) {
                 prefix += strspn(prefix, "/");
 
                 if (*prefix == 0)
-                        return true;
+                        return (char*) path;
 
                 if (*path == 0)
-                        return false;
+                        return NULL;
 
                 a = strcspn(path, "/");
                 b = strcspn(prefix, "/");
 
                 if (a != b)
-                        return false;
+                        return NULL;
 
                 if (memcmp(path, prefix, a) != 0)
-                        return false;
+                        return NULL;
 
                 path += a;
                 prefix += b;
@@ -330,12 +435,32 @@ bool path_equal(const char *a, const char *b) {
         }
 }
 
+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) {
-        char *parent;
-        int r;
-        struct file_handle *h;
+
+        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
@@ -344,13 +469,10 @@ int path_is_mount_point(const char *t, bool allow_symlink) {
         if (path_equal(t, "/"))
                 return 1;
 
-        h = alloca(MAX_HANDLE_SZ);
-        h->handle_bytes = MAX_HANDLE_SZ;
-
-        r = name_to_handle_at(AT_FDCWD, t, h, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0);
+        r = name_to_handle_at(AT_FDCWD, t, &h.handle, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0);
         if (r < 0) {
-                if (errno == ENOTSUP)
-                        /* This file system does not support
+                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;
@@ -365,15 +487,13 @@ int path_is_mount_point(const char *t, bool allow_symlink) {
         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);
-
+        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 == ENOTSUP)
+                if (errno == EOPNOTSUPP)
                         return 1;
 
                 return -errno;
@@ -399,8 +519,6 @@ fallback:
                 return r;
 
         r = lstat(parent, &b);
-        free(parent);
-
         if (r < 0)
                 return -errno;
 
@@ -415,5 +533,143 @@ 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 = 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, 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 = strappenda("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;
 }