/*-*- 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_canonicalize_absolute(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_canonicalize_absolute_uniq(char **l, const char *prefix) { if (strv_isempty(l)) return l; if (!path_strv_canonicalize_absolute(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; } } 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; char *parent; 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); free(parent); 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); free(parent); 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; return !!(st.f_flag & ST_RDONLY); } int path_is_os_tree(const char *path) { char *p; int r; /* We use /etc/os-release as flag file if something is an OS */ p = strappenda(path, "/etc/os-release"); r = access(p, F_OK); return r < 0 ? 0 : 1; } int find_binary(const char *name, char **filename) { assert(name); if (strchr(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; char *state, *w; 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(w, l, path, ":", state) { _cleanup_free_ char *p = NULL; if (asprintf(&p, "%.*s/%s", (int) l, w, 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) { const char *checker; checker = strappenda("fsck.", fstype); return find_binary(checker, NULL); }