diff options
Diffstat (limited to 'src/basic/path-util.c')
| -rw-r--r-- | src/basic/path-util.c | 644 |
1 files changed, 295 insertions, 349 deletions
diff --git a/src/basic/path-util.c b/src/basic/path-util.c index 5cbfc145a4..ec90c432a4 100644 --- a/src/basic/path-util.c +++ b/src/basic/path-util.c @@ -19,21 +19,33 @@ 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 <stdio.h> +#include <stdlib.h> +#include <string.h> #include <sys/statvfs.h> +#include <unistd.h> -#include "macro.h" -#include "util.h" +/* When we include libgen.h because we need dirname() we immediately + * undefine basename() since libgen.h defines it as a macro to the + * POSIX version which is really broken. We prefer GNU basename(). */ +#include <libgen.h> +#undef basename + +#include "alloc-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "fs-util.h" #include "log.h" -#include "strv.h" -#include "path-util.h" +#include "macro.h" #include "missing.h" -#include "fileio.h" +#include "parse-util.h" +#include "path-util.h" +#include "stat-util.h" +#include "string-util.h" +#include "strv.h" +#include "util.h" bool path_is_absolute(const char *p) { return p[0] == '/'; @@ -43,61 +55,25 @@ 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) { +int path_split_and_make_absolute(const char *p, char ***ret) { char **l; + int r; + assert(p); + assert(ret); l = strv_split(p, ":"); if (!l) - return NULL; + return -ENOMEM; - if (!path_strv_make_absolute_cwd(l)) { + r = path_strv_make_absolute_cwd(l); + if (r < 0) { strv_free(l); - return NULL; + return r; } - return l; + *ret = l; + return r; } char *path_make_absolute(const char *p, const char *prefix) { @@ -112,22 +88,31 @@ char *path_make_absolute(const char *p, const char *prefix) { return strjoin(prefix, "/", p, NULL); } -char *path_make_absolute_cwd(const char *p) { - _cleanup_free_ char *cwd = NULL; +int path_make_absolute_cwd(const char *p, char **ret) { + char *c; assert(p); + assert(ret); /* Similar to path_make_absolute(), but prefixes with the * current working directory. */ if (path_is_absolute(p)) - return strdup(p); + c = strdup(p); + else { + _cleanup_free_ char *cwd = NULL; - cwd = get_current_dir_name(); - if (!cwd) - return NULL; + cwd = get_current_dir_name(); + if (!cwd) + return -errno; + + c = strjoin(cwd, "/", p, NULL); + } + if (!c) + return -ENOMEM; - return strjoin(cwd, "/", p, NULL); + *ret = c; + return 0; } int path_make_relative(const char *from_dir, const char *to_path, char **_r) { @@ -215,8 +200,9 @@ int path_make_relative(const char *from_dir, const char *to_path, char **_r) { return 0; } -char **path_strv_make_absolute_cwd(char **l) { +int path_strv_make_absolute_cwd(char **l) { char **s; + int r; /* Goes through every item in the string list and makes it * absolute. This works in place and won't rollback any @@ -225,15 +211,15 @@ char **path_strv_make_absolute_cwd(char **l) { STRV_FOREACH(s, l) { char *t; - t = path_make_absolute_cwd(*s); - if (!t) - return NULL; + r = path_make_absolute_cwd(*s, &t); + if (r < 0) + return r; free(*s); *s = t; } - return l; + return 0; } char **path_strv_resolve(char **l, const char *prefix) { @@ -411,7 +397,7 @@ int path_compare(const char *a, const char *b) { * 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) + if (d != 0) return d; for (;;) { @@ -434,12 +420,12 @@ int path_compare(const char *a, const char *b) { /* Alphabetical sort: "/foo/aaa" before "/foo/b" */ d = memcmp(a, b, MIN(j, k)); - if (d) + if (d != 0) 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) + if (d != 0) return d; a += j; @@ -471,294 +457,66 @@ char* path_join(const char *root, const char *path, const char *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; +int find_binary(const char *name, char **ret) { + int last_error, r; + const char *p; - 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 - * 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; - } + assert(name); - 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 + if (is_path(name)) { + if (access(name, X_OK) < 0) 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; + if (ret) { + r = path_make_absolute_cwd(name, ret); + if (r < 0) + return r; + } - t = canonical; + return 0; } - r = path_get_parent(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(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); + /** + * Plain getenv, not secure_getenv, because we want + * to actually allow the user to pick the binary. + */ + p = getenv("PATH"); + if (!p) + p = DEFAULT_PATH; - if (is_path(name)) { - if (local && access(name, X_OK) < 0) - return -errno; + last_error = -ENOENT; - if (filename) { - char *p; + for (;;) { + _cleanup_free_ char *j = NULL, *element = NULL; - p = path_make_absolute_cwd(name); - if (!p) - return -ENOMEM; + r = extract_first_word(&p, &element, ":", EXTRACT_RELAX|EXTRACT_DONT_COALESCE_SEPARATORS); + if (r < 0) + return r; + if (r == 0) + break; - *filename = p; - } + if (!path_is_absolute(element)) + continue; - 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; + j = strjoin(element, "/", name, NULL); + if (!j) + return -ENOMEM; - if (access(p, X_OK) < 0) - continue; + if (access(j, X_OK) >= 0) { + /* Found it! */ - if (filename) { - *filename = path_kill_slashes(p); - p = NULL; + if (ret) { + *ret = path_kill_slashes(j); + j = NULL; } return 0; } - return -ENOENT; + last_error = -errno; } + + return last_error; } bool paths_check_timestamp(const char* const* paths, usec_t *timestamp, bool update) { @@ -796,14 +554,13 @@ bool paths_check_timestamp(const char* const* paths, usec_t *timestamp, bool upd return changed; } -int fsck_exists(const char *fstype) { +static int binary_is_good(const char *binary) { _cleanup_free_ char *p = NULL, *d = NULL; - const char *checker; int r; - checker = strjoina("fsck.", fstype); - - r = find_binary(checker, true, &p); + r = find_binary(binary, &p); + if (r == -ENOENT) + return 0; if (r < 0) return r; @@ -811,13 +568,39 @@ int fsck_exists(const char *fstype) { * 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; + if (r == -EINVAL) /* not a symlink */ + return 1; + if (r < 0) + return r; - return 0; + return !path_equal(d, "true") && + !path_equal(d, "/bin/true") && + !path_equal(d, "/usr/bin/true") && + !path_equal(d, "/dev/null"); +} + +int fsck_exists(const char *fstype) { + const char *checker; + + assert(fstype); + + if (streq(fstype, "auto")) + return -EINVAL; + + checker = strjoina("fsck.", fstype); + return binary_is_good(checker); +} + +int mkfs_exists(const char *fstype) { + const char *mkfs; + + assert(fstype); + + if (streq(fstype, "auto")) + return -EINVAL; + + mkfs = strjoina("mkfs.", fstype); + return binary_is_good(mkfs); } char *prefix_root(const char *root, const char *path) { @@ -853,3 +636,166 @@ char *prefix_root(const char *root, const char *path) { strcpy(p, path); return n; } + +int parse_path_argument_and_warn(const char *path, bool suppress_root, char **arg) { + char *p; + int r; + + /* + * This function is intended to be used in command line + * parsers, to handle paths that are passed in. It makes the + * path absolute, and reduces it to NULL if omitted or + * root (the latter optionally). + * + * NOTE THAT THIS WILL FREE THE PREVIOUS ARGUMENT POINTER ON + * SUCCESS! Hence, do not pass in uninitialized pointers. + */ + + if (isempty(path)) { + *arg = mfree(*arg); + return 0; + } + + r = path_make_absolute_cwd(path, &p); + if (r < 0) + return log_error_errno(r, "Failed to parse path \"%s\" and make it absolute: %m", path); + + path_kill_slashes(p); + if (suppress_root && path_equal(p, "/")) + p = mfree(p); + + free(*arg); + *arg = p; + return 0; +} + +char* dirname_malloc(const char *path) { + char *d, *dir, *dir2; + + assert(path); + + d = strdup(path); + if (!d) + return NULL; + + dir = dirname(d); + assert(dir); + + if (dir == d) + return d; + + dir2 = strdup(dir); + free(d); + + return dir2; +} + +bool filename_is_valid(const char *p) { + const char *e; + + if (isempty(p)) + return false; + + if (streq(p, ".")) + return false; + + if (streq(p, "..")) + return false; + + e = strchrnul(p, '/'); + if (*e != 0) + return false; + + if (e - p > FILENAME_MAX) + return false; + + return true; +} + +bool path_is_safe(const char *p) { + + if (isempty(p)) + return false; + + if (streq(p, "..") || startswith(p, "../") || endswith(p, "/..") || strstr(p, "/../")) + return false; + + if (strlen(p)+1 > PATH_MAX) + return false; + + /* The following two checks are not really dangerous, but hey, they still are confusing */ + if (streq(p, ".") || startswith(p, "./") || endswith(p, "/.") || strstr(p, "/./")) + return false; + + if (strstr(p, "//")) + return false; + + return true; +} + +char *file_in_same_dir(const char *path, const char *filename) { + char *e, *ret; + size_t k; + + assert(path); + assert(filename); + + /* This removes the last component of path and appends + * filename, unless the latter is absolute anyway or the + * former isn't */ + + if (path_is_absolute(filename)) + return strdup(filename); + + e = strrchr(path, '/'); + if (!e) + return strdup(filename); + + k = strlen(filename); + ret = new(char, (e + 1 - path) + k + 1); + if (!ret) + return NULL; + + memcpy(mempcpy(ret, path, e + 1 - path), filename, k + 1); + return ret; +} + +bool hidden_file_allow_backup(const char *filename) { + assert(filename); + + return + filename[0] == '.' || + streq(filename, "lost+found") || + streq(filename, "aquota.user") || + streq(filename, "aquota.group") || + endswith(filename, ".rpmnew") || + endswith(filename, ".rpmsave") || + endswith(filename, ".rpmorig") || + endswith(filename, ".dpkg-old") || + endswith(filename, ".dpkg-new") || + endswith(filename, ".dpkg-tmp") || + endswith(filename, ".dpkg-dist") || + endswith(filename, ".dpkg-bak") || + endswith(filename, ".dpkg-backup") || + endswith(filename, ".dpkg-remove") || + endswith(filename, ".swp"); +} + +bool hidden_file(const char *filename) { + assert(filename); + + if (endswith(filename, "~")) + return true; + + return hidden_file_allow_backup(filename); +} + +bool is_device_path(const char *path) { + + /* Returns true on paths that refer to a device, either in + * sysfs or in /dev */ + + return + path_startswith(path, "/dev/") || + path_startswith(path, "/sys/"); +} |