diff options
Diffstat (limited to 'src/basic/stat-util.c')
| -rw-r--r-- | src/basic/stat-util.c | 170 |
1 files changed, 166 insertions, 4 deletions
diff --git a/src/basic/stat-util.c b/src/basic/stat-util.c index 07154e25bb..57700e2388 100644 --- a/src/basic/stat-util.c +++ b/src/basic/stat-util.c @@ -10,11 +10,13 @@ #include <sys/types.h> #include <unistd.h> +#include "alloc-util.h" #include "dirent-util.h" #include "fd-util.h" #include "fs-util.h" #include "macro.h" #include "missing.h" +#include "parse-util.h" #include "stat-util.h" #include "string-util.h" @@ -45,6 +47,15 @@ int is_dir(const char* path, bool follow) { return !!S_ISDIR(st.st_mode); } +int is_dir_fd(int fd) { + struct stat st; + + if (fstat(fd, &st) < 0) + return -errno; + + return !!S_ISDIR(st.st_mode); +} + int is_device_node(const char *path) { struct stat info; @@ -204,15 +215,47 @@ int fd_is_network_fs(int fd) { } int fd_is_network_ns(int fd) { + struct statfs s; int r; - r = fd_is_fs_type(fd, NSFS_MAGIC); - if (r <= 0) - return r; + /* Checks whether the specified file descriptor refers to a network namespace. On old kernels there's no nice + * way to detect that, hence on those we'll return a recognizable error (EUCLEAN), so that callers can handle + * this somewhat nicely. + * + * This function returns > 0 if the fd definitely refers to a network namespace, 0 if it definitely does not + * refer to a network namespace, -EUCLEAN if we can't determine, and other negative error codes on error. */ + + if (fstatfs(fd, &s) < 0) + return -errno; + + if (!is_fs_type(&s, NSFS_MAGIC)) { + /* On really old kernels, there was no "nsfs", and network namespace sockets belonged to procfs + * instead. Handle that in a somewhat smart way. */ + + if (is_fs_type(&s, PROC_SUPER_MAGIC)) { + struct statfs t; + + /* OK, so it is procfs. Let's see if our own network namespace is procfs, too. If so, then the + * passed fd might refer to a network namespace, but we can't know for sure. In that case, + * return a recognizable error. */ + + if (statfs("/proc/self/ns/net", &t) < 0) + return -errno; + + if (s.f_type == t.f_type) + return -EUCLEAN; /* It's possible, we simply don't know */ + } + + return 0; /* No! */ + } r = ioctl(fd, NS_GET_NSTYPE); - if (r < 0) + if (r < 0) { + if (errno == ENOTTY) /* Old kernels didn't know this ioctl, let's also return a recognizable error in that case */ + return -EUCLEAN; + return -errno; + } return r == CLONE_NEWNET; } @@ -255,3 +298,122 @@ int fd_verify_regular(int fd) { return stat_verify_regular(&st); } + +int stat_verify_directory(const struct stat *st) { + assert(st); + + if (S_ISLNK(st->st_mode)) + return -ELOOP; + + if (!S_ISDIR(st->st_mode)) + return -ENOTDIR; + + return 0; +} + +int fd_verify_directory(int fd) { + struct stat st; + + assert(fd >= 0); + + if (fstat(fd, &st) < 0) + return -errno; + + return stat_verify_directory(&st); +} + +int device_path_make_major_minor(mode_t mode, dev_t devno, char **ret) { + const char *t; + + /* Generates the /dev/{char|block}/MAJOR:MINOR path for a dev_t */ + + if (S_ISCHR(mode)) + t = "char"; + else if (S_ISBLK(mode)) + t = "block"; + else + return -ENODEV; + + if (asprintf(ret, "/dev/%s/%u:%u", t, major(devno), minor(devno)) < 0) + return -ENOMEM; + + return 0; + +} + +int device_path_make_canonical(mode_t mode, dev_t devno, char **ret) { + _cleanup_free_ char *p = NULL; + int r; + + /* Finds the canonical path for a device, i.e. resolves the /dev/{char|block}/MAJOR:MINOR path to the end. */ + + assert(ret); + + if (major(devno) == 0 && minor(devno) == 0) { + char *s; + + /* A special hack to make sure our 'inaccessible' device nodes work. They won't have symlinks in + * /dev/block/ and /dev/char/, hence we handle them specially here. */ + + if (S_ISCHR(mode)) + s = strdup("/run/systemd/inaccessible/chr"); + else if (S_ISBLK(mode)) + s = strdup("/run/systemd/inaccessible/blk"); + else + return -ENODEV; + + if (!s) + return -ENOMEM; + + *ret = s; + return 0; + } + + r = device_path_make_major_minor(mode, devno, &p); + if (r < 0) + return r; + + return chase_symlinks(p, NULL, 0, ret); +} + +int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devno) { + mode_t mode; + dev_t devno; + int r; + + /* Tries to extract the major/minor directly from the device path if we can. Handles /dev/block/ and /dev/char/ + * paths, as well out synthetic inaccessible device nodes. Never goes to disk. Returns -ENODEV if the device + * path cannot be parsed like this. */ + + if (path_equal(path, "/run/systemd/inaccessible/chr")) { + mode = S_IFCHR; + devno = makedev(0, 0); + } else if (path_equal(path, "/run/systemd/inaccessible/blk")) { + mode = S_IFBLK; + devno = makedev(0, 0); + } else { + const char *w; + + w = path_startswith(path, "/dev/block/"); + if (w) + mode = S_IFBLK; + else { + w = path_startswith(path, "/dev/char/"); + if (!w) + return -ENODEV; + + mode = S_IFCHR; + } + + r = parse_dev(w, &devno); + if (r < 0) + return r; + } + + if (ret_mode) + *ret_mode = mode; + if (ret_devno) + *ret_devno = devno; + + return 0; +} |