+
+ssize_t fgetxattrat_fake(int dirfd, const char *filename, const char *attribute, void *value, size_t size, int flags) {
+ _cleanup_close_ int fd = -1;
+ ssize_t l;
+
+ /* The kernel doesn't have a fgetxattrat() command, hence let's emulate one */
+
+ fd = openat(dirfd, filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOATIME|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0));
+ if (fd < 0)
+ return -errno;
+
+ l = fgetxattr(fd, attribute, value, size);
+ if (l < 0)
+ return -errno;
+
+ return l;
+}
+
+static int parse_crtime(le64_t le, usec_t *usec) {
+ uint64_t u;
+
+ assert(usec);
+
+ u = le64toh(le);
+ if (u == 0 || u == (uint64_t) -1)
+ return -EIO;
+
+ *usec = (usec_t) u;
+ return 0;
+}
+
+int fd_getcrtime(int fd, usec_t *usec) {
+ le64_t le;
+ ssize_t n;
+
+ assert(fd >= 0);
+ assert(usec);
+
+ /* Until Linux gets a real concept of birthtime/creation time,
+ * let's fake one with xattrs */
+
+ n = fgetxattr(fd, "user.crtime_usec", &le, sizeof(le));
+ if (n < 0)
+ return -errno;
+ if (n != sizeof(le))
+ return -EIO;
+
+ return parse_crtime(le, usec);
+}
+
+int fd_getcrtime_at(int dirfd, const char *name, usec_t *usec, int flags) {
+ le64_t le;
+ ssize_t n;
+
+ n = fgetxattrat_fake(dirfd, name, "user.crtime_usec", &le, sizeof(le), flags);
+ if (n < 0)
+ return -errno;
+ if (n != sizeof(le))
+ return -EIO;
+
+ return parse_crtime(le, usec);
+}
+
+int path_getcrtime(const char *p, usec_t *usec) {
+ le64_t le;
+ ssize_t n;
+
+ assert(p);
+ assert(usec);
+
+ n = getxattr(p, "user.crtime_usec", &le, sizeof(le));
+ if (n < 0)
+ return -errno;
+ if (n != sizeof(le))
+ return -EIO;
+
+ return parse_crtime(le, usec);
+}
+
+int fd_setcrtime(int fd, usec_t usec) {
+ le64_t le;
+
+ assert(fd >= 0);
+
+ if (usec <= 0)
+ usec = now(CLOCK_REALTIME);
+
+ le = htole64((uint64_t) usec);
+ if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), 0) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int chattr_fd(int fd, bool b, unsigned mask) {
+ unsigned old_attr, new_attr;
+
+ assert(fd >= 0);
+
+ if (mask == 0)
+ return 0;
+
+ if (ioctl(fd, FS_IOC_GETFLAGS, &old_attr) < 0)
+ return -errno;
+
+ if (b)
+ new_attr = old_attr | mask;
+ else
+ new_attr = old_attr & ~mask;
+
+ if (new_attr == old_attr)
+ return 0;
+
+ if (ioctl(fd, FS_IOC_SETFLAGS, &new_attr) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int chattr_path(const char *p, bool b, unsigned mask) {
+ _cleanup_close_ int fd = -1;
+
+ assert(p);
+
+ if (mask == 0)
+ return 0;
+
+ fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fd < 0)
+ return -errno;
+
+ return chattr_fd(fd, b, mask);
+}
+
+int change_attr_fd(int fd, unsigned value, unsigned mask) {
+ unsigned old_attr, new_attr;
+
+ assert(fd >= 0);
+
+ if (mask == 0)
+ return 0;
+
+ if (ioctl(fd, FS_IOC_GETFLAGS, &old_attr) < 0)
+ return -errno;
+
+ new_attr = (old_attr & ~mask) |(value & mask);
+
+ if (new_attr == old_attr)
+ return 0;
+
+ if (ioctl(fd, FS_IOC_SETFLAGS, &new_attr) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int read_attr_fd(int fd, unsigned *ret) {
+ assert(fd >= 0);
+
+ if (ioctl(fd, FS_IOC_GETFLAGS, ret) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int read_attr_path(const char *p, unsigned *ret) {
+ _cleanup_close_ int fd = -1;
+
+ assert(p);
+ assert(ret);
+
+ fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fd < 0)
+ return -errno;
+
+ return read_attr_fd(fd, ret);
+}
+
+int make_lock_file(const char *p, int operation, LockFile *ret) {
+ _cleanup_close_ int fd = -1;
+ _cleanup_free_ char *t = NULL;
+ int r;
+
+ /*
+ * We use UNPOSIX locks if they are available. They have nice
+ * semantics, and are mostly compatible with NFS. However,
+ * they are only available on new kernels. When we detect we
+ * are running on an older kernel, then we fall back to good
+ * old BSD locks. They also have nice semantics, but are
+ * slightly problematic on NFS, where they are upgraded to
+ * POSIX locks, even though locally they are orthogonal to
+ * POSIX locks.
+ */
+
+ t = strdup(p);
+ if (!t)
+ return -ENOMEM;
+
+ for (;;) {
+ struct flock fl = {
+ .l_type = (operation & ~LOCK_NB) == LOCK_EX ? F_WRLCK : F_RDLCK,
+ .l_whence = SEEK_SET,
+ };
+ struct stat st;
+
+ fd = open(p, O_CREAT|O_RDWR|O_NOFOLLOW|O_CLOEXEC|O_NOCTTY, 0600);
+ if (fd < 0)
+ return -errno;
+
+ r = fcntl(fd, (operation & LOCK_NB) ? F_OFD_SETLK : F_OFD_SETLKW, &fl);
+ if (r < 0) {
+
+ /* If the kernel is too old, use good old BSD locks */
+ if (errno == EINVAL)
+ r = flock(fd, operation);
+
+ if (r < 0)
+ return errno == EAGAIN ? -EBUSY : -errno;
+ }
+
+ /* If we acquired the lock, let's check if the file
+ * still exists in the file system. If not, then the
+ * previous exclusive owner removed it and then closed
+ * it. In such a case our acquired lock is worthless,
+ * hence try again. */
+
+ r = fstat(fd, &st);
+ if (r < 0)
+ return -errno;
+ if (st.st_nlink > 0)
+ break;
+
+ fd = safe_close(fd);
+ }
+
+ ret->path = t;
+ ret->fd = fd;
+ ret->operation = operation;
+
+ fd = -1;
+ t = NULL;
+
+ return r;
+}
+
+int make_lock_file_for(const char *p, int operation, LockFile *ret) {
+ const char *fn;
+ char *t;
+
+ assert(p);
+ assert(ret);
+
+ fn = basename(p);
+ if (!filename_is_valid(fn))
+ return -EINVAL;
+
+ t = newa(char, strlen(p) + 2 + 4 + 1);
+ stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), fn), ".lck");
+
+ return make_lock_file(t, operation, ret);
+}
+
+void release_lock_file(LockFile *f) {
+ int r;
+
+ if (!f)
+ return;
+
+ if (f->path) {
+
+ /* If we are the exclusive owner we can safely delete
+ * the lock file itself. If we are not the exclusive
+ * owner, we can try becoming it. */
+
+ if (f->fd >= 0 &&
+ (f->operation & ~LOCK_NB) == LOCK_SH) {
+ static const struct flock fl = {
+ .l_type = F_WRLCK,
+ .l_whence = SEEK_SET,
+ };
+
+ r = fcntl(f->fd, F_OFD_SETLK, &fl);
+ if (r < 0 && errno == EINVAL)
+ r = flock(f->fd, LOCK_EX|LOCK_NB);
+
+ if (r >= 0)
+ f->operation = LOCK_EX|LOCK_NB;
+ }
+
+ if ((f->operation & ~LOCK_NB) == LOCK_EX)
+ unlink_noerrno(f->path);
+
+ free(f->path);
+ f->path = NULL;
+ }
+
+ f->fd = safe_close(f->fd);
+ f->operation = 0;
+}
+
+static size_t nul_length(const uint8_t *p, size_t sz) {
+ size_t n = 0;
+
+ while (sz > 0) {
+ if (*p != 0)
+ break;
+
+ n++;
+ p++;
+ sz--;
+ }
+
+ return n;
+}
+
+ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {
+ const uint8_t *q, *w, *e;
+ ssize_t l;
+
+ q = w = p;
+ e = q + sz;
+ while (q < e) {
+ size_t n;
+
+ n = nul_length(q, e - q);
+
+ /* If there are more than the specified run length of
+ * NUL bytes, or if this is the beginning or the end
+ * of the buffer, then seek instead of write */
+ if ((n > run_length) ||
+ (n > 0 && q == p) ||
+ (n > 0 && q + n >= e)) {
+ if (q > w) {
+ l = write(fd, w, q - w);
+ if (l < 0)
+ return -errno;
+ if (l != q -w)
+ return -EIO;
+ }
+
+ if (lseek(fd, n, SEEK_CUR) == (off_t) -1)
+ return -errno;
+
+ q += n;
+ w = q;
+ } else if (n > 0)
+ q += n;
+ else
+ q ++;
+ }
+
+ if (q > w) {
+ l = write(fd, w, q - w);
+ if (l < 0)
+ return -errno;
+ if (l != q - w)
+ return -EIO;
+ }
+
+ return q - (const uint8_t*) p;
+}
+
+void sigkill_wait(pid_t *pid) {
+ if (!pid)
+ return;
+ if (*pid <= 1)
+ return;
+
+ if (kill(*pid, SIGKILL) > 0)
+ (void) wait_for_terminate(*pid, NULL);
+}
+
+int syslog_parse_priority(const char **p, int *priority, bool with_facility) {
+ int a = 0, b = 0, c = 0;
+ int k;
+
+ assert(p);
+ assert(*p);
+ assert(priority);
+
+ if ((*p)[0] != '<')
+ return 0;
+
+ if (!strchr(*p, '>'))
+ return 0;
+
+ if ((*p)[2] == '>') {
+ c = undecchar((*p)[1]);
+ k = 3;
+ } else if ((*p)[3] == '>') {
+ b = undecchar((*p)[1]);
+ c = undecchar((*p)[2]);
+ k = 4;
+ } else if ((*p)[4] == '>') {
+ a = undecchar((*p)[1]);
+ b = undecchar((*p)[2]);
+ c = undecchar((*p)[3]);
+ k = 5;
+ } else
+ return 0;
+
+ if (a < 0 || b < 0 || c < 0 ||
+ (!with_facility && (a || b || c > 7)))
+ return 0;
+
+ if (with_facility)
+ *priority = a*100 + b*10 + c;
+ else
+ *priority = (*priority & LOG_FACMASK) | c;
+
+ *p += k;
+ return 1;
+}
+
+ssize_t string_table_lookup(const char * const *table, size_t len, const char *key) {
+ size_t i;
+
+ if (!key)
+ return -1;
+
+ for (i = 0; i < len; ++i)
+ if (streq_ptr(table[i], key))
+ return (ssize_t)i;
+
+ return -1;
+}
+
+void cmsg_close_all(struct msghdr *mh) {
+ struct cmsghdr *cmsg;
+
+ assert(mh);
+
+ for (cmsg = CMSG_FIRSTHDR(mh); cmsg; cmsg = CMSG_NXTHDR(mh, cmsg))
+ if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
+ close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int));
+}
+
+int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) {
+ struct stat buf;
+ int ret;
+
+ ret = renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE);
+ if (ret >= 0)
+ return 0;
+
+ /* Even though renameat2() exists since Linux 3.15, btrfs added
+ * support for it later. If it is not implemented, fallback to another
+ * method. */
+ if (errno != EINVAL)
+ return -errno;
+
+ /* The link()/unlink() fallback does not work on directories. But
+ * renameat() without RENAME_NOREPLACE gives the same semantics on
+ * directories, except when newpath is an *empty* directory. This is
+ * good enough. */
+ ret = fstatat(olddirfd, oldpath, &buf, AT_SYMLINK_NOFOLLOW);
+ if (ret >= 0 && S_ISDIR(buf.st_mode)) {
+ ret = renameat(olddirfd, oldpath, newdirfd, newpath);
+ return ret >= 0 ? 0 : -errno;
+ }
+
+ /* If it is not a directory, use the link()/unlink() fallback. */
+ ret = linkat(olddirfd, oldpath, newdirfd, newpath, 0);
+ if (ret < 0)
+ return -errno;
+
+ ret = unlinkat(olddirfd, oldpath, 0);
+ if (ret < 0) {
+ /* backup errno before the following unlinkat() alters it */
+ ret = errno;
+ (void) unlinkat(newdirfd, newpath, 0);
+ errno = ret;
+ return -errno;
+ }
+
+ return 0;
+}
~ianmdlvl / elogind.git / blobdiff