diff options
Diffstat (limited to 'src/basic/xattr-util.c')
| -rw-r--r-- | src/basic/xattr-util.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/src/basic/xattr-util.c b/src/basic/xattr-util.c new file mode 100644 index 0000000000..6abdaedc3e --- /dev/null +++ b/src/basic/xattr-util.c @@ -0,0 +1,195 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2010 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 <sys/xattr.h> + +#include "alloc-util.h" +#include "fd-util.h" +#include "sparse-endian.h" +#include "stdio-util.h" +#include "util.h" +#include "xattr-util.h" + +int getxattr_malloc(const char *path, const char *name, char **value, bool allow_symlink) { + char *v; + size_t l; + ssize_t n; + + assert(path); + assert(name); + assert(value); + + for (l = 100; ; l = (size_t) n + 1) { + v = new0(char, l); + if (!v) + return -ENOMEM; + + if (allow_symlink) + n = lgetxattr(path, name, v, l); + else + n = getxattr(path, name, v, l); + + if (n >= 0 && (size_t) n < l) { + *value = v; + return n; + } + + free(v); + + if (n < 0 && errno != ERANGE) + return -errno; + + if (allow_symlink) + n = lgetxattr(path, name, NULL, 0); + else + n = getxattr(path, name, NULL, 0); + if (n < 0) + return -errno; + } +} + +int fgetxattr_malloc(int fd, const char *name, char **value) { + char *v; + size_t l; + ssize_t n; + + assert(fd >= 0); + assert(name); + assert(value); + + for (l = 100; ; l = (size_t) n + 1) { + v = new0(char, l); + if (!v) + return -ENOMEM; + + n = fgetxattr(fd, name, v, l); + + if (n >= 0 && (size_t) n < l) { + *value = v; + return n; + } + + free(v); + + if (n < 0 && errno != ERANGE) + return -errno; + + n = fgetxattr(fd, name, NULL, 0); + if (n < 0) + return -errno; + } +} + +ssize_t fgetxattrat_fake(int dirfd, const char *filename, const char *attribute, void *value, size_t size, int flags) { + char fn[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1]; + _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_PATH|(flags & AT_SYMLINK_NOFOLLOW ? O_NOFOLLOW : 0)); + if (fd < 0) + return -errno; + + xsprintf(fn, "/proc/self/fd/%i", fd); + + l = getxattr(fn, 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; +} |