diff options
| -rw-r--r-- | src/libudev/Makefile.am | 4 | ||||
| -rw-r--r-- | src/libudev/libudev-device.c | 102 |
2 files changed, 104 insertions, 2 deletions
diff --git a/src/libudev/Makefile.am b/src/libudev/Makefile.am index 98d6e4e0f8..683944a671 100644 --- a/src/libudev/Makefile.am +++ b/src/libudev/Makefile.am @@ -1,8 +1,8 @@ ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAGS} -LIBUDEV_CURRENT=3 +LIBUDEV_CURRENT=4 LIBUDEV_REVISION=0 -LIBUDEV_AGE=2 +LIBUDEV_AGE=3 define move-to-rootlibdir if test "$(libdir)" != "$(rootlibdir)"; then \ diff --git a/src/libudev/libudev-device.c b/src/libudev/libudev-device.c index 3c9783ffd8..fd3e694ef6 100644 --- a/src/libudev/libudev-device.c +++ b/src/libudev/libudev-device.c @@ -1535,6 +1535,108 @@ out: return ret; } +/** + * udev_device_set_sysattr_value: + * @udev_device: udev device + * @sysattr: attribute name + * @value: new value to be set + * + * Update the contents of the sys attribute and the cached value of the device. + * + * Returns: Negative error code on failure or 0 on success. + **/ +_public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, char *value) +{ + struct udev_device *dev; + char path[UTIL_PATH_SIZE]; + struct stat statbuf; + int fd; + ssize_t size, value_len; + int ret = 0; + + if (udev_device == NULL) + return -EINVAL; + dev = udev_device; + if (sysattr == NULL) + return -EINVAL; + if (value == NULL) + value_len = 0; + else + value_len = strlen(value); +restart: + strscpyl(path, sizeof(path), udev_device_get_syspath(dev), "/", sysattr, NULL); + if (lstat(path, &statbuf) != 0) { + udev_list_entry_add(&dev->sysattr_value_list, sysattr, NULL); + ret = -ENXIO; + goto out; + } + + if (S_ISLNK(statbuf.st_mode)) { + /* + * Cannot modify core link values + */ + if (streq(sysattr, "driver") || + streq(sysattr, "subsystem") || + streq(sysattr, "module")) { + ret = -EPERM; + } else if (!streq(sysattr, "device")) { + /* resolve custom link to a device */ + strscpyl(path, sizeof(path), udev_device->syspath, "/", sysattr, NULL); + dev = udev_device_new_from_syspath(udev_device->udev, path); + if (dev != NULL) + goto restart; + ret = -ENXIO; + } else { + /* Unhandled, to not try to modify anything */ + ret = -EINVAL; + } + goto out; + } + + /* skip directories */ + if (S_ISDIR(statbuf.st_mode)) { + ret = -EISDIR; + goto out; + } + + /* skip non-readable files */ + if ((statbuf.st_mode & S_IRUSR) == 0) { + ret = -EACCES; + goto out; + } + + /* Value is limited to 4k */ + if (value_len > 4096) { + ret = -EINVAL; + goto out; + } + util_remove_trailing_chars(value, '\n'); + + /* write attribute value */ + fd = open(path, O_WRONLY|O_CLOEXEC); + if (fd < 0) { + ret = -errno; + goto out; + } + size = write(fd, value, value_len); + close(fd); + if (size < 0) { + ret = -errno; + goto out; + } + if (size < value_len) { + ret = -EIO; + goto out; + } + + /* wrote a valid value, store it in cache and return it */ + udev_list_entry_add(&dev->sysattr_value_list, sysattr, value); +out: + if (dev != udev_device) + udev_device_unref(dev); + return ret; +} + static int udev_device_sysattr_list_read(struct udev_device *udev_device) { struct dirent *dent; |