diff options
Diffstat (limited to 'src/udev/udevadm-wait.c')
| -rw-r--r-- | src/udev/udevadm-wait.c | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/src/udev/udevadm-wait.c b/src/udev/udevadm-wait.c new file mode 100644 index 0000000..5ade13d --- /dev/null +++ b/src/udev/udevadm-wait.c @@ -0,0 +1,456 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include <getopt.h> +#include <unistd.h> + +#include "sd-event.h" + +#include "alloc-util.h" +#include "chase-symlinks.h" +#include "device-monitor-private.h" +#include "device-util.h" +#include "errno-util.h" +#include "event-util.h" +#include "fd-util.h" +#include "fs-util.h" +#include "inotify-util.h" +#include "parse-util.h" +#include "path-util.h" +#include "static-destruct.h" +#include "string-table.h" +#include "strv.h" +#include "udev-util.h" +#include "udevadm.h" + +typedef enum WaitUntil { + WAIT_UNTIL_INITIALIZED, + WAIT_UNTIL_ADDED, + WAIT_UNTIL_REMOVED, + _WAIT_UNTIL_MAX, + _WAIT_UNTIL_INVALID = -EINVAL, +} WaitUntil; + +static WaitUntil arg_wait_until = WAIT_UNTIL_INITIALIZED; +static usec_t arg_timeout_usec = USEC_INFINITY; +static bool arg_settle = false; +static char **arg_devices = NULL; + +STATIC_DESTRUCTOR_REGISTER(arg_devices, strv_freep); + +static const char * const wait_until_table[_WAIT_UNTIL_MAX] = { + [WAIT_UNTIL_INITIALIZED] = "initialized", + [WAIT_UNTIL_ADDED] = "added", + [WAIT_UNTIL_REMOVED] = "removed", +}; + +DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(wait_until, WaitUntil); + +static int check_device(const char *path) { + _cleanup_(sd_device_unrefp) sd_device *dev = NULL; + int r; + + assert(path); + + if (arg_wait_until == WAIT_UNTIL_REMOVED) { + r = laccess(path, F_OK); + if (r == -ENOENT) + return true; + if (r < 0) + return r; + return false; + } + + r = sd_device_new_from_path(&dev, path); + if (r == -ENODEV) + return false; + if (r < 0) + return r; + + if (arg_wait_until == WAIT_UNTIL_INITIALIZED) + return sd_device_get_is_initialized(dev); + + return true; +} + +static bool check(void) { + int r; + + if (arg_settle) { + r = udev_queue_is_empty(); + if (r == 0) + return false; + if (r < 0) + log_warning_errno(r, "Failed to check if udev queue is empty, assuming empty: %m"); + } + + STRV_FOREACH(p, arg_devices) { + r = check_device(*p); + if (r <= 0) { + if (r < 0) + log_warning_errno(r, "Failed to check if device \"%s\" is %s, assuming not %s: %m", + *p, + wait_until_to_string(arg_wait_until), + wait_until_to_string(arg_wait_until)); + return false; + } + } + + return true; +} + +static int check_and_exit(sd_event *event) { + int r; + + assert(event); + + if (check()) { + r = sd_event_exit(event, 0); + if (r < 0) + return r; + + return 1; + } + + return 0; +} + +static int device_monitor_handler(sd_device_monitor *monitor, sd_device *device, void *userdata) { + const char *name; + int r; + + assert(monitor); + assert(device); + + if (device_for_action(device, SD_DEVICE_REMOVE) != (arg_wait_until == WAIT_UNTIL_REMOVED)) + return 0; + + if (arg_wait_until == WAIT_UNTIL_REMOVED) + /* On removed event, the received device may not contain enough information. + * Let's unconditionally check all requested devices are removed. */ + return check_and_exit(sd_device_monitor_get_event(monitor)); + + /* For other events, at first check if the received device matches with the requested devices, + * to avoid calling check() so many times within a short time. */ + + r = sd_device_get_sysname(device, &name); + if (r < 0) { + log_device_warning_errno(device, r, "Failed to get sysname of received device, ignoring: %m"); + return 0; + } + + STRV_FOREACH(p, arg_devices) { + const char *s; + + if (!path_startswith(*p, "/sys")) + continue; + + r = path_find_last_component(*p, false, NULL, &s); + if (r < 0) { + log_warning_errno(r, "Failed to extract filename from \"%s\", ignoring: %m", *p); + continue; + } + if (r == 0) + continue; + + if (strneq(s, name, r)) + return check_and_exit(sd_device_monitor_get_event(monitor)); + } + + r = sd_device_get_devname(device, &name); + if (r < 0) { + if (r != -ENOENT) + log_device_warning_errno(device, r, "Failed to get devname of received device, ignoring: %m"); + return 0; + } + + if (path_strv_contains(arg_devices, name)) + return check_and_exit(sd_device_monitor_get_event(monitor)); + + FOREACH_DEVICE_DEVLINK(device, name) + if (path_strv_contains(arg_devices, name)) + return check_and_exit(sd_device_monitor_get_event(monitor)); + + return 0; +} + +static int setup_monitor(sd_event *event, MonitorNetlinkGroup group, const char *description, sd_device_monitor **ret) { + _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor = NULL; + int r; + + assert(event); + assert(ret); + + r = device_monitor_new_full(&monitor, group, /* fd = */ -1); + if (r < 0) + return r; + + r = sd_device_monitor_attach_event(monitor, event); + if (r < 0) + return r; + + r = sd_device_monitor_set_description(monitor, description); + if (r < 0) + return r; + + r = sd_device_monitor_start(monitor, device_monitor_handler, NULL); + if (r < 0) + return r; + + *ret = TAKE_PTR(monitor); + return 0; +} + +static int on_inotify(sd_event_source *s, const struct inotify_event *event, void *userdata) { + return check_and_exit(sd_event_source_get_event(s)); +} + +static int setup_inotify(sd_event *event) { + _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL; + int r; + + assert(event); + + if (!arg_settle) + return 0; + + r = sd_event_add_inotify(event, &s, "/run/udev" , IN_CREATE | IN_DELETE, on_inotify, NULL); + if (r < 0) + return r; + + r = sd_event_source_set_description(s, "inotify-event-source"); + if (r < 0) + return r; + + return sd_event_source_set_floating(s, true); +} + +static int setup_timer(sd_event *event) { + _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL; + int r; + + assert(event); + + if (arg_timeout_usec == USEC_INFINITY) + return 0; + + r = sd_event_add_time_relative(event, &s, CLOCK_BOOTTIME, arg_timeout_usec, 0, + NULL, INT_TO_PTR(-ETIMEDOUT)); + if (r < 0) + return r; + + r = sd_event_source_set_description(s, "timeout-event-source"); + if (r < 0) + return r; + + return sd_event_source_set_floating(s, true); +} + +static int reset_timer(sd_event *e, sd_event_source **s); + +static int on_periodic_timer(sd_event_source *s, uint64_t usec, void *userdata) { + static unsigned counter = 0; + sd_event *e; + int r; + + assert(s); + + e = sd_event_source_get_event(s); + + /* Even if all devices exists, we try to wait for uevents to be emitted from kernel. */ + if (check()) + counter++; + else + counter = 0; + + if (counter >= 2) { + log_debug("All requested devices popped up without receiving kernel uevents."); + return sd_event_exit(e, 0); + } + + r = reset_timer(e, &s); + if (r < 0) + log_warning_errno(r, "Failed to reset periodic timer event source, ignoring: %m"); + + return 0; +} + +static int reset_timer(sd_event *e, sd_event_source **s) { + return event_reset_time_relative(e, s, CLOCK_BOOTTIME, 250 * USEC_PER_MSEC, 0, + on_periodic_timer, NULL, 0, "periodic-timer-event-source", false); +} + +static int setup_periodic_timer(sd_event *event) { + _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL; + int r; + + assert(event); + + r = reset_timer(event, &s); + if (r < 0) + return r; + + /* Set the lower priority than device monitor, to make uevents always dispatched first. */ + r = sd_event_source_set_priority(s, SD_EVENT_PRIORITY_NORMAL + 1); + if (r < 0) + return r; + + return sd_event_source_set_floating(s, true); +} + +static int help(void) { + printf("%s wait [OPTIONS] DEVICE [DEVICE…]\n\n" + "Wait for devices or device symlinks being created.\n\n" + " -h --help Print this message\n" + " -V --version Print version of the program\n" + " -t --timeout=SEC Maximum time to wait for the device\n" + " --initialized=BOOL Wait for devices being initialized by systemd-udevd\n" + " --removed Wait for devices being removed\n" + " --settle Also wait for all queued events being processed\n", + program_invocation_short_name); + + return 0; +} + +static int parse_argv(int argc, char *argv[]) { + enum { + ARG_INITIALIZED = 0x100, + ARG_REMOVED, + ARG_SETTLE, + }; + + static const struct option options[] = { + { "timeout", required_argument, NULL, 't' }, + { "initialized", required_argument, NULL, ARG_INITIALIZED }, + { "removed", no_argument, NULL, ARG_REMOVED }, + { "settle", no_argument, NULL, ARG_SETTLE }, + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, 'V' }, + {} + }; + + int c, r; + + while ((c = getopt_long(argc, argv, "t:hV", options, NULL)) >= 0) + switch (c) { + case 't': + r = parse_sec(optarg, &arg_timeout_usec); + if (r < 0) + return log_error_errno(r, "Failed to parse -t/--timeout= parameter: %s", optarg); + break; + + case ARG_INITIALIZED: + r = parse_boolean(optarg); + if (r < 0) + return log_error_errno(r, "Failed to parse --initialized= parameter: %s", optarg); + arg_wait_until = r ? WAIT_UNTIL_INITIALIZED : WAIT_UNTIL_ADDED; + break; + + case ARG_REMOVED: + arg_wait_until = WAIT_UNTIL_REMOVED; + break; + + case ARG_SETTLE: + arg_settle = true; + break; + + case 'V': + return print_version(); + + case 'h': + return help(); + + case '?': + return -EINVAL; + + default: + assert_not_reached(); + } + + if (optind >= argc) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Too few arguments, expected at least one device path or device symlink."); + + arg_devices = strv_copy(argv + optind); + if (!arg_devices) + return log_oom(); + + return 1; /* work to do */ +} + +int wait_main(int argc, char *argv[], void *userdata) { + _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *udev_monitor = NULL, *kernel_monitor = NULL; + _cleanup_(sd_event_unrefp) sd_event *event = NULL; + int r; + + r = parse_argv(argc, argv); + if (r <= 0) + return r; + + STRV_FOREACH(p, arg_devices) { + path_simplify(*p); + + if (!path_is_safe(*p)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Device path cannot contain \"..\"."); + + if (!is_device_path(*p)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Specified path \"%s\" does not start with \"/dev/\" or \"/sys/\".", *p); + } + + /* Check before configuring event sources, as devices may be already initialized. */ + if (check()) + return 0; + + r = sd_event_default(&event); + if (r < 0) + return log_error_errno(r, "Failed to initialize sd-event: %m"); + + r = setup_timer(event); + if (r < 0) + return log_error_errno(r, "Failed to set up timeout: %m"); + + r = setup_inotify(event); + if (r < 0) + return log_error_errno(r, "Failed to set up inotify: %m"); + + r = setup_monitor(event, MONITOR_GROUP_UDEV, "udev-uevent-monitor-event-source", &udev_monitor); + if (r < 0) + return log_error_errno(r, "Failed to set up udev uevent monitor: %m"); + + if (arg_wait_until == WAIT_UNTIL_ADDED) { + /* If --initialized=no is specified, it is not necessary to wait uevents for the specified + * devices to be processed by udevd. Hence, let's listen on the kernel's uevent stream. Then, + * we may be able to finish this program earlier when udevd is very busy. + * Note, we still need to also setup udev monitor, as this may be invoked with a devlink + * (e.g. /dev/disk/by-id/foo). In that case, the devlink may not exist when we received a + * uevent from kernel, as the udevd may not finish to process the uevent yet. Hence, we need + * to wait until the event is processed by udevd. */ + r = setup_monitor(event, MONITOR_GROUP_KERNEL, "kernel-uevent-monitor-event-source", &kernel_monitor); + if (r < 0) + return log_error_errno(r, "Failed to set up kernel uevent monitor: %m"); + + /* This is a workaround for issues #24360 and #24450. + * For some reasons, the kernel sometimes does not emit uevents for loop block device on + * attach. Hence, without the periodic timer, no event source for this program will be + * triggered, and this will be timed out. + * Theoretically, inotify watch may be better, but this program typically expected to run in + * a short time. Hence, let's use the simpler periodic timer event source here. */ + r = setup_periodic_timer(event); + if (r < 0) + return log_error_errno(r, "Failed to set up periodic timer: %m"); + } + + /* Check before entering the event loop, as devices may be initialized during setting up event sources. */ + if (check()) + return 0; + + r = sd_event_loop(event); + if (r == -ETIMEDOUT) + return log_error_errno(r, "Timed out for waiting devices being %s.", + wait_until_to_string(arg_wait_until)); + if (r < 0) + return log_error_errno(r, "Event loop failed: %m"); + + return 0; +} |