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Merge pull request #19736 from poettering/udev-trigger-uuid

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sd-device: add support for triggering devices with UUID support
This commit is contained in:
Yu Watanabe 2021-05-27 13:05:00 +09:00 committed by GitHub
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9 changed files with 192 additions and 32 deletions
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16
man/sd_id128_get_machine.xml
View File

@ -99,12 +99,16 @@
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details. The
ID is cached internally. In future a different mechanism to determine the invocation ID may be added.</para>
<para>Note that <function>sd_id128_get_machine_app_specific()</function>, <function>sd_id128_get_boot()</function>,
<function>sd_id128_get_boot_app_specific()</function>, and <function>sd_id128_get_invocation()</function> always
return UUID v4 compatible IDs. <function>sd_id128_get_machine()</function> will also return a UUID v4-compatible
ID on new installations but might not on older. It is possible to convert the machine ID into a UUID v4-compatible
one. For more information, see
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
<para>Note that <function>sd_id128_get_machine_app_specific()</function>,
<function>sd_id128_get_boot()</function>, <function>sd_id128_get_boot_app_specific()</function>, and
<function>sd_id128_get_invocation()</function> always return UUID v4 compatible IDs.
<function>sd_id128_get_machine()</function> will also return a UUID v4-compatible ID on new installations
but might not on older. It is possible to convert the machine ID into a UUID v4-compatible one. For more
information, see
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>. It is
hence guaranteed that thes functions will never return the ID consisting of all zero or all one bits
(<constant>SD_ID128_NULL</constant>, <constant>SD_ID128_ALLF</constant>) — with the possible exception of
<function>sd_id128_get_machine()</function>, as mentioned.</para>
<para>For more information about the <literal>sd_id128_t</literal>
type see

5
man/sd_id128_randomize.xml
View File

@ -42,8 +42,9 @@
<filename>/dev/urandom</filename> kernel random number
generator.</para>
<para>Note that <function>sd_id128_randomize()</function> always
returns a UUID v4-compatible ID.</para>
<para>Note that <function>sd_id128_randomize()</function> always returns a UUID v4-compatible ID. It is
hence guaranteed that this function will never return the ID consisting of all zero or all one bits
(<constant>SD_ID128_NULL</constant>, <constant>SD_ID128_ALLF</constant>).</para>
<para>For more information about the <literal>sd_id128_t</literal>
type, see

9
man/udevadm.xml
View File

@ -375,6 +375,15 @@
the same command to finish.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--uuid</option></term>
<listitem>
<para>Trigger the synthetic device events, and associate a randomized UUID with each. These UUIDs
are printed to standard output, one line for each event. These UUIDs are included in the uevent
environment block (in the <literal>SYNTH_UUID=</literal> property) and may be used to track
delivery of the generated events.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--wait-daemon[=<replaceable>SECONDS</replaceable>]</option></term>
<listitem>

5
src/basic/hash-funcs.c
View File

@ -14,7 +14,7 @@ DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(string_hash_ops_free,
char, string_hash_func, string_compare_func, free);
DEFINE_HASH_OPS_FULL(string_hash_ops_free_free,
char, string_hash_func, string_compare_func, free,
char, free);
void, free);
void path_hash_func(const char *q, struct siphash *state) {
size_t n;
@ -57,6 +57,9 @@ void path_hash_func(const char *q, struct siphash *state) {
DEFINE_HASH_OPS(path_hash_ops, char, path_hash_func, path_compare);
DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(path_hash_ops_free,
char, path_hash_func, path_compare, free);
DEFINE_HASH_OPS_FULL(path_hash_ops_free_free,
char, path_hash_func, path_compare, free,
void, free);
void trivial_hash_func(const void *p, struct siphash *state) {
siphash24_compress(&p, sizeof(p), state);

1
src/basic/hash-funcs.h
View File

@ -82,6 +82,7 @@ extern const struct hash_ops string_hash_ops_free_free;
void path_hash_func(const char *p, struct siphash *state);
extern const struct hash_ops path_hash_ops;
extern const struct hash_ops path_hash_ops_free;
extern const struct hash_ops path_hash_ops_free_free;
/* This will compare the passed pointers directly, and will not dereference them. This is hence not useful for strings
* or suchlike. */

2
src/libsystemd/libsystemd.sym
View File

@ -757,4 +757,6 @@ global:
sd_device_monitor_filter_add_match_sysattr;
sd_device_monitor_filter_add_match_parent;
sd_device_get_usec_initialized;
sd_device_trigger_with_uuid;
sd_device_get_trigger_uuid;
} LIBSYSTEMD_248;

65
src/libsystemd/sd-device/sd-device.c
View File

@ -16,6 +16,7 @@
#include "fileio.h"
#include "fs-util.h"
#include "hashmap.h"
#include "id128-util.h"
#include "macro.h"
#include "parse-util.h"
#include "path-util.h"
@ -1869,6 +1870,34 @@ _public_ int sd_device_get_property_value(sd_device *device, const char *key, co
return 0;
}
_public_ int sd_device_get_trigger_uuid(sd_device *device, sd_id128_t *ret) {
const char *s;
sd_id128_t id;
int r;
assert_return(device, -EINVAL);
/* Retrieves the UUID attached to a uevent when triggering it from userspace via
* sd_device_trigger_with_uuid() or an equivalent interface. Returns -ENOENT if the record is not
* caused by a synthetic event and -ENODATA if it was but no UUID was specified */
r = sd_device_get_property_value(device, "SYNTH_UUID", &s);
if (r < 0)
return r;
if (streq(s, "0")) /* SYNTH_UUID=0 is set whenever a device is triggered by userspace without specifying a UUID */
return -ENODATA;
r = sd_id128_from_string(s, &id);
if (r < 0)
return r;
if (ret)
*ret = id;
return 0;
}
static int device_cache_sysattr_value(sd_device *device, const char *key, char *value) {
_cleanup_free_ char *new_key = NULL, *old_value = NULL;
int r;
@ -2096,5 +2125,41 @@ _public_ int sd_device_trigger(sd_device *device, sd_device_action_t action) {
if (!s)
return -EINVAL;
/* This uses the simple no-UUID interface of kernel < 4.13 */
return sd_device_set_sysattr_value(device, "uevent", s);
}
_public_ int sd_device_trigger_with_uuid(
sd_device *device,
sd_device_action_t action,
sd_id128_t *ret_uuid) {
char buf[ID128_UUID_STRING_MAX];
const char *s, *j;
sd_id128_t u;
int r;
assert_return(device, -EINVAL);
/* If noone wants to know the UUID, use the simple interface from pre-4.13 times */
if (!ret_uuid)
return sd_device_trigger(device, action);
s = device_action_to_string(action);
if (!s)
return -EINVAL;
r = sd_id128_randomize(&u);
if (r < 0)
return r;
id128_to_uuid_string(u, buf);
j = strjoina(s, " ", buf);
r = sd_device_set_sysattr_value(device, "uevent", j);
if (r < 0)
return r;
*ret_uuid = u;
return 0;
}

3
src/systemd/sd-device.h
View File

@ -24,6 +24,7 @@
#include <sys/types.h>
#include "sd-event.h"
#include "sd-id128.h"
#include "_sd-common.h"
@ -96,11 +97,13 @@ const char *sd_device_get_sysattr_next(sd_device *device);
int sd_device_has_tag(sd_device *device, const char *tag);
int sd_device_has_current_tag(sd_device *device, const char *tag);
int sd_device_get_property_value(sd_device *device, const char *key, const char **value);
int sd_device_get_trigger_uuid(sd_device *device, sd_id128_t *ret);
int sd_device_get_sysattr_value(sd_device *device, const char *sysattr, const char **_value);
int sd_device_set_sysattr_value(sd_device *device, const char *sysattr, const char *value);
int sd_device_set_sysattr_valuef(sd_device *device, const char *sysattr, const char *format, ...) _sd_printf_(3, 4);
int sd_device_trigger(sd_device *device, sd_device_action_t action);
int sd_device_trigger_with_uuid(sd_device *device, sd_device_action_t action, sd_id128_t *ret_uuid);
/* device enumerator */

118
src/udev/udevadm-trigger.c
View File

@ -24,8 +24,14 @@
static bool arg_verbose = false;
static bool arg_dry_run = false;
static bool arg_quiet = false;
static bool arg_uuid = false;
static int exec_list(sd_device_enumerator *e, sd_device_action_t action, Set **settle_set) {
static int exec_list(
sd_device_enumerator *e,
sd_device_action_t action,
Hashmap *settle_hashmap) {
bool skip_uuid_logic = false;
const char *action_str;
sd_device *d;
int r, ret = 0;
@ -33,18 +39,33 @@ static int exec_list(sd_device_enumerator *e, sd_device_action_t action, Set **s
action_str = device_action_to_string(action);
FOREACH_DEVICE_AND_SUBSYSTEM(e, d) {
sd_id128_t id = SD_ID128_NULL;
const char *syspath;
if (sd_device_get_syspath(d, &syspath) < 0)
r = sd_device_get_syspath(d, &syspath);
if (r < 0) {
log_debug_errno(r, "Failed to get syspath of enumerated devices, ignoring: %m");
continue;
}
if (arg_verbose)
printf("%s\n", strna(syspath));
printf("%s\n", syspath);
if (arg_dry_run)
continue;
r = sd_device_trigger(d, action);
/* Use the UUID mode if the user explicitly asked for it, or if --settle has been specified,
* so that we can recognize our own uevent. */
r = sd_device_trigger_with_uuid(d, action, (arg_uuid || settle_hashmap) && !skip_uuid_logic ? &id : NULL);
if (r == -EINVAL && !arg_uuid && settle_hashmap && !skip_uuid_logic) {
/* If we specified a UUID because of the settling logic, and we got EINVAL this might
* be caused by an old kernel which doesn't know the UUID logic (pre-4.13). Let's try
* if it works without the UUID logic then. */
r = sd_device_trigger(d, action);
if (r != -EINVAL)
skip_uuid_logic = true; /* dropping the uuid stuff changed the return code,
* hence don't bother next time */
}
if (r < 0) {
/* ENOENT may be returned when a device does not have /uevent or is already
* removed. Hence, this is logged at debug level and ignored.
@ -86,10 +107,28 @@ static int exec_list(sd_device_enumerator *e, sd_device_action_t action, Set **s
continue;
}
if (settle_set) {
r = set_put_strdup(settle_set, syspath);
/* If the user asked for it, write event UUID to stdout */
if (arg_uuid)
printf(SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(id));
if (settle_hashmap) {
_cleanup_free_ sd_id128_t *mid = NULL;
_cleanup_free_ char *sp = NULL;
sp = strdup(syspath);
if (!sp)
return log_oom();
mid = newdup(sd_id128_t, &id, 1);
if (!d)
return log_oom();
r = hashmap_put(settle_hashmap, sp, mid);
if (r < 0)
return log_oom();
TAKE_PTR(sp);
TAKE_PTR(mid);
}
}
@ -97,24 +136,51 @@ static int exec_list(sd_device_enumerator *e, sd_device_action_t action, Set **s
}
static int device_monitor_handler(sd_device_monitor *m, sd_device *dev, void *userdata) {
_cleanup_free_ char *val = NULL;
Set *settle_set = userdata;
Hashmap *settle_hashmap = userdata;
sd_id128_t *settle_id;
const char *syspath;
char *k;
int r;
assert(dev);
assert(settle_set);
assert(settle_hashmap);
if (sd_device_get_syspath(dev, &syspath) < 0)
r = sd_device_get_syspath(dev, &syspath);
if (r < 0) {
log_debug_errno(r, "Failed to get syspath of device event, ignoring: %m");
return 0;
}
settle_id = hashmap_get2(settle_hashmap, syspath, (void**) &k);
if (!settle_id) {
log_debug("Got uevent for unexpected device '%s', ignoring.", syspath);
return 0;
}
if (!sd_id128_is_null(*settle_id)) { /* If this is SD_ID128_NULL then we are on pre-4.13 and have no UUID to check, hence don't */
sd_id128_t event_id;
r = sd_device_get_trigger_uuid(dev, &event_id);
if (r < 0) {
log_debug_errno(r, "Got uevent without synthetic UUID for device '%s', ignoring: %m", syspath);
return 0;
}
if (!sd_id128_equal(event_id, *settle_id)) {
log_debug("Got uevent not matching expected UUID for device '%s', ignoring.", syspath);
return 0;
}
}
if (arg_verbose)
printf("settle %s\n", syspath);
val = set_remove(settle_set, syspath);
if (!val)
log_debug("Got epoll event on syspath %s not present in syspath set", syspath);
if (arg_uuid)
printf("settle " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(*settle_id));
if (set_isempty(settle_set))
free(hashmap_remove(settle_hashmap, syspath));
free(k);
if (hashmap_isempty(settle_hashmap))
return sd_event_exit(sd_device_monitor_get_event(m), 0);
return 0;
@ -162,7 +228,8 @@ static int help(void) {
" -b --parent-match=NAME Trigger devices with that parent device\n"
" -w --settle Wait for the triggered events to complete\n"
" --wait-daemon[=SECONDS] Wait for udevd daemon to be initialized\n"
" before triggering uevents\n",
" before triggering uevents\n"
" --uuid Print synthetic uevent UUID\n",
program_invocation_short_name);
return 0;
@ -172,6 +239,7 @@ int trigger_main(int argc, char *argv[], void *userdata) {
enum {
ARG_NAME = 0x100,
ARG_PING,
ARG_UUID,
};
static const struct option options[] = {
@ -193,6 +261,7 @@ int trigger_main(int argc, char *argv[], void *userdata) {
{ "wait-daemon", optional_argument, NULL, ARG_PING },
{ "version", no_argument, NULL, 'V' },
{ "help", no_argument, NULL, 'h' },
{ "uuid", no_argument, NULL, ARG_UUID },
{}
};
enum {
@ -203,7 +272,7 @@ int trigger_main(int argc, char *argv[], void *userdata) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
_cleanup_(sd_device_monitor_unrefp) sd_device_monitor *m = NULL;
_cleanup_(sd_event_unrefp) sd_event *event = NULL;
_cleanup_set_free_ Set *settle_set = NULL;
_cleanup_hashmap_free_ Hashmap *settle_hashmap = NULL;
usec_t ping_timeout_usec = 5 * USEC_PER_SEC;
bool settle = false, ping = false;
int c, r;
@ -327,7 +396,7 @@ int trigger_main(int argc, char *argv[], void *userdata) {
break;
}
case ARG_PING: {
case ARG_PING:
ping = true;
if (optarg) {
r = parse_sec(optarg, &ping_timeout_usec);
@ -335,7 +404,10 @@ int trigger_main(int argc, char *argv[], void *userdata) {
log_error_errno(r, "Failed to parse timeout value '%s', ignoring: %m", optarg);
}
break;
}
case ARG_UUID:
arg_uuid = true;
break;
case 'V':
return print_version();
@ -377,8 +449,8 @@ int trigger_main(int argc, char *argv[], void *userdata) {
}
if (settle) {
settle_set = set_new(&string_hash_ops_free);
if (!settle_set)
settle_hashmap = hashmap_new(&path_hash_ops_free_free);
if (!settle_hashmap)
return log_oom();
r = sd_event_default(&event);
@ -393,7 +465,7 @@ int trigger_main(int argc, char *argv[], void *userdata) {
if (r < 0)
return log_error_errno(r, "Failed to attach event to device monitor: %m");
r = sd_device_monitor_start(m, device_monitor_handler, settle_set);
r = sd_device_monitor_start(m, device_monitor_handler, settle_hashmap);
if (r < 0)
return log_error_errno(r, "Failed to start device monitor: %m");
}
@ -413,11 +485,11 @@ int trigger_main(int argc, char *argv[], void *userdata) {
assert_not_reached("Unknown device type");
}
r = exec_list(e, action, settle ? &settle_set : NULL);
r = exec_list(e, action, settle_hashmap);
if (r < 0)
return r;
if (event && !set_isempty(settle_set)) {
if (event && !hashmap_isempty(settle_hashmap)) {
r = sd_event_loop(event);
if (r < 0)
return log_error_errno(r, "Event loop failed: %m");