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sd-device-enumerator: introduce sound_device_compare() and devpath_is_late_block() helper functions

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This commit is contained in:
Yu Watanabe 2022-03-10 19:08:04 +09:00
parent a321e0e463
commit 9e871965a0
1 changed files with 47 additions and 33 deletions
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80
src/libsystemd/sd-device/device-enumerator.c
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@ -223,49 +223,63 @@ int device_enumerator_add_match_is_initialized(sd_device_enumerator *enumerator)
return 1;
}
static int device_compare(sd_device * const *_a, sd_device * const *_b) {
sd_device *a = *(sd_device **)_a, *b = *(sd_device **)_b;
const char *devpath_a, *devpath_b, *sound_a;
bool delay_a, delay_b;
int r;
static int sound_device_compare(const char *devpath_a, const char *devpath_b) {
const char *sound_a, *sound_b;
size_t prefix_len;
assert_se(sd_device_get_devpath(a, &devpath_a) >= 0);
assert_se(sd_device_get_devpath(b, &devpath_b) >= 0);
assert(devpath_a);
assert(devpath_b);
/* For sound cards the control device must be enumerated last to make sure it's the final
* device node that gets ACLs applied. Applications rely on this fact and use ACL changes on
* the control node as an indicator that the ACL change of the entire sound card completed. The
* kernel makes this guarantee when creating those devices, and hence we should too when
* enumerating them. */
sound_a = strstr(devpath_a, "/sound/card");
if (sound_a) {
/* For sound cards the control device must be enumerated last to
* make sure it's the final device node that gets ACLs applied.
* Applications rely on this fact and use ACL changes on the
* control node as an indicator that the ACL change of the
* entire sound card completed. The kernel makes this guarantee
* when creating those devices, and hence we should too when
* enumerating them. */
sound_a += STRLEN("/sound/card");
sound_a = strchr(sound_a, '/');
if (!sound_a)
return 0;
if (sound_a) {
unsigned prefix_len;
sound_a += STRLEN("/sound/card");
sound_a = strchr(devpath_a, '/');
if (!sound_a)
return 0;
prefix_len = sound_a - devpath_a;
prefix_len = sound_a - devpath_a;
if (strneq(devpath_a, devpath_b, prefix_len)) {
const char *sound_b;
if (!strneq(devpath_a, devpath_b, prefix_len))
return 0;
sound_b = devpath_b + prefix_len;
sound_b = devpath_b + prefix_len;
r = CMP(!!startswith(sound_a, "/controlC"),
!!startswith(sound_b, "/controlC"));
if (r != 0)
return r;
}
}
}
return CMP(!!startswith(sound_a, "/controlC"),
!!startswith(sound_b, "/controlC"));
}
static bool devpath_is_late_block(const char *devpath) {
assert(devpath);
return strstr(devpath, "/block/md") || strstr(devpath, "/block/dm-");
}
static int device_compare(sd_device * const *a, sd_device * const *b) {
const char *devpath_a, *devpath_b;
int r;
assert(a);
assert(b);
assert(*a);
assert(*b);
assert_se(sd_device_get_devpath(*(sd_device**) a, &devpath_a) >= 0);
assert_se(sd_device_get_devpath(*(sd_device**) b, &devpath_b) >= 0);
r = sound_device_compare(devpath_a, devpath_b);
if (r != 0)
return r;
/* md and dm devices are enumerated after all other devices */
delay_a = strstr(devpath_a, "/block/md") || strstr(devpath_a, "/block/dm-");
delay_b = strstr(devpath_b, "/block/md") || strstr(devpath_b, "/block/dm-");
r = CMP(delay_a, delay_b);
r = CMP(devpath_is_late_block(devpath_a), devpath_is_late_block(devpath_b));
if (r != 0)
return r;