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Merge pull request #11144 from keszybz/dissect-image-fix

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Fix for dissect-image use in nspawn
This commit is contained in:
Lennart Poettering
2018-12-17 19:36:36 +01:00
committed by GitHub
parent 4c70a4a748 a8040b6d0a
commit 4f9cf94c4a
9 changed files with 287 additions and 408 deletions
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src/shared/dissect-image.c
+137 -87
View File
@@ -40,6 +40,7 @@
#include "string-util.h"
#include "strv.h"
#include "tmpfile-util.h"
#include "udev-util.h"
#include "user-util.h"
#include "xattr-util.h"
@@ -116,6 +117,133 @@ static bool device_is_block(sd_device *d) {
return streq(ss, "block");
}
static int enumerator_for_parent(sd_device *d, sd_device_enumerator **ret) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
int r;
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
r = sd_device_enumerator_allow_uninitialized(e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_parent(e, d);
if (r < 0)
return r;
*ret = TAKE_PTR(e);
return 0;
}
/* how many times to wait for the device nodes to appear */
#define N_DEVICE_NODE_LIST_ATTEMPTS 10
static int wait_for_partitions_to_appear(
int fd,
sd_device *d,
unsigned num_partitions,
sd_device_enumerator **ret_enumerator) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
sd_device *q;
unsigned n;
int r;
r = enumerator_for_parent(d, &e);
if (r < 0)
return r;
/* Count the partitions enumerated by the kernel */
n = 0;
FOREACH_DEVICE(e, q) {
if (sd_device_get_devnum(q, NULL) < 0)
continue;
if (!device_is_block(q))
continue;
if (device_is_mmc_special_partition(q))
continue;
r = device_wait_for_initialization(q, "block", NULL);
if (r < 0)
return r;
n++;
}
if (n == num_partitions + 1) {
*ret_enumerator = TAKE_PTR(e);
return 0; /* success! */
}
if (n > num_partitions + 1)
return log_debug_errno(SYNTHETIC_ERRNO(EIO),
"blkid and kernel partition lists do not match.");
/* The kernel has probed fewer partitions than blkid? Maybe the kernel prober is still running or it
* got EBUSY because udev already opened the device. Let's reprobe the device, which is a synchronous
* call that waits until probing is complete. */
for (unsigned j = 0; ; j++) {
if (j++ > 20)
return -EBUSY;
if (ioctl(fd, BLKRRPART, 0) >= 0)
break;
r = -errno;
if (r == -EINVAL) {
struct loop_info64 info;
/* If we are running on a loop device that has partition scanning off, return
* an explicit recognizable error about this, so that callers can generate a
* proper message explaining the situation. */
if (ioctl(fd, LOOP_GET_STATUS64, &info) >= 0 && (info.lo_flags & LO_FLAGS_PARTSCAN) == 0) {
log_debug("Device is a loop device and partition scanning is off!");
return -EPROTONOSUPPORT;
}
}
if (r != -EBUSY)
return r;
/* If something else has the device open, such as an udev rule, the ioctl will return
* EBUSY. Since there's no way to wait until it isn't busy anymore, let's just wait a bit,
* and try again.
*
* This is really something they should fix in the kernel! */
(void) usleep(50 * USEC_PER_MSEC);
}
return -EAGAIN; /* no success yet, try again */
}
static int loop_wait_for_partitions_to_appear(
int fd,
sd_device *d,
unsigned num_partitions,
sd_device_enumerator **ret_enumerator) {
_cleanup_(sd_device_unrefp) sd_device *device = NULL;
int r;
log_debug("Waiting for device (parent + %d partitions) to appear...", num_partitions);
r = device_wait_for_initialization(d, "block", &device);
if (r < 0)
return r;
for (unsigned i = 0; i < N_DEVICE_NODE_LIST_ATTEMPTS; i++) {
r = wait_for_partitions_to_appear(fd, device, num_partitions, ret_enumerator);
if (r != -EAGAIN)
return r;
}
return log_debug_errno(SYNTHETIC_ERRNO(ENXIO),
"Kernel partitions dit not appear within %d attempts",
N_DEVICE_NODE_LIST_ATTEMPTS);
}
#endif
int dissect_image(
@@ -204,6 +332,10 @@ int dissect_image(
if (!m)
return -ENOMEM;
r = sd_device_new_from_devnum(&d, 'b', st.st_rdev);
if (r < 0)
return r;
if (!(flags & DISSECT_IMAGE_GPT_ONLY) &&
(flags & DISSECT_IMAGE_REQUIRE_ROOT)) {
const char *usage = NULL;
@@ -237,6 +369,10 @@ int dissect_image(
m->encrypted = streq_ptr(fstype, "crypto_LUKS");
r = loop_wait_for_partitions_to_appear(fd, d, 0, &e);
if (r < 0)
return r;
*ret = TAKE_PTR(m);
return 0;
@@ -258,96 +394,10 @@ int dissect_image(
if (!pl)
return -errno ?: -ENOMEM;
r = sd_device_new_from_devnum(&d, 'b', st.st_rdev);
r = loop_wait_for_partitions_to_appear(fd, d, blkid_partlist_numof_partitions(pl), &e);
if (r < 0)
return r;
for (i = 0;; i++) {
int n, z;
if (i >= 10) {
log_debug("Kernel partitions never appeared.");
return -ENXIO;
}
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
r = sd_device_enumerator_allow_uninitialized(e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_parent(e, d);
if (r < 0)
return r;
/* Count the partitions enumerated by the kernel */
n = 0;
FOREACH_DEVICE(e, q) {
if (sd_device_get_devnum(q, NULL) < 0)
continue;
if (!device_is_block(q))
continue;
if (device_is_mmc_special_partition(q))
continue;
n++;
}
/* Count the partitions enumerated by blkid */
z = blkid_partlist_numof_partitions(pl);
if (n == z + 1)
break;
if (n > z + 1) {
log_debug("blkid and kernel partition list do not match.");
return -EIO;
}
if (n < z + 1) {
unsigned j = 0;
/* The kernel has probed fewer partitions than blkid? Maybe the kernel prober is still running
* or it got EBUSY because udev already opened the device. Let's reprobe the device, which is a
* synchronous call that waits until probing is complete. */
for (;;) {
if (j++ > 20)
return -EBUSY;
if (ioctl(fd, BLKRRPART, 0) < 0) {
r = -errno;
if (r == -EINVAL) {
struct loop_info64 info;
/* If we are running on a loop device that has partition scanning off,
* return an explicit recognizable error about this, so that callers
* can generate a proper message explaining the situation. */
if (ioctl(fd, LOOP_GET_STATUS64, &info) >= 0 && (info.lo_flags & LO_FLAGS_PARTSCAN) == 0) {
log_debug("Device is loop device and partition scanning is off!");
return -EPROTONOSUPPORT;
}
}
if (r != -EBUSY)
return r;
} else
break;
/* If something else has the device open, such as an udev rule, the ioctl will return
* EBUSY. Since there's no way to wait until it isn't busy anymore, let's just wait a
* bit, and try again.
*
* This is really something they should fix in the kernel! */
(void) usleep(50 * USEC_PER_MSEC);
}
}
e = sd_device_enumerator_unref(e);
}
FOREACH_DEVICE(e, q) {
unsigned long long pflags;
blkid_partition pp;
src/shared/udev-util.c
+78
View File
@@ -91,3 +91,81 @@ int udev_parse_config_full(
return 0;
}
struct DeviceMonitorData {
const char *sysname;
sd_device *device;
};
static int device_monitor_handler(sd_device_monitor *monitor, sd_device *device, void *userdata) {
struct DeviceMonitorData *data = userdata;
const char *sysname;
assert(device);
assert(data);
assert(data->sysname);
assert(!data->device);
if (sd_device_get_sysname(device, &sysname) >= 0 && streq(sysname, data->sysname)) {
data->device = sd_device_ref(device);
return sd_event_exit(sd_device_monitor_get_event(monitor), 0);
}
return 0;
}
int device_wait_for_initialization(sd_device *device, const char *subsystem, sd_device **ret) {
_cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor = NULL;
_cleanup_(sd_event_unrefp) sd_event *event = NULL;
struct DeviceMonitorData data = {};
int r;
assert(device);
assert(subsystem);
if (sd_device_get_is_initialized(device) > 0) {
if (ret)
*ret = sd_device_ref(device);
return 0;
}
assert_se(sd_device_get_sysname(device, &data.sysname) >= 0);
/* Wait until the device is initialized, so that we can get access to the ID_PATH property */
r = sd_event_default(&event);
if (r < 0)
return log_error_errno(r, "Failed to get default event: %m");
r = sd_device_monitor_new(&monitor);
if (r < 0)
return log_error_errno(r, "Failed to acquire monitor: %m");
r = sd_device_monitor_filter_add_match_subsystem_devtype(monitor, subsystem, NULL);
if (r < 0)
return log_error_errno(r, "Failed to add %s subsystem match to monitor: %m", subsystem);
r = sd_device_monitor_attach_event(monitor, event);
if (r < 0)
return log_error_errno(r, "Failed to attach event to device monitor: %m");
r = sd_device_monitor_start(monitor, device_monitor_handler, &data);
if (r < 0)
return log_error_errno(r, "Failed to start device monitor: %m");
/* Check again, maybe things changed. Udev will re-read the db if the device wasn't initialized
* yet. */
if (sd_device_get_is_initialized(device) > 0) {
if (ret)
*ret = sd_device_ref(device);
return 0;
}
r = sd_event_loop(event);
if (r < 0)
return log_error_errno(r, "Event loop failed: %m");
if (ret)
*ret = TAKE_PTR(data.device);
return 0;
}
src/shared/udev-util.h
+4
View File
@@ -1,6 +1,8 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
#include "sd-device.h"
#include "time-util.h"
typedef enum ResolveNameTiming {
@@ -23,3 +25,5 @@ int udev_parse_config_full(
static inline int udev_parse_config(void) {
return udev_parse_config_full(NULL, NULL, NULL, NULL);
}
int device_wait_for_initialization(sd_device *device, const char *subsystem, sd_device **ret);