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dissect-image: split out a chunk of dissect_image() out 

No functional change, just moving code around.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2018-12-13 13:28:58 +01:00
parent ed435031a5
commit ea887be00b
1 changed files with 119 additions and 85 deletions
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204
src/shared/dissect-image.c
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@ -116,6 +116,122 @@ 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;
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) {
int r;
for (unsigned i = 0; i < N_DEVICE_NODE_LIST_ATTEMPTS; i++) {
r = wait_for_partitions_to_appear(fd, d, 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(
@ -262,91 +378,9 @@ int dissect_image(
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);
}
r = loop_wait_for_partitions_to_appear(fd, d, blkid_partlist_numof_partitions(pl), &e);
if (r < 0)
return r;
FOREACH_DEVICE(e, q) {
unsigned long long pflags;