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Check the ringbuffer pointers for invalid values.

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If a logbook entry contains an invalid ringbuffer pointer, the error is
not returned immediately, but delayed until the end of the download.
With this approach we can download at least the dives before the
problematic logbook entry.
This commit is contained in:
Jef Driesen 2010-10-29 21:11:36 +02:00
parent ca126e9af6
commit e0860923e0
1 changed files with 24 additions and 2 deletions
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26
src/oceanic_common.c
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@ -285,6 +285,9 @@ oceanic_common_device_foreach (device_t *abstract, dive_callback_t callback, voi
end -= rb_logbook_page_end - rb_logbook_entry_end;
}
// Error status for delayed errors.
device_status_t status = DEVICE_STATUS_SUCCESS;
// The logbook ringbuffer is read backwards to retrieve the most recent
// entries first. If an already downloaded entry is identified (by means
// of its fingerprint), the transfer is aborted immediately to reduce
@ -363,6 +366,25 @@ oceanic_common_device_foreach (device_t *abstract, dive_callback_t callback, voi
break;
}
// Check for invalid ringbuffer pointers. Such pointers shouldn't
// be present, but some devices appear to have them anyway. In that
// case the error is not returned immediately, but delayed until the
// end of the download. With this approach we can download at least
// the dives before the problematic logbook entry.
unsigned int rb_entry_first = get_profile_first (logbooks + current, layout);
unsigned int rb_entry_last = get_profile_last (logbooks + current, layout);
if (rb_entry_first < layout->rb_profile_begin ||
rb_entry_first >= layout->rb_profile_end ||
rb_entry_last < layout->rb_profile_begin ||
rb_entry_last >= layout->rb_profile_end)
{
WARNING("Invalid ringbuffer pointer detected!");
status = DEVICE_STATUS_ERROR;
begin = current + PAGESIZE / 2;
abort = 1;
break;
}
// Compare the fingerprint to identify previously downloaded entries.
if (memcmp (logbooks + current, device->fingerprint, PAGESIZE / 2) == 0) {
begin = current + PAGESIZE / 2;
@ -379,7 +401,7 @@ oceanic_common_device_foreach (device_t *abstract, dive_callback_t callback, voi
// Exit if there are no (new) dives.
if (begin == end) {
free (logbooks);
return DEVICE_STATUS_SUCCESS;
return status;
}
// Calculate the total amount of bytes in the profile ringbuffer,
@ -498,5 +520,5 @@ oceanic_common_device_foreach (device_t *abstract, dive_callback_t callback, voi
free (logbooks);
free (profiles);
return DEVICE_STATUS_SUCCESS;
return status;
}