forked from osmocom/wireshark
edcaaee164
(report luns with allocation length 8 for example) Therefore it is a bit wrong to mark these packets as [malformed packets] Since they are truncated by scsi and this is NOTY an error condition. Add a new exception type : ScsiBoundsError If this exception is caught by packet-frame, then print an appropriate message instead of [malformed packet] For SCSI, add helper macros TRY_SCSI_SHORT_PACKET and END_... If the packet was not short in the normal sense (snaplen < packetlen) then intercept the exception for BoundsError and rethrow it as ScsiBoundsError instead. svn path=/trunk/; revision=17611
312 lines
11 KiB
C
312 lines
11 KiB
C
#ifndef __EXCEPTIONS_H__
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#define __EXCEPTIONS_H__
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#ifndef XCEPT_H
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#include "except.h"
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#endif
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/* Ethereal has only one exception group, to make these macros simple */
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#define XCEPT_GROUP_ETHEREAL 1
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/* Ethereal's exceptions */
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/**
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Index is out of range.
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An attempt was made to read past the end of a buffer.
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This generally means that the capture was done with a "slice"
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length or "snapshot" length less than the maximum packet size,
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and a link-layer packet was cut short by that, so not all of the
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data in the link-layer packet was available.
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**/
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#define BoundsError 1
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/**
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Index is beyond reported length (not cap_len)
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An attempt was made to read past the logical end of a buffer. This
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differs from a BoundsError in that the parent protocol established a
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limit past which this dissector should not process in the buffer and that
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limit was execeeded.
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This generally means that the packet is invalid, i.e. whatever
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code constructed the packet and put it on the wire didn't put enough
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data into it. It is therefore currently reported as a "Malformed
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packet".
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However, it also happens in some cases where the packet was fragmented
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and the fragments weren't reassembled. We need to add another length
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field to a tvbuff, so that "length of the packet from the link layer"
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and "length of the packet were it fully reassembled" are different,
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and going past the first of those without going past the second would
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throw a different exception, which would be reported as an "Unreassembled
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packet" rather than a "Malformed packet".
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**/
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#define ReportedBoundsError 2
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/**
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During dfilter parsing
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**/
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#define TypeError 3
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/**
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A bug was detected in a dissector.
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DO NOT throw this with THROW(); that means that no details about
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the dissector error will be reported. (Instead, the message will
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blame you for not providing details.)
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Instead, use the DISSECTOR_ASSERT(), etc. macros in epan/proto.h.
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**/
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#define DissectorError 4
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/**
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Index is out of range.
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An attempt was made to read past the end of a buffer.
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This error is specific to SCSI data transfers where for some CDBs
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it is normal that the data PDU might be short.
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I.e. ReportLuns initially called with allocation_length=8, just enough
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to get the "size" of lun list back after which the initiator will
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reissue the command with an allocation_length that is big enough.
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**/
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#define ScsiBoundsError 5
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/* Usage:
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*
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* TRY {
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* code;
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* }
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*
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* CATCH(exception) {
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* code;
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* }
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*
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* CATCH2(exception1, exception2) {
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* code;
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* }
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*
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* CATCH_ALL {
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* code;
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* }
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*
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* FINALLY {
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* code;
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* }
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*
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* ENDTRY;
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*
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* ********* Never use 'goto' or 'return' inside the TRY, CATCH, CATCH_ALL,
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* ********* or FINALLY blocks. Execution must proceed through ENDTRY before
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* ********* branching out.
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*
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* This is really something like:
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*
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* {
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* caught = FALSE:
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* x = setjmp();
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* if (x == 0) {
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* <TRY code>
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* }
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* if (!caught && x == 1) {
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* caught = TRUE;
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* <CATCH(1) code>
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* }
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* if (!caught && x == 2) {
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* caught = TRUE;
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* <CATCH(2) code>
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* }
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* if (!caught && (x == 3 || x == 4)) {
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* caught = TRUE;
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* <CATCH2(3,4) code>
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* }
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* if (!caught && x != 0) {
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* caught = TRUE;
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* <CATCH_ALL code>
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* }
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* <FINALLY code>
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* if(!caught) {
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* RETHROW(x)
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* }
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* }<ENDTRY tag>
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*
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* All CATCH's must precede a CATCH_ALL.
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* FINALLY must occur after any CATCH or CATCH_ALL.
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* ENDTRY marks the end of the TRY code.
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* TRY and ENDTRY are the mandatory parts of a TRY block.
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* CATCH, CATCH_ALL, and FINALLY are all optional (although
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* you'll probably use at least one, otherwise why "TRY"?)
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*
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* GET_MESSAGE returns string ptr to exception message
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* when exception is thrown via THROW_MESSAGE()
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*
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* To throw/raise an exception.
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*
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* THROW(exception)
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* RETHROW rethrow the caught exception
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*
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* A cleanup callback is a function called in case an exception occurs
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* and is not caught. It should be used to free any dynamically-allocated data.
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* A pop or call_and_pop should occur at the same statement-nesting level
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* as the push.
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*
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* CLEANUP_CB_PUSH(func, data)
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* CLEANUP_CB_POP
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* CLEANUP_CB_CALL_AND_POP
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*/
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/* we do up to three passes through the bit of code after except_try_push(),
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* and except_state is used to keep track of where we are.
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*/
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#define EXCEPT_CAUGHT 1 /* exception has been caught, no need to rethrow at
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* END_TRY */
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#define EXCEPT_RETHROWN 2 /* the exception was rethrown from a CATCH
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* block. Don't reenter the CATCH blocks, but do
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* execute FINALLY and rethrow at END_TRY */
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#define EXCEPT_FINALLY 4 /* we've entered the FINALLY block - don't allow
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* RETHROW, and don't reenter FINALLY if a
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* different exception is thrown */
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#define TRY \
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{\
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except_t *exc; \
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volatile int except_state = 0; \
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static const except_id_t catch_spec[] = { \
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{ XCEPT_GROUP_ETHEREAL, XCEPT_CODE_ANY } }; \
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except_try_push(catch_spec, 1, &exc); \
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\
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if(except_state & EXCEPT_CAUGHT) \
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except_state |= EXCEPT_RETHROWN; \
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except_state &= ~EXCEPT_CAUGHT; \
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\
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if (except_state == 0 && exc == 0) \
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/* user's code goes here */
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#define ENDTRY \
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/* rethrow the exception if necessary */ \
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if(!(except_state&EXCEPT_CAUGHT) && exc != 0) \
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except_rethrow(exc); \
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except_try_pop();\
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}
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/* the (except_state |= EXCEPT_CAUGHT) in the below is a way of setting
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* except_state before the user's code, without disrupting the user's code if
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* it's a one-liner.
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*/
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#define CATCH(x) \
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if (except_state == 0 && exc != 0 && exc->except_id.except_code == (x) && \
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(except_state |= EXCEPT_CAUGHT)) \
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/* user's code goes here */
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#define CATCH2(x,y) \
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if (except_state == 0 && exc != 0 && \
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(exc->except_id.except_code == (x) || exc->except_id.except_code == (y)) && \
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(except_state|=EXCEPT_CAUGHT)) \
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/* user's code goes here */
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#define CATCH_ALL \
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if (except_state == 0 && exc != 0 && \
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(except_state|=EXCEPT_CAUGHT)) \
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/* user's code goes here */
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#define FINALLY \
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if( !(except_state & EXCEPT_FINALLY) && (except_state|=EXCEPT_FINALLY)) \
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/* user's code goes here */
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#define THROW(x) \
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except_throw(XCEPT_GROUP_ETHEREAL, (x), NULL)
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#define THROW_MESSAGE(x, y) \
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except_throw(XCEPT_GROUP_ETHEREAL, (x), (y))
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#define GET_MESSAGE except_message(exc)
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#define RETHROW \
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{ \
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/* check we're in a catch block */ \
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g_assert(except_state == EXCEPT_CAUGHT); \
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/* we can't use except_rethrow here, as that pops a catch block \
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* off the stack, and we don't want to do that, because we want to \
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* excecute the FINALLY {} block first. \
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* except_throw doesn't provide an interface to rethrow an existing \
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* exception; however, longjmping back to except_try_push() has the \
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* desired effect. \
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* \
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* Note also that THROW and RETHROW should provide much the same \
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* functionality in terms of which blocks to enter, so any messing \
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* about with except_state in here would indicate that THROW is \
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* doing the wrong thing. \
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*/ \
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longjmp(except_ch.except_jmp,1); \
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}
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#define EXCEPT_CODE except_code(exc)
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/* Register cleanup functions in case an exception is thrown and not caught.
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* From the Kazlib documentation, with modifications for use with the
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* Ethereal-specific macros:
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*
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* CLEANUP_PUSH(func, arg)
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*
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* The call to CLEANUP_PUSH shall be matched with a call to
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* CLEANUP_CALL_AND_POP or CLEANUP_POP which must occur in the same
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* statement block at the same level of nesting. This requirement allows
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* an implementation to provide a CLEANUP_PUSH macro which opens up a
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* statement block and a CLEANUP_POP which closes the statement block.
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* The space for the registered pointers can then be efficiently
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* allocated from automatic storage.
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*
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* The CLEANUP_PUSH macro registers a cleanup handler that will be
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* called if an exception subsequently occurs before the matching
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* CLEANUP_[CALL_AND_]POP is executed, and is not intercepted and
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* handled by a try-catch region that is nested between the two.
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*
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* The first argument to CLEANUP_PUSH is a pointer to the cleanup
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* handler, a function that returns nothing and takes a single
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* argument of type void*. The second argument is a void* value that
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* is registered along with the handler. This value is what is passed
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* to the registered handler, should it be called.
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*
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* Cleanup handlers are called in the reverse order of their nesting:
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* inner handlers are called before outer handlers.
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*
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* The program shall not leave the cleanup region between
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* the call to the macro CLEANUP_PUSH and the matching call to
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* CLEANUP_[CALL_AND_]POP by means other than throwing an exception,
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* or calling CLEANUP_[CALL_AND_]POP.
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*
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* Within the call to the cleanup handler, it is possible that new
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* exceptions may happen. Such exceptions must be handled before the
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* cleanup handler terminates. If the call to the cleanup handler is
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* terminated by an exception, the behavior is undefined. The exception
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* which triggered the cleanup is not yet caught; thus the program
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* would be effectively trying to replace an exception with one that
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* isn't in a well-defined state.
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*
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*
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* CLEANUP_POP and CLEANUP_CALL_AND_POP
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*
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* A call to the CLEANUP_POP or CLEANUP_CALL_AND_POP macro shall match
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* each call to CLEANUP_PUSH which shall be in the same statement block
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* at the same nesting level. It shall match the most recent such a
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* call that is not matched by a previous CLEANUP_[CALL_AND_]POP at
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* the same level.
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*
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* These macros causes the registered cleanup handler to be removed. If
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* CLEANUP_CALL_AND_POP is called, the cleanup handler is called.
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* In that case, the registered context pointer is passed to the cleanup
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* handler. If CLEANUP_POP is called, the cleanup handler is not called.
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*
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* The program shall not leave the region between the call to the
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* macro CLEANUP_PUSH and the matching call to CLEANUP_[CALL_AND_]POP
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* other than by throwing an exception, or by executing the
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* CLEANUP_CALL_AND_POP.
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*
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*/
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#define CLEANUP_PUSH(f,a) except_cleanup_push((f),(a))
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#define CLEANUP_POP except_cleanup_pop(0)
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#define CLEANUP_CALL_AND_POP except_cleanup_pop(1)
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#endif /* __EXCEPTIONS_H__ */
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