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Allow re-entrancy and provide a global counter of the number of

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interrupts hooked.
This commit is contained in:
Michael Brown
2006-05-13 11:44:11 +00:00
parent d822b3d4cd
commit 63499e9cfd
1 changed files with 20 additions and 0 deletions
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20
src/arch/i386/interface/pcbios/biosint.c
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@@ -7,6 +7,17 @@
* *
*/ */
/**
* Hooked interrupt count
*
* At exit, after unhooking all possible interrupts, this counter
* should be examined. If it is non-zero, it means that we failed to
* unhook at least one interrupt vector, and so must not free up the
* memory we are using. (Note that this also implies that we should
* re-hook INT 15 in order to hide ourselves from the memory map).
*/
int hooked_bios_interrupts = 0;
/** /**
* Hook INT vector * Hook INT vector
* *
@@ -26,9 +37,15 @@ void hook_bios_interrupt ( unsigned int interrupt, unsigned int handler,
.offset = handler, .offset = handler,
}; };
if ( ( chain_vector->segment != 0 ) ||
( chain_vector->offset != 0 ) ) {
/* Already hooked; do nothing */
return;
}
copy_from_real ( chain_vector, 0, ( interrupt * 4 ), copy_from_real ( chain_vector, 0, ( interrupt * 4 ),
sizeof ( *chain_vector ) ); sizeof ( *chain_vector ) );
copy_to_real ( 0, ( interrupt * 4 ), &vector, sizeof ( vector ) ); copy_to_real ( 0, ( interrupt * 4 ), &vector, sizeof ( vector ) );
hooked_bios_interrupts++;
} }
/** /**
@@ -53,5 +70,8 @@ int unhook_bios_interrupt ( unsigned int interrupt, unsigned int handler,
return -EBUSY; return -EBUSY;
copy_to_real ( 0, ( interrupt * 4 ), chain_vector, copy_to_real ( 0, ( interrupt * 4 ), chain_vector,
sizeof ( *chain_vector ) ); sizeof ( *chain_vector ) );
chain_vector->segment = 0;
chain_vector->offset = 0;
hooked_bios_interrupts--;
return 0; return 0;
} }