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syscalls: fix latent brk/obreak bug.

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Bogus calls to ChunkGenerator with negative size were triggering
a new assertion that was added there.
Also did a little renaming and cleanup in the process.
This commit is contained in:
Steve Reinhardt
2008-11-15 09:30:10 -08:00
parent ba8936120e
commit 4514f565e3
9 changed files with 32 additions and 18 deletions
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18
src/sim/syscall_emul.cc
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@@ -107,21 +107,27 @@ getpagesizeFunc(SyscallDesc *desc, int num, LiveProcess *p, ThreadContext *tc)
SyscallReturn
obreakFunc(SyscallDesc *desc, int num, LiveProcess *p, ThreadContext *tc)
brkFunc(SyscallDesc *desc, int num, LiveProcess *p, ThreadContext *tc)
{
Addr junk;
// change brk addr to first arg
Addr new_brk = tc->getSyscallArg(0);
if (new_brk != 0) {
// in Linux at least, brk(0) returns the current break value
// (note that the syscall and the glibc function have different behavior)
if (new_brk == 0)
return p->brk_point;
if (new_brk > p->brk_point) {
// might need to allocate some new pages
for (ChunkGenerator gen(p->brk_point, new_brk - p->brk_point,
VMPageSize); !gen.done(); gen.next()) {
if (!p->pTable->translate(gen.addr(), junk))
if (!p->pTable->translate(gen.addr()))
p->pTable->allocate(roundDown(gen.addr(), VMPageSize),
VMPageSize);
}
p->brk_point = new_brk;
}
p->brk_point = new_brk;
DPRINTF(SyscallVerbose, "Break Point changed to: %#X\n", p->brk_point);
return p->brk_point;
}

6
src/sim/syscall_emul.hh
View File

@@ -191,9 +191,9 @@ SyscallReturn exitFunc(SyscallDesc *desc, int num,
SyscallReturn getpagesizeFunc(SyscallDesc *desc, int num,
LiveProcess *p, ThreadContext *tc);
/// Target obreak() handler: set brk address.
SyscallReturn obreakFunc(SyscallDesc *desc, int num,
LiveProcess *p, ThreadContext *tc);
/// Target brk() handler: set brk address.
SyscallReturn brkFunc(SyscallDesc *desc, int num,
LiveProcess *p, ThreadContext *tc);
/// Target close() handler.
SyscallReturn closeFunc(SyscallDesc *desc, int num,