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Issue 182: linux handler doesn't have sigcontext if called from a previous signal handler. r=mento / Liu Li

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git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@188 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
ted.mielczarek
2007-06-11 16:01:46 +00:00
parent 2e86dfe705
commit 21d58c7281
7 changed files with 87 additions and 25 deletions
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26
src/client/linux/handler/linux_thread.cc
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@@ -381,4 +381,30 @@ bool LinuxThread::IsAddressMapped(uintptr_t address) const {
return addr.is_mapped;
}
bool LinuxThread::FindSigContext(uintptr_t sighandler_ebp,
struct sigcontext **sig_ctx) {
uintptr_t previous_ebp;
const int MAX_STACK_DEPTH = 10;
int depth_counter = 0;
do {
// We're looking for a |struct sigcontext| as the second parameter
// to a signal handler function call. Luckily, the sigcontext
// has an ebp member which should match the ebp pointed to
// by the ebp of the signal handler frame.
previous_ebp = reinterpret_cast<uintptr_t>(GetNextFrame(
reinterpret_cast<void**>(sighandler_ebp)));
// The stack looks like this:
// | previous ebp | previous eip | first param | second param |,
// so we need to offset by 3 to get to the second parameter.
*sig_ctx = reinterpret_cast<struct sigcontext*>(sighandler_ebp +
3 * sizeof(uintptr_t));
sighandler_ebp = previous_ebp;
depth_counter++;
} while(previous_ebp != (*sig_ctx)->ebp && sighandler_ebp != 0 &&
IsAddressMapped(sighandler_ebp) && depth_counter < MAX_STACK_DEPTH);
return previous_ebp == (*sig_ctx)->ebp && previous_ebp != 0;
}
} // namespace google_breakpad