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base: Improve handling of thread IDs for remote GDB.

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The remote GDB protocol encode thread IDs as positive integers, where 0
is a special value which indicates "pick any thread", and -1 is a
special value which indicates all threads.

The previous implementation would look like it worked handling the
special value -1 (for instance) because it see the '-' of "-1", stop
looking for digits, and return the default value 0.

This new implementation handles -1 as a special case, and will report an
error if no digits were found otherwise.

Also this change adds an encodeThreadId method to convert a ContextID
into a GDB thread ID by adding one to avoid the special value 0.

Change-Id: Iec54fbd9563d20a56011f48d50d69111ed1467b8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/44606
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit is contained in:
Gabe Black
2021-04-12 04:39:03 -07:00
parent 7e85c8b712
commit 2f78ad6f7b
1 changed files with 44 additions and 3 deletions
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47
src/base/remote_gdb.cc
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@@ -283,6 +283,43 @@ hex2i(const char **srcp)
return r;
}
bool
parseThreadId(const char **srcp, bool &all, bool &any, ContextID &tid)
{
all = any = false;
tid = 0;
const char *src = *srcp;
if (*src == '-') {
// This could be the start of -1, which means all threads.
src++;
if (*src++ != '1')
return false;
*srcp += 2;
all = true;
return true;
}
tid = hex2i(srcp);
// If *srcp still points to src, no characters were consumed and no thread
// id was found. Without this check, we can't tell the difference between
// zero and a parsing error.
if (*srcp == src)
return false;
if (tid == 0)
any = true;
tid--;
return true;
}
int
encodeThreadId(ContextID id)
{
// Thread ID 0 is reserved and means "pick any thread".
return id + 1;
}
enum GdbBreakpointType
{
GdbSoftBp = '0',
@@ -864,8 +901,12 @@ bool
BaseRemoteGDB::cmdSetThread(GdbCommand::Context &ctx)
{
const char *p = ctx.data + 1; // Ignore the subcommand byte.
if (hex2i(&p) != tc->contextId())
ContextID tid = 0;
bool all, any;
if (!parseThreadId(&p, all, any, tid))
throw CmdError("E01");
if (any || all || tid != tc->contextId())
throw CmdError("E02");
send("OK");
return true;
}
@@ -945,7 +986,7 @@ std::map<std::string, BaseRemoteGDB::QuerySetCommand>
void
BaseRemoteGDB::queryC(QuerySetCommand::Context &ctx)
{
send(csprintf("QC%x", tc->contextId()).c_str());
send(csprintf("QC%x", encodeThreadId(tc->contextId())).c_str());
}
void
@@ -1005,7 +1046,7 @@ BaseRemoteGDB::queryXfer(QuerySetCommand::Context &ctx)
void
BaseRemoteGDB::queryFThreadInfo(QuerySetCommand::Context &ctx)
{
send(csprintf("m%x", tc->contextId()).c_str());
send(csprintf("m%x", encodeThreadId(tc->contextId())).c_str());
}
void