gdbstub: add support to Xfer:auxv:read: packet

This allows gdb to access the target’s auxiliary vector,
which can be helpful for telling system libraries important details
about the hardware, operating system, and process.

Signed-off-by: Lirong Yuan <yuanzi@google.com>
[AJB: minor tweaks to test case, update MAINTAINERS, restrict to Linux]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200730193932.3654677-1-yuanzi@google.com>
Message-Id: <20210108224256.2321-7-alex.bennee@linaro.org>
This commit is contained in:
Lirong Yuan 2021-01-08 22:42:42 +00:00 committed by Alex Bennée
parent c00506aa26
commit 51c623b0de
4 changed files with 121 additions and 0 deletions

View file

@ -2322,6 +2322,7 @@ R: Philippe Mathieu-Daudé <philmd@redhat.com>
S: Maintained
F: gdbstub*
F: gdb-xml/
F: tests/tcg/multiarch/gdbstub/
Memory API
M: Paolo Bonzini <pbonzini@redhat.com>

View file

@ -2172,6 +2172,12 @@ static void handle_query_supported(GdbCmdContext *gdb_ctx, void *user_ctx)
";ReverseStep+;ReverseContinue+");
}
#ifdef CONFIG_USER_ONLY
if (gdbserver_state.c_cpu->opaque) {
g_string_append(gdbserver_state.str_buf, ";qXfer:auxv:read+");
}
#endif
if (gdb_ctx->num_params &&
strstr(gdb_ctx->params[0].data, "multiprocess+")) {
gdbserver_state.multiprocess = true;
@ -2233,6 +2239,46 @@ static void handle_query_xfer_features(GdbCmdContext *gdb_ctx, void *user_ctx)
gdbserver_state.str_buf->len, true);
}
#if defined(CONFIG_USER_ONLY) && defined(CONFIG_LINUX_USER)
static void handle_query_xfer_auxv(GdbCmdContext *gdb_ctx, void *user_ctx)
{
TaskState *ts;
unsigned long offset, len, saved_auxv, auxv_len;
const char *mem;
if (gdb_ctx->num_params < 2) {
put_packet("E22");
return;
}
offset = gdb_ctx->params[0].val_ul;
len = gdb_ctx->params[1].val_ul;
ts = gdbserver_state.c_cpu->opaque;
saved_auxv = ts->info->saved_auxv;
auxv_len = ts->info->auxv_len;
mem = (const char *)(saved_auxv + offset);
if (offset > auxv_len) {
put_packet("E00");
return;
}
if (len > (MAX_PACKET_LENGTH - 5) / 2) {
len = (MAX_PACKET_LENGTH - 5) / 2;
}
if (len < auxv_len - offset) {
g_string_assign(gdbserver_state.str_buf, "m");
memtox(gdbserver_state.str_buf, mem, len);
} else {
g_string_assign(gdbserver_state.str_buf, "l");
memtox(gdbserver_state.str_buf, mem, auxv_len - offset);
}
put_packet_binary(gdbserver_state.str_buf->str,
gdbserver_state.str_buf->len, true);
}
#endif
static void handle_query_attached(GdbCmdContext *gdb_ctx, void *user_ctx)
{
put_packet(GDB_ATTACHED);
@ -2338,6 +2384,14 @@ static GdbCmdParseEntry gdb_gen_query_table[] = {
.cmd_startswith = 1,
.schema = "s:l,l0"
},
#if defined(CONFIG_USER_ONLY) && defined(CONFIG_LINUX_USER)
{
.handler = handle_query_xfer_auxv,
.cmd = "Xfer:auxv:read::",
.cmd_startswith = 1,
.schema = "l,l0"
},
#endif
{
.handler = handle_query_attached,
.cmd = "Attached:",

View file

@ -55,6 +55,15 @@ run-gdbstub-sha1: sha1
"basic gdbstub support")
EXTRA_RUNS += run-gdbstub-sha1
run-gdbstub-qxfer-auxv-read: sha1
$(call run-test, $@, $(GDB_SCRIPT) \
--gdb $(HAVE_GDB_BIN) \
--qemu $(QEMU) --qargs "$(QEMU_OPTS)" \
--bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \
"basic gdbstub qXfer:auxv:read support")
EXTRA_RUNS += run-gdbstub-sha1 run-gdbstub-qxfer-auxv-read
endif

View file

@ -0,0 +1,57 @@
from __future__ import print_function
#
# Test auxiliary vector is loaded via gdbstub
#
# This is launched via tests/guest-debug/run-test.py
#
import gdb
import sys
failcount = 0
def report(cond, msg):
"Report success/fail of test"
if cond:
print ("PASS: %s" % (msg))
else:
print ("FAIL: %s" % (msg))
global failcount
failcount += 1
def run_test():
"Run through the tests one by one"
auxv = gdb.execute("info auxv", False, True)
report(isinstance(auxv, str), "Fetched auxv from inferior")
report(auxv.find("sha1"), "Found test binary name in auxv")
#
# This runs as the script it sourced (via -x, via run-test.py)
#
try:
inferior = gdb.selected_inferior()
arch = inferior.architecture()
print("ATTACHED: %s" % arch.name())
except (gdb.error, AttributeError):
print("SKIPPING (not connected)", file=sys.stderr)
exit(0)
if gdb.parse_and_eval('$pc') == 0:
print("SKIP: PC not set")
exit(0)
try:
# These are not very useful in scripts
gdb.execute("set pagination off")
gdb.execute("set confirm off")
# Run the actual tests
run_test()
except (gdb.error):
print ("GDB Exception: %s" % (sys.exc_info()[0]))
failcount += 1
pass
print("All tests complete: %d failures" % failcount)
exit(failcount)