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/* Smoke testing GDB process attach with thread-local variable access.
Copyright (C) 2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* This test runs GDB against a forked copy of itself, to check
whether libthread_db can be loaded, and that access to thread-local
variables works. */
#include <errno.h>
#include <stdlib.h>
#include <support/check.h>
#include <support/support.h>
#include <support/temp_file.h>
#include <support/test-driver.h>
#include <support/xstdio.h>
#include <support/xthread.h>
#include <support/xunistd.h>
#include <unistd.h>
/* Starts out as zero, changed to 1 or 2 by the debugger, depending on
the thread. */
__thread volatile int altered_by_debugger;
/* Writes the GDB script to run the test to PATH. */
static void
write_gdbscript (const char *path, int tested_pid)
{
FILE *fp = xfopen (path, "w");
fprintf (fp,
"set trace-commands on\n"
"set debug libthread-db 1\n"
#if DO_ADD_SYMBOL_FILE
/* Do not do this unconditionally to work around a GDB
assertion failure: ../../gdb/symtab.c:6404:
internal-error: CORE_ADDR get_msymbol_address(objfile*,
const minimal_symbol*): Assertion `(objf->flags &
OBJF_MAINLINE) == 0' failed. */
"add-symbol-file %1$s/nptl/tst-pthread-gdb-attach\n"
#endif
"set auto-load safe-path %1$s/nptl_db\n"
"set libthread-db-search-path %1$s/nptl_db\n"
"attach %2$d\n",
support_objdir_root, tested_pid);
fputs ("break debugger_inspection_point\n"
"continue\n"
"thread 1\n"
"print altered_by_debugger\n"
"print altered_by_debugger = 1\n"
"thread 2\n"
"print altered_by_debugger\n"
"print altered_by_debugger = 2\n"
"continue\n",
fp);
xfclose (fp);
}
/* The test sets a breakpoint on this function and alters the
altered_by_debugger thread-local variable. */
void __attribute__ ((weak))
debugger_inspection_point (void)
{
}
/* Thread function for the test thread in the subprocess. */
static void *
subprocess_thread (void *closure)
{
/* Wait until altered_by_debugger changes the value away from 0. */
while (altered_by_debugger == 0)
{
usleep (100 * 1000);
debugger_inspection_point ();
}
TEST_COMPARE (altered_by_debugger, 2);
return NULL;
}
/* This function implements the subprocess under test. It creates a
second thread, waiting for its value to change to 2, and checks
that the main thread also changed its value to 1. */
static void
in_subprocess (void)
{
pthread_t thr = xpthread_create (NULL, subprocess_thread, NULL);
TEST_VERIFY (xpthread_join (thr) == NULL);
TEST_COMPARE (altered_by_debugger, 1);
_exit (0);
}
static int
do_test (void)
{
pid_t tested_pid = xfork ();
if (tested_pid == 0)
in_subprocess ();
char *tested_pid_string = xasprintf ("%d", tested_pid);
char *gdbscript;
xclose (create_temp_file ("tst-pthread-gdb-attach-", &gdbscript));
write_gdbscript (gdbscript, tested_pid);
pid_t gdb_pid = xfork ();
if (gdb_pid == 0)
{
clearenv ();
xdup2 (STDOUT_FILENO, STDERR_FILENO);
execlp ("gdb", "gdb", "-nx", "-batch", "-x", gdbscript, NULL);
if (errno == ENOENT)
_exit (EXIT_UNSUPPORTED);
else
_exit (1);
}
int status;
TEST_COMPARE (xwaitpid (gdb_pid, &status, 0), gdb_pid);
if (WIFEXITED (status) && WEXITSTATUS (status) == EXIT_UNSUPPORTED)
/* gdb is not installed. */
return EXIT_UNSUPPORTED;
TEST_COMPARE (status, 0);
TEST_COMPARE (xwaitpid (tested_pid, &status, 0), tested_pid);
TEST_COMPARE (status, 0);
free (tested_pid_string);
free (gdbscript);
return 0;
}
#include <support/test-driver.c>
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