From ecf45d2cc7667ed4692d07e52fc77a2c9a8adf1c Mon Sep 17 00:00:00 2001 From: Sandra Loosemore Date: Wed, 26 Oct 2016 12:12:01 -0500 Subject: PR 20569, segv in follow_exec The following testcases make GDB crash whenever an invalid sysroot is provided, when GDB is unable to find a valid path to the symbol file: gdb.base/catch-syscall.exp gdb.base/execl-update-breakpoints.exp gdb.base/foll-exec-mode.exp gdb.base/foll-exec.exp gdb.base/foll-vfork.exp gdb.base/pie-execl.exp gdb.multi/bkpt-multi-exec.exp gdb.python/py-finish-breakpoint.exp gdb.threads/execl.exp gdb.threads/non-ldr-exc-1.exp gdb.threads/non-ldr-exc-2.exp gdb.threads/non-ldr-exc-3.exp gdb.threads/non-ldr-exc-4.exp gdb.threads/thread-execl.exp The immediate cause of the segv is that follow_exec is passing a NULL argument (the result of exec_file_find) to strlen. However, the problem is deeper than that: follow_exec simply isn't prepared for the case where sysroot translation fails to locate the new executable. Actually all callers of exec_file_find have bugs due to confusion between host and target pathnames. This commit attempts to fix all that. In terms of the testcases that were formerly segv'ing, GDB now prints a warning but continues execution of the new program, so that the tests now mostly FAIL instead. You could argue the FAILs are due to a legitimate problem with the test environment setting up the sysroot translation incorrectly. A new representative test is added which exercises the ne wwarning code path even with native testing. Tested on x86_64 Fedora 23, native and gdbserver. gdb/ChangeLog: 2016-10-25 Sandra Loosemore Luis Machado Pedro Alves PR gdb/20569 * exceptions.c (exception_print_same): Moved here from exec.c. * exceptions.h (exception_print_same): Declare. * exec.h: Include "symfile-add-flags.h". (try_open_exec_file): New declaration. * exec.c (exception_print_same): Moved to exceptions.c. (try_open_exec_file): New function. (exec_file_locate_attach): Rename exec_file and full_exec_path variables to avoid confusion between target and host pathnames. Move pathname processing logic to exec_file_find. Do not return early if pathname lookup fails; Call try_open_exec_file. * infrun.c (follow_exec): Split and rename execd_pathname variable to avoid confusion between target and host pathnames. Warn if pathname lookup fails. Pass target pathname to target_follow_exec, not hostpathname. Call try_open_exec_file. * main.c (symbol_file_add_main_adapter): New function. (captured_main_1): Use it. * solib-svr4.c (open_symbol_file_object): Adjust to pass symfile_add_flags to symbol_file_add_main. * solib.c (exec_file_find): Incorporate fallback logic for relative pathnames formerly in exec_file_locate_attach. * symfile.c (symbol_file_add_main, symbol_file_add_main_1): Replace 'from_tty' parameter with a symfile_add_file. (symbol_file_command): Adjust to pass symfile_add_flags to symbol_file_add_main. * symfile.h (symbol_file_add_main): Replace 'from_tty' parameter with a symfile_add_file. gdb/testsuite/ChangeLog: 2016-10-25 Luis Machado * gdb.base/exec-invalid-sysroot.exp: New file. --- gdb/exceptions.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'gdb/exceptions.c') diff --git a/gdb/exceptions.c b/gdb/exceptions.c index 9a10f66..9919938 100644 --- a/gdb/exceptions.c +++ b/gdb/exceptions.c @@ -256,3 +256,21 @@ catch_errors (catch_errors_ftype *func, void *func_args, char *errstring, return 0; return val; } + +/* See exceptions.h. */ + +int +exception_print_same (struct gdb_exception e1, struct gdb_exception e2) +{ + const char *msg1 = e1.message; + const char *msg2 = e2.message; + + if (msg1 == NULL) + msg1 = ""; + if (msg2 == NULL) + msg2 = ""; + + return (e1.reason == e2.reason + && e1.error == e2.error + && strcmp (msg1, msg2) == 0); +} -- cgit v1.1