diff --git a/gdb/ChangeLog b/gdb/ChangeLog index d03d5aecdb3..ad74df67712 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2016-04-13 Luis Machado + + * exec.c (exec_file_locate_attach): Guard a couple functions + that can throw errors. + (exception_print_same): New helper function. + 2016-04-13 Pedro Alves PR remote/19840 diff --git a/gdb/exec.c b/gdb/exec.c index a10ab9b4d07..c998ab19bd2 100644 --- a/gdb/exec.c +++ b/gdb/exec.c @@ -135,6 +135,25 @@ exec_file_clear (int from_tty) printf_unfiltered (_("No executable file now.\n")); } +/* Returns non-zero if exceptions E1 and E2 are equal. Returns zero + otherwise. */ + +static 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 (e1.message, e2.message) == 0); +} + /* See gdbcore.h. */ void @@ -142,6 +161,7 @@ exec_file_locate_attach (int pid, int from_tty) { char *exec_file, *full_exec_path = NULL; struct cleanup *old_chain; + struct gdb_exception prev_err = exception_none; /* Do nothing if we already have an executable filename. */ exec_file = (char *) get_exec_file (0); @@ -181,9 +201,45 @@ exec_file_locate_attach (int pid, int from_tty) } old_chain = make_cleanup (xfree, full_exec_path); + make_cleanup (free_current_contents, &prev_err.message); - exec_file_attach (full_exec_path, from_tty); - symbol_file_add_main (full_exec_path, from_tty); + /* exec_file_attach and symbol_file_add_main may throw an error if the file + cannot be opened either locally or remotely. + + This happens for example, when the file is first found in the local + sysroot (above), and then disappears (a TOCTOU race), or when it doesn't + exist in the target filesystem, or when the file does exist, but + is not readable. + + Even without a symbol file, the remote-based debugging session should + continue normally instead of ending abruptly. Hence we catch thrown + errors/exceptions in the following code. */ + TRY + { + exec_file_attach (full_exec_path, from_tty); + } + CATCH (err, RETURN_MASK_ERROR) + { + if (err.message != NULL) + warning ("%s", err.message); + + prev_err = err; + + /* Save message so it doesn't get trashed by the catch below. */ + prev_err.message = xstrdup (err.message); + } + END_CATCH + + TRY + { + symbol_file_add_main (full_exec_path, from_tty); + } + CATCH (err, RETURN_MASK_ERROR) + { + if (!exception_print_same (prev_err, err)) + warning ("%s", err.message); + } + END_CATCH do_cleanups (old_chain); }