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authorSandra Loosemore <sandra@codesourcery.com>2016-10-26 12:12:01 -0500
committerPedro Alves <palves@redhat.com>2016-10-26 16:47:46 +0100
commitecf45d2cc7667ed4692d07e52fc77a2c9a8adf1c (patch)
treeabc757e04ab221b35d3d0db5afba7f9f82da645a /gdb/exec.c
parentb15cc25cbe7c13e450f77b4a309223b9b3da3936 (diff)
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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 <sandra@codesourcery.com> Luis Machado <lgustavo@codesourcery.com> Pedro Alves <palves@redhat.com> 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 <lgustavo@codesourcery.com> * gdb.base/exec-invalid-sysroot.exp: New file.
Diffstat (limited to 'gdb/exec.c')
-rw-r--r--gdb/exec.c125
1 files changed, 54 insertions, 71 deletions
diff --git a/gdb/exec.c b/gdb/exec.c
index 6e2a296..eeca005 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -136,73 +136,16 @@ 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 (msg1, msg2) == 0);
-}
-
-/* See gdbcore.h. */
+/* See exec.h. */
void
-exec_file_locate_attach (int pid, int defer_bp_reset, int from_tty)
+try_open_exec_file (const char *exec_file_host, struct inferior *inf,
+ symfile_add_flags add_flags)
{
- 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);
- if (exec_file != NULL)
- return;
-
- /* Try to determine a filename from the process itself. */
- exec_file = target_pid_to_exec_file (pid);
- if (exec_file == NULL)
- {
- warning (_("No executable has been specified and target does not "
- "support\n"
- "determining executable automatically. "
- "Try using the \"file\" command."));
- return;
- }
-
- /* If gdb_sysroot is not empty and the discovered filename
- is absolute then prefix the filename with gdb_sysroot. */
- if (*gdb_sysroot != '\0' && IS_ABSOLUTE_PATH (exec_file))
- {
- full_exec_path = exec_file_find (exec_file, NULL);
- if (full_exec_path == NULL)
- return;
- }
- else
- {
- /* It's possible we don't have a full path, but rather just a
- filename. Some targets, such as HP-UX, don't provide the
- full path, sigh.
-
- Attempt to qualify the filename against the source path.
- (If that fails, we'll just fall back on the original
- filename. Not much more we can do...) */
- if (!source_full_path_of (exec_file, &full_exec_path))
- full_exec_path = xstrdup (exec_file);
- }
-
- old_chain = make_cleanup (xfree, full_exec_path);
- make_cleanup (free_current_contents, &prev_err.message);
+ old_chain = make_cleanup (free_current_contents, &prev_err.message);
/* exec_file_attach and symbol_file_add_main may throw an error if the file
cannot be opened either locally or remotely.
@@ -217,7 +160,9 @@ exec_file_locate_attach (int pid, int defer_bp_reset, int from_tty)
errors/exceptions in the following code. */
TRY
{
- exec_file_attach (full_exec_path, from_tty);
+ /* We must do this step even if exec_file_host is NULL, so that
+ exec_file_attach will clear state. */
+ exec_file_attach (exec_file_host, add_flags & SYMFILE_VERBOSE);
}
CATCH (err, RETURN_MASK_ERROR)
{
@@ -232,20 +177,58 @@ exec_file_locate_attach (int pid, int defer_bp_reset, int from_tty)
}
END_CATCH
- TRY
+ if (exec_file_host != NULL)
{
- if (defer_bp_reset)
- current_inferior ()->symfile_flags |= SYMFILE_DEFER_BP_RESET;
- symbol_file_add_main (full_exec_path, from_tty);
+ TRY
+ {
+ symbol_file_add_main (exec_file_host, add_flags);
+ }
+ CATCH (err, RETURN_MASK_ERROR)
+ {
+ if (!exception_print_same (prev_err, err))
+ warning ("%s", err.message);
+ }
+ END_CATCH
}
- CATCH (err, RETURN_MASK_ERROR)
+
+ do_cleanups (old_chain);
+}
+
+/* See gdbcore.h. */
+
+void
+exec_file_locate_attach (int pid, int defer_bp_reset, int from_tty)
+{
+ char *exec_file_target, *exec_file_host;
+ struct cleanup *old_chain;
+ symfile_add_flags add_flags = 0;
+
+ /* Do nothing if we already have an executable filename. */
+ if (get_exec_file (0) != NULL)
+ return;
+
+ /* Try to determine a filename from the process itself. */
+ exec_file_target = target_pid_to_exec_file (pid);
+ if (exec_file_target == NULL)
{
- if (!exception_print_same (prev_err, err))
- warning ("%s", err.message);
+ warning (_("No executable has been specified and target does not "
+ "support\n"
+ "determining executable automatically. "
+ "Try using the \"file\" command."));
+ return;
}
- END_CATCH
- current_inferior ()->symfile_flags &= ~SYMFILE_DEFER_BP_RESET;
+ exec_file_host = exec_file_find (exec_file_target, NULL);
+ old_chain = make_cleanup (xfree, exec_file_host);
+
+ if (defer_bp_reset)
+ add_flags |= SYMFILE_DEFER_BP_RESET;
+
+ if (from_tty)
+ add_flags |= SYMFILE_VERBOSE;
+
+ /* Attempt to open the exec file. */
+ try_open_exec_file (exec_file_host, current_inferior (), add_flags);
do_cleanups (old_chain);
}