[PATCH 1/4] Implement 'set honor-dontdump-flag' command

Sergio Lopez
2017-11-28T13:22:18Z

Commit df8411da087dc05481926f4c4a82deabc5bc3859 implemented support for
checking /proc/PID/coredump_filter, and also changed gcore behavior to
unconditionally honor the VM_DONTDUMP flag, preventing sections marked
as such for being dumped into the core file.

This patch adds support for the 'set honor-dontdump-flag' command for
instructing gdb to ignore the VM_DONTDUMP flag. Combined with 'set
use-coredump-filter', this allows the user to restore the old behavior,
dumping all sections (except the ones marked as IO) unconditionally.

ChangeLog
2017-11-28 Sergio Lopez <slp@redhat.com>

* linux-tdep.c (honor_dontdump_flag): New variable.
(dump_mapping_p): Use honor_dontdump_flag variable.
(_initialize_linux_tdep): New command 'set honor-dontdump-flag'.
---
gdb/ChangeLog | 6 ++++++
gdb/linux-tdep.c | 19 ++++++++++++++++++-
2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ebb969998c..ce68fee776 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2017-11-28 Sergio Lopez <slp@redhat.com>
+
+ * linux-tdep.c (honor_dontdump_flag): New variable.
+ (dump_mapping_p): Use honor_dontdump_flag variable.
+ (_initialize_linux_tdep): New command 'set honor-dontdump-flag'.
+
2017-11-27 Tom Tromey <tom@tromey.com>

* Makefile.in (REMOTE_OBS): Remove.
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index 24237b8d39..5f4a1cdad1 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -93,6 +93,11 @@ struct smaps_vmflags

static int use_coredump_filter = 1;

+/* Whether to honor the VM_DONTDUMP flag in /proc/PID/smaps when
+ generating a corefile. */
+
+static int honor_dontdump_flag = 1;
+
/* This enum represents the signals' numbers on a generic architecture
running the Linux kernel. The definition of "generic" comes from
the file <include/uapi/asm-generic/signal.h>, from the Linux kernel
@@ -655,7 +660,7 @@ dump_mapping_p (filter_flags filterflags, const struct smaps_vmflags *v,
return 0;

/* Check if we should exclude this mapping. */
- if (v->exclude_coredump)
+ if (honor_dontdump_flag && v->exclude_coredump)
return 0;

/* Update our notion of whether this mapping is shared or
@@ -2517,4 +2522,16 @@ of /proc/PID/coredump_filter when generating the corefile. For more information
about this file, refer to the manpage of core(5)."),
NULL, show_use_coredump_filter,
&setlist, &showlist);
+
+ add_setshow_boolean_cmd ("honor-dontdump-flag", class_files,
+ &honor_dontdump_flag, _("\
+Set whether gcore should honor the VM_DONTDUMP flag."),
+ _("\
+Show whether gcore should honor the VM_DONTDUMP flag."),
+ _("\
+Use this command to set whether gcore should honor the VM_DONTDUMP\n\
+flag from /proc/PID/smaps when generating the corefile. For more information\n\
+about this file, refer to the manpage of proc(5) and core(5)."),
+ NULL, show_use_coredump_filter,
+ &setlist, &showlist);
}
--
2.14.3