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[RFC][PATCH] fix gdb segv when objfile can't be opened
- From: Mike Gulick <mike dot gulick at mathworks dot com>
- To: gdb-patches at sourceware dot org
- Date: Thu, 19 Oct 2017 10:10:25 -0400
- Subject: [RFC][PATCH] fix gdb segv when objfile can't be opened
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This fixes PR 16577.
This patch changes gdb_bfd_map_section to issue a warning rather than an
error if it is unable to read the object file, and sets the size of the
section/frame that it attempted to read to 0 on error.
The description of gdb_bfd_map_section states that it will try to read
or map the contents of the section SECT, and if successful, the section
data is returned and *size is set to the size of the section data. This
function was throwing an error and leaving *size as-is. Setting the
section size to 0 indicates to dwarf2_build_frame_info that there is no
data to read, otherwise it will try to read from an invalid frame
pointer.
Changing the error to a warning allows this to be handled gracefully.
Additionally, the error was clobbering the breakpoint output indicating
the current frame (function name, arguments, source file, and line number).
E.g.
Thread 3 "foo" hit Breakpoint 1, BFD: reopening
/tmp/jna-1013829440/jna2973250704389291330.tmp: No such file or directory
BFD: reopening /tmp/jna-1013829440/jna2973250704389291330.tmp: No such
file or directory
(gdb)
While the "BFD: reopening ..." messages will still appear interspersed
in the
breakpoint output, the current frame info is now displayed:
Thread 3 "foo" hit Breakpoint 1, BFD: reopening
/tmp/jna-1013829440/jna1875755897659885075.tmp: No such file or directory
BFD: reopening /tmp/jna-1013829440/jna1875755897659885075.tmp: No such
file or directory
warning: Can't read data for section '.eh_frame' in file
'/tmp/jna-1013829440/jna1875755897659885075.tmp'
do_something () at file.cpp:80
80 {
(gdb)
---
gdb/gdb_bfd.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/gdb/gdb_bfd.c b/gdb/gdb_bfd.c
index 29080b8..229f5ae 100644
--- a/gdb/gdb_bfd.c
+++ b/gdb/gdb_bfd.c
@@ -705,9 +705,15 @@ gdb_bfd_map_section (asection *sectp, bfd_size_type
*size)
data = NULL;
if (!bfd_get_full_section_contents (abfd, sectp, &data))
- error (_("Can't read data for section '%s' in file '%s'"),
- bfd_get_section_name (abfd, sectp),
- bfd_get_filename (abfd));
+ {
+ warning (_("Can't read data for section '%s' in file '%s'"),
+ bfd_get_section_name (abfd, sectp),
+ bfd_get_filename (abfd));
+ /* Section is invalid -- set size to 0 and return NULL */
+ descriptor->size = 0;
+ *size = descriptor->size;
+ return (const gdb_byte *) NULL;
+ }
descriptor->data = data;
done:
--
2.1.4