Check return value of bfd_init

  Alan recently added a way for BFD library users to check whether they
were in fact loading a compatible version of BFD:

https://sourceware.org/ml/binutils/2018-10/msg00198.html

It seemed reasonable to me that gdb should do this check as well, in
case someone is dynamically linking against BFD.  Tested by rebuilding
and then starting the resulting gdb.

gdb/ChangeLog
2018-10-25  Tom Tromey  <tom@tromey.com>

	* main.c (captured_main_1): Check return value of bfd_init.
---
 gdb/ChangeLog | 4 ++++
 gdb/main.c    | 3 ++-
 2 files changed, 6 insertions(+), 1 deletion(-)
  

On 2018-10-25 11:03 a.m., Tom Tromey wrote:
> Alan recently added a way for BFD library users to check whether they

> were in fact loading a compatible version of BFD:

> 

> https://sourceware.org/ml/binutils/2018-10/msg00198.html

> 

> It seemed reasonable to me that gdb should do this check as well, in

> case someone is dynamically linking against BFD.  Tested by rebuilding

> and then starting the resulting gdb.

> 

> gdb/ChangeLog

> 2018-10-25  Tom Tromey  <tom@tromey.com>

> 

> 	* main.c (captured_main_1): Check return value of bfd_init.

> ---

>  gdb/ChangeLog | 4 ++++

>  gdb/main.c    | 3 ++-

>  2 files changed, 6 insertions(+), 1 deletion(-)

> 

> diff --git a/gdb/ChangeLog b/gdb/ChangeLog

> index 61dc039d4fe..a90c2978185 100644

> --- a/gdb/ChangeLog

> +++ b/gdb/ChangeLog

> @@ -1,3 +1,7 @@

> +2018-10-25  Tom Tromey  <tom@tromey.com>

> +

> +	* main.c (captured_main_1): Check return value of bfd_init.

> +

>  2018-10-25  Andrew Burgess  <andrew.burgess@embecosm.com>

>  

>  	* python/py-function.c (convert_values_to_python): Return

> diff --git a/gdb/main.c b/gdb/main.c

> index 8709357e924..96def3080eb 100644

> --- a/gdb/main.c

> +++ b/gdb/main.c

> @@ -506,7 +506,8 @@ captured_main_1 (struct captured_main_args *context)

>    textdomain (PACKAGE);

>  #endif

>  

> -  bfd_init ();

> +  if (bfd_init () != BFD_INIT_MAGIC)

> +    error (_("fatal error: libbfd ABI mismatch"));

>    notice_open_fds ();

>  

>    saved_command_line = (char *) xstrdup ("");

> 


It doesn't work to call error that early.  Try to reverse the condition and start
gdb, you'll get:

$ ./gdb
ASAN:SIGSEGV
=================================================================
==12947==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000090 (pc 0x0000013a7a2f bp 0x7ffcbd048510 sp 0x7ffcbd048460 T0)
    #0 0x13a7a2e in gdb_main(captured_main_args*) /home/emaisin/src/binutils-gdb/gdb/main.c:1194
    #1 0xb27098 in main /home/emaisin/src/binutils-gdb/gdb/gdb.c:32
    #2 0x7ff24431482f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #3 0xb26ef8 in _start (/home/emaisin/build/binutils-gdb/gdb/gdb+0xb26ef8)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/emaisin/src/binutils-gdb/gdb/main.c:1194 gdb_main(captured_main_args*)
==12947==ABORTING


So fprintf to stderr and exit instead?

Simon
  

>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:

Simon> It doesn't work to call error that early.

Sorry about that.

For me the problem isn't the call to error, it is a crash in
gdb_main when trying to call exception_print.

Moving the call to bfd_init below the call to "new ui" makes it work.

Tom