[2/2,nto] Improve ABI sniffing.
Commit Message
Use qnx specific notes to figure out the OS.
gdb/ChangeLog:
* gdb/nto-tdep.c (QNX_NOTE_NAME, QNX_INFO_SECT_NAME): New defines.
(nto_sniff_abi_note_section): New function.
(nto_elf_osabi_sniffer): Use new function to recognize nto specific
binary.
---
gdb/nto-tdep.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 44 insertions(+), 2 deletions(-)
Comments
On 10/20/2015 07:10 PM, Aleksandar Ristovski wrote:
> Use qnx specific notes to figure out the OS.
>
> gdb/ChangeLog:
> * gdb/nto-tdep.c (QNX_NOTE_NAME, QNX_INFO_SECT_NAME): New defines.
> (nto_sniff_abi_note_section): New function.
> (nto_elf_osabi_sniffer): Use new function to recognize nto specific
> binary.
> ---
> gdb/nto-tdep.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 44 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/nto-tdep.c b/gdb/nto-tdep.c
> index e50d302..48826cb 100644
> --- a/gdb/nto-tdep.c
> +++ b/gdb/nto-tdep.c
> @@ -32,6 +32,9 @@
> #include "gdbcore.h"
> #include "objfiles.h"
>
> +#define QNX_NOTE_NAME "QNX"
> +#define QNX_INFO_SECT_NAME "QNX_info"
> +
> #ifdef __CYGWIN__
> #include <sys/cygwin.h>
> #endif
> @@ -332,12 +335,51 @@ nto_dummy_supply_regset (struct regcache *regcache, char *regs)
> /* Do nothing. */
> }
>
> +static void
> +nto_sniff_abi_note_section (bfd *abfd, asection *sect, void *obj)
> +{
> + const char *sectname;
> + unsigned int sectsize;
> + char *note; // buffer holding the section contents
Please use /**/ format for comments, and write full sentences - start
with uppercase, period at end. Usually that leads to putting the comment
above, e.g.:
+ /* Buffer holding the section contents. */
+ char *note;
> + unsigned int namelen;
> + const char *name;
> +
> + sectname = bfd_get_section_name (abfd, sect);
> + sectsize = bfd_section_size (abfd, sect);
> +
> + /* TODO: limit the note size here, for now limit is 128 bytes
> + (enough to check the name and type). */
This reads like limiting is left to do, but then it does
implement a limit. So this TODO comment is confusing.
You should also make sure the section is the at least
the minimum size you expect though.
> + if (sectsize > 128)
> + sectsize = 128;
> +
> + if (sectname && strstr (sectname, QNX_INFO_SECT_NAME) != NULL)
> + *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
> +
sectname != NULL
> + if (sectname && strstr (sectname, "note") != NULL)
sectname != NULL
> + {
> + note = alloca (sectsize);
For C++, write:
note = (char *) alloca (sectsize);
> + bfd_get_section_contents (abfd, sect, note, 0, sectsize);
> + namelen = (unsigned int) bfd_h_get_32 (abfd, note);
> + name = note + 12;
> +
> + if (namelen > 0
> + && (0 == strcmp (name, QNX_NOTE_NAME)))
> + *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
> + }
> +}
> +
> enum gdb_osabi
> nto_elf_osabi_sniffer (bfd *abfd)
> {
> - if (nto_is_nto_target)
> + enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
> +
> + bfd_map_over_sections (abfd,
> + nto_sniff_abi_note_section,
> + &osabi);
> +
> + if (osabi == GDB_OSABI_UNKNOWN && nto_is_nto_target)
> return nto_is_nto_target (abfd);
...
nto_is_nto_target = procfs_is_nto_target;
...
static enum gdb_osabi
procfs_is_nto_target (bfd *abfd)
{
return GDB_OSABI_QNXNTO;
}
So that basically could be rewritten as:
if (osabi == GDB_OSABI_UNKNOWN && nto_is_nto_target)
return GDB_OSABI_QNXNTO;
But, do we still need this nto_is_nto_target hack here?
Now with proper sniffing, can't we just remove it altogether?
> - return GDB_OSABI_UNKNOWN;
> + return osabi;
> }
>
> static const char *nto_thread_state_str[] =
>
Thanks,
Pedro Alves
@@ -32,6 +32,9 @@
#include "gdbcore.h"
#include "objfiles.h"
+#define QNX_NOTE_NAME "QNX"
+#define QNX_INFO_SECT_NAME "QNX_info"
+
#ifdef __CYGWIN__
#include <sys/cygwin.h>
#endif
@@ -332,12 +335,51 @@ nto_dummy_supply_regset (struct regcache *regcache, char *regs)
/* Do nothing. */
}
+static void
+nto_sniff_abi_note_section (bfd *abfd, asection *sect, void *obj)
+{
+ const char *sectname;
+ unsigned int sectsize;
+ char *note; // buffer holding the section contents
+ unsigned int namelen;
+ const char *name;
+
+ sectname = bfd_get_section_name (abfd, sect);
+ sectsize = bfd_section_size (abfd, sect);
+
+ /* TODO: limit the note size here, for now limit is 128 bytes
+ (enough to check the name and type). */
+ if (sectsize > 128)
+ sectsize = 128;
+
+ if (sectname && strstr (sectname, QNX_INFO_SECT_NAME) != NULL)
+ *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+
+ if (sectname && strstr (sectname, "note") != NULL)
+ {
+ note = alloca (sectsize);
+ bfd_get_section_contents (abfd, sect, note, 0, sectsize);
+ namelen = (unsigned int) bfd_h_get_32 (abfd, note);
+ name = note + 12;
+
+ if (namelen > 0
+ && (0 == strcmp (name, QNX_NOTE_NAME)))
+ *(enum gdb_osabi *) obj = GDB_OSABI_QNXNTO;
+ }
+}
+
enum gdb_osabi
nto_elf_osabi_sniffer (bfd *abfd)
{
- if (nto_is_nto_target)
+ enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
+
+ bfd_map_over_sections (abfd,
+ nto_sniff_abi_note_section,
+ &osabi);
+
+ if (osabi == GDB_OSABI_UNKNOWN && nto_is_nto_target)
return nto_is_nto_target (abfd);
- return GDB_OSABI_UNKNOWN;
+ return osabi;
}
static const char *nto_thread_state_str[] =