perf symbols: Save DSO loading errno to better report errors

Before, when some problem happened while trying to load the kernel
symtab, 'perf top' would show:

      ┌─Warning:───────────────────────────┐
      │The vmlinux file can't be used.     │
      │Kernel samples will not be resolved.│
      │                                    │
      │                                    │
      │Press any key...                    │
      └────────────────────────────────────┘

Now, it reports:

  # perf top --vmlinux /dev/null

      ┌─Warning:───────────────────────────────────────────┐
      │The /tmp/passwd file can't be used: Invalid ELF file│
      │Kernel samples will not be resolved.                │
      │                                                    │
      │                                                    │
      │Press any key...                                    │
      └────────────────────────────────────────────────────┘

This is possible because we now register the reason for not being able
to load the symtab in the dso->load_errno member, and provide a
dso__strerror_load() routine to format this error into a strerror like
string with a short reason for the error while loading.

That can be just forwarding the dso__strerror_load() call to
strerror_r(), or, for a separate errno range providing a custom message.

Reported-by: Ingo Molnar <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions