Add helper function for basename

musl does not provide GNU version of basename and lately have removed
the definiton from string.h [1] which exposes this problem. It can be
made to work by providing a local implementation of basename which
implements the GNU basename behavior, this makes it work across C
libraries which have POSIX implementation only.

[1] https://git.musl-libc.org/cgit/musl/commit/?id=725e17ed6dff4d0cd22487bb64470881e86a92e7

    * lib/system.h (xbasename): New static inline functions.
    Poison basename.
    * libdw/dwarf_getsrc_file.c (dwarf_getsrc_file): Use xbasename.
    * libdwfl/core-file.c (dwfl_core_file_report): Likewise.
    * libdwfl/dwfl_module_getsrc_file.c (dwfl_module_getsrc_file):
    Likewise.
    * libdwfl/dwfl_segment_report_module.c (dwfl_segment_report_module):
    Likewise.
    * libdwfl/find-debuginfo.c (find_debuginfo_in_path): Likewise.
    * libdwfl/link_map.c (report_r_debug): Likewise.
    * libdwfl/linux-kernel-modules.c (try_kernel_name): Likewise.
    * src/addr2line.c (print_dwarf_function): Likewise.
    (print_src): Likewise.
    * src/ar.c (do_oper_insert): Likewise.
    And cast away const in entry.key assignment.
    * src/nm.c (show_symbols): Use xbasename.
    * src/stack.c (module_callback): Likewise.
    * src/strip.c (handle_elf): Likewise.
    * tests/show-die-info.c: Include system.h.
    (dwarf_tag_string): Use xbasename.
    * tests/varlocs.c: Likewise.
    * debuginfod/debuginfod.cxx: Move include system.h to the end.
    (register_file_name): Rename basename to filename.

Signed-off-by: Khem Raj <[email protected]>
Signed-off-by: Mark Wielaard <[email protected]>

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/system.h b/lib/system.h
index 1c914efc..0db12d99 100644
--- a/lib/system.h
+++ b/lib/system.h
@@ -1,6 +1,7 @@
 /* Declarations for common convenience functions.
    Copyright (C) 2006-2011 Red Hat, Inc.
    Copyright (C) 2022 Mark J. Wielaard <[email protected]>
+   Copyright (C) 2023 Khem Raj.
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -211,4 +212,17 @@ extern char *__cxa_demangle (const char *mangled_name, char *output_buffer,
   extern int never_defined_just_used_for_checking[(expr) ? 1 : -1]	\
     __attribute__ ((unused))
 
+/* We really want a basename implementation that doesn't modify the
+   input argument.  Normally you get that from string.h with _GNU_SOURCE
+   define.  But some libc implementations don't define it and other
+   define it, but provide an implementation that still modifies the
+   argument.  So define our own and poison a bare basename symbol.  */
+static inline const char *
+xbasename(const char *s)
+{
+  const char *p = strrchr(s, '/');
+  return p ? p+1 : s;
+}
+#pragma GCC poison basename
+
 #endif /* system.h */