readelf: Add optional "SECTION" argument for --notes.

There are multiple sections that can contain ELF Notes. It is sometimes
nice to just list the notes from a specific section.

  -n, --notes[=SECTION]      Display the ELF notes

Signed-off-by: Mark Wielaard <mark@klomp.org>

diff --git a/src/ChangeLog b/src/ChangeLog
index c2102fcda4b0deaf46c073083717924fbb53aa52..ad673c1179a7acdcf4c05488103220e752dfa0c3 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2019-08-26  Mark Wielaard  <mark@klomp.org>
+
+       * readelf (options): Add OPTION_ARG_OPTIONAL "SECTION" for notes.
+       (notes_section): New global variable.
+       (parse_opt): Set notes_section.
+       (handle_notes): Check if notes_section is set.
+
 2019-07-26  Florian Weimer  <fweimer@redhat.com>
            Mark Wielaard  <mark@klomp.org>
 

diff --git a/src/readelf.c b/src/readelf.c
index 2084fb1fedfa794ae49f69191f90310afcecc889..24be7a9ad7ab74dfd865a1ed4becf9266ef717ea 100644 (file)
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -114,7 +114,7 @@ static const struct argp_option options[] =
   { "symbols", 's', "SECTION", OPTION_ARG_OPTIONAL,
     N_("Display the symbol table sections"), 0 },
   { "version-info", 'V', NULL, 0, N_("Display versioning information"), 0 },
-  { "notes", 'n', NULL, 0, N_("Display the ELF notes"), 0 },
+  { "notes", 'n', "SECTION", OPTION_ARG_OPTIONAL, N_("Display the ELF notes"), 0 },
   { "arch-specific", 'A', NULL, 0,
     N_("Display architecture specific information, if any"), 0 },
   { "exception", 'e', NULL, 0,
@@ -190,6 +190,9 @@ static bool print_symbol_table;
 /* A specific section name, or NULL to print all symbol tables.  */
 static char *symbol_table_section;
 
+/* A specific section name, or NULL to print all ELF notes.  */
+static char *notes_section;
+
 /* True if the version information should be printed.  */
 static bool print_version_info;
 
@@ -439,6 +442,7 @@ parse_opt (int key, char *arg,
     case 'n':
       print_notes = true;
       any_control_option = true;
+      notes_section = arg;
       break;
     case 'r':
       print_relocations = true;
@@ -12408,6 +12412,13 @@ handle_notes (Ebl *ebl, GElf_Ehdr *ehdr)
            /* Not what we are looking for.  */
            continue;
 
+         if (notes_section != NULL)
+           {
+             char *sname = elf_strptr (ebl->elf, shstrndx, shdr->sh_name);
+             if (sname == NULL || strcmp (sname, notes_section) != 0)
+               continue;
+           }
+
          printf (gettext ("\
 \nNote section [%2zu] '%s' of %" PRIu64 " bytes at offset %#0" PRIx64 ":\n"),
                  elf_ndxscn (scn),