readelf: Add --dyn-sym option.

It is already possible to select the symbol table to print by name,
using --symbols=SECTION. This allows printing the dynamic symbol table
with --symbols=.dynsym. binutils readelf allows printing just the
dynamic symbol table by type using --dyn-sym. Add the same option
and document it. Also add a testcase to show --symbols=.dynsym and
--dyn-sym produce the same output.

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

6 files changed, 40 insertions, 3 deletions

diff --git a/doc/ChangeLog b/doc/ChangeLog
index 722752da..00a61ac3 100644
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,3 +1,8 @@
+2019-09-02  Mark Wielaard  <mark@klomp.org>
+
+	* readelf.1 (symbols): Add optional section name.
+	(dyn-sym): Document new option.
+
 2019-08-28  Mark Wielaard  <mark@klomp.org>
 
 	* COPYING: Rename to...
diff --git a/doc/readelf.1 b/doc/readelf.1
index 4f0dd00a..33263819 100644
--- a/doc/readelf.1
+++ b/doc/readelf.1
@@ -146,7 +146,8 @@ eu-readelf [\fB\-a\fR|\fB\-\-all\fR]
         [\fB\-S\fR|\fB\-\-section\-headers\fR|\fB\-\-sections\fR]
         [\fB\-g\fR|\fB\-\-section\-groups\fR]
         [\fB\-e\fR|\fB\-\-exception\fR]
-        [\fB\-s\fR|\fB\-\-symbols\fR]
+        [\fB\-s\fR|\fB\-\-symbols\fR] [section name] ]
+        [\fB\-\-dyn-syms\fR]
         [\fB\-n\fR|\fB\-\-notes\fR [section name] ]
         [\fB\-r\fR|\fB\-\-relocs\fR]
         [\fB\-d\fR|\fB\-\-dynamic\fR]
@@ -254,7 +255,7 @@ of the symbol tables.
 .IP "\fB\-s\fR" 4
 .IX Item "-s"
 .PD 0
-.IP "\fB\-\-symbols\fR" 4
+.IP "\fB\-\-symbols\fR [section name]" 4
 .IX Item "--symbols"
 .PD
 Displays the entries in symbol table section of the file, if it has one.
@@ -265,6 +266,10 @@ symbol name, preceeded by an @ character.  For example
 when resolving unversioned references to the symbol then it is
 displayed as a suffix preceeded by two @ characters.  For example
 \&\fBfoo@@VER_2\fR.
+.IP "\fB\-\-dyn-syms\fR" 4
+.IX Item "--dyn-syms"
+.PD
+Display (only) the dynamic symbol table.
 .IP "\fB\-e\fR" 4
 .IX Item "-e"
 .PD 0
diff --git a/src/ChangeLog b/src/ChangeLog
index a945c429..3007c30d 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2019-09-02  Mark Wielaard  <mark@klomp.org>
+
+	* readelf.c (PRINT_DYNSYM_TABLE): New argp key value.
+	(argp_opt): Add syn-sym.
+	(print_dynsym_table): New static bool.
+	(parse_opt): Handle PRINT_DYNSYM_TABLE.
+	(process_elf_file): Check print_dynsym_table.
+
 2019-08-27  Mark Wielaard  <mark@klomp.org>
 
 	* readelf.c (for_each_section_argument): Call (*dump) also for
diff --git a/src/readelf.c b/src/readelf.c
index 77f9c3a3..5d2b5f43 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -84,6 +84,9 @@ ARGP_PROGRAM_BUG_ADDRESS_DEF = PACKAGE_BUGREPORT;
 /* argp key value for --dwarf-skeleton, non-ascii.  */
 #define DWARF_SKELETON 257
 
+/* argp key value for --dyn-syms, non-ascii.  */
+#define PRINT_DYNSYM_TABLE 258
+
 /* Terrible hack for hooking unrelated skeleton/split compile units,
    see __libdw_link_skel_split in print_debug.  */
 static bool do_not_close_dwfl = false;
@@ -113,6 +116,8 @@ static const struct argp_option options[] =
   { "sections", 'S', NULL, OPTION_ALIAS | OPTION_HIDDEN, NULL, 0 },
   { "symbols", 's', "SECTION", OPTION_ARG_OPTIONAL,
     N_("Display the symbol table sections"), 0 },
+  { "dyn-syms", PRINT_DYNSYM_TABLE, NULL, 0,
+    N_("Display (only) the dynamic symbol table"), 0 },
   { "version-info", 'V', NULL, 0, N_("Display versioning information"), 0 },
   { "notes", 'n', "SECTION", OPTION_ARG_OPTIONAL, N_("Display the ELF notes"), 0 },
   { "arch-specific", 'A', NULL, 0,
@@ -187,6 +192,9 @@ static bool print_section_header;
 /* True if the symbol table should be printed.  */
 static bool print_symbol_table;
 
+/* True if (only) the dynsym table should be printed.  */
+static bool print_dynsym_table;
+
 /* A specific section name, or NULL to print all symbol tables.  */
 static char *symbol_table_section;
 
@@ -457,6 +465,10 @@ parse_opt (int key, char *arg,
       any_control_option = true;
       symbol_table_section = arg;
       break;
+    case PRINT_DYNSYM_TABLE:
+      print_dynsym_table = true;
+      any_control_option = true;
+      break;
     case 'V':
       print_version_info = true;
       any_control_option = true;
@@ -998,7 +1010,7 @@ process_elf_file (Dwfl_Module *dwflmod, int fd)
     print_relocs (pure_ebl, ehdr);
   if (print_histogram)
     handle_hash (ebl);
-  if (print_symbol_table)
+  if (print_symbol_table || print_dynsym_table)
     print_symtab (ebl, SHT_DYNSYM);
   if (print_version_info)
     print_verinfo (ebl);
diff --git a/tests/ChangeLog b/tests/ChangeLog
index b01ff965..97b8dedb 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,7 @@
+2019-09-02  Mark Wielaard  <mark@klomp.org>
+
+	* run-readelf-s.sh: Add --dyn-syms case.
+
 2019-09-07  Mark Wielaard  <mark@klomp.org>
 
 	* Makefile.am (EXTRA_DIST): Add run-disasm-riscv64.sh,
diff --git a/tests/run-readelf-s.sh b/tests/run-readelf-s.sh
index 82c3417e..527c436c 100755
--- a/tests/run-readelf-s.sh
+++ b/tests/run-readelf-s.sh
@@ -281,6 +281,9 @@ cat testfile.dynsym.in testfile.symtab.in \
 cat testfile.dynsym.in \
   | testrun_compare ${abs_top_builddir}/src/readelf \
     --symbols=.dynsym testfilebaztab
+cat testfile.dynsym.in \
+  | testrun_compare ${abs_top_builddir}/src/readelf \
+    --dyn-syms testfilebaztab
 
 # Display just .symtab
 cat testfile.symtab.in \