[PATCH 1/3] Do check-textrel test using readelf rather than a build-time C program.

[Roland McGrath <roland at hack dot frob dot com>]

---
 ChangeLog                 |   12 +++
 config.make.in            |    1 +
 elf/Makefile              |   27 ++++---
 elf/check-textrel.c       |  198 ---------------------------------------------
 scripts/check-textrel.awk |   41 +++++++++
 5 files changed, 70 insertions(+), 209 deletions(-)
 delete mode 100644 elf/check-textrel.c
 create mode 100644 scripts/check-textrel.awk

diff --git a/ChangeLog b/ChangeLog
index 3298de4..7755e67 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2012-05-01  Roland McGrath  <roland@hack.frob.com>
+
+	* scripts/check-textrel.awk: New file.
+	* elf/Makefile ($(objpfx)check-textrel): Target removed.
+	(check-textrel-CFLAGS): Variable removed.
+	(all-built-dso): Use := to define.o
+	($(all-built-dso:=.dyn)): New static pattern rule.
+	(generated): Add those targets.
+	($(objpfx)check-textrel.out): Use the script on the .dyn files.
+	* config.make.in (READELF): New substituted variable.
+	* elf/check-textrel.c: File removed.
+
 2012-05-01  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #2550]
diff --git a/config.make.in b/config.make.in
index 1f4185b..5f6f9e2 100644
--- a/config.make.in
+++ b/config.make.in
@@ -112,6 +112,7 @@ BISON = @BISON@
 AUTOCONF = @AUTOCONF@
 OBJDUMP = @OBJDUMP@
 OBJCOPY = @OBJCOPY@
+READELF = @READELF@
 
 # Installation tools.
 INSTALL = @INSTALL@
diff --git a/elf/Makefile b/elf/Makefile
index 32d113e..9d4a814 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -872,10 +872,6 @@ CFLAGS-tst-pie1.c += $(pie-ccflag)
 
 $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so
 
-check-textrel-CFLAGS = -O -Wall -D_XOPEN_SOURCE=600 -D_BSD_SOURCE
-$(objpfx)check-textrel: check-textrel.c
-	$(native-compile)
-
 check-execstack-CFLAGS = -O -Wall -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -std=gnu99 \
 			 $(objpfx:%/=-I%)
 $(objpfx)check-execstack: check-execstack.c $(objpfx)check-execstack.h
@@ -895,14 +891,23 @@ $(objpfx)check-localplt: check-localplt.c
 ifeq (yes,$(build-shared))
 tests: $(objpfx)check-textrel.out $(objpfx)check-execstack.out
 
-all-built-dso = $(common-objpfx)libc.so \
-		$(filter-out $(common-objpfx)linkobj/libc.so, \
-			     $(sort $(wildcard $(common-objpfx)*/lib*.so \
-					       $(common-objpfx)iconvdata/*.so)))
+all-built-dso := $(common-objpfx)libc.so \
+		 $(filter-out $(common-objpfx)linkobj/libc.so, \
+			      $(sort $(wildcard $(addprefix $(common-objpfx), \
+			      	     			    */lib*.so \
+					        	    iconvdata/*.so))))
 
-$(objpfx)check-textrel.out: $(objpfx)check-textrel $(all-built-dso)
-	$(dir $<)$(notdir $<) $(filter-out $<, $^) > $@
-generated += check-textrel check-textrel.out
+$(all-built-dso:=.dyn): %.dyn: %
+	@rm -f $@T
+	$(READELF) -W -d $< > $@T
+	test -s $@T
+	mv -f $@T $@
+generated += $(all-built-dso:=.dyn)
+
+$(objpfx)check-textrel.out: $(..)scripts/check-textrel.awk \
+			    $(all-built-dso:=.dyn)
+	$(AWK) -f $^ > $@
+generated += check-textrel.out
 
 $(objpfx)check-execstack.out: $(objpfx)check-execstack $(all-built-dso)
 	$(dir $<)$(notdir $<) $(filter-out $<, $^) > $@
diff --git a/elf/check-textrel.c b/elf/check-textrel.c
deleted file mode 100644
index 6372019..0000000
--- a/elf/check-textrel.c
+++ /dev/null
@@ -1,198 +0,0 @@
-/* Check for text relocations in DSOs.
-   Copyright (C) 2002, 2003, 2006 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contribute by Ulrich Drepper <drepper@redhat.com>. 2002.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
-
-#include <byteswap.h>
-#include <elf.h>
-#include <endian.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-
-#ifdef BITS
-
-# define AB(name) _AB (name, BITS)
-# define _AB(name, bits) __AB (name, bits)
-# define __AB(name, bits) name##bits
-# define E(name) _E (name, BITS)
-# define _E(name, bits) __E (name, bits)
-# define __E(name, bits) Elf##bits##_##name
-# define SWAP(val) \
-  ({ __typeof (val) __res;						      \
-     if (((ehdr.e_ident[EI_DATA] == ELFDATA2MSB				      \
-	   && BYTE_ORDER == LITTLE_ENDIAN)				      \
-	  || (ehdr.e_ident[EI_DATA] == ELFDATA2LSB			      \
-	      && BYTE_ORDER == BIG_ENDIAN))				      \
-	 && sizeof (val) != 1)						      \
-       {								      \
-	 if (sizeof (val) == 2)						      \
-	   __res = bswap_16 (val);					      \
-	 else if (sizeof (val) == 4)					      \
-	   __res = bswap_32 (val);					      \
-	 else								      \
-	   __res = bswap_64 (val);					      \
-       }								      \
-     else								      \
-       __res = (val);							      \
-     __res; })
-
-
-static int
-AB(handle_file) (const char *fname, int fd)
-{
-  E(Ehdr) ehdr;
-
-  if (pread (fd, &ehdr, sizeof (ehdr), 0) != sizeof (ehdr))
-    {
-    read_error:
-      printf ("%s: read error: %m\n", fname);
-      return 1;
-    }
-
-  const size_t phnum = SWAP (ehdr.e_phnum);
-  const size_t phentsize = SWAP (ehdr.e_phentsize);
-
-  /* Read the program header.  */
-  E(Phdr) *phdr = alloca (phentsize * phnum);
-  if (pread (fd, phdr, phentsize * phnum, SWAP (ehdr.e_phoff))
-      != phentsize * phnum)
-    goto read_error;
-
-  /* Search for the PT_DYNAMIC entry.  */
-  size_t cnt;
-  E(Phdr) *dynphdr = NULL;
-  for (cnt = 0; cnt < phnum; ++cnt)
-    if (SWAP (phdr[cnt].p_type) == PT_DYNAMIC)
-      dynphdr = &phdr[cnt];
-    else if (SWAP (phdr[cnt].p_type) == PT_LOAD
-	     && (SWAP (phdr[cnt].p_flags) & (PF_X | PF_W)) == (PF_X | PF_W))
-      {
-	printf ("%s: segment %zu is executable and writable\n",
-		fname, cnt);
-#if !defined __sparc__ \
-    && !defined __alpha__ \
-    && (!defined __powerpc__ || defined __powerpc64__ || defined HAVE_PPC_SECURE_PLT)
-	/* sparc, sparc64, alpha and powerpc32 (the last one only when using
-	   -mbss-plt) are expected to have PF_X | PF_W segment containing .plt
-	   section, it is part of their ABI.  It is bad security wise, nevertheless
-	   this test shouldn't fail because of this.  */
-	return 1;
-#endif
-      }
-
-  if (dynphdr == NULL)
-    {
-      printf ("%s: no DYNAMIC segment found\n", fname);
-      return 1;
-    }
-
-  /* Read the dynamic segment.  */
-  size_t pmemsz = SWAP(dynphdr->p_memsz);
-  E(Dyn) *dyn = alloca (pmemsz);
-  if (pread (fd, dyn, pmemsz, SWAP(dynphdr->p_offset)) != pmemsz)
-    goto read_error;
-
-  /* Search for an DT_TEXTREL entry of DT_FLAGS with the DF_TEXTREL
-     bit set.  */
-  for (cnt = 0; (cnt + 1) * sizeof (E(Dyn)) - 1 < pmemsz; ++cnt)
-    {
-      unsigned int tag = SWAP (dyn[cnt].d_tag);
-
-      if (tag == DT_NULL)
-	/* We reached the end.  */
-	break;
-
-      if (tag == DT_TEXTREL
-	  || (tag == DT_FLAGS
-	      && (SWAP (dyn[cnt].d_un.d_val) & DF_TEXTREL) != 0))
-	{
-	  /* Urgh!  The DSO has text relocations.  */
-	  printf ("%s: text relocations used\n", fname);
-	  return 1;
-	}
-    }
-
-  printf ("%s: OK\n", fname);
-
-  return 0;
-}
-
-# undef BITS
-#else
-
-# define BITS 32
-# include "check-textrel.c"
-
-# define BITS 64
-# include "check-textrel.c"
-
-
-static int
-handle_file (const char *fname)
-{
-  int fd = open (fname, O_RDONLY);
-  if (fd == -1)
-    {
-      printf ("cannot open %s: %m\n", fname);
-      return 1;
-    }
-
-  /* Read was is supposed to be the ELF header.  Read the initial
-     bytes to determine whether this is a 32 or 64 bit file.  */
-  char ident[EI_NIDENT];
-  if (read (fd, ident, EI_NIDENT) != EI_NIDENT)
-    {
-      printf ("%s: read error: %m\n", fname);
-      close (fd);
-      return 1;
-    }
-
-  if (memcmp (&ident[EI_MAG0], ELFMAG, SELFMAG) != 0)
-    {
-      printf ("%s: not an ELF file\n", fname);
-      close (fd);
-      return 1;
-    }
-
-  int result;
-  if (ident[EI_CLASS] == ELFCLASS64)
-    result = handle_file64 (fname, fd);
-  else
-    result = handle_file32 (fname, fd);
-
-  close (fd);
-
-  return result;
-}
-
-
-int
-main (int argc, char *argv[])
-{
-  int cnt;
-  int result = 0;
-
-  for (cnt = 1; cnt < argc; ++cnt)
-    result |= handle_file (argv[cnt]);
-
-  return result;
-}
-#endif
diff --git a/scripts/check-textrel.awk b/scripts/check-textrel.awk
new file mode 100644
index 0000000..e7f2d70
--- /dev/null
+++ b/scripts/check-textrel.awk
@@ -0,0 +1,41 @@
+# This awk script expects to get command-line files that are each
+# the output of 'readelf -d' on a single shared object.
+# It exits successfully (0) if none contained any TEXTREL markers.
+# It fails (1) if any did contain a TEXTREL marker.
+# It fails (2) if the input did not take the expected form.
+
+BEGIN { result = textrel = sanity = 0 }
+
+function check_one(name) {
+  if (!sanity) {
+    print name ": *** input did not look like readelf -d output";
+    result = 2;
+  } else if (textrel) {
+    print name ": *** text relocations used";
+    result = result ? result : 1;
+  } else {
+    print name ": OK";
+  }
+
+  textrel = sanity = 0;
+}
+
+FILENAME != lastfile {
+  if (lastfile)
+    check_one(lastfile);
+  lastfile = FILENAME;
+}
+
+$1 == "Tag" && $2 == "Type" { sanity = 1 }
+$2 == "(TEXTREL)" { textrel = 1 }
+$2 == "(FLAGS)" {
+  for (i = 3; i <= NF; ++i) {
+    if ($i == "TEXTREL")
+      textrel = 1;
+  }
+}
+
+END {
+  check_one(lastfile);
+  exit(result);
+}
-- 
1.7.7.3