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

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

---
 ChangeLog            |    9 ++
 elf/Makefile         |   39 ++++---
 elf/check-localplt.c |  298 --------------------------------------------------
 scripts/localplt.awk |   59 ++++++++++
 4 files changed, 91 insertions(+), 314 deletions(-)
 delete mode 100644 elf/check-localplt.c
 create mode 100644 scripts/localplt.awk

diff --git a/ChangeLog b/ChangeLog
index 634d96c..44a69c7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2012-05-01  Roland McGrath  <roland@hack.frob.com>
 
+	* scripts/localplt.awk: New file.
+	* elf/Makefile ($(objpfx)check-localplt): Target removed.
+	(check-localplt-CFLAGS): Variable removed.
+	($(all-built-dso:=.jmprel)): New static pattern rule.
+	(generated): Add those targets.
+	(localplt-built-dso): New variable.
+	($(objpfx)check-localplt.out): Use the script on the .jmprel files.
+	* elf/check-localplt.c: File removed.
+
 	* scripts/check-execstack.awk: New file.
 	* elf/Makefile ($(objpfx)check-execstack): Target removed.
 	(check-execstack-CFLAGS): Variable removed.
diff --git a/elf/Makefile b/elf/Makefile
index 29b0b05..636fa7b 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -872,18 +872,14 @@ CFLAGS-tst-pie1.c += $(pie-ccflag)
 
 $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so
 
-check-localplt-CFLAGS = -O -Wall -D_GNU_SOURCE -std=gnu99
-$(objpfx)check-localplt: check-localplt.c
-	$(native-compile)
-
 ifeq (yes,$(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 $(addprefix $(common-objpfx), \
-			      	     			    */lib*.so \
-					        	    iconvdata/*.so))))
+							    */lib*.so \
+							    iconvdata/*.so))))
 
 $(all-built-dso:=.dyn): %.dyn: %
 	@rm -f $@T
@@ -927,6 +923,13 @@ generated += check-execstack.out
 $(objpfx)tst-dlmodcount: $(libdl)
 $(objpfx)tst-dlmodcount.out: $(test-modules)
 
+$(all-built-dso:=.jmprel): %.jmprel: % Makefile
+	@rm -f $@T
+	$(READELF) -W -S -d -r $< > $@T
+	test -s $@T
+	mv -f $@T $@
+generated += $(all-built-dso:=.jmprel)
+
 check-data := $(firstword $(wildcard \
 		$(foreach D,$(add-ons) scripts,\
 			  $(patsubst %,$(..)$D/data/localplt-%.data,\
@@ -938,20 +941,24 @@ check-data := $(firstword $(wildcard \
 
 tests: $(objpfx)check-localplt.out
 
+localplt-built-dso := $(addprefix $(common-objpfx),\
+				  libc.so \
+				  math/libm.so \
+				  rt/librt.so \
+				  dlfcn/libdl.so \
+				  resolv/libresolv.so \
+				  crypt/libcrypt.so \
+		       )
 ifeq ($(have-thread-library),yes)
-thread-dso := $(filter-out %_nonshared.a, $(shared-thread-library))
+localplt-built-dso += $(filter-out %_nonshared.a, $(shared-thread-library))
 endif
 
-$(objpfx)check-localplt.out: $(objpfx)check-localplt \
-			     $(common-objpfx)libc.so \
-			     $(common-objpfx)math/libm.so $(thread-dso) \
-			     $(common-objpfx)rt/librt.so \
-			     $(common-objpfx)dlfcn/libdl.so \
-			     $(common-objpfx)resolv/libresolv.so \
-			     $(common-objpfx)crypt/libcrypt.so \
+$(objpfx)check-localplt.out: $(..)scripts/check-localplt.awk \
+			     $(..)scripts/localplt.awk \
+			     $(localplt-built-dso:=.jmprel) \
 			     $(check-data)
-	$(dir $<)$(notdir $<) $(filter-out $< $(check-data),$^) | \
-	  $(AWK) -f $(..)scripts/check-localplt.awk $(check-data) -
+	$(AWK) -f $(filter-out $< $(check-data),$^) | \
+	  $(AWK) -f $< $(check-data) -
 endif
 
 $(objpfx)tst-dlopenrpathmod.so: $(libdl)
diff --git a/elf/check-localplt.c b/elf/check-localplt.c
deleted file mode 100644
index edab1d2..0000000
--- a/elf/check-localplt.c
+++ /dev/null
@@ -1,298 +0,0 @@
-/* Show local PLT use in DSOs.
-   Copyright (C) 2006 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contribute by Ulrich Drepper <drepper@redhat.com>. 2006.
-
-   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 <stdint.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 EE(name) _EE (name, BITS)
-# define _EE(name, bits) __EE (name, bits)
-# define __EE(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];
-	break;
-      }
-
-  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 (pread64 (fd, dyn, pmemsz, SWAP(dynphdr->p_offset)) != pmemsz)
-    goto read_error;
-
-  /* Search for an DT_PLTREL, DT_JMPREL, DT_PLTRELSZ, DT_STRTAB,
-     DT_STRSZ, and DT_SYMTAB entries.  */
-  size_t pltrel_idx = SIZE_MAX;
-  size_t jmprel_idx = SIZE_MAX;
-  size_t pltrelsz_idx = SIZE_MAX;
-  size_t strtab_idx = SIZE_MAX;
-  size_t strsz_idx = SIZE_MAX;
-  size_t symtab_idx = SIZE_MAX;
-  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_PLTREL)
-	pltrel_idx = cnt;
-      else if (tag == DT_JMPREL)
-	jmprel_idx = cnt;
-      else if (tag == DT_PLTRELSZ)
-	pltrelsz_idx = cnt;
-      else if (tag == DT_STRTAB)
-	strtab_idx = cnt;
-      else if (tag == DT_STRSZ)
-	strsz_idx = cnt;
-      else if (tag == DT_SYMTAB)
-	symtab_idx = cnt;
-    }
-
-  if (pltrel_idx == SIZE_MAX || jmprel_idx == SIZE_MAX
-      || pltrelsz_idx == SIZE_MAX || strtab_idx == SIZE_MAX
-      || strsz_idx == SIZE_MAX || symtab_idx == SIZE_MAX)
-    {
-      puts ("not all PLT information found");
-      return 1;
-    }
-
-  E(Xword) relsz = SWAP (dyn[pltrelsz_idx].d_un.d_val);
-
-  void *relmem = NULL;
-  char *strtab = NULL;
-  E(Xword) symtab_offset = 0;
-
-  /* Find the offset of DT_JMPREL and load the data.  */
-  for (cnt = 0; cnt < phnum; ++cnt)
-    if (SWAP (phdr[cnt].p_type) == PT_LOAD)
-      {
-	E(Addr) vaddr = SWAP (phdr[cnt].p_vaddr);
-	E(Xword) memsz = SWAP (phdr[cnt].p_memsz);
-
-	if (vaddr <= SWAP (dyn[jmprel_idx].d_un.d_val)
-	    && vaddr + memsz >= SWAP (dyn[jmprel_idx].d_un.d_val) + relsz)
-	  {
-	    relmem = alloca (SWAP (dyn[pltrelsz_idx].d_un.d_val));
-	    if (pread64 (fd, relmem, relsz,
-			 SWAP (phdr[cnt].p_offset)
-			 + SWAP (dyn[jmprel_idx].d_un.d_val) - vaddr)
-		!= relsz)
-	      {
-		puts ("cannot read JMPREL");
-		return 1;
-	      }
-	  }
-
-	if (vaddr <= SWAP (dyn[symtab_idx].d_un.d_val)
-	    && vaddr + memsz > SWAP (dyn[symtab_idx].d_un.d_val))
-	  symtab_offset = (SWAP (phdr[cnt].p_offset)
-			   + SWAP (dyn[symtab_idx].d_un.d_val) - vaddr);
-
-	if (vaddr <= SWAP (dyn[strtab_idx].d_un.d_val)
-	    && vaddr + memsz >= (SWAP (dyn[strtab_idx].d_un.d_val)
-				 + SWAP(dyn[strsz_idx].d_un.d_val)))
-	  {
-	    strtab = alloca (SWAP(dyn[strsz_idx].d_un.d_val));
-	    if (pread64 (fd, strtab, SWAP(dyn[strsz_idx].d_un.d_val),
-			 SWAP (phdr[cnt].p_offset)
-			 + SWAP (dyn[strtab_idx].d_un.d_val) - vaddr)
-		!= SWAP(dyn[strsz_idx].d_un.d_val))
-	      {
-		puts ("cannot read STRTAB");
-		return 1;
-	      }
-	  }
-      }
-
-  if (relmem == NULL || strtab == NULL || symtab_offset == 0)
-    {
-      puts ("couldn't load PLT data");
-      return 1;
-    }
-
-  if (SWAP (dyn[pltrel_idx].d_un.d_val) == DT_RELA)
-    for (E(Rela) *rela = relmem; (char *) rela - (char *) relmem < relsz;
-	 ++rela)
-      {
-	E(Sym) sym;
-
-	if (pread64 (fd, &sym, sizeof (sym),
-		     symtab_offset
-		     + EE(R_SYM) (SWAP (rela->r_info)) * sizeof (sym))
-	    != sizeof (sym))
-	  {
-	    puts ("cannot read symbol");
-	    return 1;
-	  }
-
-	if (sym.st_value != 0)
-	  /* This symbol is locally defined.  */
-	  printf ("%s: %s\n", basename (fname), strtab + SWAP (sym.st_name));
-      }
-  else
-    for (E(Rel) *rel = relmem; (char *) rel - (char *) relmem < relsz; ++rel)
-      {
-	E(Sym) sym;
-
-	if (pread64 (fd, &sym, sizeof (sym),
-		     symtab_offset
-		     + EE(R_SYM) (SWAP (rel->r_info)) * sizeof (sym))
-	    != sizeof (sym))
-	  {
-	    puts ("cannot read symbol");
-	    return 1;
-	  }
-
-	if (sym.st_value != 0)
-	  /* This symbol is locally defined.  */
-	  printf ("%s: %s\n", basename (fname), strtab + SWAP (sym.st_name));
-      }
-
-  return 0;
-}
-
-# undef BITS
-#else
-
-# define BITS 32
-# include "check-localplt.c"
-
-# define BITS 64
-# include "check-localplt.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/localplt.awk b/scripts/localplt.awk
new file mode 100644
index 0000000..2265b02
--- /dev/null
+++ b/scripts/localplt.awk
@@ -0,0 +1,59 @@
+# This awk script expects to get command-line files that are each
+# the output of 'readelf -WSdr' on a single shared object, and named
+# .../NAME.jmprel where NAME is the unadorned file name of the shared object.
+# It writes "NAME: SYMBOL" for each PLT entry in NAME that refers to a
+# symbol defined in the same object.
+
+BEGIN { result = 0 }
+
+FILENAME != lastfile {
+  if (lastfile && jmprel_offset == 0) {
+    print FILENAME ": *** failed to find expected output (readelf -WSdr)";
+    result = 2;
+  }
+  lastfile = FILENAME;
+  jmprel_offset = 0;
+  delete section_offset_by_address;
+}
+
+/^Section Headers:/ { in_shdrs = 1; next }
+in_shdrs && !/^ +\[/ { in_shdrs = 0 }
+
+in_shdrs && /^ +\[/ { sub(/\[ +/, "[") }
+in_shdrs {
+  address = strtonum("0x" $4);
+  offset = strtonum("0x" $5);
+  section_offset_by_address[address] = offset;
+}
+
+in_shdrs { next }
+
+$1 == "Offset" && $2 == "Info" { in_relocs = 1; next }
+NF == 0 { in_relocs = 0 }
+
+in_relocs && relocs_offset == jmprel_offset && NF >= 5 {
+  symval = strtonum("0x" $4);
+  if (symval != 0)
+    print whatfile, $5
+}
+
+in_relocs { next }
+
+$1 == "Relocation" && $2 == "section" && $5 == "offset" {
+  relocs_offset = strtonum($6);
+  whatfile = gensub(/^.*\/([^/]+)\.jmprel$/, "\\1:", 1, FILENAME);
+  next
+}
+
+$2 == "(JMPREL)" {
+  jmprel_addr = strtonum($3);
+  if (jmprel_addr in section_offset_by_address) {
+    jmprel_offset = section_offset_by_address[jmprel_addr];
+  } else {
+    print FILENAME ": *** DT_JMPREL does not match any section's address";
+    result = 2;
+  }
+  next
+}
+
+END { exit(result) }
-- 
1.7.7.3