2.5-18.1

1 files changed, 299 insertions, 0 deletions

diff --git a/elf/check-localplt.c b/elf/check-localplt.c
new file mode 100644
index 0000000..b4358a8
--- /dev/null
+++ b/elf/check-localplt.c
@@ -0,0 +1,299 @@
+/* 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#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