auto import from //depot/cupcake/@135843

1 files changed, 224 insertions, 0 deletions

diff --git a/libelf/nlist.c b/libelf/nlist.c
new file mode 100644
index 00000000..cc42a31e
--- /dev/null
+++ b/libelf/nlist.c
@@ -0,0 +1,224 @@
+/* Extract symbol list from binary.
+   Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
+   Written by Ulrich Drepper <drepper@redhat.com>, 1998.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, version 2.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <fcntl.h>
+#include <gelf.h>
+#include <libelf.h>
+#include <nlist.h>
+#include <unistd.h>
+
+#include "libelfP.h"
+
+
+struct hashentry
+{
+  const char *str;
+  GElf_Sym sym;
+};
+#define TYPE struct hashentry
+/* XXX Use a better hash function some day.  */
+#define HASHFCT(str, len) INTUSE(elf_hash) (str)
+#define COMPARE(p1, p2) strcmp ((p1)->str, (p2)->str)
+#define CLASS static
+#define PREFIX nlist_
+#define xcalloc(n, m) calloc (n, m)
+#define next_prime(s) __libelf_next_prime (s)
+#include <fixedsizehash.h>
+
+
+int
+nlist (const char *filename, struct nlist *nl)
+{
+  int fd;
+  Elf *elf;
+  Elf_Scn *scn = NULL;
+  Elf_Scn *symscn = NULL;
+  GElf_Shdr shdr_mem;
+  GElf_Shdr *shdr = NULL;
+  Elf_Data *data;
+  struct nlist_fshash *table;
+  size_t nsyms;
+  size_t cnt;
+
+  /* Open the file.  */
+  fd = open (filename, O_RDONLY);
+  if (fd == -1)
+    {
+      __libelf_seterrno (ELF_E_NOFILE);
+      goto fail;
+    }
+
+  /* For compatibility reasons (`nlist' existed before ELF and libelf)
+     we don't expect the caller to set the ELF version.  Do this here
+     if it hasn't happened yet.  */
+  if (__libelf_version_initialized == 0)
+    INTUSE(elf_version) (EV_CURRENT);
+
+  /* Now get an ELF descriptor.  */
+  elf = INTUSE(elf_begin) (fd, ELF_C_READ_MMAP, NULL);
+  if (elf == NULL)
+    goto fail;
+
+  /* Find a symbol table.  We prefer the real symbol table but if it
+     does not exist use the dynamic symbol table.  */
+  while ((scn = INTUSE(elf_nextscn) (elf, scn)) != NULL)
+    {
+      shdr = INTUSE(gelf_getshdr) (scn, &shdr_mem);
+      if (shdr == NULL)
+	goto fail_close;
+
+      /* That is what we are looking for.  */
+      if (shdr->sh_type == SHT_SYMTAB)
+	{
+	  symscn = scn;
+	  break;
+	}
+
+      /* Better than nothing.  Remember this section.  */
+      if (shdr->sh_type == SHT_DYNSYM)
+	symscn = scn;
+    }
+
+  if (symscn == NULL)
+    /* We haven't found anything.  Fail.  */
+    goto fail_close;
+
+  /* Re-get the section header in case we found only the dynamic symbol
+     table.  */
+  if (scn == NULL)
+    shdr = INTUSE(gelf_getshdr) (symscn, &shdr_mem);
+  /* SHDR->SH_LINK now contains the index of the string section.  */
+
+  /* Get the data for the symbol section.  */
+  data = INTUSE(elf_getdata) (symscn, NULL);
+  if (data == NULL)
+    goto fail_close;
+
+  /* How many symbols are there?  */
+  nsyms = (shdr->sh_size
+	   / INTUSE(gelf_fsize) (elf, ELF_T_SYM, 1, data->d_version));
+
+  /* Create the hash table.  */
+  table = nlist_fshash_init (nsyms);
+  if (table == NULL)
+    {
+      __libelf_seterrno (ELF_E_NOMEM);
+      goto fail_close;
+    }
+
+  /* Iterate over all the symbols in the section.  */
+  for (cnt = 0; cnt < nsyms; ++cnt)
+    {
+      struct hashentry mem;
+      GElf_Sym *sym;
+
+      /* Get the symbol.  */
+      sym = INTUSE(gelf_getsym) (data, cnt, &mem.sym);
+      if (sym == NULL)
+	goto fail_dealloc;
+
+      /* Get the name of the symbol.  */
+      mem.str = INTUSE(elf_strptr) (elf, shdr->sh_link, sym->st_name);
+      if (mem.str == NULL)
+	goto fail_dealloc;
+
+      /* Don't allow zero-length strings.  */
+      if (mem.str[0] == '\0')
+	continue;
+
+      /* And add it to the hash table.  Note that we are using the
+         overwrite version.  This will ensure that
+	 a) global symbols are preferred over local symbols since
+	    they are all located at the end
+	 b) if there are multiple local symbols with the same name
+	    the last one is used.
+      */
+      (void) nlist_fshash_overwrite (table, mem.str, 0, &mem);
+    }
+
+  /* Now it is time to look for the symbols the user asked for.
+     XXX What is a `null name/null string'?  This is what the
+     standard says terminates the list.  Is it a null pointer
+     or a zero-length string?  We test for both...  */
+  while (nl->n_name != NULL && nl->n_name[0] != '\0')
+    {
+      struct hashentry search;
+      const struct hashentry *found;
+
+      /* Search for a matching entry in the hash table.  */
+      search.str = nl->n_name;
+      found = nlist_fshash_find (table, nl->n_name, 0, &search);
+
+      if (found != NULL)
+	{
+	  /* Found it.  */
+	  nl->n_value = found->sym.st_value;
+	  nl->n_scnum = found->sym.st_shndx;
+	  nl->n_type = GELF_ST_TYPE (found->sym.st_info);
+	  /* XXX What shall we fill in the next fields?  */
+	  nl->n_sclass = 0;
+	  nl->n_numaux = 0;
+	}
+      else
+	{
+	  /* Not there.  */
+	  nl->n_value = 0;
+	  nl->n_scnum = 0;
+	  nl->n_type = 0;
+	  nl->n_sclass = 0;
+	  nl->n_numaux = 0;
+	}
+
+      /* Next search request.  */
+      ++nl;
+    }
+
+  /* Free the resources.  */
+  nlist_fshash_fini (table);
+
+  /* We do not need the ELF descriptor anymore.  */
+  (void) elf_end (elf);
+
+  return 0;
+
+ fail_dealloc:
+  nlist_fshash_fini (table);
+
+ fail_close:
+  /* We do not need the ELF descriptor anymore.  */
+  (void) elf_end (elf);
+
+ fail:
+  /* We have to set all entries to zero.  */
+  while (nl->n_name != NULL && nl->n_name[0] != '\0')
+    {
+      nl->n_value = 0;
+      nl->n_scnum = 0;
+      nl->n_type = 0;
+      nl->n_sclass = 0;
+      nl->n_numaux = 0;
+
+      /* Next entry.  */
+      ++nl;
+    }
+
+  return -1;
+}