Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 2003-2005 Sun Microsystems, Inc.  All Rights Reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code 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

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 #include <unistd.h>

 #include <sys/procfs.h>

 #include <search.h>

 #include <stdlib.h>

 #include <string.h>

 #include "symtab.h"

 #include "salibelf.h"

 // ----------------------------------------------------

 // functions for symbol lookups

 // ----------------------------------------------------

 struct elf_section {

   ELF_SHDR   *c_shdr;

   void       *c_data;

 };

 struct elf_symbol {

   char *name;

   uintptr_t offset;

   uintptr_t size;

 };

 typedef struct symtab {

   char *strs;

   size_t num_symbols;

   struct elf_symbol *symbols;

   struct hsearch_data *hash_table;

 } symtab_t;

 // read symbol table from given fd.

 struct symtab* build_symtab(int fd) {

   ELF_EHDR ehdr;

   char *names = NULL;

   struct symtab* symtab = NULL;

   // Reading of elf header

   struct elf_section *scn_cache = NULL;

   int cnt = 0;

   ELF_SHDR* shbuf = NULL;

   ELF_SHDR* cursct = NULL;

   ELF_PHDR* phbuf = NULL;

   ELF_PHDR* phdr = NULL;

   uintptr_t baseaddr = (uintptr_t)-1;

   lseek(fd, (off_t)0L, SEEK_SET);

   if (! read_elf_header(fd, &ehdr)) {

     // not an elf

     return NULL;

   }

   // read ELF header

   if ((shbuf = read_section_header_table(fd, &ehdr)) == NULL) {

     goto quit;

   }

   baseaddr = find_base_address(fd, &ehdr);

   scn_cache = (struct elf_section *)

               calloc(ehdr.e_shnum * sizeof(struct elf_section), 1);

   if (scn_cache == NULL) {

     goto quit;

   }

   for (cursct = shbuf, cnt = 0; cnt < ehdr.e_shnum; cnt++) {

     scn_cache[cnt].c_shdr = cursct;

     if (cursct->sh_type == SHT_SYMTAB || cursct->sh_type == SHT_STRTAB) {

       if ( (scn_cache[cnt].c_data = read_section_data(fd, &ehdr, cursct)) == NULL) {

          goto quit;

       }

     }

     cursct++;

   }

   for (cnt = 1; cnt < ehdr.e_shnum; cnt++) {

     ELF_SHDR *shdr = scn_cache[cnt].c_shdr;

     if (shdr->sh_type == SHT_SYMTAB) {

       ELF_SYM  *syms;

       int j, n, rslt;

       size_t size;

       // FIXME: there could be multiple data buffers associated with the

       // same ELF section. Here we can handle only one buffer. See man page

       // for elf_getdata on Solaris.

       // guarantee(symtab == NULL, "multiple symtab");

       symtab = (struct symtab*)calloc(1, sizeof(struct symtab));

       if (symtab == NULL) {

          goto quit;

       }

       // the symbol table

       syms = (ELF_SYM *)scn_cache[cnt].c_data;

       // number of symbols

       n = shdr->sh_size / shdr->sh_entsize;

       // create hash table, we use hcreate_r, hsearch_r and hdestroy_r to

       // manipulate the hash table.

       symtab->hash_table = (struct hsearch_data*) calloc(1, sizeof(struct hsearch_data));

       rslt = hcreate_r(n, symtab->hash_table);

       // guarantee(rslt, "unexpected failure: hcreate_r");

       // shdr->sh_link points to the section that contains the actual strings

       // for symbol names. the st_name field in ELF_SYM is just the

       // string table index. we make a copy of the string table so the

       // strings will not be destroyed by elf_end.

       size = scn_cache[shdr->sh_link].c_shdr->sh_size;

       symtab->strs = (char *)malloc(size);

       memcpy(symtab->strs, scn_cache[shdr->sh_link].c_data, size);

       // allocate memory for storing symbol offset and size;

       symtab->num_symbols = n;

       symtab->symbols = (struct elf_symbol *)calloc(n , sizeof(struct elf_symbol));

       // copy symbols info our symtab and enter them info the hash table

       for (j = 0; j < n; j++, syms++) {

         ENTRY item, *ret;

         char *sym_name = symtab->strs + syms->st_name;

         // skip non-object and non-function symbols

         int st_type = ELF_ST_TYPE(syms->st_info);

         if ( st_type != STT_FUNC && st_type != STT_OBJECT)

            continue;

         // skip empty strings and undefined symbols

         if (*sym_name == '\0' || syms->st_shndx == SHN_UNDEF) continue;

         symtab->symbols[j].name   = sym_name;

         symtab->symbols[j].offset = syms->st_value - baseaddr;

         symtab->symbols[j].size   = syms->st_size;

         item.key = sym_name;

         item.data = (void *)&(symtab->symbols[j]);

         hsearch_r(item, ENTER, &ret, symtab->hash_table);

       }

     }

   }

 quit:

   if (shbuf) free(shbuf);

   if (phbuf) free(phbuf);

   if (scn_cache) {

     for (cnt = 0; cnt < ehdr.e_shnum; cnt++) {

       if (scn_cache[cnt].c_data != NULL) {

         free(scn_cache[cnt].c_data);

       }

     }

     free(scn_cache);

   }

   return symtab;

 }

 void destroy_symtab(struct symtab* symtab) {

   if (!symtab) return;

   if (symtab->strs) free(symtab->strs);

   if (symtab->symbols) free(symtab->symbols);

   if (symtab->hash_table) {

      hdestroy_r(symtab->hash_table);

      free(symtab->hash_table);

   }

   free(symtab);

 }

 uintptr_t search_symbol(struct symtab* symtab, uintptr_t base,

                       const char *sym_name, int *sym_size) {

   ENTRY item;

   ENTRY* ret = NULL;

   // library does not have symbol table

   if (!symtab || !symtab->hash_table)

      return (uintptr_t)NULL;

   item.key = (char*) strdup(sym_name);

   hsearch_r(item, FIND, &ret, symtab->hash_table);

   if (ret) {

     struct elf_symbol * sym = (struct elf_symbol *)(ret->data);

     uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset);

     if (sym_size) *sym_size = sym->size;

     free(item.key);

     return rslt;

   }

 quit:

   free(item.key);

   return (uintptr_t) NULL;

 }

 const char* nearest_symbol(struct symtab* symtab, uintptr_t offset,

                            uintptr_t* poffset) {

   int n = 0;

   if (!symtab) return NULL;

   for (; n < symtab->num_symbols; n++) {

      struct elf_symbol* sym = &(symtab->symbols[n]);

      if (sym->name != NULL &&

          offset >= sym->offset && offset < sym->offset + sym->size) {

         if (poffset) *poffset = (offset - sym->offset);

         return sym->name;

      }

   }

   return NULL;

 }