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preloader: Properly use the ELF hash table when looking up a symbol.

This commit is contained in:
Alexandre Julliard 2006-07-31 15:48:32 +02:00
parent d4da27aec3
commit 8aab67d238
1 changed files with 30 additions and 7 deletions
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37
loader/preloader.c
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@ -745,6 +745,19 @@ static void map_so_lib( const char *name, struct wld_link_map *l)
}
static unsigned int elf_hash( const char *name )
{
unsigned int hi, hash = 0;
while (*name)
{
hash = (hash << 4) + (unsigned char)*name++;
hi = hash & 0xf0000000;
hash ^= hi;
hash ^= hi >> 24;
}
return hash;
}
/*
* Find a symbol in the symbol table of the executable loaded
*/
@ -753,8 +766,8 @@ static void *find_symbol( const ElfW(Phdr) *phdr, int num, const char *var )
const ElfW(Dyn) *dyn = NULL;
const ElfW(Phdr) *ph;
const ElfW(Sym) *symtab = NULL;
const Elf_Symndx *hashtab = NULL;
const char *strings = NULL;
uint32_t i, symtabend = 0;
/* check the values */
#ifdef DUMP_SYMS
@ -785,7 +798,7 @@ static void *find_symbol( const ElfW(Phdr) *phdr, int num, const char *var )
if( dyn->d_tag == DT_SYMTAB )
symtab = (const ElfW(Sym) *)dyn->d_un.d_ptr;
if( dyn->d_tag == DT_HASH )
symtabend = *((const uint32_t *)dyn->d_un.d_ptr + 1);
hashtab = (const Elf_Symndx *)dyn->d_un.d_ptr;
#ifdef DUMP_SYMS
wld_printf("%x %x\n", dyn->d_tag, dyn->d_un.d_ptr );
#endif
@ -794,15 +807,25 @@ static void *find_symbol( const ElfW(Phdr) *phdr, int num, const char *var )
if( (!symtab) || (!strings) ) return NULL;
for (i = 0; i < symtabend; i++)
if (hashtab)
{
if( ( ELF32_ST_BIND(symtab[i].st_info) == STT_OBJECT ) &&
( 0 == wld_strcmp( strings+symtab[i].st_name, var ) ) )
Elf_Symndx nbuckets = hashtab[0];
unsigned int hash = elf_hash(var) % nbuckets;
const Elf_Symndx *buckets = hashtab + 2;
const Elf_Symndx *chains = buckets + nbuckets;
Elf_Symndx idx = buckets[hash];
while (idx != STN_UNDEF)
{
if( ( ELF32_ST_BIND(symtab[idx].st_info) == STT_OBJECT ) &&
!wld_strcmp( strings + symtab[idx].st_name, var ))
{
#ifdef DUMP_SYMS
wld_printf("Found %s -> %x\n", strings+symtab[i].st_name, symtab[i].st_value );
wld_printf("Found %s -> %x\n", strings + symtab[idx].st_name, symtab[idx].st_value );
#endif
return (void*)symtab[i].st_value;
return (void*)symtab[idx].st_value;
}
idx = chains[idx];
}
}
return NULL;