1 #include <common.h>
2 #include <debug.h>
3 #include <libelf.h>
4 #include <hash.h>
5 #include <string.h>
6
setup_hash(Elf_Data * hash_data,Elf32_Word nbuckets,Elf32_Word nchains)7 void setup_hash(Elf_Data *hash_data,
8 Elf32_Word nbuckets,
9 Elf32_Word nchains)
10 {
11 hash_data->d_size = 2;
12 hash_data->d_size += nbuckets;
13 hash_data->d_size += nchains;
14 hash_data->d_buf = CALLOC(hash_data->d_size, sizeof(Elf32_Word));
15 hash_data->d_size *= sizeof(Elf32_Word);
16 ((Elf32_Word *)hash_data->d_buf)[0] = nbuckets;
17 ((Elf32_Word *)hash_data->d_buf)[1] = nchains;
18 }
19
add_to_hash(Elf_Data * hash_data,const char * symbol,int symindex)20 void add_to_hash(Elf_Data *hash_data,
21 const char *symbol,
22 int symindex)
23 {
24 Elf32_Word *buckets = (Elf32_Word *)hash_data->d_buf;
25 Elf32_Word nbuckets = *buckets++;
26 Elf32_Word *chains = ++buckets + nbuckets;
27 Elf32_Word last_chain_index;
28 unsigned long bucket = elf_hash(symbol) % nbuckets;
29
30 ASSERT(symindex != STN_UNDEF);
31
32 if (buckets[bucket] == STN_UNDEF) {
33 INFO("Adding [%s] to hash at bucket [%ld] (first add)\n",
34 symbol, bucket);
35 buckets[bucket] = symindex;
36 }
37 else {
38 INFO("Collision on adding [%s] to hash at bucket [%ld]\n",
39 symbol, bucket);
40 last_chain_index = buckets[bucket];
41 while (chains[last_chain_index] != STN_UNDEF) {
42 INFO("\ttrying at chain index [%d]...\n", last_chain_index);
43 last_chain_index = chains[last_chain_index];
44 }
45 INFO("\tsuccess at chain index [%d]...\n", last_chain_index);
46 chains[last_chain_index] = symindex;
47 }
48 }
49
hash_lookup(Elf * elf,section_info_t * hash_info,section_info_t * symtab_info,const char * symname,GElf_Sym * sym_mem)50 int hash_lookup(Elf *elf,
51 section_info_t *hash_info,
52 section_info_t *symtab_info,
53 const char *symname,
54 GElf_Sym *sym_mem)
55 {
56 Elf32_Word *hash_data = (Elf32_Word *)hash_info->data->d_buf;
57 Elf32_Word index;
58 Elf32_Word nbuckets = *hash_data++;
59 Elf32_Word *buckets = ++hash_data;
60 Elf32_Word *chains = hash_data + nbuckets;
61
62 GElf_Sym *sym;
63
64 index = buckets[elf_hash(symname) % nbuckets];
65 while(index != STN_UNDEF)
66 {
67 sym = gelf_getsymshndx (symtab_info->data, NULL, index, sym_mem, NULL);
68 FAILIF_LIBELF(NULL == sym, gelf_getsymshndx);
69 if (!strcmp(symname,
70 elf_strptr(elf, symtab_info->hdr->sh_link, sym->st_name)))
71 break;
72 index = chains[index];
73 }
74
75 return index;
76 }
77