/* Elf file, section, and symbol manipulation routines. Copyright 1996, 1997 Linux International. Contributed by Richard Henderson This file is part of the Linux modutils. 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; either version 2 of the License, or (at your option) any later version. 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. */ #ident "$Id: obj_common.c,v 1.1.1.1 1998/01/06 20:51:08 ewt Exp $" #include #include #include #include #include /*======================================================================*/ /* Standard ELF hash function. */ inline unsigned long obj_elf_hash_n(const char *name, unsigned long n) { unsigned long h = 0; unsigned long g; unsigned char ch; while (n > 0) { ch = *name++; h = (h << 4) + ch; if ((g = (h & 0xf0000000)) != 0) { h ^= g >> 24; h &= ~g; } n--; } return h; } unsigned long obj_elf_hash (const char *name) { return obj_elf_hash_n(name, strlen(name)); } void obj_set_symbol_compare (struct obj_file *f, int (*cmp)(const char *, const char *), unsigned long (*hash)(const char *)) { if (cmp) f->symbol_cmp = cmp; if (hash) { struct obj_symbol *tmptab[HASH_BUCKETS], *sym, *next; int i; f->symbol_hash = hash; memcpy(tmptab, f->symtab, sizeof(tmptab)); memset(f->symtab, 0, sizeof(f->symtab)); for (i = 0; i < HASH_BUCKETS; ++i) for (sym = tmptab[i]; sym ; sym = next) { unsigned long h = hash(sym->name) % HASH_BUCKETS; next = sym->next; sym->next = f->symtab[h]; f->symtab[h] = sym; } } } struct obj_symbol * obj_add_symbol (struct obj_file *f, const char *name, int info, int secidx, ElfW(Addr) value, unsigned long size) { struct obj_symbol *sym; unsigned long hash = f->symbol_hash(name) % HASH_BUCKETS; for (sym = f->symtab[hash]; sym; sym = sym->next) if (f->symbol_cmp(sym->name, name) == 0) { int o_secidx = sym->secidx; int o_info = sym->info; int o_type = ELFW(ST_TYPE)(o_info); int o_binding = ELFW(ST_BIND)(o_info); int n_type = ELFW(ST_TYPE)(info); int n_binding = ELFW(ST_BIND)(info); /* A redefinition! Is it legal? */ if (secidx == SHN_UNDEF) return sym; else if (o_secidx == SHN_UNDEF) goto found; else if (n_binding == STB_LOCAL) goto found; else if (o_binding == STB_LOCAL) return sym; else if (n_binding == STB_WEAK) return sym; else if (o_binding == STB_WEAK) goto found; /* Don't unify COMMON symbols with object types the programmer doesn't expect. */ else if (secidx == SHN_COMMON && (o_type == STT_NOTYPE || o_type == STT_OBJECT)) return sym; else if (o_secidx == SHN_COMMON && (n_type == STT_NOTYPE || n_type == STT_OBJECT)) goto found; else { /* Don't report an error if the symbol is coming from the kernel or some external module. */ if (secidx <= SHN_HIRESERVE) error("%s multiply defined", name); return sym; } } /* Completely new symbol. */ sym = arch_new_symbol(); sym->next = f->symtab[hash]; f->symtab[hash] = sym; sym->ksymidx = -1; found: sym->name = name; sym->value = value; sym->size = size; sym->secidx = secidx; sym->info = info; return sym; } struct obj_symbol * obj_find_symbol (struct obj_file *f, const char *name) { struct obj_symbol *sym; unsigned long hash = f->symbol_hash(name) % HASH_BUCKETS; for (sym = f->symtab[hash]; sym; sym = sym->next) if (f->symbol_cmp(sym->name, name) == 0) return sym; return NULL; } ElfW(Addr) obj_symbol_final_value (struct obj_file *f, struct obj_symbol *sym) { if (sym) { if (sym->secidx >= SHN_LORESERVE) return sym->value; return sym->value + f->sections[sym->secidx]->header.sh_addr; } else { /* As a special case, a NULL sym has value zero. */ return 0; } } struct obj_section * obj_find_section (struct obj_file *f, const char *name) { int i, n = f->header.e_shnum; for (i = 0; i < n; ++i) if (strcmp(f->sections[i]->name, name) == 0) return f->sections[i]; return NULL; } static int obj_load_order_cmp(struct obj_section *a, struct obj_section *b) { unsigned long af, bf, ac, bc; af = a->header.sh_flags; bf = b->header.sh_flags; ac = 0; if (af & SHF_ALLOC) ac |= 16; if (!(af & SHF_WRITE)) ac |= 8; if (af & SHF_EXECINSTR) ac |= 4; if (a->header.sh_type != SHT_NOBITS) ac |= 2; bc = 0; if (bf & SHF_ALLOC) bc |= 16; if (!(bf & SHF_WRITE)) bc |= 8; if (bf & SHF_EXECINSTR) bc |= 4; if (b->header.sh_type != SHT_NOBITS) bc |= 2; return bc - ac; } void obj_insert_section_load_order (struct obj_file *f, struct obj_section *sec) { struct obj_section **p; for (p = f->load_order_search_start; *p ; p = &(*p)->load_next) if (obj_load_order_cmp(sec, *p) < 0) break; sec->load_next = *p; *p = sec; } struct obj_section * obj_create_alloced_section (struct obj_file *f, const char *name, unsigned long align, unsigned long size) { int newidx = f->header.e_shnum++; struct obj_section *sec; f->sections = xrealloc(f->sections, (newidx+1) * sizeof(sec)); f->sections[newidx] = sec = arch_new_section(); memset(sec, 0, sizeof(*sec)); sec->header.sh_type = SHT_PROGBITS; sec->header.sh_flags = SHF_WRITE|SHF_ALLOC; sec->header.sh_size = size; sec->header.sh_addralign = align; sec->name = name; sec->idx = newidx; if (size) sec->contents = xmalloc(size); obj_insert_section_load_order(f, sec); return sec; } struct obj_section * obj_create_alloced_section_first (struct obj_file *f, const char *name, unsigned long align, unsigned long size) { int newidx = f->header.e_shnum++; struct obj_section *sec; f->sections = xrealloc(f->sections, (newidx+1) * sizeof(sec)); f->sections[newidx] = sec = arch_new_section(); memset(sec, 0, sizeof(*sec)); sec->header.sh_type = SHT_PROGBITS; sec->header.sh_flags = SHF_WRITE|SHF_ALLOC; sec->header.sh_size = size; sec->header.sh_addralign = align; sec->name = name; sec->idx = newidx; if (size) sec->contents = xmalloc(size); sec->load_next = f->load_order; f->load_order = sec; if (f->load_order_search_start == &f->load_order) f->load_order_search_start = &sec->load_next; return sec; } void * obj_extend_section (struct obj_section *sec, unsigned long more) { unsigned long oldsize = sec->header.sh_size; sec->contents = xrealloc(sec->contents, sec->header.sh_size += more); return sec->contents + oldsize; }