cosmopolitan/libc/elf/elf.h

125 lines
4.9 KiB
C

#ifndef COSMOPOLITAN_LIBC_ELF_H_
#define COSMOPOLITAN_LIBC_ELF_H_
#ifndef __STRICT_ANSI__
#include "libc/bits/safemacros.h"
#include "libc/elf/def.h"
#include "libc/elf/struct/ehdr.h"
#include "libc/elf/struct/phdr.h"
#include "libc/elf/struct/shdr.h"
#include "libc/elf/struct/sym.h"
#include "libc/limits.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
/*───────────────────────────────────────────────────────────────────────────│─╗
│ cosmopolitan § executable & linkable format ─╬─│┼
╚────────────────────────────────────────────────────────────────────────────│*/
struct MappedFile;
Elf64_Ehdr *mapelfread(const char *, struct MappedFile *);
char *getelfstringtable(const Elf64_Ehdr *, size_t);
Elf64_Sym *getelfsymboltable(const Elf64_Ehdr *, size_t, Elf64_Xword *);
Elf64_Shdr *getelfsectionbyaddress(const Elf64_Ehdr *, size_t, void *);
forceinline void checkelfaddress(const Elf64_Ehdr *elf, size_t mapsize,
intptr_t addr, size_t addrsize) {
#if !(TRUSTWORTHY + ELF_TRUSTWORTHY + 0) || ELF_UNTRUSTWORTHY + 0
if (addr < (intptr_t)elf || addr + addrsize > (intptr_t)elf + mapsize) {
abort();
}
#endif
}
static inline bool iself64binary(const Elf64_Ehdr *elf, size_t mapsize) {
return mapsize >= sizeof(Elf64_Ehdr) &&
memcmp(elf->e_ident, ELFMAG, 4) == 0 &&
(elf->e_ident[EI_CLASS] == ELFCLASSNONE ||
elf->e_ident[EI_CLASS] == ELFCLASS64);
}
static inline bool iselfsymbolcontent(const Elf64_Sym *sym) {
return sym->st_size > 0 && (ELF64_ST_TYPE(sym->st_info) == STT_FUNC ||
ELF64_ST_TYPE(sym->st_info) == STT_OBJECT);
}
static inline Elf64_Phdr *getelfsegmentheaderaddress(const Elf64_Ehdr *elf,
size_t mapsize,
unsigned i) {
intptr_t addr =
((intptr_t)elf + (intptr_t)elf->e_phoff + (intptr_t)elf->e_phentsize * i);
checkelfaddress(elf, mapsize, addr, elf->e_phentsize);
return (Elf64_Phdr *)addr;
}
static inline Elf64_Shdr *getelfsectionheaderaddress(const Elf64_Ehdr *elf,
size_t mapsize,
Elf64_Half i) {
intptr_t addr =
((intptr_t)elf + (intptr_t)elf->e_shoff + (intptr_t)elf->e_shentsize * i);
checkelfaddress(elf, mapsize, addr, elf->e_shentsize);
return (Elf64_Shdr *)addr;
}
static inline void *getelfsectionaddress(const Elf64_Ehdr *elf, size_t mapsize,
const Elf64_Shdr *shdr) {
intptr_t addr, size;
addr = (intptr_t)elf + (intptr_t)shdr->sh_offset;
size = (intptr_t)shdr->sh_size;
checkelfaddress(elf, mapsize, addr, size);
return (void *)addr;
}
static inline char *getelfsectionnamestringtable(const Elf64_Ehdr *elf,
size_t mapsize) {
if (!elf->e_shoff || !elf->e_shentsize) return NULL;
return getelfsectionaddress(
elf, mapsize, getelfsectionheaderaddress(elf, mapsize, elf->e_shstrndx));
}
static inline void getelfvirtualaddressrange(const Elf64_Ehdr *elf,
size_t elfsize,
intptr_t *out_start,
intptr_t *out_end) {
unsigned i;
Elf64_Phdr *phdr;
intptr_t start, end, pstart, pend;
start = INTPTR_MAX;
end = 0;
for (i = 0; i < elf->e_phnum; ++i) {
phdr = getelfsegmentheaderaddress(elf, elfsize, i);
if (phdr->p_type != PT_LOAD) continue;
pstart = phdr->p_vaddr;
pend = phdr->p_vaddr + phdr->p_memsz;
if (pstart < start) start = pstart;
if (pend > end) end = pend;
}
if (out_start) *out_start = start;
if (out_end) *out_end = end;
}
static inline char *getelfstring(const Elf64_Ehdr *elf, size_t mapsize,
const char *strtab, Elf64_Word rva) {
intptr_t addr = (intptr_t)strtab + rva;
#if !(TRUSTWORTHY + ELF_TRUSTWORTHY + 0)
checkelfaddress(elf, mapsize, addr, 0);
checkelfaddress(elf, mapsize, addr,
strnlen((char *)addr, (intptr_t)elf + mapsize - addr) + 1);
#endif
return (char *)addr;
}
static inline const char *getelfsectionname(const Elf64_Ehdr *elf,
size_t mapsize, Elf64_Shdr *shdr) {
if (!elf || !shdr) return NULL;
return getelfstring(elf, mapsize, getelfsectionnamestringtable(elf, mapsize),
shdr->sh_name);
}
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* !ANSI */
#endif /* COSMOPOLITAN_LIBC_ELF_H_ */