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#include <shared/flags.h>
#include <shared/syscalls.h>
#include <user/lib/elf.h>
#include <user/lib/elfload.h>
void elf_execf(libc_file *f) {
const size_t cap = 0x60000;
size_t pos = 0;
void *buf = malloc(cap); // TODO a way to get file size
if (!buf) goto fail;
while (!f->eof) {
long ret = file_read(f, buf, cap - pos);
if (ret < 0) goto fail;
pos += ret;
if (pos >= cap) goto fail;
}
elf_exec(buf);
fail:
free(buf);
}
static bool valid_ehdr(const struct Elf64_Ehdr *h) {
return h->e_ident[0] == 0x7f
&& h->e_ident[1] == 'E'
&& h->e_ident[2] == 'L'
&& h->e_ident[3] == 'F'
&& h->e_type == ET_EXEC
&& h->e_machine == EM_X86_64
&& h->e_version == 1;
}
static bool load_phdr(const void *base, size_t idx) {
const struct Elf64_Ehdr *ehdr = base;
const struct Elf64_Phdr *phdr = base + ehdr->e_phoff + idx * ehdr->e_phentsize;
if (phdr->p_type != PT_LOAD) {
printf("unknown type %x\n", phdr->p_type);
return false;
}
// TODO overlap check
// TODO don't ignore flags
_syscall_memflag((void*)phdr->p_vaddr, phdr->p_memsz, MEMFLAG_PRESENT);
// TODO check that filesz <= memsz
memcpy((void*)phdr->p_vaddr, base + phdr->p_offset, phdr->p_filesz);
return true;
}
void elf_exec(void *base) {
struct Elf64_Ehdr *ehdr = base;
if (!valid_ehdr(ehdr)) return;
for (size_t phi = 0; phi < ehdr->e_phnum; phi++) {
if (!load_phdr(base, phi))
return;
}
((void(*)())ehdr->e_entry)();
_syscall_exit(1);
}
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