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// See LICENSE for license details.
#include "file.h"
#include "pk.h"
#include "vm.h"
#include <sys/stat.h>
#include <fcntl.h>
#include <elf.h>
#include <string.h>
void load_elf(const char* fn, elf_info* info)
{
file_t* file = file_open(fn, O_RDONLY, 0);
if (IS_ERR_VALUE(file))
goto fail;
Elf64_Ehdr eh64;
ssize_t ehdr_size = file_pread(file, &eh64, sizeof(eh64), 0);
if (ehdr_size < (ssize_t)sizeof(eh64) ||
!(eh64.e_ident[0] == '\177' && eh64.e_ident[1] == 'E' &&
eh64.e_ident[2] == 'L' && eh64.e_ident[3] == 'F'))
goto fail;
uintptr_t min_vaddr = -1, max_vaddr = 0;
#define LOAD_ELF do { \
eh = (typeof(eh))&eh64; \
size_t phdr_size = eh->e_phnum*sizeof(*ph); \
if (phdr_size > info->phdr_size) \
goto fail; \
ssize_t ret = file_pread(file, (void*)info->phdr, phdr_size, eh->e_phoff); \
if (ret < (ssize_t)phdr_size) \
goto fail; \
info->phnum = eh->e_phnum; \
info->phent = sizeof(*ph); \
ph = (typeof(ph))info->phdr; \
info->is_supervisor = (eh->e_entry >> (8*sizeof(eh->e_entry)-1)) != 0; \
if (info->is_supervisor) \
info->first_free_paddr = ROUNDUP(info->first_free_paddr, SUPERPAGE_SIZE); \
for (int i = 0; i < eh->e_phnum; i++) \
if (ph[i].p_type == PT_LOAD && ph[i].p_memsz && ph[i].p_vaddr < min_vaddr) \
min_vaddr = ph[i].p_vaddr; \
if (info->is_supervisor) \
min_vaddr = ROUNDDOWN(min_vaddr, SUPERPAGE_SIZE); \
else \
min_vaddr = ROUNDDOWN(min_vaddr, RISCV_PGSIZE); \
uintptr_t bias = 0; \
if (info->is_supervisor || eh->e_type == ET_DYN) \
bias = info->first_free_paddr - min_vaddr; \
info->entry = eh->e_entry; \
if (!info->is_supervisor) { \
info->entry += bias; \
min_vaddr += bias; \
} \
info->bias = bias; \
int flags = MAP_FIXED | MAP_PRIVATE; \
if (info->is_supervisor) \
flags |= MAP_POPULATE; \
for (int i = eh->e_phnum - 1; i >= 0; i--) { \
if(ph[i].p_type == PT_LOAD && ph[i].p_memsz) { \
uintptr_t prepad = ph[i].p_vaddr % RISCV_PGSIZE; \
uintptr_t vaddr = ph[i].p_vaddr + bias; \
if (vaddr + ph[i].p_memsz > max_vaddr) \
max_vaddr = vaddr + ph[i].p_memsz; \
if (info->is_supervisor) { \
if (!__valid_user_range(vaddr - prepad, vaddr + ph[i].p_memsz)) \
goto fail; \
ret = file_pread(file, (void*)vaddr, ph[i].p_filesz, ph[i].p_offset); \
if (ret < (ssize_t)ph[i].p_filesz) \
goto fail; \
memset((void*)vaddr - prepad, 0, prepad); \
memset((void*)vaddr + ph[i].p_filesz, 0, ph[i].p_memsz - ph[i].p_filesz); \
} else { \
int flags2 = flags | (prepad ? MAP_POPULATE : 0); \
if (__do_mmap(vaddr - prepad, ph[i].p_filesz + prepad, -1, flags2, file, ph[i].p_offset - prepad) != vaddr - prepad) \
goto fail; \
memset((void*)vaddr - prepad, 0, prepad); \
size_t mapped = ROUNDUP(ph[i].p_filesz + prepad, RISCV_PGSIZE) - prepad; \
if (ph[i].p_memsz > mapped) \
if (__do_mmap(vaddr + mapped, ph[i].p_memsz - mapped, -1, flags|MAP_ANONYMOUS, 0, 0) != vaddr + mapped) \
goto fail; \
} \
} \
} \
} while(0)
info->elf64 = IS_ELF64(eh64);
if (info->elf64)
{
Elf64_Ehdr* eh;
Elf64_Phdr* ph;
LOAD_ELF;
}
else if (IS_ELF32(eh64))
{
Elf32_Ehdr* eh;
Elf32_Phdr* ph;
LOAD_ELF;
}
else
goto fail;
info->first_user_vaddr = min_vaddr;
info->first_vaddr_after_user = ROUNDUP(max_vaddr - info->bias, RISCV_PGSIZE);
info->brk_min = max_vaddr;
file_decref(file);
return;
fail:
panic("couldn't open ELF program: %s!", fn);
}
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