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#include <stdint.h>
#include "drive.h"
#include "elf.h"
#include "task.h"
#include "util.h"
#include "paging.h"
#include "pmap.h"
#define ELF_MAGIC 0x464c457f
enum {
ELF_32 = 1,
ELF_64 = 2
};
enum {
LITTLE_ENDIAN = 1,
BIG_ENDIAN = 2
};
enum {
//...
ARCH_X86 = 0x03
//...
};
struct elf_header {
uint32_t magic;
uint8_t word_size;
uint8_t endianness;
uint8_t elf_version;
uint8_t target_os;//ignored
uint8_t os_abi_version;//should be zero
uint8_t reserved[7];
uint16_t object_type;//TODO
uint16_t architecture;//should be ARCH_X86
uint32_t elf_version_2;
uint32_t entry_vma;
uint32_t phtable_fa;
uint32_t shtable_fa;
uint32_t flags;
uint16_t eh_size;
uint16_t phentry_size;
uint16_t phtable_count;
uint16_t shentry_size;
uint16_t shtable_count;
uint16_t sh_names_entry;
} __attribute__ ((packed));
enum {
PT_UNUSED = 0,
PT_LOADME = 1,
PT_DYNLINK = 2,
PT_INTERP = 3,
PT_COMMENT = 4,
PT_SHARED = 5,
PT_PHTABLE = 6,
PT_TL_TMPL = 7
};
enum {
PH_WRITABLE = 0x02
};
struct ph_entry {
uint32_t type;
uint32_t fa;
uint32_t vma;//must be page-aligned
uint32_t pma;//ignored
uint32_t fs;
uint32_t vms;
uint32_t flags;
uint32_t align;
} __attribute__ ((packed));
uint32_t try_elf_run(const struct drive *d, const char *path, const char *pass_old_vma, uint32_t io_handle) {
file_id_t h = d->get_file(d, path);
if (!h)
return 0;
struct elf_header ehead;
fmcpy(&ehead, d, h, 0, sizeof(struct elf_header));
if ((ehead.magic != ELF_MAGIC) ||
(ehead.word_size != ELF_32) ||
(ehead.endianness != LITTLE_ENDIAN) ||
ehead.os_abi_version) {
d->free_file(d, h);
return 0;
}
uint32_t phtable_size = ehead.phentry_size * ehead.phtable_count;
uint16_t phtable_pages = (phtable_size - 1) / 4096 + 1;
void *phtable = allocate_kernel_pages(phtable_pages);
fmcpy(phtable, d, h, ehead.phtable_fa, phtable_size);
void *pd = new_task_pd();
for (uint32_t phi = 0; phi < ehead.phtable_count; ++phi) {
struct ph_entry *entry = phtable + phi * ehead.phentry_size;
if (entry->type != PT_LOADME)
continue;
void *pma = pd_user_allocate(pd, entry->vma, (entry->vms - 1) / 4096 + 1, entry->flags & PH_WRITABLE);
fmcpy(pma, d, h, entry->fa, entry->fs);
for (uint8_t *pma_i = pma + entry->fs; pma_i < (uint8_t *)pma + entry->vms; ++pma_i)
*pma_i = 0;
}
free_pages(phtable, phtable_pages);
d->free_file(d, h);
const char *pass = vma_to_pma(active_task->page_directory, pass_old_vma);
uint32_t pass_l = 0;
while (pass[pass_l++])
;
void *pass_vma;
void *pass_pma;
user_allocate_anywhere_readonly_together(pd, ((pass_l - 1) >> 12) + 1, &pass_vma, &pass_pma);
//TODO: handle error condition
memcpy(pass_pma, pass, pass_l);
struct task_state tstate;
tstate.page_directory = pd;
tstate.ret_addr = ehead.entry_vma;
tstate.stack_bottom = 0;
tstate.edx = (uint32_t)pass_vma;
tstate.esi = active_task - tasks + 1;
tstate.edi = io_handle;
tstate.esp = 0;
const char *path_end_start = path;
for (const char *i = path; *i; ++i)
if (*i == '/')
path_end_start = i + 1;
uint8_t i;
for (i = 0; i < TASK_NAME_LEN; ++i) {
if (!path_end_start[i])
break;
tstate.name[i] = path_end_start[i];
}
tstate.name[i] = '\0';
return new_task(tstate);
}
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