minix/lib/libexec/exec_elf.c

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2010-12-10 10:27:56 +01:00
#define _SYSTEM 1
#include <minix/type.h>
#include <minix/const.h>
#include <sys/param.h>
#include <assert.h>
#include <unistd.h>
#include <errno.h>
#include <libexec.h>
/* For verbose logging */
#define ELF_DEBUG 0
/* Support only 32-bit ELF objects */
#define __ELF_WORD_SIZE 32
static int __elfN(check_header)(const Elf_Ehdr *hdr);
int read_header_elf(
const char *exec_hdr, /* executable header */
vir_bytes *text_addr, /* text virtual address */
vir_bytes *text_filebytes, /* text segment size (in the file) */
vir_bytes *text_membytes, /* text segment size (in memory) */
vir_bytes *data_addr, /* data virtual address */
vir_bytes *data_filebytes, /* data segment size (in the file) */
vir_bytes *data_membytes, /* data segment size (in memory) */
phys_bytes *tot_bytes, /* total size */
vir_bytes *pc, /* program entry point (initial PC) */
off_t *text_offset, /* file offset to text segment */
off_t *data_offset /* file offset to data segment */
)
{
const Elf_Ehdr *hdr = NULL;
const Elf_Phdr *phdr = NULL;
unsigned long seg_filebytes, seg_membytes, seg_addr;
int i = 0;
assert(exec_hdr != NULL);
*text_addr = *text_filebytes = *text_membytes = 0;
*data_addr = *data_filebytes = *data_membytes = 0;
*tot_bytes = *pc = *text_offset = *data_offset = 0;
hdr = (const Elf_Ehdr *)exec_hdr;
if (__elfN(check_header)(hdr) != OK || (hdr->e_type != ET_EXEC))
{
return ENOEXEC;
}
if ((hdr->e_phoff > PAGE_SIZE) ||
(hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
return ENOEXEC;
}
phdr = (const Elf_Phdr *)(exec_hdr + hdr->e_phoff);
if (!_minix_aligned(phdr, Elf_Addr)) {
2010-12-10 10:27:56 +01:00
return ENOEXEC;
}
#if ELF_DEBUG
printf("Program header file offset (phoff): %d\n", hdr->e_phoff);
printf("Section header file offset (shoff): %d\n", hdr->e_shoff);
printf("Program header entry size (phentsize): %d\n", hdr->e_phentsize);
printf("Program header entry num (phnum): %d\n", hdr->e_phnum);
printf("Section header entry size (shentsize): %d\n", hdr->e_shentsize);
printf("Section header entry num (shnum): %d\n", hdr->e_shnum);
printf("Section name strings index (shstrndx): %d\n", hdr->e_shstrndx);
printf("Entry Point: 0x%x\n", hdr->e_entry);
#endif
for (i = 0; i < hdr->e_phnum; i++) {
switch (phdr[i].p_type) {
case PT_LOAD:
if (phdr[i].p_memsz == 0)
break;
seg_addr = phdr[i].p_vaddr;
seg_filebytes = phdr[i].p_filesz;
seg_membytes = round_page(phdr[i].p_memsz + phdr[i].p_vaddr -
trunc_page(phdr[i].p_vaddr));
if (hdr->e_entry >= phdr[i].p_vaddr &&
hdr->e_entry < (phdr[i].p_vaddr + phdr[i].p_memsz)) {
*text_addr = seg_addr;
*text_filebytes = seg_filebytes;
*text_membytes = seg_membytes;
*pc = (vir_bytes)hdr->e_entry;
*text_offset = phdr[i].p_offset;
} else {
*data_addr = seg_addr;
*data_filebytes = seg_filebytes;
*data_membytes = seg_membytes;
*data_offset = phdr[i].p_offset;
}
break;
default:
break;
}
}
*tot_bytes = 0; /* Use default stack size */
#if ELF_DEBUG
printf("Text addr: 0x%x\n", *text_addr);
printf("Text filebytes: 0x%x\n", *text_filebytes);
printf("Text membytes: 0x%x\n", *text_membytes);
printf("Data addr: 0x%x\n", *data_addr);
printf("Data filebyte: 0x%x\n", *data_filebytes);
printf("Data membytes: 0x%x\n", *data_membytes);
printf("Tot bytes: 0x%x\n", *tot_bytes);
printf("PC: 0x%x\n", *pc);
printf("Text offset: 0x%x\n", *text_offset);
printf("Data offset: 0x%x\n", *data_offset);
#endif
return OK;
}
static int __elfN(check_header)(const Elf_Ehdr *hdr)
{
if (!IS_ELF(*hdr) ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_phentsize != sizeof(Elf_Phdr) ||
hdr->e_version != ELF_TARG_VER)
return ENOEXEC;
return OK;
}