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elf32.c File Reference

ELF32 file format loader. More...

#include <const.h>
#include <errno.h>
#include <arch/mem.h>
#include <kernel/console.h>
#include <kernel/fat.h>
#include <kernel/kernel_map.h>
#include <kernel/keyboard.h>
#include <kernel/kmalloc.h>
#include <kernel/elf32.h>

Go to the source code of this file.

Functions
int	elf32_check (elf32_hdr_t *f)
	Check if a file has a valid elf32 header. Parameters: f  The file header. Returns: 0 if success; -ENOEXEC if f is not a valid ELF32 header.
uint32_t	elf32_copy_sections (elf32_hdr_t *f)
	Copy the ELF32 sections at the right locations in memory. Parameters: f  The buffer where the ELF32 file is located. Returns: the entry point address on success; NULL if an error occurs.
int	elf32_load_file (char *file_name, void *file_buffer)
	Load an ELF32 file into a buffer. Parameters: file_name  The name of the file to be loaded. file_buffer  The buffer where the file will be loaded. Returns: 0 on success; -ENOENT if the file doesn't exist; -ENOEXEC if the file is not a valid ELF32 file.
int	elf32_exec (void *f, int argc, char **argv)
	Execute a file.

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Detailed Description

ELF32 file format loader.

Author:

Andrea Righi <drizzt@inwind.it>

Date:

Last update:
2003-01-24 Andrea Righi: Skip NULL sections when copying them to memory.

Note:

Copyright (©) 2003 Andrea Righi

Definition in file elf32.c.

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Function Documentation

int elf32_check (  elf32_hdr_t *    f )

Check if a file has a valid elf32 header. Parameters: f  The file header. Returns: 0 if success; -ENOEXEC if f is not a valid ELF32 header. Definition at line 30 of file elf32.c. { // Check if "f" is a valid ELF32 header // #ifdef ELF32_DEBUG kprintf("\n\rFile header:"); kprintf("\n\rmagic[]=%c%c%c%c class=%u data=%u", f->e_ident[EI_MAG0], f->e_ident[EI_MAG1], f->e_ident[EI_MAG2], f->e_ident[EI_MAG3], f->e_ident[EI_CLASS], f->e_ident[EI_DATA] ); #endif // Magic number check // if ( (f->e_ident[EI_MAG0] != ELF_MAG0) || (f->e_ident[EI_MAG1] != ELF_MAG1) || (f->e_ident[EI_MAG2] != ELF_MAG2) || (f->e_ident[EI_MAG3] != ELF_MAG3) ) return( -ENOEXEC ); // Class check // if ( f->e_ident[EI_CLASS] != ELF_CLASS32 ) return( -ENOEXEC ); // Data encoding check // if ( f->e_ident[EI_DATA] != ELF_DATA2LSB ) return( -ENOEXEC ); // Check OK! // return(0); }

uint32_t elf32_copy_sections (  elf32_hdr_t *    f )

Copy the ELF32 sections at the right locations in memory. Parameters: f  The buffer where the ELF32 file is located. Returns: the entry point address on success; NULL if an error occurs. Definition at line 71 of file elf32.c. { elf32_shdr_t *sec; int sec_num; int sec_entsize; int i; void copy_section(elf32_shdr_t *sec) { #ifdef ELF32_DEBUG kprintf("\n\rsh_name = %#010x", sec->sh_name); kprintf("\n\rsh_type = %#010x", sec->sh_type); kprintf("\n\rsh_flags = %#010x", sec->sh_flags); kprintf("\n\rsh_addr = %#010x", sec->sh_addr); kprintf("\n\rsh_offset = %#010x", sec->sh_offset); kprintf("\n\rsh_size = %#010x", sec->sh_size); kprintf("\n\rsh_link = %#010x", sec->sh_link); kprintf("\n\rsh_info = %#010x", sec->sh_info); kprintf("\n\rsh_addralign = %#010x", sec->sh_addralign); kprintf("\n\rsh_entsize = %#010x", sec->sh_entsize); kprintf("\n\r"); #endif // Skip NULL sections. if( (sec->sh_addr==NULL) || (sec->sh_offset==NULL) ) return; // Copy this section into the current address space. memcpy( (void *)(sec->sh_addr), (void *)((uint32_t)f + sec->sh_offset), sec->sh_size ); } // Check if it is a valid ELF32 file // if ( elf32_check(f)<0 ) return(NULL); // Get the section informations // sec_num = f->e_shnum; sec_entsize = f->e_shentsize; #ifdef ELF32_DEBUG kprintf("\n\rEntry point @ %#010x", f->e_entry); kprintf("\n\rsec_num=%#010x, sec_entsize=%#010x\n\r", sec_num, sec_entsize); #endif // First of all check if the sections are not in the user space // boundaries. // ----- User Sections (4KB - 1GB) // ----- User Heap (1GB - 2GB) // ----- User Stack (2GB - 3GB) sec = (elf32_shdr_t *)((uint32_t)f->e_shoff + (uint32_t)f); for (i=0; i<sec_num; i++) { if ( (sec->sh_addr >= K_VIR_START) || (sec->sh_addr + sec->sh_size) >= K_VIR_START ) return( NULL ); (uint32_t)sec += sec_entsize; } // Copy the sections in memory // sec = (elf32_shdr_t *)((uint32_t)f->e_shoff + (uint32_t)f); for (i=0; i<sec_num; i++) { copy_section( sec ); (uint32_t)sec += sec_entsize; } return( f->e_entry ); }

int elf32_exec (  void *    f, int    argc, char **    argv )

Execute a file. Definition at line 164 of file elf32.c. { int (*entry)(int argc, char **argv) = (int(*)(int argc, char **argv))(((elf32_hdr_t *)f)->e_entry); return( entry(argc, argv) ); }

int elf32_load_file (  char *    file_name, void *    file_buffer )

Load an ELF32 file into a buffer. Parameters: file_name  The name of the file to be loaded. file_buffer  The buffer where the file will be loaded. Returns: 0 on success; -ENOENT if the file doesn't exist; -ENOEXEC if the file is not a valid ELF32 file. Definition at line 147 of file elf32.c. { // Load the file into the buffer // // TODO: replace with: // int fread(void *buf, size_t size, size_t count, FILE *stream); if ( !(load_file(file_name, file_buffer)) ) return( -ENOENT ); // Check if it is a valid ELF file // if ( elf32_check((elf32_hdr_t *)file_buffer) < 0 ) return( -ENOEXEC ); // The ELF32 file is successfully loaded // return(0); }

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