fw_elf¶
这是一个从 bnx2 固件文件创建 ELF 的工具。[^1]
用法：
Usage: ./fw_elf <mips.fw> <com|cp|rxp|tpat|txp> <out.elf>
示例：
[daniel@daniel-pc gsoc]$ ./fw_elf bnx2_bnx2-mips-06-6.2.3.fw txp txp.elf
Done
这会生成带有适当的 .text、.data 和 .rodata 节的 txp.elf 文件。该文件应当可以方便地加载到反汇编器/调试器中。
代码¶
#include <libelf.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <utils.h>
typedef uint32_t __be32;
struct bnx2_fw_file_section {
__be32 addr;
__be32 len;
__be32 offset;
} __attribute__ ((__packed__));
struct bnx2_mips_fw_file_entry {
__be32 start_addr;
struct bnx2_fw_file_section text;
struct bnx2_fw_file_section data;
struct bnx2_fw_file_section rodata;
} __attribute__ ((__packed__));
struct bnx2_mips_fw_file {
struct bnx2_mips_fw_file_entry com;
struct bnx2_mips_fw_file_entry cp;
struct bnx2_mips_fw_file_entry rxp;
struct bnx2_mips_fw_file_entry tpat;
struct bnx2_mips_fw_file_entry txp;
} __attribute__ ((__packed__));
char string_tbl[] = {
'\0',
'.','t','e','x','t','\0',
'.','d','a','t','a','\0',
'.','r','o','d','a','t','a','\0',
};
int main ( int argc, char *argv[] ) {
int fd;
FILE *fp;
Elf *e;
Elf_Scn *scn;
Elf_Data *data;
Elf32_Ehdr *ehdr;
Elf32_Phdr *phdr;
Elf32_Shdr *shdr;
struct bnx2_mips_fw_file fw;
struct bnx2_mips_fw_file_entry *entry;
uint8_t *text_bytes;
uint8_t *data_bytes;
uint8_t *rodata_bytes;
if ( argc != 4 ) {
fprintf ( stderr, "Usage: %s <mips.fw> <com|cp|rxp|tpat|txp> <out.elf>\n", argv[0] );
return 1;
}
fp = fopen ( argv[1], "rb" );
if ( ! fp ) {
fprintf ( stderr, "Failed to open file '%s'\n", argv[1] );
return 1;
}
if ( fread ( &fw, sizeof ( struct bnx2_mips_fw_file ), 1, fp ) != 1 ) {
fprintf ( stderr, "I/O error for file '%s'\n", argv[1] );
return 1;
}
if ( strcmp ( argv[2], "com" ) == 0 )
entry = &fw.com;
else if ( strcmp ( argv[2], "cp" ) == 0 )
entry = &fw.cp;
else if ( strcmp ( argv[2], "rxp" ) == 0 )
entry = &fw.cp;
else if ( strcmp ( argv[2], "tpat" ) == 0 )
entry = &fw.cp;
else if ( strcmp ( argv[2], "txp" ) == 0 )
entry = &fw.cp;
else {
fprintf ( stderr, "Invalid CPU argument (see usage)\n" );
return 1;
}
entry->start_addr = be32_to_cpu ( entry->start_addr );
entry->text.addr = be32_to_cpu ( entry->text.addr );
entry->text.len = be32_to_cpu ( entry->text.len );
entry->text.offset = be32_to_cpu ( entry->text.offset );
entry->data.addr = be32_to_cpu ( entry->data.addr );
entry->data.len = be32_to_cpu ( entry->data.len );
entry->data.offset = be32_to_cpu ( entry->data.offset );
entry->rodata.addr = be32_to_cpu ( entry->rodata.addr );
entry->rodata.len = be32_to_cpu ( entry->rodata.len );
entry->rodata.offset = be32_to_cpu ( entry->rodata.offset );
if ( elf_version ( EV_CURRENT ) == EV_NONE ) {
fprintf ( stderr, "libelf initialization failed\n" );
return 1;
}
fd = open ( argv[3], O_WRONLY | O_CREAT, 0777 );
if ( fd < 0 ) {
fprintf ( stderr, "Failed to open output file '%s'\n", argv[3] );
return 1;
}
if ( ( e = elf_begin ( fd, ELF_C_WRITE, NULL ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg( -1 ) );
return 1;
}
if ( ( ehdr = elf32_newehdr ( e ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
ehdr->e_machine = EM_MIPS;
ehdr->e_type = ET_EXEC;
ehdr->e_version = EV_CURRENT;
ehdr->e_entry = entry->start_addr;
if ( ( phdr = elf32_newphdr ( e, 1 ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
if ( ( scn = elf_newscn ( e ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
if ( ( data = elf_newdata ( scn ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
text_bytes = malloc ( entry->text.len );
if ( ! text_bytes ) {
fprintf ( stderr, "malloc failed\n" );
return 1;
}
if ( fseek ( fp, entry->text.offset, SEEK_SET ) != 0 ) {
fprintf ( stderr, "I/O error for file '%s'\n", argv[1] );
return 1;
}
if ( fread ( text_bytes, 1, entry->text.len, fp ) != entry->text.len ) {
fprintf ( stderr, "I/O error for file '%s'\n", argv[1] );
return 1;
}
data->d_align = 1;
data->d_off = 0LL;
data->d_buf = text_bytes;
data->d_type = ELF_T_BYTE;
data->d_size = entry->text.len;
data->d_version = EV_CURRENT;
if ( ( shdr = elf32_getshdr ( scn ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
shdr->sh_name = 1;
shdr->sh_type = SHT_PROGBITS;
shdr->sh_flags = SHF_ALLOC | SHF_EXECINSTR;
shdr->sh_addr = entry->text.addr;
shdr->sh_entsize = 0;
if ( ( scn = elf_newscn ( e ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
if ( ( data = elf_newdata ( scn ) ) == NULL ) {
return 1;
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
}
data_bytes = malloc ( entry->data.len );
if ( ! data_bytes ) {
fprintf ( stderr, "malloc failed\n" );
return 1;
}
if ( fseek ( fp, entry->data.offset, SEEK_SET ) != 0 ) {
fprintf ( stderr, "I/O error for file '%s'\n", argv[1] );
return 1;
}
if ( fread ( data_bytes, 1, entry->data.len, fp ) != entry->data.len ) {
fprintf ( stderr, "I/O error for file '%s'\n", argv[1] );
return 1;
}
data->d_align = 1;
data->d_off = 0LL;
data->d_buf = data_bytes;
data->d_type = ELF_T_BYTE;
data->d_size = entry->data.len;
data->d_version = EV_CURRENT;
if ( ( shdr = elf32_getshdr ( scn ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
shdr->sh_name = 7;
shdr->sh_type = SHT_PROGBITS;
shdr->sh_flags = SHF_ALLOC | SHF_WRITE;
shdr->sh_addr = entry->data.addr;
shdr->sh_entsize = 0;
if ( ( scn = elf_newscn ( e ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
if ( ( data = elf_newdata ( scn ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
rodata_bytes = malloc ( entry->rodata.len );
if ( ! rodata_bytes ) {
fprintf ( stderr, "malloc failed\n" );
return 1;
}
if ( fseek ( fp, entry->rodata.offset, SEEK_SET ) != 0 ) {
fprintf ( stderr, "I/O error for file '%s'\n", argv[1] );
return 1;
}
if ( fread ( rodata_bytes, 1, entry->rodata.len, fp ) != entry->rodata.len ) {
fprintf ( stderr, "I/O error for file '%s'\n", argv[1] );
return 1;
}
fclose ( fp );
data->d_align = 1;
data->d_off = 0LL;
data->d_buf = rodata_bytes;
data->d_type = ELF_T_BYTE;
data->d_size = entry->rodata.len;
data->d_version = EV_CURRENT;
if ( ( shdr = elf32_getshdr ( scn ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
shdr->sh_name = 13;
shdr->sh_type = SHT_PROGBITS;
shdr->sh_flags = SHF_ALLOC;
shdr->sh_addr = entry->rodata.addr;
shdr->sh_entsize = 0;
if ( ( scn = elf_newscn ( e ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
if ( ( data = elf_newdata ( scn ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
data->d_align = 1;
data->d_buf = string_tbl;
data->d_off = 0LL;
data->d_size = sizeof ( string_tbl );
data->d_type = ELF_T_BYTE;
data->d_version = EV_CURRENT;
if ( ( shdr = elf32_getshdr ( scn ) ) == NULL ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
shdr->sh_name = 0;
shdr->sh_type = SHT_STRTAB;
shdr->sh_flags = SHF_STRINGS | SHF_ALLOC;
shdr->sh_entsize = 0;
ehdr->e_shstrndx = elf_ndxscn ( scn );
if ( elf_update ( e, ELF_C_NULL ) < 0 ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
phdr->p_type = PT_PHDR;
phdr->p_offset = ehdr->e_phoff;
phdr->p_filesz = elf32_fsize ( ELF_T_PHDR, 1, EV_CURRENT );
phdr->p_vaddr = 0x8000000;
elf_flagphdr ( e, ELF_C_SET, ELF_F_DIRTY );
if ( elf_update ( e, ELF_C_WRITE ) < 0 ) {
fprintf ( stderr, "libelf error: %s\n", elf_errmsg ( -1 ) );
return 1;
}
elf_end ( e );
close ( fd );
printf ( "Done\n" );
return 0;
}
[^1]: git firmware repository