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#include "elf.h"
void elf_init(struct elf_params_t *params)
{
params->has_start_addr = false;
params->start_addr = 0;
params->first_section = NULL;
params->last_section = NULL;
}
extern void *xmalloc(size_t s);
static struct elf_section_t *elf_add_section(struct elf_params_t *params)
{
struct elf_section_t *sec = xmalloc(sizeof(struct elf_section_t));
if(params->first_section == NULL)
params->first_section = params->last_section = sec;
else
{
params->last_section->next = sec;
params->last_section = sec;
}
sec->next = NULL;
return sec;
}
void elf_add_load_section(struct elf_params_t *params,
uint32_t load_addr, uint32_t size, const void *section)
{
struct elf_section_t *sec = elf_add_section(params);
sec->type = EST_LOAD;
sec->addr = load_addr;
sec->size = size;
sec->section = xmalloc(size);
memcpy(sec->section, section, size);
}
void elf_add_fill_section(struct elf_params_t *params,
uint32_t fill_addr, uint32_t size, uint32_t pattern)
{
if(pattern != 0x00)
{
printf("oops, non-zero filling, ignore fill section\n");
return;
}
struct elf_section_t *sec = elf_add_section(params);
sec->type = EST_FILL;
sec->addr = fill_addr;
sec->size = size;
sec->pattern = pattern;
}
void elf_output(struct elf_params_t *params, elf_write_fn_t write, void *user)
{
Elf32_Ehdr ehdr;
uint32_t phnum = 0;
struct elf_section_t *sec = params->first_section;
uint32_t offset = 0;
Elf32_Phdr phdr;
Elf32_Shdr shdr;
memset(&ehdr, 0, EI_NIDENT);
uint32_t bss_strtbl = 0;
uint32_t text_strtbl = bss_strtbl + strlen(".bss") + 1;
uint32_t strtbl_size = text_strtbl + strlen(".text") + 1;
while(sec)
{
if(sec->type == EST_LOAD)
{
sec->offset = offset;
offset += sec->size;
}
phnum++;
sec = sec->next;
}
uint32_t strtbl_offset = offset;
ehdr.e_ident[EI_MAG0] = ELFMAG0;
ehdr.e_ident[EI_MAG1] = ELFMAG1;
ehdr.e_ident[EI_MAG2] = ELFMAG2;
ehdr.e_ident[EI_MAG3] = ELFMAG3;
ehdr.e_ident[EI_CLASS] = ELFCLASS32;
ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
ehdr.e_ident[EI_VERSION] = EV_CURRENT;
ehdr.e_ident[EI_OSABI] = ELFOSABI_NONE;
ehdr.e_ident[EI_ABIVERSION] = 0;
ehdr.e_type = ET_EXEC;
ehdr.e_machine = EM_ARM;
ehdr.e_version = EV_CURRENT;
ehdr.e_entry = params->start_addr;
ehdr.e_flags = 0;
if(params->has_start_addr)
ehdr.e_flags |= EF_ARM_HASENTRY;
ehdr.e_ehsize = sizeof ehdr;
ehdr.e_phentsize = sizeof phdr;
ehdr.e_phnum = phnum;
ehdr.e_shentsize = sizeof shdr;
ehdr.e_shnum = phnum + 1;
ehdr.e_shstrndx = ehdr.e_shnum - 1;
ehdr.e_phoff = ehdr.e_ehsize;
ehdr.e_shoff = ehdr.e_ehsize + ehdr.e_phnum * ehdr.e_phentsize;
write(user, 0, &ehdr, sizeof ehdr);
uint32_t data_offset = ehdr.e_ehsize + ehdr.e_phnum * ehdr.e_phentsize +
ehdr.e_shnum * ehdr.e_shentsize;
sec = params->first_section;
offset = ehdr.e_phoff;
while(sec)
{
sec->offset += data_offset;
phdr.p_type = PT_LOAD;
if(sec->type == EST_LOAD)
phdr.p_offset = sec->offset;
else
phdr.p_offset = 0;
phdr.p_paddr = sec->addr;
phdr.p_vaddr = phdr.p_paddr; /* assume identity map ? */
phdr.p_memsz = sec->size;
if(sec->type == EST_LOAD)
phdr.p_filesz = phdr.p_memsz;
else
phdr.p_filesz = 0;
phdr.p_flags = PF_X | PF_W | PF_R;
phdr.p_align = 0;
write(user, offset, &phdr, sizeof phdr);
offset += sizeof(Elf32_Phdr);
sec = sec->next;
}
sec = params->first_section;
offset = ehdr.e_shoff;
while(sec)
{
shdr.sh_name = text_strtbl;
if(sec->type == EST_LOAD)
shdr.sh_type = SHT_PROGBITS;
else
shdr.sh_type = SHT_NOBITS;
shdr.sh_flags = SHF_ALLOC | SHF_EXECINSTR;
shdr.sh_addr = sec->addr;
shdr.sh_offset = sec->offset;
shdr.sh_size = sec->size;
shdr.sh_link = SHN_UNDEF;
shdr.sh_info = 0;
shdr.sh_addralign = 1;
shdr.sh_entsize = 0;
write(user, offset, &shdr, sizeof shdr);
offset += sizeof(Elf32_Shdr);
sec = sec->next;
}
{
shdr.sh_name = bss_strtbl;
shdr.sh_type = SHT_STRTAB;
shdr.sh_flags = 0;
shdr.sh_addr = 0;
shdr.sh_offset = strtbl_offset + data_offset;
shdr.sh_size = strtbl_size;
shdr.sh_link = SHN_UNDEF;
shdr.sh_info = 0;
shdr.sh_addralign = 1;
shdr.sh_entsize = 0;
write(user, offset, &shdr, sizeof shdr);
offset += sizeof(Elf32_Shdr);
}
sec = params->first_section;
while(sec)
{
if(sec->type == EST_LOAD)
write(user, sec->offset, sec->section, sec->size);
sec = sec->next;
}
write(user, strtbl_offset + data_offset, ".bss\0.text\0", strtbl_size);
}
bool elf_is_empty(struct elf_params_t *params)
{
return params->first_section == NULL;
}
void elf_set_start_addr(struct elf_params_t *params, uint32_t addr)
{
params->has_start_addr = true;
params->start_addr = addr;
}
void elf_release(struct elf_params_t *params)
{
struct elf_section_t *sec, *next_sec;
sec = params->first_section;
while(sec)
{
next_sec = sec->next;
if(sec->type == EST_LOAD)
free(sec->section);
free(sec);
sec = next_sec;
}
params->first_section = NULL;
params->last_section = NULL;
}
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