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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <lcq/elf.h>
u8 TEST_PROG[] = {
0x48, 0xc7, 0xc0, 0x3c, 0x00, 0x00, 0x00, /* mov $0x3c,%rax */
0x48, 0xc7, 0xc7, 0x2a, 0x00, 0x00, 0x00, /* mov $0x2a,%rdi */
0x0f, 0x05 /* syscall */
};
int main(int argc, char **argv) {
elf_ctx e = {0};
elf_header h = {0};
elf_section_header sh = {0};
elf_program_header ph = {0};
i64 i = 0;
if (argc < 3) { fprintf(stderr, "usage: %s MODE ELF-PATH\n", argv[0]); return 1; }
if (strcmp(argv[1], "read") == 0) {
e = elf_load_from_path(argv[2]);
elf_read_header(&h, &e);
printf("%d %d %d %d %d\n", e.ident.file_class, e.ident.endianness, e.ident.version, e.ident.abi, e.ident.abi_version);
printf("type=%u, machine=%u\n", h.type, h.machine);
printf("version=%u, entry=0x%lx\n", h.version, h.entry);
printf("ph=%lu, sh=%lu\n", h.program_header_offset, h.section_header_offset);
printf("flags=%u, eh=%u\n", h.flags, h.elf_header_size);
printf("ph_ent_size=%u, ph_ents=%u\n", h.program_header_entry_size, h.program_header_entries);
printf("sh_ent_size=%u, sh_ents=%u\n", h.section_header_entry_size, h.section_header_entries);
printf("nametable=%u\n", h.section_name_table_index);
for (i = 0; i < h.section_header_entries; ++i) {
char *name = NULL;
elf_read_section_header(&sh, &e, elf_section_header_offset(&h, (u64) i));
name = elf_read_section_name(&e, &h, &sh);
printf("section %ld (%s) type: %u\n", i, name, sh.type);
}
for (i = 0; i < h.section_header_entries; ++i) {
elf_read_section_header(&sh, &e, elf_section_header_offset(&h, (u64) i));
if (sh.type == ELF_SECTION_TYPE_SYMTAB) {
u64 symoff = 0;
for (symoff = 0; symoff < sh.size; symoff += sh.entry_size) {
elf_symbol s = {0};
elf_read_symbol(&s, &e, sh.offset + symoff);
printf("symbol offset %ld (%s) type: %u\n",
symoff,
elf_read_symbol_name(&e, &h, &sh, &s),
s.type
);
}
}
}
} else {
elf_symbol s = {0};
i64 len = 1024 * 16;
u8 *buf = calloc((size_t) len, sizeof(u8));
FILE *f = NULL;
u64 sh_off = 0,
shstrtab_off = 0,
shstrtab_name_off = 0,
shstrtab_len = 0,
strtab_off = 0,
strtab_name_off = 0,
strtab_len = 0,
symtab_off = 0,
symtab_name_off = 0,
symtab_len = 0,
text_off = 0,
text_name_off = 0,
text_len = 0,
program_header_off = 0,
off = 0,
symbols = 0,
sections = 0;
e = elf_ctx_new(buf, len, ELF_CLASS_64, ELF_ENDIANNESS_LITTLE);
off = ELF64_HEADER_SIZE;
/* make space for program header */
program_header_off = off;
off += ELF64_PROGRAM_HEADER_SIZE;
/* write shstrtab */
shstrtab_off = off;
e.buf[off++] = 0;
shstrtab_name_off = off - shstrtab_off; elf_write_bytes(&e, &off, ELF_STRTAB_BYTES_OFF(".shstrtab"));
strtab_name_off = off - shstrtab_off; elf_write_bytes(&e, &off, ELF_STRTAB_BYTES_OFF(".strtab"));
symtab_name_off = off - shstrtab_off; elf_write_bytes(&e, &off, ELF_STRTAB_BYTES_OFF(".symtab"));
text_name_off = off - shstrtab_off; elf_write_bytes(&e, &off, ELF_STRTAB_BYTES_OFF(".text"));
e.buf[off++] = 0;
shstrtab_len = off - shstrtab_off;
/* write strtab */
strtab_off = off;
e.buf[off++] = 0;
elf_write_bytes(&e, &off, ELF_STRTAB_BYTES_OFF("_start"));
e.buf[off++] = 0;
strtab_len = off - strtab_off;
/* write symtab */
symtab_off = off;
printf("symtab_off: %lu\n", symtab_off);
/* null symbol */
symbols += 1;
s.size = 0;
s.value = 0;
s.name_index = 0;
s.bind = ELF_SYMBOL_BINDING_LOCAL;
s.type = ELF_SYMBOL_TYPE_NOTYPE;
s.visibility = ELF_SYMBOL_VISIBILITY_DEFAULT;
s.section_header_index = 0;
elf_write_symbol(&s, &e, off);
off += ELF64_SYMBOL_SIZE;
/* _start */
symbols += 1;
s.size = 0;
s.value = 0x401000;
s.name_index = 1;
s.bind = ELF_SYMBOL_BINDING_GLOBAL;
s.type = ELF_SYMBOL_TYPE_NOTYPE;
s.visibility = ELF_SYMBOL_VISIBILITY_DEFAULT;
s.section_header_index = 4;
elf_write_symbol(&s, &e, off);
off += ELF64_SYMBOL_SIZE;
symtab_len = off - symtab_off;
/* write text */
/* text_off = off; */
text_off = 0x1000;
text_len = text_off;
elf_write_bytes(&e, &text_len, TEST_PROG, sizeof(TEST_PROG));
/* text_len = off - text_off; */
text_len -= text_off;
/* write section headers */
sh_off = off;
/* null section */
sections += 1;
sh.name_index = 0; sh.type = ELF_SECTION_TYPE_NULL;
sh.flags = 0; sh.addr = 0; sh.offset = 0; sh.size = 0;
sh.link = 0; sh.info = 0; sh.addr_alignment = 0; sh.entry_size = 0;
elf_write_section_header(&sh, &e, off); off += ELF64_SECTION_HEADER_SIZE;
/* .shstrtab */
sections += 1;
sh.name_index = (u32) shstrtab_name_off; sh.type = ELF_SECTION_TYPE_STRTAB;
sh.flags = 0; sh.addr = 0; sh.offset = shstrtab_off; sh.size = shstrtab_len;
sh.link = 0; sh.info = 0; sh.addr_alignment = 0; sh.entry_size = 0;
elf_write_section_header(&sh, &e, off); off += ELF64_SECTION_HEADER_SIZE;
/* .strtab */
sections += 1;
sh.name_index = (u32) strtab_name_off; sh.type = ELF_SECTION_TYPE_STRTAB;
sh.flags = 0; sh.addr = 0; sh.offset = strtab_off; sh.size = strtab_len;
sh.link = 0; sh.info = 0; sh.addr_alignment = 0; sh.entry_size = 0;
elf_write_section_header(&sh, &e, off); off += ELF64_SECTION_HEADER_SIZE;
/* .symtab */
sections += 1;
sh.name_index = (u32) symtab_name_off; sh.type = ELF_SECTION_TYPE_SYMTAB;
sh.flags = 0; sh.addr = 0; sh.offset = symtab_off; sh.size = symtab_len;
sh.link = 2; sh.info = 1; sh.addr_alignment = 0; sh.entry_size = ELF64_SYMBOL_SIZE;
elf_write_section_header(&sh, &e, off); off += ELF64_SECTION_HEADER_SIZE;
/* .text */
sections += 1;
sh.name_index = (u32) text_name_off; sh.type = ELF_SECTION_TYPE_PROGBITS;
sh.flags = ELF_SECTION_FLAG_ALLOC | ELF_SECTION_FLAG_EXECINSTR;
sh.addr = 0x401000; sh.offset = text_off; sh.size = text_len;
sh.link = 0; sh.info = 0; sh.addr_alignment = 0; sh.entry_size = 0;
elf_write_section_header(&sh, &e, off); off += ELF64_SECTION_HEADER_SIZE;
/* write program header */
ph.type = ELF_PROGRAM_HEADER_TYPE_LOAD;
ph.offset = text_off;
ph.virtual_addr = 0x401000;
ph.physical_addr = 0;
ph.file_size = (u32) text_len;
ph.mem_size = (u32) text_len;
ph.flags = ELF_PROGRAM_HEADER_FLAG_R | ELF_PROGRAM_HEADER_FLAG_X;
ph.align = 0;
elf_write_program_header(&ph, &e, program_header_off);
/* write header at the start */
h.type = ELF_TYPE_EXEC;
h.machine = ELF_MACHINE_AMD64;
h.version = 1;
h.entry = 0x401000;
h.program_header_offset = program_header_off;
h.program_header_entry_size = ELF64_PROGRAM_HEADER_SIZE;
h.program_header_entries = 1;
h.section_header_offset = sh_off;
h.section_header_entry_size = ELF64_SECTION_HEADER_SIZE;
h.section_header_entries = (u16) sections;
h.section_name_table_index = 1;
elf_write_header(&h, &e);
f = fopen(argv[2], "w+");
fwrite(buf, sizeof(u8), (size_t) len, f);
fclose(f);
}
return 0;
}
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