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basic nm for mac os

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This commit is contained in:
Dmytro Voroshylov 2019-06-15 17:22:50 +03:00
parent ec4151422d
commit 33627101f9
2 changed files with 78 additions and 50 deletions
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1
meson.build
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@ -11,7 +11,6 @@ add_global_arguments(
'-Wall', '-Wall',
'-Wextra', '-Wextra',
'-Werror', '-Werror',
'-Wcast-align',
'-Wwrite-strings', '-Wwrite-strings',
'-Wunreachable-code', '-Wunreachable-code',
'-Winit-self', '-Winit-self',

127
src/main.c
View file

@ -1,8 +1,29 @@
#include "libft.h" #include "libft.h"
#include <fcntl.h> #include <fcntl.h>
#include <sys/stat.h> #include <sys/stat.h>
#include <elf.h>
#include <stdio.h> #include <stdio.h>
#include <mach-o/loader.h>
#include <mach-o/nlist.h>
static void print_addr(void *addr)
{
size_t i;
size_t bit_4;
size_t count;
count = sizeof(addr) * 2;
i = 0;
while (i < count)
{
bit_4 = ((size_t)addr >> ((count - i - 1) * 4)) & 0xf;
if (bit_4 < 10)
ft_putnbr(bit_4);
else
ft_putchar('a' + bit_4 - 10);
i++;
}
}
int main(int argc, char **argv) int main(int argc, char **argv)
{ {
@ -27,61 +48,69 @@ int main(int argc, char **argv)
char *file; char *file;
file = malloc(stat_buff.st_size); file = malloc(stat_buff.st_size);
read(fd, file, stat_buff.st_size); read(fd, file, stat_buff.st_size);
Elf64_Ehdr *elf_header;
elf_header = (Elf64_Ehdr *)file; uint32_t magic = *(uint32_t *)file;
if (elf_header->e_ident[EI_MAG0] != ELFMAG0 ||
elf_header->e_ident[EI_MAG1] != ELFMAG1 || if (magic != MH_MAGIC && magic != MH_MAGIC_64)
elf_header->e_ident[EI_MAG2] != ELFMAG2)
{ {
ft_putstr("not a valid magic number for elf binary file\n"); ft_putstr("not a mach-o file\n");
return (1); return (1);
} }
if (elf_header->e_ident[EI_CLASS] != ELFCLASS64)
{ if (magic == MH_MAGIC)
ft_putstr("sorry, only 64bit elf binaries for now"); ft_putstr("32 bit mach-o file\n");
return (1);
}
Elf64_Shdr *section_table;
Elf64_Shdr *section_names;
Elf64_Shdr *section_entity;
Elf64_Sym *symbol_table;
char *symbol_names;
int symbol_table_size;
int symbol_table_entity_size;
section_table = (Elf64_Shdr *)(file + elf_header->e_shoff); if (magic == MH_MAGIC_64)
section_names = section_table + elf_header->e_shstrndx;
char *string;
int i = 0;
while (i < elf_header->e_shnum)
{ {
section_entity = section_table + i; struct mach_header_64 *hdr = (struct mach_header_64 *)file;
string = file + section_names->sh_offset + section_entity->sh_name; // ft_putstr("64 bit mach-o file\n");
printf("%d entity name: %s type: %d\n", i, string, section_entity->sh_type); // ft_putstr("# of cmds: ");
if (section_entity->sh_type == SHT_SYMTAB) // ft_putnbr(hdr->ncmds);
// ft_putstr("\n");
// ft_putstr("total cmds memory: ");
// ft_putnbr(hdr->sizeofcmds);
// ft_putstr("\n");
struct load_command *load_cmd;
struct symtab_command *symtab_cmd;
uint32_t load_cmd_offset = sizeof(struct mach_header_64);
uint32_t i = 0;
while (i < hdr->ncmds)
{ {
printf("found symbol table! index: %d\n", i); load_cmd = (struct load_command *)(file + load_cmd_offset);
symbol_table = (Elf64_Sym *)(file + section_entity->sh_offset); if (load_cmd->cmd == LC_SYMTAB)
symbol_table_size = section_entity->sh_size; {
symbol_table_entity_size = section_entity->sh_entsize; symtab_cmd = (struct symtab_command *)load_cmd;
// ft_putstr("found symbol table load command\n");
// ft_putstr("# of symbols: ");
// ft_putnbr(symtab_cmd->nsyms);
// ft_putstr("\n");
uint32_t j = 0;
struct nlist_64 *symbol_table = (struct nlist_64 *)
(file + symtab_cmd->symoff);
struct nlist_64 symbol;
char *str_table = file + symtab_cmd->stroff;
while(j < symtab_cmd->nsyms)
{
symbol = symbol_table[j];
if (symbol.n_value)
print_addr((void *)symbol.n_value);
else
ft_putstr(" ");
int type = symbol.n_type & N_TYPE;
if (type == N_UNDF)
ft_putstr(" U ");
if (type == N_ABS)
ft_putstr(" A ");
if (type == N_SECT)
ft_putstr(" T ");
ft_putstr(str_table + symbol.n_un.n_strx);
ft_putstr("\n");
j++;
}
}
load_cmd_offset += load_cmd->cmdsize;
i++;
} }
if (section_entity->sh_type == SHT_STRTAB && i != elf_header->e_shstrndx)
{
printf("found symbol names! index: %d\n", i);
symbol_names = file + section_entity->sh_offset;
}
i++;
} }
int j = 0;
Elf64_Sym *symbol;
while (symbol_table_size > 0)
{
symbol = symbol_table + j;
string = symbol_names + symbol->st_name;
printf("%d: %s\n", j, string);
symbol_table_size -= symbol_table_entity_size;
j++;
}
return(0);
} }