ft_elf/nm/nm32.c

#include "ft_nm.h"

int is_32_section_init(t_elf32 *nm, int i) {
    for (Elf32_Xword j = 0; j < nm->shdr[i].sh_size; j++) {
        if (nm->ptr + nm->shdr[i].sh_offset + j != 0) return 1;
    }
    return 0;
}

char *get_32_name(t_elf32 *nm, int sym) {
    if (nm->opts.a && ELF64_ST_TYPE(nm->symtab[sym].st_info) == STT_SECTION)
        return nm->string_table + nm->shdr[nm->symtab[sym].st_shndx].sh_name;
    else return nm->linked_symnames + nm->symtab[sym].st_name;
}

char get_32_type(t_elf32 *nm, int i) {
    Elf32_Ehdr *ehdr      = nm->ehdr;
    Elf32_Sym   sym       = nm->symtab[i];
    uint32_t    bind      = ELF32_ST_BIND(sym.st_info);
    int         is_global = bind == STB_GLOBAL;

    if (sym.st_shndx == SHN_ABS) return is_global ? 'A' : bind == STB_WEAK ? 'W' : 'a';

    if (sym.st_shndx == SHN_UNDEF) return bind == STB_WEAK ? 'w' : 'U';

    char ret = "NDTDFDB         "[ELF32_ST_TYPE(sym.st_info)];
    if (ret == 'N') {
        if (bind == STB_WEAK) return 'W';
        if (is_32_section_init(nm, sym.st_shndx) || sym.st_value) ret = 'D';
    }
    if (ret == 'D') {
        if (ehdr->e_ident[EI_OSABI] == ELFOSABI_FREEBSD && bind == STB_GNU_UNIQUE) ret = 'u';
        else if (bind == STB_WEAK) return 'V';  // should be 'V' or 'W'
        else if (is_sym_bss(nm->string_table + nm->shdr[sym.st_shndx].sh_name)) ret = 'B';
        else if (sym.st_shndx == SHN_COMMON) ret = 'C';
        else {
            Elf32_Shdr shdr = nm->shdr[sym.st_shndx];
            if (shdr.sh_type == SHT_NOBITS && !(shdr.sh_flags & SHF_EXECINSTR)) ret = 'B';
            else if (!(shdr.sh_flags & SHF_WRITE)) {
                if (shdr.sh_flags & SHF_EXECINSTR) ret = 'T';
                else if (is_sec_read_only2(nm->string_table + shdr.sh_name))
                    return 't';
                else if (is_sec_read_only(nm->string_table + shdr.sh_name) && sym.st_value == 0)
                    return 'n';
                else if (is_sym_debug(nm->string_table + shdr.sh_name))
                    return 'N';
                else if (is_sym_text2(nm->string_table + shdr.sh_name))
                    return 'a';
                else ret = 'R';
            }
        }
    } else if (ret == 'T')
        if (bind == STB_WEAK) return 'W';
    return is_global ? ret : tolower(ret);
}

void create_32_order_array(t_elf32 *nm, int symbol_num) {
    for (int i = 0; i < symbol_num; i++) {
        for (int j = i + 1; j < symbol_num; j++) {
            int   left  = nm->ordered_sym_ids[i];
            int   right = nm->ordered_sym_ids[j];
            char *l     = get_32_name(nm, left);
            char *r     = get_32_name(nm, right);

            int cmp = strcmp_ignored(l, r);
            if ((nm->opts.r && (cmp < 0 || (!cmp && left < right))) ||
                (!nm->opts.r && (cmp > 0 || (!cmp && left > right)))) {
                int tmp                = nm->ordered_sym_ids[i];
                nm->ordered_sym_ids[i] = nm->ordered_sym_ids[j];
                nm->ordered_sym_ids[j] = tmp;
            }
        }
    }
}

int print_32_symtab(t_elf32 *nm) {
    int sym_num = nm->symtab_end - nm->symtab;
    for (int i = 0; i < sym_num; i++) {
        int id = nm->opts.p == 0 ? nm->ordered_sym_ids[i] : i;
        if (nm->sym_names[id] == NULL) continue;
        if (nm->opts.a || nm->sym_types[id] == 'w' || nm->sym_types[id] == 'U' ||
            (!nm->opts.u && ELF64_ST_TYPE(nm->symtab[id].st_info) != STT_FILE)) {
            char type = nm->sym_types[id];
            if (strlen(nm->sym_names[id]) == 0 && (!nm->opts.a || type == 'u' || type == 'U'))
                continue;
            if (type == 'U' || type == 'w') ft_printf("%8c", ' ');
            else ft_printf("%08x", nm->symtab[id].st_value);
            ft_printf(" %c", type);
            char *name = get_32_name(nm, id);
            ft_printf(" %s\n", name);
        }
    }
    return (0);
}

int parse_32_symtab(t_elf32 *nm) {
    Elf32_Shdr *shdr = &nm->shdr[nm->ehdr->e_shstrndx];
    nm->string_table = (char *)(nm->ptr + shdr->sh_offset);
    for (int i = 0; i < nm->ehdr->e_shnum; i++) {
        if (nm->shdr[i].sh_type == SHT_SYMTAB ||
            (nm->opts.D && nm->shdr[i].sh_type == SHT_DYNSYM)) {
            nm->symtab     = (Elf32_Sym *)(nm->ptr + nm->shdr[i].sh_offset);
            nm->symtab_end = nm->symtab + (nm->shdr[i].sh_size / sizeof(Elf32_Sym));

            int symbol_num      = nm->shdr[i].sh_size / nm->shdr[i].sh_entsize;
            nm->linked_symnames = (char *)(nm->ptr + nm->shdr[nm->shdr[i].sh_link].sh_offset);
            nm->sym_names       = malloc(sizeof(char *) * symbol_num);
            nm->ordered_sym_ids = malloc(sizeof(int) * symbol_num);
            nm->sym_types       = malloc(sizeof(char) * symbol_num);
            for (int j = 0; j < symbol_num; j++) {
                nm->sym_types[j]       = get_32_type(nm, j);
                nm->sym_names[j]       = get_32_name(nm, j);
                nm->ordered_sym_ids[j] = j;
            }
            if (nm->opts.p == 0) create_32_order_array(nm, symbol_num);
            print_32_symtab(nm);
            free(nm->sym_names);
            free(nm->sym_types);
            free(nm->ordered_sym_ids);
            return (i);
        }
        nm->symtab          = NULL;
        nm->symtab_end      = NULL;
        nm->sym_names       = NULL;
        nm->ordered_sym_ids = NULL;
    }
    return (0);
}

int ft_nm32(char *filename, int filesize, char *file, t_elf_opts opts) {
    t_elf32 nm;

    nm.file = filename;
    nm.size = filesize;
    nm.ptr  = file;
    nm.opts = opts;
    nm.ehdr = (Elf32_Ehdr *)nm.ptr;
    nm.shdr = (Elf32_Shdr *)(nm.ptr + nm.ehdr->e_shoff);
    nm.name = malloc(nm.ehdr->e_shnum * sizeof(char *));

    if (file[EI_DATA] != ET_REL && nm.ehdr->e_entry == 0) return -1;
    if (nm.ehdr->e_shnum == 0) return -2;
    if (nm.ehdr->e_shoff + nm.ehdr->e_shnum * nm.ehdr->e_shentsize > nm.size) return -3;

    for (int i = 0; i < nm.ehdr->e_shnum; i++) nm.name[i] = &nm.string_table[nm.shdr[i].sh_name];
    return parse_32_symtab(&nm) ? 0 : -2;
}