/*
 * Create an ELF object.
 *
 * $Id: prog5.txt 2133 2011-11-10 08:28:22Z jkoshy $
 */

#include <err.h>
#include <fcntl.h>
#include <libelf.h> @\co{1}@
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

uint32_t hash_words[] = { @\co{2}@
    0x01234567,
    0x89abcdef,
    0xdeadc0de
};

char string_table[] = { @\co{3}@
    /* Offset 0 */  '\0',
    /* Offset 1 */  '.', 'f', 'o', 'o', '\0',
    /* Offset 6 */  '.', 's', 'h', 's', 't',
                    'r', 't', 'a', 'b', '\0'
};

int
main(int argc, char **argv)
{
    int fd;
    Elf *e;
    Elf_Scn *scn;
    Elf_Data *data;
    Elf32_Ehdr *ehdr;
    Elf32_Phdr *phdr;
    Elf32_Shdr *shdr;

    if (argc != 2)
        errx(EXIT_FAILURE, "usage: %s file-name", argv[0]);

    if (elf_version(EV_CURRENT) == EV_NONE)
        errx(EXIT_FAILURE, "ELF library initialization "
            "failed: %s", elf_errmsg(-1));

    if ((fd = open(argv[1], O_WRONLY|O_CREAT, 0777)) < 0) @\co{4}@
        err(EXIT_FAILURE, "open \%s\" failed", argv[1]);

    if ((e = elf_begin(fd, ELF_C_WRITE, NULL)) == NULL) @\co{5}@
        errx(EXIT_FAILURE, "elf_begin() failed: %s.",
            elf_errmsg(-1));

    if ((ehdr = elf32_newehdr(e)) == NULL) @\co{6}@
        errx(EXIT_FAILURE, "elf32_newehdr() failed: %s.",
            elf_errmsg(-1));

    ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
    ehdr->e_machine = EM_PPC; /* 32-bit PowerPC object */
    ehdr->e_type = ET_EXEC;

    if ((phdr = elf32_newphdr(e, 1)) == NULL) @\co{7}@
        errx(EXIT_FAILURE, "elf32_newphdr() failed: %s.",
            elf_errmsg(-1));

    if ((scn = elf_newscn(e)) == NULL) @\co{8}@
        errx(EXIT_FAILURE, "elf_newscn() failed: %s.",
            elf_errmsg(-1));

    if ((data = elf_newdata(scn)) == NULL)
        errx(EXIT_FAILURE, "elf_newdata() failed: %s.",
            elf_errmsg(-1));

    data->d_align = 4;
    data->d_off  = 0LL;
    data->d_buf  = hash_words;
    data->d_type = ELF_T_WORD;
    data->d_size = sizeof(hash_words);
    data->d_version = EV_CURRENT;

    if ((shdr = elf32_getshdr(scn)) == NULL)
        errx(EXIT_FAILURE, "elf32_getshdr() failed: %s.",
            elf_errmsg(-1));

    shdr->sh_name = 1;
    shdr->sh_type = SHT_HASH;
    shdr->sh_flags = SHF_ALLOC;
    shdr->sh_entsize = 0;

    if ((scn = elf_newscn(e)) == NULL) @\co{9}@
        errx(EXIT_FAILURE, "elf_newscn() failed: %s.",
            elf_errmsg(-1));

    if ((data = elf_newdata(scn)) == NULL)
        errx(EXIT_FAILURE, "elf_newdata() failed: %s.",
            elf_errmsg(-1));

    data->d_align = 1;
    data->d_buf = string_table;
    data->d_off = 0LL;
    data->d_size = sizeof(string_table);
    data->d_type = ELF_T_BYTE;
    data->d_version = EV_CURRENT;

    if ((shdr = elf32_getshdr(scn)) == NULL)
        errx(EXIT_FAILURE, "elf32_getshdr() failed: %s.",
            elf_errmsg(-1));

    shdr->sh_name = 6;
    shdr->sh_type = SHT_STRTAB;
    shdr->sh_flags = SHF_STRINGS | SHF_ALLOC;
    shdr->sh_entsize = 0;

    elf_setshstrndx(e, elf_ndxscn(scn)); @\co{10}@

    if (elf_update(e, ELF_C_NULL) < 0) @\co{11}@
        errx(EXIT_FAILURE, "elf_update(NULL) failed: %s.",
            elf_errmsg(-1));

    phdr->p_type = PT_PHDR;
    phdr->p_offset = ehdr->e_phoff;
    phdr->p_filesz = elf32_fsize(ELF_T_PHDR, 1, EV_CURRENT);

    (void) elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);

    if (elf_update(e, ELF_C_WRITE) < 0) @\co{12}@
        errx(EXIT_FAILURE, "elf_update() failed: %s.",
            elf_errmsg(-1));

    (void) elf_end(e);
    (void) close(fd);

    exit(EXIT_SUCCESS);
}