vpx/build/make/obj_int_extract.c

/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */


#include <stdio.h>
#include <stdlib.h>

#include "vpx_config.h"

#if defined(_MSC_VER) || defined(__MINGW32__)
#include <io.h>
#include <share.h>
#include "vpx/vpx_integer.h"
#else
#include <stdint.h>
#include <unistd.h>
#endif

#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdarg.h>

typedef enum
{
    OUTPUT_FMT_PLAIN,
    OUTPUT_FMT_RVDS,
    OUTPUT_FMT_GAS,
} output_fmt_t;

int log_msg(const char *fmt, ...)
{
    int res;
    va_list ap;
    va_start(ap, fmt);
    res = vfprintf(stderr, fmt, ap);
    va_end(ap);
    return res;
}

#if defined(__GNUC__) && __GNUC__

#if defined(__MACH__)

#include <mach-o/loader.h>
#include <mach-o/nlist.h>

int parse_macho(uint8_t *base_buf, size_t sz)
{
    int i, j;
    struct mach_header header;
    uint8_t *buf = base_buf;
    int base_data_section = 0;
    int bits = 0;

    /* We can read in mach_header for 32 and 64 bit architectures
     * because it's identical to mach_header_64 except for the last
     * element (uint32_t reserved), which we don't use. Then, when
     * we know which architecture we're looking at, increment buf
     * appropriately.
     */
    memcpy(&header, buf, sizeof(struct mach_header));

    if (header.magic == MH_MAGIC)
    {
        if (header.cputype == CPU_TYPE_ARM
            || header.cputype == CPU_TYPE_X86)
        {
            bits = 32;
            buf += sizeof(struct mach_header);
        }
        else
        {
            log_msg("Bad cputype for object file. Currently only tested for CPU_TYPE_[ARM|X86].\n");
            goto bail;
        }
    }
    else if (header.magic == MH_MAGIC_64)
    {
        if (header.cputype == CPU_TYPE_X86_64)
        {
            bits = 64;
            buf += sizeof(struct mach_header_64);
        }
        else
        {
            log_msg("Bad cputype for object file. Currently only tested for CPU_TYPE_X86_64.\n");
            goto bail;
        }
    }
    else
    {
        log_msg("Bad magic number for object file. 0x%x or 0x%x expected, 0x%x found.\n",
                MH_MAGIC, MH_MAGIC_64, header.magic);
        goto bail;
    }

    if (header.filetype != MH_OBJECT)
    {
        log_msg("Bad filetype for object file. Currently only tested for MH_OBJECT.\n");
        goto bail;
    }

    for (i = 0; i < header.ncmds; i++)
    {
        struct load_command lc;

        memcpy(&lc, buf, sizeof(struct load_command));

        if (lc.cmd == LC_SEGMENT)
        {
            uint8_t *seg_buf = buf;
            struct section s;
            struct segment_command seg_c;

            memcpy(&seg_c, seg_buf, sizeof(struct segment_command));
            seg_buf += sizeof(struct segment_command);

            /* Although each section is given it's own offset, nlist.n_value
             * references the offset of the first section. This isn't
             * apparent without debug information because the offset of the
             * data section is the same as the first section. However, with
             * debug sections mixed in, the offset of the debug section
             * increases but n_value still references the first section.
             */
            if (seg_c.nsects < 1)
            {
                log_msg("Not enough sections\n");
                goto bail;
            }

            memcpy(&s, seg_buf, sizeof(struct section));
            base_data_section = s.offset;
        }
        else if (lc.cmd == LC_SEGMENT_64)
        {
            uint8_t *seg_buf = buf;
            struct section_64 s;
            struct segment_command_64 seg_c;

            memcpy(&seg_c, seg_buf, sizeof(struct segment_command_64));
            seg_buf += sizeof(struct segment_command_64);

            /* Explanation in LG_SEGMENT */
            if (seg_c.nsects < 1)
            {
                log_msg("Not enough sections\n");
                goto bail;
            }

            memcpy(&s, seg_buf, sizeof(struct section_64));
            base_data_section = s.offset;
        }
        else if (lc.cmd == LC_SYMTAB)
        {
            if (base_data_section != 0)
            {
                struct symtab_command sc;
                uint8_t *sym_buf = base_buf;
                uint8_t *str_buf = base_buf;

                memcpy(&sc, buf, sizeof(struct symtab_command));

                if (sc.cmdsize != sizeof(struct symtab_command))
                {
                    log_msg("Can't find symbol table!\n");
                    goto bail;
                }

                sym_buf += sc.symoff;
                str_buf += sc.stroff;

                for (j = 0; j < sc.nsyms; j++)
                {
                    /* Location of string is cacluated each time from the
                     * start of the string buffer.  On darwin the symbols
                     * are prefixed by "_", so we bump the pointer by 1.
                     * The target value is defined as an int in asm_*_offsets.c,
                     * which is 4 bytes on all targets we currently use.
                     */
                    if (bits == 32)
                    {
                        struct nlist nl;
                        int val;

                        memcpy(&nl, sym_buf, sizeof(struct nlist));
                        sym_buf += sizeof(struct nlist);

                        memcpy(&val, base_buf + base_data_section + nl.n_value,
                               sizeof(val));
                        printf("%-40s EQU %5d\n",
                               str_buf + nl.n_un.n_strx + 1, val);
                    }
                    else /* if (bits == 64) */
                    {
                        struct nlist_64 nl;
                        int val;

                        memcpy(&nl, sym_buf, sizeof(struct nlist_64));
                        sym_buf += sizeof(struct nlist_64);

                        memcpy(&val, base_buf + base_data_section + nl.n_value,
                               sizeof(val));
                        printf("%-40s EQU %5d\n",
                               str_buf + nl.n_un.n_strx + 1, val);
                    }
                }
            }
        }

        buf += lc.cmdsize;
    }

    return 0;
bail:
    return 1;

}

int main(int argc, char **argv)
{
    int fd;
    char *f;
    struct stat stat_buf;
    uint8_t *file_buf;
    int res;

    if (argc < 2 || argc > 3)
    {
        fprintf(stderr, "Usage: %s [output format] <obj file>\n\n", argv[0]);
        fprintf(stderr, "  <obj file>\tMachO format object file to parse\n");
        fprintf(stderr, "Output Formats:\n");
        fprintf(stderr, "  gas  - compatible with GNU assembler\n");
        fprintf(stderr, "  rvds - compatible with armasm\n");
        goto bail;
    }

    f = argv[2];

    if (!((!strcmp(argv[1], "rvds")) || (!strcmp(argv[1], "gas"))))
        f = argv[1];

    fd = open(f, O_RDONLY);

    if (fd < 0)
    {
        perror("Unable to open file");
        goto bail;
    }

    if (fstat(fd, &stat_buf))
    {
        perror("stat");
        goto bail;
    }

    file_buf = malloc(stat_buf.st_size);

    if (!file_buf)
    {
        perror("malloc");
        goto bail;
    }

    if (read(fd, file_buf, stat_buf.st_size) != stat_buf.st_size)
    {
        perror("read");
        goto bail;
    }

    if (close(fd))
    {
        perror("close");
        goto bail;
    }

    res = parse_macho(file_buf, stat_buf.st_size);
    free(file_buf);

    if (!res)
        return EXIT_SUCCESS;

bail:
    return EXIT_FAILURE;
}

#elif defined(__ELF__)
#include "elf.h"

#define COPY_STRUCT(dst, buf, ofst, sz) do {\
        if(ofst + sizeof((*(dst))) > sz) goto bail;\
        memcpy(dst, buf+ofst, sizeof((*(dst))));\
    } while(0)

#define ENDIAN_ASSIGN(val, memb) do {\
        if(!elf->le_data) {log_msg("Big Endian data not supported yet!\n");goto bail;}\
        (val) = (memb);\
    } while(0)

#define ENDIAN_ASSIGN_IN_PLACE(memb) do {\
        ENDIAN_ASSIGN(memb, memb);\
    } while(0)

typedef struct
{
    uint8_t      *buf; /* Buffer containing ELF data */
    size_t        sz;  /* Buffer size */
    int           le_data; /* Data is little-endian */
    unsigned char e_ident[EI_NIDENT]; /* Magic number and other info */
    int           bits; /* 32 or 64 */
    Elf32_Ehdr    hdr32;
    Elf64_Ehdr    hdr64;
} elf_obj_t;

int parse_elf_header(elf_obj_t *elf)
{
    int res;
    /* Verify ELF Magic numbers */
    COPY_STRUCT(&elf->e_ident, elf->buf, 0, elf->sz);
    res = elf->e_ident[EI_MAG0] == ELFMAG0;
    res &= elf->e_ident[EI_MAG1] == ELFMAG1;
    res &= elf->e_ident[EI_MAG2] == ELFMAG2;
    res &= elf->e_ident[EI_MAG3] == ELFMAG3;
    res &= elf->e_ident[EI_CLASS] == ELFCLASS32
        || elf->e_ident[EI_CLASS] == ELFCLASS64;
    res &= elf->e_ident[EI_DATA] == ELFDATA2LSB;

    if (!res) goto bail;

    elf->le_data = elf->e_ident[EI_DATA] == ELFDATA2LSB;

    /* Read in relevant values */
    if (elf->e_ident[EI_CLASS] == ELFCLASS32)
    {
        elf->bits = 32;
        COPY_STRUCT(&elf->hdr32, elf->buf, 0, elf->sz);

        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_type);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_machine);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_version);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_entry);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_phoff);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_shoff);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_flags);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_ehsize);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_phentsize);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_phnum);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_shentsize);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_shnum);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr32.e_shstrndx);
    }
    else /* if (elf->e_ident[EI_CLASS] == ELFCLASS64) */
    {
        elf->bits = 64;
        COPY_STRUCT(&elf->hdr64, elf->buf, 0, elf->sz);

        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_type);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_machine);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_version);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_entry);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_phoff);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_shoff);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_flags);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_ehsize);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_phentsize);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_phnum);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_shentsize);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_shnum);
        ENDIAN_ASSIGN_IN_PLACE(elf->hdr64.e_shstrndx);
    }

    return 0;
bail:
    log_msg("Failed to parse ELF file header");
    return 1;
}

int parse_elf_section(elf_obj_t *elf, int idx, Elf32_Shdr *hdr32, Elf64_Shdr *hdr64)
{
    if (hdr32)
    {
        if (idx >= elf->hdr32.e_shnum)
            goto bail;

        COPY_STRUCT(hdr32, elf->buf, elf->hdr32.e_shoff + idx * elf->hdr32.e_shentsize,
                    elf->sz);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_name);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_type);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_flags);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_addr);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_offset);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_size);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_link);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_info);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_addralign);
        ENDIAN_ASSIGN_IN_PLACE(hdr32->sh_entsize);
    }
    else /* if (hdr64) */
    {
        if (idx >= elf->hdr64.e_shnum)
            goto bail;

        COPY_STRUCT(hdr64, elf->buf, elf->hdr64.e_shoff + idx * elf->hdr64.e_shentsize,
                    elf->sz);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_name);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_type);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_flags);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_addr);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_offset);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_size);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_link);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_info);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_addralign);
        ENDIAN_ASSIGN_IN_PLACE(hdr64->sh_entsize);
    }

    return 0;
bail:
    return 1;
}

char *parse_elf_string_table(elf_obj_t *elf, int s_idx, int idx)
{
    if (elf->bits == 32)
    {
        Elf32_Shdr shdr;

        if (parse_elf_section(elf, s_idx, &shdr, NULL))
        {
            log_msg("Failed to parse ELF string table: section %d, index %d\n",
                    s_idx, idx);
            return "";
        }

        return (char *)(elf->buf + shdr.sh_offset + idx);
    }
    else /* if (elf->bits == 64) */
    {
        Elf64_Shdr shdr;

        if (parse_elf_section(elf, s_idx, NULL, &shdr))
        {
            log_msg("Failed to parse ELF string table: section %d, index %d\n",
                    s_idx, idx);
            return "";
        }

        return (char *)(elf->buf + shdr.sh_offset + idx);
    }
}

int parse_elf_symbol(elf_obj_t *elf, unsigned int ofst, Elf32_Sym *sym32, Elf64_Sym *sym64)
{
    if (sym32)
    {
        COPY_STRUCT(sym32, elf->buf, ofst, elf->sz);
        ENDIAN_ASSIGN_IN_PLACE(sym32->st_name);
        ENDIAN_ASSIGN_IN_PLACE(sym32->st_value);
        ENDIAN_ASSIGN_IN_PLACE(sym32->st_size);
        ENDIAN_ASSIGN_IN_PLACE(sym32->st_info);
        ENDIAN_ASSIGN_IN_PLACE(sym32->st_other);
        ENDIAN_ASSIGN_IN_PLACE(sym32->st_shndx);
    }
    else /* if (sym64) */
    {
        COPY_STRUCT(sym64, elf->buf, ofst, elf->sz);
        ENDIAN_ASSIGN_IN_PLACE(sym64->st_name);
        ENDIAN_ASSIGN_IN_PLACE(sym64->st_value);
        ENDIAN_ASSIGN_IN_PLACE(sym64->st_size);
        ENDIAN_ASSIGN_IN_PLACE(sym64->st_info);
        ENDIAN_ASSIGN_IN_PLACE(sym64->st_other);
        ENDIAN_ASSIGN_IN_PLACE(sym64->st_shndx);
    }
    return 0;
bail:
    return 1;
}

int parse_elf(uint8_t *buf, size_t sz, output_fmt_t mode)
{
    elf_obj_t    elf;
    unsigned int ofst;
    int          i;
    Elf32_Off    strtab_off32;
    Elf64_Off    strtab_off64; /* save String Table offset for later use */

    memset(&elf, 0, sizeof(elf));
    elf.buf = buf;
    elf.sz = sz;

    /* Parse Header */
    if (parse_elf_header(&elf))
      goto bail;

    if (elf.bits == 32)
    {
        Elf32_Shdr shdr;
        for (i = 0; i < elf.hdr32.e_shnum; i++)
        {
            parse_elf_section(&elf, i, &shdr, NULL);

            if (shdr.sh_type == SHT_STRTAB)
            {
                char strtsb_name[128];

                strcpy(strtsb_name, (char *)(elf.buf + shdr.sh_offset + shdr.sh_name));

                if (!(strcmp(strtsb_name, ".shstrtab")))
                {
                    /* log_msg("found section: %s\n", strtsb_name); */
                    strtab_off32 = shdr.sh_offset;
                    break;
                }
            }
        }
    }
    else /* if (elf.bits == 64) */
    {
        Elf64_Shdr shdr;
        for (i = 0; i < elf.hdr64.e_shnum; i++)
        {
            parse_elf_section(&elf, i, NULL, &shdr);

            if (shdr.sh_type == SHT_STRTAB)
            {
                char strtsb_name[128];

                strcpy(strtsb_name, (char *)(elf.buf + shdr.sh_offset + shdr.sh_name));

                if (!(strcmp(strtsb_name, ".shstrtab")))
                {
                    /* log_msg("found section: %s\n", strtsb_name); */
                    strtab_off64 = shdr.sh_offset;
                    break;
                }
            }
        }
    }

    /* Parse all Symbol Tables */
    if (elf.bits == 32)
    {
        Elf32_Shdr shdr;
        for (i = 0; i < elf.hdr32.e_shnum; i++)
        {
            parse_elf_section(&elf, i, &shdr, NULL);

            if (shdr.sh_type == SHT_SYMTAB)
            {
                for (ofst = shdr.sh_offset;
                     ofst < shdr.sh_offset + shdr.sh_size;
                     ofst += shdr.sh_entsize)
                {
                    Elf32_Sym sym;

                    parse_elf_symbol(&elf, ofst, &sym, NULL);

                    /* For all OBJECTS (data objects), extract the value from the
                     * proper data segment.
                     */
                    /* if (ELF32_ST_TYPE(sym.st_info) == STT_OBJECT && sym.st_name)
                        log_msg("found data object %s\n",
                                parse_elf_string_table(&elf,
                                                       shdr.sh_link,
                                                       sym.st_name));
                     */

                    if (ELF32_ST_TYPE(sym.st_info) == STT_OBJECT
                        && sym.st_size == 4)
                    {
                        Elf32_Shdr dhdr;
                        int val = 0;
                        char section_name[128];

                        parse_elf_section(&elf, sym.st_shndx, &dhdr, NULL);

                        /* For explanition - refer to _MSC_VER version of code */
                        strcpy(section_name, (char *)(elf.buf + strtab_off32 + dhdr.sh_name));
                        /* log_msg("Section_name: %s, Section_type: %d\n", section_name, dhdr.sh_type); */

                        if (strcmp(section_name, ".bss"))
                        {
                            if (sizeof(val) != sym.st_size)
                            {
                                /* The target value is declared as an int in
                                 * asm_*_offsets.c, which is 4 bytes on all
                                 * targets we currently use. Complain loudly if
                                 * this is not true.
                                 */
                                log_msg("Symbol size is wrong\n");
                                goto bail;
                            }

                            memcpy(&val,
                                   elf.buf + dhdr.sh_offset + sym.st_value,
                                   sym.st_size);
                        }

                        if (!elf.le_data)
                        {
                            log_msg("Big Endian data not supported yet!\n");
                            goto bail;
                        }

                        switch (mode)
                        {
                            case OUTPUT_FMT_RVDS:
                                printf("%-40s EQU %5d\n",
                                       parse_elf_string_table(&elf,
                                                              shdr.sh_link,
                                                              sym.st_name),
                                       val);
                                break;
                            case OUTPUT_FMT_GAS:
                                printf(".equ %-40s, %5d\n",
                                       parse_elf_string_table(&elf,
                                                              shdr.sh_link,
                                                              sym.st_name),
                                       val);
                                break;
                            default:
                                printf("%s = %d\n",
                                       parse_elf_string_table(&elf,
                                                              shdr.sh_link,
                                                              sym.st_name),
                                       val);
                        }
                    }
                }
            }
        }
    }
    else /* if (elf.bits == 64) */
    {
        Elf64_Shdr shdr;
        for (i = 0; i < elf.hdr64.e_shnum; i++)
        {
            parse_elf_section(&elf, i, NULL, &shdr);

            if (shdr.sh_type == SHT_SYMTAB)
            {
                for (ofst = shdr.sh_offset;
                     ofst < shdr.sh_offset + shdr.sh_size;
                     ofst += shdr.sh_entsize)
                {
                    Elf64_Sym sym;

                    parse_elf_symbol(&elf, ofst, NULL, &sym);

                    /* For all OBJECTS (data objects), extract the value from the
                     * proper data segment.
                     */
                    /* if (ELF64_ST_TYPE(sym.st_info) == STT_OBJECT && sym.st_name)
                        log_msg("found data object %s\n",
                                parse_elf_string_table(&elf,
                                                       shdr.sh_link,
                                                       sym.st_name));
                     */

                    if (ELF64_ST_TYPE(sym.st_info) == STT_OBJECT
                        && sym.st_size == 4)
                    {
                        Elf64_Shdr dhdr;
                        int val = 0;
                        char section_name[128];

                        parse_elf_section(&elf, sym.st_shndx, NULL, &dhdr);

                        /* For explanition - refer to _MSC_VER version of code */
                        strcpy(section_name, (char *)(elf.buf + strtab_off64 + dhdr.sh_name));
                        /* log_msg("Section_name: %s, Section_type: %d\n", section_name, dhdr.sh_type); */

                        if ((strcmp(section_name, ".bss")))
                        {
                            if (sizeof(val) != sym.st_size)
                            {
                                /* The target value is declared as an int in
                                 * asm_*_offsets.c, which is 4 bytes on all
                                 * targets we currently use. Complain loudly if
                                 * this is not true.
                                 */
                                log_msg("Symbol size is wrong\n");
                                goto bail;
                            }

                            memcpy(&val,
                                   elf.buf + dhdr.sh_offset + sym.st_value,
                                   sym.st_size);
                        }

                        if (!elf.le_data)
                        {
                            log_msg("Big Endian data not supported yet!\n");
                            goto bail;
                        }

                        switch (mode)
                        {
                            case OUTPUT_FMT_RVDS:
                                printf("%-40s EQU %5d\n",
                                       parse_elf_string_table(&elf,
                                                              shdr.sh_link,
                                                              sym.st_name),
                                       val);
                                break;
                            case OUTPUT_FMT_GAS:
                                printf(".equ %-40s, %5d\n",
                                       parse_elf_string_table(&elf,
                                                              shdr.sh_link,
                                                              sym.st_name),
                                       val);
                                break;
                            default:
                                printf("%s = %d\n",
                                       parse_elf_string_table(&elf,
                                                              shdr.sh_link,
                                                              sym.st_name),
                                       val);
                        }
                    }
                }
            }
        }
    }

    if (mode == OUTPUT_FMT_RVDS)
        printf("    END\n");

    return 0;
bail:
    log_msg("Parse error: File does not appear to be valid ELF32 or ELF64\n");
    return 1;
}

int main(int argc, char **argv)
{
    int fd;
    output_fmt_t mode;
    char *f;
    struct stat stat_buf;
    uint8_t *file_buf;
    int res;

    if (argc < 2 || argc > 3)
    {
        fprintf(stderr, "Usage: %s [output format] <obj file>\n\n", argv[0]);
        fprintf(stderr, "  <obj file>\tELF format object file to parse\n");
        fprintf(stderr, "Output Formats:\n");
        fprintf(stderr, "  gas  - compatible with GNU assembler\n");
        fprintf(stderr, "  rvds - compatible with armasm\n");
        goto bail;
    }

    f = argv[2];

    if (!strcmp(argv[1], "rvds"))
        mode = OUTPUT_FMT_RVDS;
    else if (!strcmp(argv[1], "gas"))
        mode = OUTPUT_FMT_GAS;
    else
        f = argv[1];


    fd = open(f, O_RDONLY);

    if (fd < 0)
    {
        perror("Unable to open file");
        goto bail;
    }

    if (fstat(fd, &stat_buf))
    {
        perror("stat");
        goto bail;
    }

    file_buf = malloc(stat_buf.st_size);

    if (!file_buf)
    {
        perror("malloc");
        goto bail;
    }

    if (read(fd, file_buf, stat_buf.st_size) != stat_buf.st_size)
    {
        perror("read");
        goto bail;
    }

    if (close(fd))
    {
        perror("close");
        goto bail;
    }

    res = parse_elf(file_buf, stat_buf.st_size, mode);
    free(file_buf);

    if (!res)
        return EXIT_SUCCESS;

bail:
    return EXIT_FAILURE;
}
#endif
#endif


#if defined(_MSC_VER) || defined(__MINGW32__)
/*  See "Microsoft Portable Executable and Common Object File Format Specification"
    for reference.
*/
#define get_le32(x) ((*(x)) | (*(x+1)) << 8 |(*(x+2)) << 16 | (*(x+3)) << 24 )
#define get_le16(x) ((*(x)) | (*(x+1)) << 8)

int parse_coff(unsigned __int8 *buf, size_t sz)
{
    unsigned int nsections, symtab_ptr, symtab_sz, strtab_ptr;
    unsigned int sectionrawdata_ptr;
    unsigned int i;
    unsigned __int8 *ptr;
    unsigned __int32 symoffset;

    char **sectionlist;  //this array holds all section names in their correct order.
    //it is used to check if the symbol is in .bss or .data section.

    nsections = get_le16(buf + 2);
    symtab_ptr = get_le32(buf + 8);
    symtab_sz = get_le32(buf + 12);
    strtab_ptr = symtab_ptr + symtab_sz * 18;

    if (nsections > 96)
        goto bail;

    sectionlist = malloc(nsections * sizeof * sectionlist);

    //log_msg("COFF: Found %u symbols in %u sections.\n", symtab_sz, nsections);

    /*
    The size of optional header is always zero for an obj file. So, the section header
    follows the file header immediately.
    */

    ptr = buf + 20;     //section header

    for (i = 0; i < nsections; i++)
    {
        char sectionname[9] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
        strncpy(sectionname, ptr, 8);
        //log_msg("COFF: Parsing section %s\n",sectionname);

        sectionlist[i] = malloc(strlen(sectionname) + 1);
        strcpy(sectionlist[i], sectionname);

        if (!strcmp(sectionname, ".data")) sectionrawdata_ptr = get_le32(ptr + 20);

        ptr += 40;
    }

    //log_msg("COFF: Symbol table at offset %u\n", symtab_ptr);
    //log_msg("COFF: raw data pointer ofset for section .data is %u\n", sectionrawdata_ptr);

    /*  The compiler puts the data with non-zero offset in .data section, but puts the data with
        zero offset in .bss section. So, if the data in in .bss section, set offset=0.
        Note from Wiki: In an object module compiled from C, the bss section contains
        the local variables (but not functions) that were declared with the static keyword,
        except for those with non-zero initial values. (In C, static variables are initialized
        to zero by default.) It also contains the non-local (both extern and static) variables
        that are also initialized to zero (either explicitly or by default).
        */
    //move to symbol table
    /* COFF symbol table:
        offset      field
        0           Name(*)
        8           Value
        12          SectionNumber
        14          Type
        16          StorageClass
        17          NumberOfAuxSymbols
        */
    ptr = buf + symtab_ptr;

    for (i = 0; i < symtab_sz; i++)
    {
        __int16 section = get_le16(ptr + 12); //section number

        if (section > 0 && ptr[16] == 2)
        {
            //if(section > 0 && ptr[16] == 3 && get_le32(ptr+8)) {

            if (get_le32(ptr))
            {
                char name[9] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
                strncpy(name, ptr, 8);
                //log_msg("COFF: Parsing symbol %s\n",name);
                printf("%-40s EQU ", name + 1);
            }
            else
            {
                //log_msg("COFF: Parsing symbol %s\n",
                //        buf + strtab_ptr + get_le32(ptr+4));
                printf("%-40s EQU ", buf + strtab_ptr + get_le32(ptr + 4) + 1);
            }

            if (!(strcmp(sectionlist[section-1], ".bss")))
            {
                symoffset = 0;
            }
            else
            {
                symoffset = get_le32(buf + sectionrawdata_ptr + get_le32(ptr + 8));
            }

            //log_msg("      Section: %d\n",section);
            //log_msg("      Class:   %d\n",ptr[16]);
            //log_msg("      Address: %u\n",get_le32(ptr+8));
            //log_msg("      Offset: %u\n", symoffset);

            printf("%5d\n", symoffset);
        }

        ptr += 18;
    }

    printf("    END\n");

    for (i = 0; i < nsections; i++)
    {
        free(sectionlist[i]);
    }

    free(sectionlist);

    return 0;
bail:

    for (i = 0; i < nsections; i++)
    {
        free(sectionlist[i]);
    }

    free(sectionlist);

    return 1;
}

int main(int argc, char **argv)
{
    int fd;
    output_fmt_t mode;
    const char *f;
    struct _stat stat_buf;
    unsigned __int8 *file_buf;
    int res;

    if (argc < 2 || argc > 3)
    {
        fprintf(stderr, "Usage: %s [output format] <obj file>\n\n", argv[0]);
        fprintf(stderr, "  <obj file>\tELF format object file to parse\n");
        fprintf(stderr, "Output Formats:\n");
        fprintf(stderr, "  gas  - compatible with GNU assembler\n");
        fprintf(stderr, "  rvds - compatible with armasm\n");
        goto bail;
    }

    f = argv[2];

    if (!strcmp(argv[1], "rvds"))
        mode = OUTPUT_FMT_RVDS;
    else if (!strcmp(argv[1], "gas"))
        mode = OUTPUT_FMT_GAS;
    else
        f = argv[1];

    fd = _sopen(f, _O_BINARY, _SH_DENYNO, _S_IREAD | _S_IWRITE);

    if (_fstat(fd, &stat_buf))
    {
        perror("stat");
        goto bail;
    }

    file_buf = malloc(stat_buf.st_size);

    if (!file_buf)
    {
        perror("malloc");
        goto bail;
    }

    if (_read(fd, file_buf, stat_buf.st_size) != stat_buf.st_size)
    {
        perror("read");
        goto bail;
    }

    if (_close(fd))
    {
        perror("close");
        goto bail;
    }

    res = parse_coff(file_buf, stat_buf.st_size);

    free(file_buf);

    if (!res)
        return EXIT_SUCCESS;

bail:
    return EXIT_FAILURE;
}
#endif