/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2018, Joyent, Inc.
 */

#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <strings.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/inttypes.h>
#include <sys/elf.h>
#include <sys/elf_notes.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/statvfs.h>

static char *pname;
static char *fname;
static char *image;     /* pointer to the ELF file in memory */

#define ELFSEEK(offset) ((void *)(image + offset))

/*
 * Extract the PT_LOAD bits and format them into a .s
 */
static void
extract32(Elf32_Ehdr *eh)
{
        Elf32_Phdr *phdr;
        caddr_t allphdrs;
        int i;
        int c;
        unsigned char *bytes;
        uint_t cnt = 10;

        allphdrs = NULL;

        if (eh->e_type != ET_EXEC) {
                (void) fprintf(stderr, "%s: not ET_EXEC, e_type = 0x%x\n",
                    pname, eh->e_type);
                exit(1);
        }
        if (eh->e_phnum == 0 || eh->e_phoff == 0) {
                (void) fprintf(stderr, "%s: no program headers\n", pname);
                exit(1);
        }

        /*
         * Get the program headers.
         */
        allphdrs = ELFSEEK(eh->e_phoff);
        if (allphdrs == NULL) {
                (void) fprintf(stderr, "%s: Failed to get %d program hdrs\n",
                    pname, eh->e_phnum);
                exit(1);
        }

        /*
         * Find the PT_LOAD section
         */
        for (i = 0; i < eh->e_phnum; i++) {
                /*LINTED [ELF program header alignment]*/
                phdr = (Elf32_Phdr *)(allphdrs + eh->e_phentsize * i);

                if (phdr->p_type != PT_LOAD)
                        continue;

                if (phdr->p_memsz == 0)
                        continue;

                bytes = ELFSEEK(phdr->p_offset);
                for (c = 0; c < phdr->p_filesz; ++c) {
                        if (c % cnt == 0)
                                (void) printf("\n       .byte   ");
                        else
                                (void) printf(",");
                        (void) printf("0x%x", bytes[c]);
                }
                for (; c < phdr->p_memsz; ++c) {
                        if (c % cnt == 0) {
                                (void) printf("\n       .byte   ");
                                cnt = 20;
                        } else {
                                (void) printf(", ");
                        }
                        (void) printf("0");
                }
                (void) printf("\n");
                return;
        }

        (void) fprintf(stderr, "%s: Failed finding PT_LOAD section\n", pname);
        exit(1);
}

static void
extract64(Elf64_Ehdr *eh)
{
        Elf64_Phdr *phdr;
        caddr_t allphdrs;
        int i;
        int c;
        unsigned char *bytes;
        uint_t cnt = 10;

        allphdrs = NULL;

        if (eh->e_type != ET_EXEC) {
                (void) fprintf(stderr, "%s: not ET_EXEC, e_type = 0x%x\n",
                    pname, eh->e_type);
                exit(1);
        }
        if (eh->e_phnum == 0 || eh->e_phoff == 0) {
                (void) fprintf(stderr, "%s: no program headers\n", pname);
                exit(1);
        }

        /*
         * Get the program headers.
         */
        allphdrs = ELFSEEK(eh->e_phoff);
        if (allphdrs == NULL) {
                (void) fprintf(stderr, "%s: Failed to get %d program hdrs\n",
                    pname, eh->e_phnum);
                exit(1);
        }

        /*
         * Find the PT_LOAD section
         */
        for (i = 0; i < eh->e_phnum; i++) {
                /*LINTED [ELF program header alignment]*/
                phdr = (Elf64_Phdr *)(allphdrs + eh->e_phentsize * i);

                if (phdr->p_type != PT_LOAD)
                        continue;

                if (phdr->p_memsz == 0)
                        continue;

                bytes = ELFSEEK(phdr->p_offset);
                for (c = 0; c < phdr->p_filesz; ++c) {
                        if (c % cnt == 0)
                                (void) printf("\n       .byte   ");
                        else
                                (void) printf(",");
                        (void) printf("0x%x", bytes[c]);
                }
                for (; c < phdr->p_memsz; ++c) {
                        if (c % cnt == 0) {
                                (void) printf("\n       .byte   ");
                                cnt = 20;
                        } else {
                                (void) printf(", ");
                        }
                        (void) printf("0");
                }
                (void) printf("\n");
                return;
        }

        (void) fprintf(stderr, "%s: Failed finding PT_LOAD section\n", pname);
        exit(1);
}

int
main(int argc, char **argv)
{
        int fd;
        uchar_t *ident;
        void *hdr = NULL;
        struct stat stats;
        ssize_t r;
        size_t pgsz;
        uint_t len;

        /*
         * we expect one argument -- the elf file
         */
        if (argc != 2) {
                (void) fprintf(stderr, "usage: %s <unix-elf-file>\n", argv[0]);
                exit(1);
        }

        pname = strrchr(argv[0], '/');
        if (pname == NULL)
                pname = argv[0];
        else
                ++pname;

        fname = argv[1];
        fd = open(fname, O_RDONLY);
        if (fd < 0) {
                (void) fprintf(stderr, "%s: open(%s, O_RDONLY) failed, %s\n",
                    pname, fname, strerror(errno));
                exit(1);
        }

        if (stat(fname, &stats) < 0) {
                (void) fprintf(stderr, "%s: stat(%s, ...) failed, %s\n",
                    pname, fname, strerror(errno));
                exit(1);
        }

        pgsz = getpagesize();
        len = (stats.st_size + (pgsz - 1)) & (~(pgsz - 1));

        /*
         * mmap the file
         */
        image = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, 0);
        if (image == MAP_FAILED) {
                (void) fprintf(stderr, "%s: mmap() of %s failed, %s\n",
                    pname, fname, strerror(errno));
                exit(1);
        }

        ident = ELFSEEK(0);
        if (ident[EI_MAG0] != ELFMAG0 || ident[EI_MAG1] != ELFMAG1 ||
            ident[EI_MAG2] != ELFMAG2 || ident[EI_MAG3] != ELFMAG3) {
                (void) fprintf(stderr, "%s: not an ELF file!\n", pname);
                exit(1);
        }

        if (ident[EI_CLASS] == ELFCLASS32) {
                hdr = ELFSEEK(0);
                extract32(hdr);
        } else if (ident[EI_CLASS] == ELFCLASS64) {
                hdr = ELFSEEK(0);
                extract64(hdr);
        } else {
                (void) fprintf(stderr, "%s: Wrong ELF class 0x%x\n", pname,
                    ident[EI_CLASS]);
                exit(1);
        }
        return (0);
}