/*
 * This software is part of the SBCL system. See the README file for
 * more information.
 *
 * This software is derived from the CMU CL system, which was
 * written at Carnegie Mellon University and released into the
 * public domain. The software is in the public domain and is
 * provided with absolutely no warranty. See the COPYING and CREDITS
 * files for more information.
 */

#ifndef LISP_FEATURE_WIN32
#include <sys/types.h>
#include <sys/stat.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <sys/file.h>

#include "sbcl.h"
#include "runtime.h"
#include "os.h"
#include "core.h"
#include "globals.h"
#include "save.h"
#include "dynbind.h"
#include "lispregs.h"
#include "validate.h"
#include "gc-internal.h"
#include "thread.h"

#include "genesis/static-symbols.h"
#include "genesis/symbol.h"

#if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_SB_LUTEX)
#include "genesis/lutex.h"
#endif

static void
write_lispobj(lispobj obj, FILE *file)
{
    fwrite(&obj, sizeof(lispobj), 1, file);
}

static long
write_bytes(FILE *file, char *addr, long bytes, os_vm_offset_t file_offset)
{
    long count, here, data;

    bytes = (bytes+os_vm_page_size-1)&~(os_vm_page_size-1);

#ifdef LISP_FEATURE_WIN32
    /* touch every single page in the space to force it to be mapped. */
    for (count = 0; count < bytes; count += 0x1000) {
        volatile int temp = addr[count];
    }
#endif

    fflush(file);
    here = ftell(file);
    fseek(file, 0, SEEK_END);
    data = (ftell(file)+os_vm_page_size-1)&~(os_vm_page_size-1);
    fseek(file, data, SEEK_SET);

    while (bytes > 0) {
        count = fwrite(addr, 1, bytes, file);
        if (count > 0) {
            bytes -= count;
            addr += count;
        }
        else {
            perror("error writing to save file");
            bytes = 0;
        }
    }
    fflush(file);
    fseek(file, here, SEEK_SET);
    return ((data - file_offset) / os_vm_page_size) - 1;
}

#if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_SB_LUTEX)
/* saving lutexes in the core */
static void **lutex_addresses;
static long n_lutexes = 0;
static long max_lutexes = 0;

static long
default_scan_action(lispobj *obj)
{
    return (sizetab[widetag_of(*obj)])(obj);
}

static long
lutex_scan_action(lispobj *obj)
{
    /* note the address of the lutex */
    if(n_lutexes >= max_lutexes) {
        max_lutexes *= 2;
        lutex_addresses = realloc(lutex_addresses, max_lutexes * sizeof(void *));
        gc_assert(lutex_addresses);
    }

    lutex_addresses[n_lutexes++] = obj;

    return (*sizetab[widetag_of(*obj)])(obj);
}

typedef long (*scan_table[256])(lispobj *obj);

static void
scan_objects(lispobj *start, long n_words, scan_table table)
{
    lispobj *end = start + n_words;
    lispobj *object_ptr;
    long n_words_scanned;
    for (object_ptr = start;
         object_ptr < end;
         object_ptr += n_words_scanned) {
        lispobj obj = *object_ptr;

        n_words_scanned = (table[widetag_of(obj)])(object_ptr);
    }
}

static void
scan_for_lutexes(lispobj *addr, long n_words)
{
    static int initialized = 0;
    static scan_table lutex_scan_table;

    if (!initialized) {
        int i;

        /* allocate a little space to get started */
        lutex_addresses = malloc(16*sizeof(void *));
        gc_assert(lutex_addresses);
        max_lutexes = 16;

        /* initialize the mapping table */
        for(i = 0; i < ((sizeof lutex_scan_table)/(sizeof lutex_scan_table[0])); ++i) {
            lutex_scan_table[i] = default_scan_action;
        }

        lutex_scan_table[LUTEX_WIDETAG] = lutex_scan_action;

        initialized = 1;
    }

    /* do the scan */
    scan_objects(addr, n_words, lutex_scan_table);
}
#endif

static void
output_space(FILE *file, int id, lispobj *addr, lispobj *end, os_vm_offset_t file_offset)
{
    size_t words, bytes, data;
    static char *names[] = {NULL, "dynamic", "static", "read-only"};

    write_lispobj(id, file);
    words = end - addr;
    write_lispobj(words, file);

    bytes = words * sizeof(lispobj);

#if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_SB_LUTEX)
    printf("scanning space for lutexes...\n");
    scan_for_lutexes((char *)addr, words);
#endif

    printf("writing %lu bytes from the %s space at 0x%08lx\n",
           (unsigned long)bytes, names[id], (unsigned long)addr);

    data = write_bytes(file, (char *)addr, bytes, file_offset);

    write_lispobj(data, file);
    write_lispobj((long)addr / os_vm_page_size, file);
    write_lispobj((bytes + os_vm_page_size - 1) / os_vm_page_size, file);
}

FILE *
open_core_for_saving(char *filename)
{
    /* Open the output file. We don't actually need the file yet, but
     * the fopen() might fail for some reason, and we want to detect
     * that and back out before we do anything irreversible. */
    unlink(filename);
    return fopen(filename, "wb");
}

boolean
save_to_filehandle(FILE *file, char *filename, lispobj init_function,
                   boolean make_executable)
{
    struct thread *th;
    os_vm_offset_t core_start_pos, core_end_pos, core_size;

    /* Smash the enclosing state. (Once we do this, there's no good
     * way to go back, which is a sufficient reason that this ends up
     * being SAVE-LISP-AND-DIE instead of SAVE-LISP-AND-GO-ON). */
    printf("[undoing binding stack and other enclosing state... ");
    fflush(stdout);
    for_each_thread(th) {       /* XXX really? */
        unbind_to_here((lispobj *)th->binding_stack_start,th);
        SetSymbolValue(CURRENT_CATCH_BLOCK, 0,th);
        SetSymbolValue(CURRENT_UNWIND_PROTECT_BLOCK, 0,th);
    }
    printf("done]\n");
    fflush(stdout);

    /* (Now we can actually start copying ourselves into the output file.) */

    printf("[saving current Lisp image into %s:\n", filename);
    fflush(stdout);

    core_start_pos = ftell(file);
    write_lispobj(CORE_MAGIC, file);

    write_lispobj(VERSION_CORE_ENTRY_TYPE_CODE, file);
    write_lispobj(3, file);
    write_lispobj(SBCL_CORE_VERSION_INTEGER, file);

    write_lispobj(BUILD_ID_CORE_ENTRY_TYPE_CODE, file);
    write_lispobj(/* (We're writing the word count of the entry here, and the 2
          * term is one word for the leading BUILD_ID_CORE_ENTRY_TYPE_CODE
          * word and one word where we store the count itself.) */
         2 + strlen((const char *)build_id),
         file);
    {
        unsigned char *p;
        for (p = (unsigned char *)build_id; *p; ++p)
            write_lispobj(*p, file);
    }

    write_lispobj(NEW_DIRECTORY_CORE_ENTRY_TYPE_CODE, file);
    write_lispobj(/* (word count = 3 spaces described by 5 words each, plus the
          * entry type code, plus this count itself) */
         (5*3)+2, file);
    output_space(file,
                 READ_ONLY_CORE_SPACE_ID,
                 (lispobj *)READ_ONLY_SPACE_START,
                 (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0),
                 core_start_pos);
    output_space(file,
                 STATIC_CORE_SPACE_ID,
                 (lispobj *)STATIC_SPACE_START,
                 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0),
                 core_start_pos);
#ifdef LISP_FEATURE_GENCGC
    /* Flush the current_region, updating the tables. */
    gc_alloc_update_all_page_tables();
    update_dynamic_space_free_pointer();
#endif
#ifdef reg_ALLOC
#ifdef LISP_FEATURE_GENCGC
    output_space(file,
                 DYNAMIC_CORE_SPACE_ID,
                 (lispobj *)DYNAMIC_SPACE_START,
                 dynamic_space_free_pointer,
                 core_start_pos);
#else
    output_space(file,
                 DYNAMIC_CORE_SPACE_ID,
                 (lispobj *)current_dynamic_space,
                 dynamic_space_free_pointer,
                 core_start_pos);
#endif
#else
    output_space(file,
                 DYNAMIC_CORE_SPACE_ID,
                 (lispobj *)DYNAMIC_SPACE_START,
                 (lispobj *)SymbolValue(ALLOCATION_POINTER,0),
                 core_start_pos);
#endif

    write_lispobj(INITIAL_FUN_CORE_ENTRY_TYPE_CODE, file);
    write_lispobj(3, file);
    write_lispobj(init_function, file);

#ifdef LISP_FEATURE_GENCGC
    {
        size_t size = (last_free_page*sizeof(long)+os_vm_page_size-1)
            &~(os_vm_page_size-1);
        long *data = calloc(size, 1);
        if (data) {
            long offset;
            int i;
            for (i = 0; i < last_free_page; i++) {
                data[i] = page_table[i].first_object_offset;
            }
            write_lispobj(PAGE_TABLE_CORE_ENTRY_TYPE_CODE, file);
            write_lispobj(4, file);
            write_lispobj(size, file);
            offset = write_bytes(file, (char *) data, size, core_start_pos);
            write_lispobj(offset, file);
        }
    }
#endif

#if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_SB_LUTEX)
    if(n_lutexes > 0) {
        long offset;
        printf("writing %ld lutexes to the core...\n", n_lutexes);
        write_lispobj(LUTEX_TABLE_CORE_ENTRY_TYPE_CODE, file);
        /* word count of the entry */
        write_lispobj(4, file);
        /* indicate how many lutexes we saved */
        write_lispobj(n_lutexes, file);
        /* save the lutexes */
        offset = write_bytes(file, (char *) lutex_addresses,
                             n_lutexes * sizeof(*lutex_addresses),
                             core_start_pos);

        write_lispobj(offset, file);
    }
#endif

    write_lispobj(END_CORE_ENTRY_TYPE_CODE, file);

    /* Write a trailing header, ignored when parsing the core normally.
     * This is used to locate the start of the core when the runtime is
     * prepended to it. */
    fseek(file, 0, SEEK_END);
    core_end_pos = ftell(file);
    core_size = core_end_pos - core_start_pos;

    fwrite(&core_size, sizeof(os_vm_offset_t), 1, file);
    write_lispobj(CORE_MAGIC, file);
    fclose(file);

#ifndef LISP_FEATURE_WIN32
    if (make_executable)
        chmod (filename, 0755);
#endif

    printf("done]\n");
    exit(0);
}

/* Slurp the executable portion of the runtime into a malloced buffer
 * and return it.  Places the size in bytes of the runtime into
 * 'size_out'.  Returns NULL if the runtime cannot be loaded from
 * 'runtime_path'. */
void *
load_runtime(char *runtime_path, size_t *size_out)
{
    void *buf = NULL;
    FILE *input = NULL;
    size_t size, count;
    os_vm_offset_t core_offset;

    core_offset = search_for_embedded_core (runtime_path);
    if ((input = fopen(runtime_path, "rb")) == NULL) {
        fprintf(stderr, "Unable to open runtime: %s\n", runtime_path);
        goto lose;
    }

    fseek(input, 0, SEEK_END);
    size = (size_t) ftell(input);
    fseek(input, 0, SEEK_SET);

    if (core_offset != -1 && size > core_offset)
        size = core_offset;

    buf = successful_malloc(size);
    if ((count = fread(buf, 1, size, input)) != size) {
        fprintf(stderr, "Premature EOF while reading runtime.\n");
        goto lose;
    }

    fclose(input);
    *size_out = size;
    return buf;

lose:
    if (input != NULL)
        fclose(input);
    if (buf != NULL)
        free(buf);
    return NULL;
}

boolean
save_runtime_to_filehandle(FILE *output, void *runtime, size_t runtime_size)
{
    size_t padding;
    void *padbytes;

    fwrite(runtime, 1, runtime_size, output);

    padding = (os_vm_page_size - (runtime_size % os_vm_page_size)) & ~os_vm_page_size;
    if (padding > 0) {
        padbytes = successful_malloc(padding);
        memset(padbytes, 0, padding);
        fwrite(padbytes, 1, padding, output);
        free(padbytes);
    }

    return 1;
}

FILE *
prepare_to_save(char *filename, boolean prepend_runtime, void **runtime_bytes,
                size_t *runtime_size)
{
    FILE *file;
    char *runtime_path;

    if (prepend_runtime) {
        runtime_path = os_get_runtime_executable_path();

        if (runtime_path == NULL) {
            fprintf(stderr, "Unable to get default runtime path.\n");
            return NULL;
        }

        *runtime_bytes = load_runtime(runtime_path, runtime_size);
        free(runtime_path);

        if (*runtime_bytes == NULL)
            return 0;
    }

    file = open_core_for_saving(filename);
    if (file == NULL) {
        free(*runtime_bytes);
        perror(filename);
        return NULL;
    }

    return file;
}

boolean
save(char *filename, lispobj init_function, boolean prepend_runtime)
{
    FILE *file;
    void *runtime_bytes = NULL;
    size_t runtime_size;

    file = prepare_to_save(filename, prepend_runtime, &runtime_bytes, &runtime_size);
    if (file == NULL)
        return 1;

    if (prepend_runtime)
        save_runtime_to_filehandle(file, runtime_bytes, runtime_size);

    return save_to_filehandle(file, filename, init_function, prepend_runtime);
}