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/*

 * This file is part of the FDNPKG project

 * http://fdnpkg.sourceforge.net

 *

 * Copyright (C) 2012-2016 Mateusz Viste. All rights reserved.

 *

 * Simple library providing functions to unzip files from zip archives.

 */

#include <stdio.h>     /* printf(), FILE, fclose()... */

#include <stdlib.h>    /* NULL */

#include <string.h>    /* memset() */

#include <time.h>      /* mktime() */

#include <utime.h>     /* utime() */

#include <unistd.h>   /* unlink() */

#include "crc32.h"

#include "kprintf.h"

#include "parsecmd.h"

#ifndef NOLZMA

  #include "lzmadec.h"   /* LZMA support */

#endif

#include "inf.h"   /* DEFLATE support */

#include "version.h"

#include "libunzip.h"  /* include self for control */

/* converts a "DOS format" timestamp into unix timestamp. The DOS timestamp is constructed an array of 4 bytes, that contains following data at the bit level:

 * HHHHHMMM MMMSSSSS YYYYYYYM MMMDDDDD

 *  where:

 * day of month is always within 1-31 range;

 * month is always within 1-12 range;

 * year starts from 1980 and continues for 127 years

 * seconds are actually not 0-59 but rather 0-29 as there are only 32 possible values – to get actual seconds multiply this field by 2;

 * minutes are always within 0-59 range;

 * hours are always within 0-23 range.     */

static time_t dostime2unix(unsigned char *buff) {

  struct tm curtime;

  time_t result;

  memset(&curtime, 0, sizeof(curtime)); /* make sure to set everything in curtime to 0's */

  curtime.tm_sec = (buff[0] & 31) << 1; /* seconds (0..60) */

  curtime.tm_min = (((buff[1] << 8) | buff[0]) >> 5) & 63 ; /* minutes after the hour (0..59) */

  curtime.tm_hour = (buff[1] >> 3); /* hours since midnight (0..23) */

  curtime.tm_mday = buff[2] & 31; /* day of the month (1..31) */

  curtime.tm_mon = ((((buff[3] << 8) | buff[2]) >> 5) & 15) - 1; /* months since January (0, 11) */

  curtime.tm_year = (buff[3] >> 1) + 80; /* years since 1900 */

  curtime.tm_wday = 0; /* days since Sunday (0..6) - leave 0, mktime() will set it */

  curtime.tm_yday = 0; /* days since January 1 (0..365]) - leave 0, mktime() will set it */

  curtime.tm_isdst = -1; /* Daylight Saving Time flag. Positive if DST is in effect, zero if not and negative if no information is available */

  result = mktime(&curtime);

  if (result == (time_t)-1) return(0);

  return(result);

}

#ifndef NOLZMA

/* this is a wrapper on malloc(), used as a callback by lzmadec */

static void *SzAlloc(void *p, size_t size) {

  p = p; /* for gcc to not complain */

  if (size == 0) return(0);

  return(malloc(size));

}

/* this is a wrapper on free(), used as a callback by lzmadec */

static void SzFree(void *p, void *address) {

  p = p;  /* for gcc to not complain */

  free(address);

}

#endif

/* opens a zip file and provides the list of files in the archive.

   returns a pointer to a ziplist (linked list) with all records, or NULL on error.

   The ziplist is allocated automatically, and must be freed via zip_freelist. */

struct ziplist *zip_listfiles(FILE *fd) {

  struct ziplist *reslist = NULL;

  struct ziplist *newentry;

  unsigned long entrysig;

  unsigned short filenamelen, extrafieldlen, filecommentlen;

  unsigned long compfilelen;

  int centraldirectoryfound = 0;

  unsigned int ux;

  unsigned char hdrbuff[64];

  rewind(fd);  /* make sure the file cursor is at the very beginning of the file */

  for (;;) { /* read entry after entry */

    int x, eofflag;

    long longbuff;

    entrysig = 0;

    eofflag = 0;

    /* read the entry signature first */

    for (x = 0; x < 32; x += 8) {

      if ((longbuff = fgetc(fd)) == EOF) {

        eofflag = 1;

        break;

      }

      entrysig |= (longbuff << x);

    }

    if (eofflag != 0) break;

    /* printf("sig: 0x%08x\n", entrysig); */

    if (entrysig == 0x04034b50ul) { /* local file */

      unsigned int generalpurposeflags;

      /* read and parse the zip header */

      fread(hdrbuff, 1, 26, fd);

      /* read filename's length so I can allocate the proper amound of mem */

      filenamelen = hdrbuff[23];

      filenamelen <<= 8;

      filenamelen |= hdrbuff[22];

      /* create new entry and link it into the list */

      newentry = calloc(sizeof(struct ziplist) + filenamelen, 1);

      if (newentry == NULL) {

        kitten_puts(8, 0, "Out of memory!");

        zip_freelist(&reslist);

        break;

      }

      newentry->nextfile = reslist;

      newentry->flags = 0;

      reslist = newentry;

      /* read further areas of the header, and fill zip entry */

      generalpurposeflags = hdrbuff[3];  /* parse the general */

      generalpurposeflags <<= 8;         /* purpose flags and */

      generalpurposeflags |= hdrbuff[2]; /* save them for later */

      newentry->compmethod = hdrbuff[4] | (hdrbuff[5] << 8);

      newentry->timestamp = dostime2unix(&hdrbuff[6]);

      newentry->crc32 = 0;

      for (x = 13; x >= 10; x--) {

        newentry->crc32 <<= 8;

        newentry->crc32 |= hdrbuff[x];

      }

      newentry->compressedfilelen = 0;

      for (x = 17; x >= 14; x--) {

        newentry->compressedfilelen <<= 8;

        newentry->compressedfilelen |= hdrbuff[x];

      }

      newentry->filelen = 0;

      for (x = 21; x >= 18; x--) {

        newentry->filelen <<= 8;

        newentry->filelen |= hdrbuff[x];

      }

      extrafieldlen = hdrbuff[25];

      extrafieldlen <<= 8;

      extrafieldlen |= hdrbuff[24];

      /* printf("Filename len: %d / extrafield len: %d / compfile len: %ld / filelen: %ld\n", filenamelen, extrafieldlen, newentry->compressedfilelen, newentry->filelen); */

      /* check general purpose flags */

      if ((generalpurposeflags & 1) != 0) newentry->flags |= ZIP_FLAG_ENCRYPTED;

      /* parse the filename */

      for (ux = 0; ux < filenamelen; ux++) newentry->filename[ux] = fgetc(fd); /* store filename */

      if (newentry->filename[filenamelen - 1] == '/') newentry->flags |= ZIP_FLAG_ISADIR; /* if filename ends with / it's a dir. Note that ZIP forbids the usage of '\' in ZIP paths anyway */

      /* printf("Filename: %s (%ld bytes compressed)\n", newentry->filename, newentry->compressedfilelen); */

      newentry->dataoffset = ftell(fd) + extrafieldlen;

      /* skip rest of fields and data */

      fseek(fd, (extrafieldlen + newentry->compressedfilelen), SEEK_CUR);

    } else if (entrysig == 0x02014b50ul) { /* central directory */

      centraldirectoryfound = 1;

      /* parse header now */

      fread(hdrbuff, 1, 42, fd);

      filenamelen = hdrbuff[22] | (hdrbuff[23] << 8);

      extrafieldlen = hdrbuff[24] | (hdrbuff[25] << 8);

      filecommentlen = hdrbuff[26] | (hdrbuff[27] << 8);

      compfilelen = 0;

      for (x = 17; x >= 14; x--) {

        compfilelen <<= 8;

        compfilelen |= hdrbuff[x];

      }

      /* printf("central dir\n"); */

      /* skip rest of fields and data */

      fseek(fd, (filenamelen + extrafieldlen + compfilelen + filecommentlen), SEEK_CUR);

    } else if (entrysig == 0x08074b50ul) { /* Data descriptor header */

      /* no need to read the header we just have to skip it */

      fseek(fd, 12, SEEK_CUR); /* the header is 3x4 bytes (CRC + compressed len + uncompressed len) */

    } else { /* unknown sig */

      kitten_printf(8, 1, "unknown zip sig: 0x%08lx", entrysig);

      puts("");

      zip_freelist(&reslist);

      break;

    }

  }

  /* if we got no central directory record, the file is incomplete */

  if (centraldirectoryfound == 0) zip_freelist(&reslist);

  return(reslist);

}

/* unzips a file. zipfd points to the open zip file, curzipnode to the entry to extract, and fulldestfilename is the destination file where to unzip it. returns 0 on success, non-zero otherwise. */

int zip_unzip(FILE *zipfd, struct ziplist *curzipnode, char *fulldestfilename) {

  #define buffsize 32 * 1024l /* MUST be at least 32K */

  FILE *filefd;

  unsigned long cksum;

  int extract_res;

  unsigned char *buff;

  struct utimbuf filetimestamp;

  /* first of all, check we support the compression method */

  switch (curzipnode->compmethod) {

    case 0:  /* stored */

    case 8:  /* deflated */

#ifndef NOLZMA

    case 14: /* lzma */

#endif

      break;

    default: /* unsupported compression method, sorry */

      return(-1);

      break;

  }

  /* open the dst file */

  filefd = fopen(fulldestfilename, "wb");

  if (filefd == NULL) return(-2);  /* failed to open the dst file */

  /* allocate buffers for data I/O */

  buff = malloc(buffsize);

  if (buff == NULL) {

    fclose(filefd);

    unlink(fulldestfilename); /* remove the failed file once it is closed */

    return(-6);

  }

  if (fseek(zipfd, curzipnode->dataoffset, SEEK_SET) != 0) { /* set the reading position inside the zip file */

    free(buff);

    fclose(filefd);

    unlink(fulldestfilename); /* remove the failed file once it is closed */

    return(-7);

  }

  extract_res = -255;

  cksum = crc32_init(); /* init the crc32 */

  if (curzipnode->compmethod == 0) { /* if the file is stored, copy it over */

    long i, toread;

    extract_res = 0;   /* assume we will succeed */

    for (i = 0; i < curzipnode->filelen;) {

      toread = curzipnode->filelen - i;

      if (toread > buffsize) toread = buffsize;

      if (fread(buff, toread, 1, zipfd) != 1) extract_res = -3;   /* read a chunk of data */

      crc32_feed(&cksum, buff, toread); /* update the crc32 checksum */

      if (fwrite(buff, toread, 1, filefd) != 1) extract_res = -4; /* write data chunk to dst file */

      i += toread;

    }

  } else if (curzipnode->compmethod == 8) {  /* if the file is deflated, inflate it */

    extract_res = inf(zipfd, filefd, buff, &cksum, curzipnode->compressedfilelen);

#ifndef NOLZMA

  } else if (curzipnode->compmethod == 14) {  /* LZMA */

    #define lzmaoutbufflen 32768u

    long bytesread, bytesreadtotal = 0, byteswritetotal = 0;

    SizeT buffoutreslen;

    ISzAlloc g_alloc;

    ELzmaStatus lzmastatus;

    SRes lzmaresult;

    CLzmaDec lzmahandle;

    unsigned char lzmahdr[LZMA_PROPS_SIZE]; /* 5 bytes of properties */

    unsigned char *lzmaoutbuff;

    extract_res = -5; /* assume we will fail. if we don't - then we will update this flag */

    lzmaoutbuff = malloc(lzmaoutbufflen);

    if (lzmaoutbuff == NULL) {

      free(buff);

      fclose(filefd);   /* close the dst file */

      return(-33);

    }

    fread(lzmahdr, 4, 1, zipfd); /* load the 4 bytes long 'zip-lzma header */

    bytesreadtotal = 4; /* remember we read 4 bytes already */

    /* lzma properties should be exactly 5 bytes long. If it's not, it's either not valid lzma, or some version that wasn't existing yet when I wrote these words. Also, check that the lzma content is at least 9 bytes long and that our previous malloc() calls suceeded. */

    if ((lzmahdr[2] == 5) && (lzmahdr[3] == 0) && (curzipnode->compressedfilelen >= 9)) {

      extract_res = 0;  /* since we got so far, let's assume we will succeed now */

      g_alloc.Alloc = SzAlloc; /* these will be used as callbacks by lzma to manage memory */

      g_alloc.Free = SzFree;

      fread(lzmahdr, sizeof(lzmahdr), 1, zipfd); /* load the lzma header */

      bytesreadtotal += sizeof(lzmahdr);

      /* Note, that in a 'normal' lzma stream we would have now 8 bytes with the uncompressed length of the file. Here we don't. ZIP cut this information out, since it stores it already in its own header. */

      memset(&lzmahandle, 0, sizeof(lzmahandle)); /* reset the whole lzmahandle structure - not doing this leads to CRASHES!!! */

      LzmaDec_Init(&lzmahandle);

      lzmaresult = LzmaDec_Allocate(&lzmahandle, lzmahdr, LZMA_PROPS_SIZE, &g_alloc); /* forget not to LzmaDec_Free() later! */

      if (lzmaresult != 0) extract_res = -13;

      while (extract_res == 0) {

        bytesread = buffsize;

        if (bytesread > curzipnode->compressedfilelen - bytesreadtotal) bytesread = curzipnode->compressedfilelen - bytesreadtotal;

        buffoutreslen = lzmaoutbufflen;

        /* printf("Will read %d bytes from input stream\n", bytesread); */

        fread(buff, bytesread, 1, zipfd); /* read stuff from input stream */

        fseek(zipfd, 0 - bytesread, SEEK_CUR); /* get back to the position at the start of our chunk of data */

        lzmaresult = LzmaDec_DecodeToBuf(&lzmahandle, lzmaoutbuff, &buffoutreslen, buff, (SizeT *)&bytesread, LZMA_FINISH_ANY, &lzmastatus);

        bytesreadtotal += bytesread;

        /* printf("expanded %ld bytes into %ld (total read: %ld bytes)\n", (long)bytesread, (long)buffoutreslen, (long)bytesreadtotal); */

        fseek(zipfd, bytesread, SEEK_CUR); /* go forward to the position next to the input we processed */

        if (lzmaresult != SZ_OK) {

          extract_res = -20;

          if (lzmaresult == SZ_ERROR_DATA) extract_res = -21;        /* DATA ERROR */

          if (lzmaresult == SZ_ERROR_MEM) extract_res = -22;         /* MEMORY ALLOC ERROR */

          if (lzmaresult == SZ_ERROR_UNSUPPORTED) extract_res = -23; /* UNSUPPORTED PROPERTY */

          if (lzmaresult == SZ_ERROR_INPUT_EOF) extract_res = -24;   /* NEED MORE INPUT */

          break;

        }

        /* check that we haven't got TOO MUCH decompressed data, and trim if necessary. It happens that LZMA provides a few bytes more than it should at the end of the stream. */

        if (byteswritetotal + (long)buffoutreslen > curzipnode->filelen) {

          buffoutreslen = curzipnode->filelen - byteswritetotal;

        }

        byteswritetotal += buffoutreslen;

        fwrite(lzmaoutbuff, buffoutreslen, 1, filefd); /* write stuff to output file */

        crc32_feed(&cksum, lzmaoutbuff, buffoutreslen);

        /* if (lzmastatus == LZMA_STATUS_FINISHED_WITH_MARK) puts("lzma says we are done!"); */

        if ((lzmastatus == LZMA_STATUS_FINISHED_WITH_MARK) || (bytesreadtotal >= curzipnode->compressedfilelen)) {

          extract_res = 0; /* looks like we succeeded! */

          break;

        }

      }

      LzmaDec_Free(&lzmahandle, &g_alloc); /* this will free all the stuff we allocated via LzmaDec_Allocate() */

      /* printf("Processed %d bytes of input into %d bytes of output. CRC32: %08lX\n", bytesreadtotal, byteswritetotal, crc32); */

    }

    free(lzmaoutbuff);

#endif

  }

  /* clean up memory, close the dst file and terminates crc32 */

  free(buff);

  fclose(filefd);   /* close the dst file */

  crc32_finish(&cksum);

  /* printf("extract_res=%d / cksum_expected=%08lX / cksum_obtained=%08lX\n", extract_res, curzipnode->crc32, cksum); */

  if (extract_res != 0) {  /* was the extraction process successful? */

    unlink(fulldestfilename); /* remove the failed file */

    return(extract_res);

  }

  if (cksum != curzipnode->crc32) { /* is the crc32 ok after extraction? */

    unlink(fulldestfilename); /* remove the failed file */

    return(-9);

  }

  /* Set the timestamp of the new file to what was set in the zip file */

  filetimestamp.actime  = curzipnode->timestamp;

  filetimestamp.modtime = curzipnode->timestamp;

  utime(fulldestfilename, &filetimestamp);

  return(0);

}

/* Call this to free a ziplist computed by zip_listfiles() */

void zip_freelist(struct ziplist **ziplist) {

  struct ziplist *zipentrytobefreed;

  while (*ziplist != NULL) { /* iterate through the linked list and free all nodes */

    zipentrytobefreed = *ziplist;

    *ziplist = zipentrytobefreed->nextfile;

    /* free the node entry */

    free(zipentrytobefreed);

  }

  *ziplist = NULL;

}