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 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */
​
/* For reference see
 * http://www.pkware.com/company/standards/appnote/
 * http://www.info-zip.org/pub/infozip/doc/appnote-iz-latest.zip
 */
​
/* TODO
 * Endian issues
 * Zip64 + other methods
 * Improve handling of zip format, ie.
 * - deferred CRC, comp. & uncomp. lengths (zip header flags bit 3)
 * - unix file permissions, etc.
 * - central directory
 */
​
#include "libbb.h"
#include "unarchive.h"
​
enum {
#if BB_BIG_ENDIAN
    ZIP_FILEHEADER_MAGIC = 0x504b0304,
    ZIP_CDS_MAGIC        = 0x504b0102,
    ZIP_CDS_END_MAGIC    = 0x504b0506,
    ZIP_CDE_MAGIC        = 0x504b0506,
    ZIP_DD_MAGIC         = 0x504b0708,
#else
    ZIP_FILEHEADER_MAGIC = 0x04034b50,
    ZIP_CDS_MAGIC        = 0x02014b50,
    ZIP_CDS_END_MAGIC    = 0x06054b50,
    ZIP_CDE_MAGIC        = 0x06054b50,
    ZIP_DD_MAGIC         = 0x08074b50,
#endif
};
​
#define ZIP_HEADER_LEN 26
​
typedef union {
    uint8_t raw[ZIP_HEADER_LEN];
    struct {
        uint16_t version;                       /* 0-1 */
        uint16_t flags;                         /* 2-3 */
        uint16_t method;                        /* 4-5 */
        uint16_t modtime;                       /* 6-7 */
        uint16_t moddate;                       /* 8-9 */
        uint32_t crc32 PACKED;        /* 10-13 */
        uint32_t cmpsize PACKED;      /* 14-17 */
        uint32_t ucmpsize PACKED;     /* 18-21 */
        uint16_t filename_len;                  /* 22-23 */
        uint16_t extra_len;                     /* 24-25 */
        uint16_t version;               /* 0-1 */
        uint16_t flags;                 /* 2-3 */
        uint16_t method;                /* 4-5 */
        uint16_t modtime;               /* 6-7 */
        uint16_t moddate;               /* 8-9 */
        uint32_t crc32 PACKED;          /* 10-13 */
        uint32_t cmpsize PACKED;        /* 14-17 */
        uint32_t ucmpsize PACKED;       /* 18-21 */
        uint16_t filename_len;          /* 22-23 */
        uint16_t extra_len;             /* 24-25 */
    } formatted PACKED;
} zip_header_t; /* PACKED - gcc 4.2.1 doesn't like it (spews warning) */
​
/* Check the offset of the last element, not the length.  This leniency
 * allows for poor packing, whereby the overall struct may be too long,
 * even though the elements are all in the right place.
 */
struct BUG_zip_header_must_be_26_bytes {
    char BUG_zip_header_must_be_26_bytes[
        offsetof(zip_header_t, formatted.extra_len) + 2 ==
            ZIP_HEADER_LEN ? 1 : -1];
        offsetof(zip_header_t, formatted.extra_len) + 2
            == ZIP_HEADER_LEN ? 1 : -1];
};
​
#define FIX_ENDIANNESS(zip_header) do { \
#define FIX_ENDIANNESS_ZIP(zip_header) do { \
    (zip_header).formatted.version      = SWAP_LE16((zip_header).formatted.version     ); \
    (zip_header).formatted.flags        = SWAP_LE16((zip_header).formatted.flags       ); \
    (zip_header).formatted.method       = SWAP_LE16((zip_header).formatted.method      ); \
    (zip_header).formatted.modtime      = SWAP_LE16((zip_header).formatted.modtime     ); \
    (zip_header).formatted.moddate      = SWAP_LE16((zip_header).formatted.moddate     ); \
    (zip_header).formatted.crc32        = SWAP_LE32((zip_header).formatted.crc32       ); \
    (zip_header).formatted.cmpsize      = SWAP_LE32((zip_header).formatted.cmpsize     ); \
    (zip_header).formatted.ucmpsize     = SWAP_LE32((zip_header).formatted.ucmpsize    ); \
    (zip_header).formatted.filename_len = SWAP_LE16((zip_header).formatted.filename_len); \
    (zip_header).formatted.extra_len    = SWAP_LE16((zip_header).formatted.extra_len   ); \
} while (0)
​
static void unzip_skip(int fd, off_t skip)
#define CDS_HEADER_LEN 42
​
typedef union {
    uint8_t raw[CDS_HEADER_LEN];
    struct {
        /* uint32_t signature; 50 4b 01 02 */
        uint16_t version_made_by;       /* 0-1 */
        uint16_t version_needed;        /* 2-3 */
        uint16_t cds_flags;             /* 4-5 */
        uint16_t method;                /* 6-7 */
        uint16_t mtime;                 /* 8-9 */
        uint16_t mdate;                 /* 10-11 */
        uint32_t crc32;                 /* 12-15 */
        uint32_t cmpsize;               /* 16-19 */
        uint32_t ucmpsize;              /* 20-23 */
        uint16_t file_name_length;      /* 24-25 */
        uint16_t extra_field_length;    /* 26-27 */
        uint16_t file_comment_length;   /* 28-29 */
        uint16_t disk_number_start;     /* 30-31 */
        uint16_t internal_file_attributes; /* 32-33 */
        uint32_t external_file_attributes PACKED; /* 34-37 */
        uint32_t relative_offset_of_local_header PACKED; /* 38-41 */
    } formatted PACKED;
} cds_header_t;
​
struct BUG_cds_header_must_be_42_bytes {
    char BUG_cds_header_must_be_42_bytes[
        offsetof(cds_header_t, formatted.relative_offset_of_local_header) + 4
            == CDS_HEADER_LEN ? 1 : -1];
};
​
#define FIX_ENDIANNESS_CDS(cds_header) do { \
    (cds_header).formatted.crc32        = SWAP_LE32((cds_header).formatted.crc32       ); \
    (cds_header).formatted.cmpsize      = SWAP_LE32((cds_header).formatted.cmpsize     ); \
    (cds_header).formatted.ucmpsize     = SWAP_LE32((cds_header).formatted.ucmpsize    ); \
    (cds_header).formatted.file_name_length = SWAP_LE16((cds_header).formatted.file_name_length); \
    (cds_header).formatted.extra_field_length = SWAP_LE16((cds_header).formatted.extra_field_length); \
    (cds_header).formatted.file_comment_length = SWAP_LE16((cds_header).formatted.file_comment_length); \
} while (0)
​
#define CDE_HEADER_LEN 16
​
typedef union {
    uint8_t raw[CDE_HEADER_LEN];
    struct {
        /* uint32_t signature; 50 4b 05 06 */
        uint16_t this_disk_no;
        uint16_t disk_with_cds_no;
        uint16_t cds_entries_on_this_disk;
        uint16_t cds_entries_total;
        uint32_t cds_size;
        uint32_t cds_offset;
        /* uint16_t file_comment_length; */
        /* .ZIP file comment (variable size) */
    } formatted PACKED;
} cde_header_t;
​
struct BUG_cde_header_must_be_16_bytes {
    char BUG_cde_header_must_be_16_bytes[
        sizeof(cde_header_t) == CDE_HEADER_LEN ? 1 : -1];
};
​
#define FIX_ENDIANNESS_CDE(cde_header) do { \
    (cde_header).formatted.cds_offset = SWAP_LE16((cde_header).formatted.cds_offset); \
} while (0)
​
enum { zip_fd = 3 };
​
​
#if ENABLE_DESKTOP
/* NB: does not preserve file position! */
static uint32_t find_cds_offset(void)
{
    unsigned char buf[1024];
    cde_header_t cde_header;
    unsigned char *p;
    off_t end;
​
    end = xlseek(zip_fd, 0, SEEK_END);
    if (end < 1024)
        end = 1024;
    end -= 1024;
    xlseek(zip_fd, end, SEEK_SET);
    full_read(zip_fd, buf, 1024);
​
    p = buf;
    while (p <= buf + 1024 - CDE_HEADER_LEN - 4) {
        if (*p != 'P') {
            p++;
            continue;
        }
        if (*++p != 'K')
            continue;
        if (*++p != 5)
            continue;
        if (*++p != 6)
            continue;
        /* we found CDE! */
        memcpy(cde_header.raw, p + 1, CDE_HEADER_LEN);
        FIX_ENDIANNESS_CDE(cde_header);
        return cde_header.formatted.cds_offset;
    }
    bb_error_msg_and_die("can't find file table");
};
​
static uint32_t read_next_cds(int count_m1, uint32_t cds_offset, cds_header_t *cds_ptr)
{
    bb_copyfd_exact_size(fd, -1, skip);
    off_t org;
​
    org = xlseek(zip_fd, 0, SEEK_CUR);
​
    if (!cds_offset)
        cds_offset = find_cds_offset();
​
    while (count_m1-- >= 0) {
        xlseek(zip_fd, cds_offset + 4, SEEK_SET);
        xread(zip_fd, cds_ptr->raw, CDS_HEADER_LEN);
        FIX_ENDIANNESS_CDS(*cds_ptr);
        cds_offset += 4 + CDS_HEADER_LEN
            + cds_ptr->formatted.file_name_length
            + cds_ptr->formatted.extra_field_length
            + cds_ptr->formatted.file_comment_length;
    }
​
    xlseek(zip_fd, org, SEEK_SET);
    return cds_offset;
};
#endif
​
static void unzip_skip(off_t skip)
{
    bb_copyfd_exact_size(zip_fd, -1, skip);
}
​
static void unzip_create_leading_dirs(const char *fn)
{
    /* Create all leading directories */
    char *name = xstrdup(fn);
    if (bb_make_directory(dirname(name), 0777, FILEUTILS_RECUR)) {
        bb_error_msg_and_die("exiting"); /* bb_make_directory is noisy */
    }
    free(name);
}
​
static void unzip_extract(zip_header_t *zip_header, int src_fd, int dst_fd)
static void unzip_extract(zip_header_t *zip_header, int dst_fd)
{
    if (zip_header->formatted.method == 0) {
        /* Method 0 - stored (not compressed) */
        off_t size = zip_header->formatted.ucmpsize;
        if (size)
            bb_copyfd_exact_size(src_fd, dst_fd, size);
            bb_copyfd_exact_size(zip_fd, dst_fd, size);
    } else {
        /* Method 8 - inflate */
        inflate_unzip_result res;
        if (inflate_unzip(&res, zip_header->formatted.cmpsize, src_fd, dst_fd) < 0)
        if (inflate_unzip(&res, zip_header->formatted.cmpsize, zip_fd, dst_fd) < 0)
            bb_error_msg_and_die("inflate error");
        /* Validate decompression - crc */
        if (zip_header->formatted.crc32 != (res.crc ^ 0xffffffffL)) {
            bb_error_msg_and_die("crc error");
        }
        /* Validate decompression - size */
        if (zip_header->formatted.ucmpsize != res.bytes_out) {
            /* Don't die. Who knows, maybe len calculation
             * was botched somewhere. After all, crc matched! */
            bb_error_msg("bad length");
Show more
​
int unzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int unzip_main(int argc, char **argv)
{
    enum { O_PROMPT, O_NEVER, O_ALWAYS };
​
    zip_header_t zip_header;
    smallint verbose = 1;
    smallint listing = 0;
    smallint overwrite = O_PROMPT;
#if ENABLE_DESKTOP
    uint32_t cds_offset;
    unsigned cds_entries;
#endif
    unsigned total_size;
    unsigned total_entries;
    int src_fd = -1;
    int dst_fd = -1;
    char *src_fn = NULL;
    char *dst_fn = NULL;
    llist_t *zaccept = NULL;
    llist_t *zreject = NULL;
    char *base_dir = NULL;
    int i, opt;
    int opt_range = 0;
    char key_buf[80];
    struct stat stat_buf;
Show more
            bb_show_usage();
        }
    }
​
    if (src_fn == NULL) {
        bb_show_usage();
    }
​
    /* Open input file */
    if (LONE_DASH(src_fn)) {
        src_fd = STDIN_FILENO;
        xdup2(STDIN_FILENO, zip_fd);
        /* Cannot use prompt mode since zip data is arriving on STDIN */
        if (overwrite == O_PROMPT)
            overwrite = O_NEVER;
    } else {
        static const char extn[][5] = {"", ".zip", ".ZIP"};
        int orig_src_fn_len = strlen(src_fn);
        int src_fd = -1;
​
        for (i = 0; (i < 3) && (src_fd == -1); i++) {
            strcpy(src_fn + orig_src_fn_len, extn[i]);
            src_fd = open(src_fn, O_RDONLY);
        }
        if (src_fd == -1) {
            src_fn[orig_src_fn_len] = '\0';
            bb_error_msg_and_die("can't open %s, %s.zip, %s.ZIP", src_fn, src_fn, src_fn);
        }
        xmove_fd(src_fd, zip_fd);
    }
​
    /* Change dir if necessary */
    if (base_dir)
        xchdir(base_dir);
​
    if (verbose) {
        printf("Archive:  %s\n", src_fn);
        if (listing){
            puts("  Length     Date   Time    Name\n"
                 " --------    ----   ----    ----");
        }
    }
​
    total_size = 0;
    total_entries = 0;
#if ENABLE_DESKTOP
    cds_entries = 0;
    cds_offset = 0;
#endif
    while (1) {
        uint32_t magic;
​
        /* Check magic number */
        xread(src_fd, &magic, 4);
        xread(zip_fd, &magic, 4);
        /* Central directory? It's at the end, so exit */
        if (magic == ZIP_CDS_MAGIC)
            break;
#if ENABLE_DESKTOP
        /* Data descriptor? It was a streaming file, go on */
        if (magic == ZIP_DD_MAGIC) {
            /* skip over duplicate crc32, cmpsize and ucmpsize */
            unzip_skip(3 * 4);
            continue;
        }
#endif
        if (magic != ZIP_FILEHEADER_MAGIC)
            bb_error_msg_and_die("invalid zip magic %08X", (int)magic);
​
        /* Read the file header */
        xread(src_fd, zip_header.raw, ZIP_HEADER_LEN);
        FIX_ENDIANNESS(zip_header);
        xread(zip_fd, zip_header.raw, ZIP_HEADER_LEN);
        FIX_ENDIANNESS_ZIP(zip_header);
        if ((zip_header.formatted.method != 0) && (zip_header.formatted.method != 8)) {
            bb_error_msg_and_die("unsupported method %d", zip_header.formatted.method);
        }
        if (zip_header.formatted.flags & (0x0008|0x0001)) {
#if !ENABLE_DESKTOP
        if (zip_header.formatted.flags & 0x0009) {
            bb_error_msg_and_die("zip flags 1 and 8 are not supported");
        }
#else
        if (zip_header.formatted.flags & 0x0001) {
            /* 0x0001 - encrypted */
            bb_error_msg_and_die("zip flag 1 (encryption) is not supported");
        }
        if (zip_header.formatted.flags & 0x0008) {
            cds_header_t cds_header;
            /* 0x0008 - streaming. [u]cmpsize can be reliably gotten
             * only from Central Directory. See unzip_doc.txt */
            bb_error_msg_and_die("zip flags 8 and 1 are not supported");
            cds_offset = read_next_cds(total_entries - cds_entries, cds_offset, &cds_header);
            cds_entries = total_entries + 1;
            zip_header.formatted.crc32    = cds_header.formatted.crc32;
            zip_header.formatted.cmpsize  = cds_header.formatted.cmpsize;
            zip_header.formatted.ucmpsize = cds_header.formatted.ucmpsize;
        }
#endif
​
        /* Read filename */
        free(dst_fn);
        dst_fn = xzalloc(zip_header.formatted.filename_len + 1);
        xread(src_fd, dst_fn, zip_header.formatted.filename_len);
        xread(zip_fd, dst_fn, zip_header.formatted.filename_len);
​
        /* Skip extra header bytes */
        unzip_skip(src_fd, zip_header.formatted.extra_len);
        unzip_skip(zip_header.formatted.extra_len);
​
        /* Filter zip entries */
        if (find_list_entry(zreject, dst_fn)
         || (zaccept && !find_list_entry(zaccept, dst_fn))
        ) { /* Skip entry */
            i = 'n';
​
        } else { /* Extract entry */
            if (listing) { /* List entry */
                if (verbose) {
                    unsigned dostime = zip_header.formatted.modtime | (zip_header.formatted.moddate << 16);
                    printf("%9u  %02u-%02u-%02u %02u:%02u   %s\n",
                       zip_header.formatted.ucmpsize,
                       (dostime & 0x01e00000) >> 21,
                       (dostime & 0x001f0000) >> 16,
                       (((dostime & 0xfe000000) >> 25) + 1980) % 100,
                       (dostime & 0x0000f800) >> 11,
                       (dostime & 0x000007e0) >> 5,
                       dst_fn);
                    total_size += zip_header.formatted.ucmpsize;
                    total_entries++;
                } else {
                    /* short listing -- filenames only */
                    puts(dst_fn);
                }
                i = 'n';
            } else if (dst_fd == STDOUT_FILENO) { /* Extracting to STDOUT */
                i = -1;
            } else if (last_char_is(dst_fn, '/')) { /* Extract directory */
                if (stat(dst_fn, &stat_buf) == -1) {
                    if (errno != ENOENT) {
                        bb_perror_msg_and_die("cannot stat '%s'", dst_fn);
                        bb_perror_msg_and_die("can't stat '%s'", dst_fn);
                    }
                    if (verbose) {
                        printf("   creating: %s\n", dst_fn);
                    }
                    unzip_create_leading_dirs(dst_fn);
                    if (bb_make_directory(dst_fn, 0777, 0)) {
                        bb_error_msg_and_die("exiting");
                    }
                } else {
                    if (!S_ISDIR(stat_buf.st_mode)) {
                        bb_error_msg_and_die("'%s' exists but is not directory", dst_fn);
                    }
                }
                i = 'n';
​
            } else {  /* Extract file */
 check_file:
                if (stat(dst_fn, &stat_buf) == -1) { /* File does not exist */
                    if (errno != ENOENT) {
                        bb_perror_msg_and_die("cannot stat '%s'", dst_fn);
                        bb_perror_msg_and_die("can't stat '%s'", dst_fn);
                    }
                    i = 'y';
                } else { /* File already exists */
                    if (overwrite == O_NEVER) {
                        i = 'n';
                    } else if (S_ISREG(stat_buf.st_mode)) { /* File is regular file */
                        if (overwrite == O_ALWAYS) {
                            i = 'y';
                        } else {
                            printf("replace %s? [y]es, [n]o, [A]ll, [N]one, [r]ename: ", dst_fn);
                            if (!fgets(key_buf, sizeof(key_buf), stdin)) {
                                bb_perror_msg_and_die("cannot read input");
                                bb_perror_msg_and_die("can't read input");
                            }
                            i = key_buf[0];
                        }
                    } else { /* File is not regular file */
                        bb_error_msg_and_die("'%s' exists but is not regular file", dst_fn);
                    }
                }
            }
        }
​
        switch (i) {
        case 'A':
            overwrite = O_ALWAYS;
        case 'y': /* Open file and fall into unzip */
            unzip_create_leading_dirs(dst_fn);
            dst_fd = xopen(dst_fn, O_WRONLY | O_CREAT | O_TRUNC);
        case -1: /* Unzip */
            if (verbose) {
                printf("  inflating: %s\n", dst_fn);
            }
            unzip_extract(&zip_header, src_fd, dst_fd);
            unzip_extract(&zip_header, dst_fd);
            if (dst_fd != STDOUT_FILENO) {
                /* closing STDOUT is potentially bad for future business */
                close(dst_fd);
            }
            break;
​
        case 'N':
            overwrite = O_NEVER;
        case 'n':
            /* Skip entry data */
            unzip_skip(src_fd, zip_header.formatted.cmpsize);
            unzip_skip(zip_header.formatted.cmpsize);
            break;
​
        case 'r':
            /* Prompt for new name */
            printf("new name: ");
            if (!fgets(key_buf, sizeof(key_buf), stdin)) {
                bb_perror_msg_and_die("cannot read input");
                bb_perror_msg_and_die("can't read input");
            }
            free(dst_fn);
            dst_fn = xstrdup(key_buf);
            chomp(dst_fn);
            goto check_file;
​
        default:
            printf("error: invalid response [%c]\n",(char)i);
            goto check_file;
        }
​
// Looks like bug (data descriptor cannot be identified this way)
//      /* Data descriptor section */
//      if (zip_header.formatted.flags & 4) {
//          /* skip over duplicate crc, compressed size and uncompressed size */
//          unzip_skip(src_fd, 12);
//      }
        total_entries++;
    }
​
    if (listing && verbose) {
        printf(" --------                   -------\n"
               "%9d                   %d files\n",
               total_size, total_entries);
    }
​
    return 0;
}