unzip: handle "central directory"

 needed for OpenOffice, gmail attachment .zips etc
 conditional on CONFIG_DESKTOP

function                                             old     new   delta
unzip_main                                          1643    1939    +296
find_cds_offset                                        -     173    +173
unzip_skip                                            11      16      +5
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/0 up/down: 474/0)             Total: 474 bytes

1 files changed, 196 insertions, 47 deletions

diff --git a/archival/unzip.c b/archival/unzip.c
index 1c9bc246c..e468ff451 100644
--- a/archival/unzip.c
+++ b/archival/unzip.c
@@ -16,12 +16,7 @@
  */
 
 /* 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"
@@ -31,12 +26,12 @@ 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
 };
@@ -46,16 +41,16 @@ enum {
 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) */
 
@@ -65,11 +60,11 @@ typedef union {
  */
 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      ); \
@@ -82,9 +77,138 @@ struct BUG_zip_header_must_be_26_bytes {
         (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)
@@ -97,17 +221,17 @@ static void unzip_create_leading_dirs(const char *fn)
         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)) {
@@ -131,9 +255,12 @@ int unzip_main(int argc, char **argv)
         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;
@@ -221,13 +348,14 @@ int unzip_main(int argc, char **argv)
 
         /* 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]);
@@ -237,6 +365,7 @@ int unzip_main(int argc, char **argv)
                         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 */
@@ -253,37 +382,63 @@ int unzip_main(int argc, char **argv)
 
         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)
@@ -304,7 +459,6 @@ int unzip_main(int argc, char **argv)
                                            (dostime & 0x000007e0) >> 5,
                                            dst_fn);
                                         total_size += zip_header.formatted.ucmpsize;
-                                        total_entries++;
                                 } else {
                                         /* short listing -- filenames only */
                                         puts(dst_fn);
@@ -315,7 +469,7 @@ int unzip_main(int argc, char **argv)
                         } 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);
@@ -335,7 +489,7 @@ int unzip_main(int argc, char **argv)
  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 */
@@ -347,7 +501,7 @@ int unzip_main(int argc, char **argv)
                                                 } 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];
                                                 }
@@ -368,7 +522,7 @@ int unzip_main(int argc, char **argv)
                         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);
@@ -379,14 +533,14 @@ int unzip_main(int argc, char **argv)
                         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);
@@ -398,12 +552,7 @@ int unzip_main(int argc, char **argv)
                         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) {