unzip: restore unix file mode if possible. closes bug 1045

function                                             old     new   delta
unzip_main                                          2197    2188      -9
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/1 up/down: 173/-182)           Total: -9 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 88 insertions, 55 deletions

diff --git a/archival/unzip.c b/archival/unzip.c
index afab3280d..868166bb1 100644
--- a/archival/unzip.c
+++ b/archival/unzip.c
@@ -25,12 +25,12 @@
 enum {
 #if BB_BIG_ENDIAN
 	ZIP_FILEHEADER_MAGIC = 0x504b0304,
-	ZIP_CDS_MAGIC        = 0x504b0102,
-	ZIP_CDE_MAGIC        = 0x504b0506,
+	ZIP_CDF_MAGIC        = 0x504b0102, /* central directory's file header */
+	ZIP_CDE_MAGIC        = 0x504b0506, /* "end of central directory" record */
 	ZIP_DD_MAGIC         = 0x504b0708,
 #else
 	ZIP_FILEHEADER_MAGIC = 0x04034b50,
-	ZIP_CDS_MAGIC        = 0x02014b50,
+	ZIP_CDF_MAGIC        = 0x02014b50,
 	ZIP_CDE_MAGIC        = 0x06054b50,
 	ZIP_DD_MAGIC         = 0x08074b50,
 #endif
@@ -77,15 +77,15 @@ struct BUG_zip_header_must_be_26_bytes {
 	(zip_header).formatted.extra_len    = SWAP_LE16((zip_header).formatted.extra_len   ); \
 } while (0)
 
-#define CDS_HEADER_LEN 42
+#define CDF_HEADER_LEN 42
 
 typedef union {
-	uint8_t raw[CDS_HEADER_LEN];
+	uint8_t raw[CDF_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 cdf_flags;             /* 4-5 */
 		uint16_t method;                /* 6-7 */
 		uint16_t mtime;                 /* 8-9 */
 		uint16_t mdate;                 /* 10-11 */
@@ -100,21 +100,25 @@ typedef union {
 		uint32_t external_file_attributes PACKED; /* 34-37 */
 		uint32_t relative_offset_of_local_header PACKED; /* 38-41 */
 	} formatted PACKED;
-} cds_header_t;
+} cdf_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];
+struct BUG_cdf_header_must_be_42_bytes {
+	char BUG_cdf_header_must_be_42_bytes[
+		offsetof(cdf_header_t, formatted.relative_offset_of_local_header) + 4
+			== CDF_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); \
+#define FIX_ENDIANNESS_CDF(cdf_header) do { \
+	(cdf_header).formatted.crc32        = SWAP_LE32((cdf_header).formatted.crc32       ); \
+	(cdf_header).formatted.cmpsize      = SWAP_LE32((cdf_header).formatted.cmpsize     ); \
+	(cdf_header).formatted.ucmpsize     = SWAP_LE32((cdf_header).formatted.ucmpsize    ); \
+	(cdf_header).formatted.file_name_length = SWAP_LE16((cdf_header).formatted.file_name_length); \
+	(cdf_header).formatted.extra_field_length = SWAP_LE16((cdf_header).formatted.extra_field_length); \
+	(cdf_header).formatted.file_comment_length = SWAP_LE16((cdf_header).formatted.file_comment_length); \
+	IF_DESKTOP( \
+	(cdf_header).formatted.version_made_by = SWAP_LE16((cdf_header).formatted.version_made_by); \
+	(cdf_header).formatted.external_file_attributes = SWAP_LE32((cdf_header).formatted.external_file_attributes); \
+	) \
 } while (0)
 
 #define CDE_HEADER_LEN 16
@@ -124,11 +128,11 @@ typedef union {
 	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 disk_with_cdf_no;
+		uint16_t cdf_entries_on_this_disk;
+		uint16_t cdf_entries_total;
+		uint32_t cdf_size;
+		uint32_t cdf_offset;
 		/* uint16_t file_comment_length; */
 		/* .ZIP file comment (variable size) */
 	} formatted PACKED;
@@ -140,7 +144,7 @@ struct BUG_cde_header_must_be_16_bytes {
 };
 
 #define FIX_ENDIANNESS_CDE(cde_header) do { \
-	(cde_header).formatted.cds_offset = SWAP_LE32((cde_header).formatted.cds_offset); \
+	(cde_header).formatted.cdf_offset = SWAP_LE32((cde_header).formatted.cdf_offset); \
 } while (0)
 
 enum { zip_fd = 3 };
@@ -148,7 +152,7 @@ enum { zip_fd = 3 };
 
 #if ENABLE_DESKTOP
 /* NB: does not preserve file position! */
-static uint32_t find_cds_offset(void)
+static uint32_t find_cdf_offset(void)
 {
 	unsigned char buf[1024];
 	cde_header_t cde_header;
@@ -177,32 +181,30 @@ static uint32_t find_cds_offset(void)
 		/* we found CDE! */
 		memcpy(cde_header.raw, p + 1, CDE_HEADER_LEN);
 		FIX_ENDIANNESS_CDE(cde_header);
-		return cde_header.formatted.cds_offset;
+		return cde_header.formatted.cdf_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)
+static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr)
 {
 	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;
-	}
+	if (!cdf_offset)
+		cdf_offset = find_cdf_offset();
+
+	xlseek(zip_fd, cdf_offset + 4, SEEK_SET);
+	xread(zip_fd, cdf_ptr->raw, CDF_HEADER_LEN);
+	FIX_ENDIANNESS_CDF(*cdf_ptr);
+	cdf_offset += 4 + CDF_HEADER_LEN
+		+ cdf_ptr->formatted.file_name_length
+		+ cdf_ptr->formatted.extra_field_length
+		+ cdf_ptr->formatted.file_comment_length;
 
 	xlseek(zip_fd, org, SEEK_SET);
-	return cds_offset;
+	return cdf_offset;
 };
 #endif
 
@@ -258,8 +260,7 @@ int unzip_main(int argc, char **argv)
 	smallint listing = 0;
 	smallint overwrite = O_PROMPT;
 #if ENABLE_DESKTOP
-	uint32_t cds_offset;
-	unsigned cds_entries;
+	uint32_t cdf_offset;
 #endif
 	unsigned long total_usize;
 	unsigned long total_size;
@@ -435,20 +436,42 @@ int unzip_main(int argc, char **argv)
 		}
 	}
 
+/* Example of an archive with one 0-byte long file named 'z'
+ * created by Zip 2.31 on Unix:
+ * 0000 [50 4b]03 04 0a 00 00 00 00 00 42 1a b8 3c 00 00 |PK........B..<..|
+ *       sig........ vneed flags compr mtime mdate crc32>
+ * 0010  00 00 00 00 00 00 00 00 00 00 01 00 15 00 7a 55 |..............zU|
+ *      >..... csize...... usize...... fnlen exlen fn ex>
+ * 0020  54 09 00 03 cc d3 f9 4b cc d3 f9 4b 55 78 04 00 |T......K...KUx..|
+ *      >tra_field......................................
+ * 0030  00 00 00 00[50 4b]01 02 17 03 0a 00 00 00 00 00 |....PK..........|
+ *       ........... sig........ vmade vneed flags compr
+ * 0040  42 1a b8 3c 00 00 00 00 00 00 00 00 00 00 00 00 |B..<............|
+ *       mtime mdate crc32...... csize...... usize......
+ * 0050  01 00 0d 00 00 00 00 00 00 00 00 00 a4 81 00 00 |................|
+ *       fnlen exlen clen. dnum. iattr eattr...... relofs> (eattr = rw-r--r--)
+ * 0060  00 00 7a 55 54 05 00 03 cc d3 f9 4b 55 78 00 00 |..zUT......KUx..|
+ *      >..... fn extra_field...........................
+ * 0070 [50 4b]05 06 00 00 00 00 01 00 01 00 3c 00 00 00 |PK..........<...|
+ * 0080  34 00 00 00 00 00                               |4.....|
+ */
 	total_usize = 0;
 	total_size = 0;
 	total_entries = 0;
 #if ENABLE_DESKTOP
-	cds_entries = 0;
-	cds_offset = 0;
+	cdf_offset = 0;
 #endif
 	while (1) {
 		uint32_t magic;
+		mode_t dir_mode = 0777;
+#if ENABLE_DESKTOP
+		mode_t file_mode = 0666;
+#endif
 
 		/* Check magic number */
 		xread(zip_fd, &magic, 4);
 		/* Central directory? It's at the end, so exit */
-		if (magic == ZIP_CDS_MAGIC)
+		if (magic == ZIP_CDF_MAGIC)
 			break;
 #if ENABLE_DESKTOP
 		/* Data descriptor? It was a streaming file, go on */
@@ -476,15 +499,21 @@ int unzip_main(int argc, char **argv)
 			/* 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 */
-			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;
+
+		{
+			cdf_header_t cdf_header;
+			cdf_offset = read_next_cdf(cdf_offset, &cdf_header);
+			if (zip_header.formatted.flags & 0x0008) {
+				/* 0x0008 - streaming. [u]cmpsize can be reliably gotten
+				 * only from Central Directory. See unzip_doc.txt */
+				zip_header.formatted.crc32    = cdf_header.formatted.crc32;
+				zip_header.formatted.cmpsize  = cdf_header.formatted.cmpsize;
+				zip_header.formatted.ucmpsize = cdf_header.formatted.ucmpsize;
+			}
+			if ((cdf_header.formatted.version_made_by >> 8) == 3) {
+				/* this archive is created on Unix */
+				dir_mode = file_mode = (cdf_header.formatted.external_file_attributes >> 16);
+			}
 		}
 #endif
 
@@ -550,7 +579,7 @@ int unzip_main(int argc, char **argv)
 						printf("   creating: %s\n", dst_fn);
 					}
 					unzip_create_leading_dirs(dst_fn);
-					if (bb_make_directory(dst_fn, 0777, 0)) {
+					if (bb_make_directory(dst_fn, dir_mode, 0)) {
 						bb_error_msg_and_die("exiting");
 					}
 				} else {
@@ -592,7 +621,11 @@ int unzip_main(int argc, char **argv)
 			overwrite = O_ALWAYS;
 		case 'y': /* Open file and fall into unzip */
 			unzip_create_leading_dirs(dst_fn);
+#if ENABLE_DESKTOP
+			dst_fd = xopen3(dst_fn, O_WRONLY | O_CREAT | O_TRUNC, file_mode);
+#else
 			dst_fd = xopen(dst_fn, O_WRONLY | O_CREAT | O_TRUNC);
+#endif
 		case -1: /* Unzip */
 			if (!quiet) {
 				printf("  inflating: %s\n", dst_fn);