This is primarily to allow deb_extract to be independent of the tar applet.

TODO: This function and its conterpart in tar.c should be merged

libbb/untar.c

@@ -0,0 +1,200 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * NOTE: This is used by deb_extract to avoid calling the whole tar applet.
+ * Its functionality should be merged with tar to avoid duplication
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "libbb.h"
+
+extern int untar(FILE *src_tar_file, int untar_function, char *base_path)
+{
+	typedef struct raw_tar_header {
+        char name[100];               /*   0-99 */
+        char mode[8];                 /* 100-107 */
+        char uid[8];                  /* 108-115 */
+        char gid[8];                  /* 116-123 */
+        char size[12];                /* 124-135 */
+        char mtime[12];               /* 136-147 */
+        char chksum[8];               /* 148-155 */
+        char typeflag;                /* 156-156 */
+        char linkname[100];           /* 157-256 */
+        char magic[6];                /* 257-262 */
+        char version[2];              /* 263-264 */
+        char uname[32];               /* 265-296 */
+        char gname[32];               /* 297-328 */
+        char devmajor[8];             /* 329-336 */
+        char devminor[8];             /* 337-344 */
+        char prefix[155];             /* 345-499 */
+        char padding[12];             /* 500-512 */
+	} raw_tar_header_t;
+
+//	const int dpkg_deb_contents = 1;
+//	const int dpkg_deb_control = 2;
+//	const int dpkg_deb_info = 4;
+	const int untar_extract = 8;
+//	const int dpkg_deb_verbose_extract = 16;
+//	const int dpkg_deb_list = 32;
+
+	raw_tar_header_t raw_tar_header;
+	unsigned char *temp = (unsigned char *) &raw_tar_header;
+	long i;
+	long next_header_offset = 0;
+	long uncompressed_count = 0;
+	size_t size;
+	mode_t mode;
+
+//	signal(SIGCHLD, child_died);
+
+	while (fread((char *) &raw_tar_header, 1, 512, src_tar_file)==512) {
+		long sum = 0;
+		char *dir;
+
+		uncompressed_count += 512;
+
+		/* Check header has valid magic */
+		if (strncmp(raw_tar_header.magic, "ustar", 5) != 0) {
+			/* Put this pack after TODO (check child still alive) is done */
+//			error_msg("Invalid tar magic");
+			break;
+		}
+
+		/* Do checksum on headers */
+        for (i =  0; i < 148 ; i++) {
+			sum += temp[i];
+		}
+        sum += ' ' * 8;
+		for (i =  156; i < 512 ; i++) {
+			sum += temp[i];
+		}
+        if (sum != strtol(raw_tar_header.chksum, NULL, 8)) {
+			error_msg("Invalid tar header checksum");
+			break;
+		}
+
+		/* convert to type'ed variables */
+        size = strtol(raw_tar_header.size, NULL, 8);
+		parse_mode(raw_tar_header.mode, &mode);
+
+		/* start of next header is at */
+		next_header_offset = uncompressed_count + size;
+		if (size % 512 != 0) {
+			next_header_offset += (512 - size % 512);
+		}
+
+		/*
+		 * seek to start of control file, return length
+		 *
+		if (dpkg_untar_function & dpkg_untar_seek_control) {
+			if ((raw_tar_header.typeflag == '0') || (raw_tar_header.typeflag == '\0')) {
+				char *tar_filename;
+
+				tar_filename = strrchr(raw_tar_header.name, '/');
+				if (tar_filename == NULL) {
+					tar_filename = strdup(raw_tar_header.name);
+				} else {
+					tar_filename++;
+				}
+
+				if (strcmp(tar_filename, "control") == 0) {
+					return(size);
+				}
+			}
+
+		}
+*/
+		/* extract files */
+		dir = xmalloc(strlen(raw_tar_header.name) + strlen(base_path) + 2);
+
+		sprintf(dir, "%s/%s", base_path, raw_tar_header.name);
+		create_path(dir, 0777);
+		switch (raw_tar_header.typeflag ) {
+			case '0':
+			case '\0':
+				/* If the name ends in a '/' then assume it is
+				 * supposed to be a directory, and fall through
+				 */
+				if (raw_tar_header.name[strlen(raw_tar_header.name)-1] != '/') {
+					if (untar_function & untar_extract) {
+						int out_count=0;
+						FILE *dst_file;
+	
+						dst_file = wfopen(dir, "w");
+						if (copy_file_chunk(src_tar_file, dst_file, size) == FALSE) {
+							error_msg_and_die("Couldnt extract file");
+						}
+						uncompressed_count += out_count;
+						fclose(dst_file);
+						break;
+					}
+				}
+			case '5':
+				if (untar_function & untar_extract) {
+					if (create_path(dir, mode) != TRUE) {
+						free(dir);
+						perror_msg("%s: Cannot mkdir", raw_tar_header.name); 
+						return(EXIT_FAILURE);
+					}
+				}
+				break;
+			case '1':
+				if (untar_function & untar_extract) {
+					if (link(raw_tar_header.linkname, raw_tar_header.name) < 0) {
+						free(dir);
+						perror_msg("%s: Cannot create hard link to '%s'", raw_tar_header.name, raw_tar_header.linkname); 
+						return(EXIT_FAILURE);
+					}
+				}
+				break;
+			case '2':
+				if (untar_function & untar_extract) {
+					if (symlink(raw_tar_header.linkname, raw_tar_header.name) < 0) {
+						free(dir);
+						perror_msg("%s: Cannot create symlink to '%s'", raw_tar_header.name, raw_tar_header.linkname); 
+						return(EXIT_FAILURE);
+					}
+				}
+				break;
+			case '3':
+			case '4':
+			case '6':
+//				if (tarExtractSpecial( &header, extractFlag, tostdoutFlag)==FALSE)
+//					errorFlag=TRUE;
+//				break;
+			default:
+				error_msg("Unknown file type '%c' in tar file", raw_tar_header.typeflag);
+				free(dir);
+				return(EXIT_FAILURE);
+		}
+		free(dir);
+	}
+	/* skip to start of next header */
+	while(uncompressed_count < next_header_offset) {
+		char ch[2];
+		if (fread(ch, 1, 1, src_tar_file) != 1) {
+			error_msg("read error\n");
+			getchar();
+		} else {
+			uncompressed_count++;
+		}
+	}
+		/* 
+		 * TODO: Check that gunzip child hasnt finished
+		 */
+	return(EXIT_SUCCESS);
+}