From: norbert@mozart.informatik.rwth-aachen.de (Norbert Kiesel)
Subject: tar-1.11 bugs (with fixes)
Organization: GNUs Not Usenet
Distribution: gnu
Date: Thu, 10 Sep 1992 21:02:20 GMT

Hello,
there are bugs within tar-1.11 which make it quite useless: both the
creation and the extracting of tar files fails (and dumps core)
because tar isn't aware of the current file name. The variable
current_file_name either points into a data block which is filled with
the contents of the files (extraction) or points to nowhere (creation
with verbose flag).

I've changed (i.e hacked :-) the program to avoid this errors (patch
below). However, I think the maintainers of tar should have a close
look upon the usage of the global variables and clean this code!


		so long

			Norbert


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--- list.c~	Tue Sep  8 22:22:38 1992
+++ list.c	Thu Sep 10 18:47:49 1992
@@ -529,6 +529,8 @@
 		fprintf(msg_file,"rec %10d: ",baserec + (ar_record - ar_block));
 	/* annofile(msg_file, (char *)NULL); */
 	
+	current_file_name = head->header.arch_name;
+	
 	if (f_verbose <= 1) {
 		/* Just the fax, mam. */
 		char *name;
--- extract.c~	Tue Sep  8 22:09:11 1992
+++ extract.c	Thu Sep 10 18:26:17 1992
@@ -147,7 +147,9 @@
 /*	int end_nulls; */
 	char **longp;
 	char *bp;
+	char *name;
 	
+	
 	saverec(&head);			/* Make sure it sticks around */
 	userec(head);			/* And go past it in the archive */
 	decode_header(head, &hstat, &head_standard, 1);	/* Snarf fields */
@@ -183,11 +185,15 @@
 		 }
 	 }
 
-	 switch (head->header.linkflag) {
+	namelen = strlen(skipcrud + current_file_name);
+	name = (char *) malloc((sizeof(char)) * namelen);
+	strcpy(name, skipcrud+current_file_name);
+	
+	switch (head->header.linkflag) {
 
-	 default:
+	default:
 		 msg("Unknown file type '%c' for %s, extracted as normal file",
-			 head->header.linkflag, skipcrud+current_file_name);
+			 head->header.linkflag, name);
 		 /* FALL THRU */
 
 	 /* 
@@ -266,8 +272,8 @@
 		  * Appears to be a file.
 		  * See if it's really a directory.
 		  */
-		 namelen = strlen(skipcrud+current_file_name)-1;
-		 if (current_file_name[skipcrud+namelen] == '/')
+		 namelen = strlen(name)-1;
+		 if (name[namelen] == '/')
 			 goto really_dir;
 
 		 /* FIXME, deal with protection issues */
@@ -319,16 +325,14 @@
 			 /*
 			  * With 3-arg open(), we can do this up right.
 			  */
-			 fd = open(skipcrud + current_file_name,
-				   openflag, hstat.st_mode);
+			 fd = open(name, openflag, hstat.st_mode);
  #endif
 		 }
 
 		 if (fd < 0) {
-			 if (make_dirs(skipcrud + current_file_name))
+			 if (make_dirs(name))
 				 goto again_file;
-			 msg_perror("Could not create file %s",
-				    skipcrud + current_file_name);
+			 msg_perror("Could not create file %s", name);
 			 if (head->header.isextended)
 				 skip_extended_headers();
 			 skip_file((long)hstat.st_size);
@@ -337,8 +341,6 @@
 
 	 extract_file:
 		 if (head->header.linkflag == LF_SPARSE) {
-			 char	*name;
-			 int	namelen;
 
 			 /*
 			  * Kludge alert.  NAME is assigned to header.name
@@ -348,9 +350,7 @@
 			  * that happen to contain the filename will look
 			  * REAL interesting unless we do this.
 			  */
-			 namelen = strlen(skipcrud + current_file_name);
-			 name = (char *) malloc((sizeof(char)) * namelen);
-			 bcopy(skipcrud+current_file_name, name, namelen);
+			 namelen = strlen(name);
 			 size = hstat.st_size;
 			 extract_sparse_file(fd, &size, hstat.st_size, name);
 		 }			
@@ -410,10 +410,10 @@
 			  */
 			 if(check<0)
 				 msg_perror("couldn't write to file %s",
-					    skipcrud + current_file_name);
+					    name);
 			 else
 			   msg("could only write %d of %d bytes to file %s",
-			       written,check,skipcrud + current_file_name);
+			       written,check,name);
 			 skip_file((long)(size - written));
 			 break;	/* Still do the close, mod time, chmod, etc */
 		 }
@@ -450,8 +450,7 @@
 		 }*/
 		 check = close(fd);
 		 if (check < 0) {
-			 msg_perror("Error while closing %s",
-				    skipcrud + current_file_name);
+			 msg_perror("Error while closing %s", name);
 		 }
 
 
@@ -464,11 +463,9 @@
 		  * user; if running as root, we extract as the original owner.
 		  */
 		 if (we_are_root || f_do_chown) {
-			 if (chown(skipcrud + current_file_name,
-				   hstat.st_uid, hstat.st_gid) < 0) {
+			 if (chown(name, hstat.st_uid, hstat.st_gid) < 0) {
 			   msg_perror("cannot chown file %s to uid %d gid %d",
-				      skipcrud + current_file_name,
-				      hstat.st_uid,hstat.st_gid);
+				      name, hstat.st_uid,hstat.st_gid);
 			 }
 		 }
 
@@ -485,9 +482,8 @@
 				acc_upd_times[0]=hstat.st_atime;
 			else acc_upd_times[0] = now;	         /* Accessed now */
 			acc_upd_times[1] = hstat.st_mtime; /* Mod'd */
-			if (utime(skipcrud + current_file_name,
-				  acc_upd_times) < 0) {
-			  msg_perror("couldn't change access and modification times of %s",skipcrud + current_file_name);
+			if (utime(name, acc_upd_times) < 0) {
+			  msg_perror("couldn't change access and modification times of %s",name);
 			}
 		}
 		/* We do the utime before the chmod because some versions of
@@ -509,11 +505,9 @@
 		 */
 		if ((!f_keep)
 		    || (hstat.st_mode & (S_ISUID|S_ISGID|S_ISVTX))) {
-		  if (chmod(skipcrud + current_file_name,
-			    notumask & (int)hstat.st_mode) < 0) {
+		  if (chmod(name, notumask & (int)hstat.st_mode) < 0) {
 		    msg_perror("cannot change mode of file %s to %ld",
-			       skipcrud + current_file_name,
-			       notumask & (int)hstat.st_mode);
+			       name, notumask & (int)hstat.st_mode);
 			}
 		}
 
@@ -525,22 +519,21 @@
 	{
 		struct stat st1,st2;
 
-		check = link (current_link_name, skipcrud + current_file_name);
+		check = link (current_link_name, name);
 
 		if (check == 0)
 			break;
-		if (make_dirs(skipcrud + current_file_name))
+		if (make_dirs(name))
 			goto again_link;
 		if(f_gnudump && errno==EEXIST)
 			break;
 		if(stat(current_link_name, &st1) == 0
-		   && stat(current_file_name + skipcrud, &st2)==0
+		   && stat(name, &st2)==0
 		   && st1.st_dev==st2.st_dev
 		   && st1.st_ino==st2.st_ino)
 			break;
 		msg_perror("Could not link %s to %s",
-			   skipcrud + current_file_name,
-			   current_link_name);
+			   name, current_link_name);
 	}
 		break;
 
@@ -547,12 +540,11 @@
 #ifdef S_ISLNK
 	case LF_SYMLINK:
 	again_symlink:
-		 check = symlink(current_link_name,
-				 skipcrud + current_file_name);
+		 check = symlink(current_link_name, name);
 		/* FIXME, don't worry uid, gid, etc... */
 		if (check == 0)
 			break;
-		if (make_dirs(current_file_name + skipcrud))
+		if (make_dirs(name))
 			goto again_symlink;
 		msg_perror("Could not create symlink to %s",
 			   current_link_name);
@@ -571,13 +563,11 @@
 #endif
 #if defined(S_IFCHR) || defined(S_IFBLK)
 	make_node:
-		check = mknod(current_file_name + skipcrud,
-			      (int) hstat.st_mode, (int) hstat.st_rdev);
+		check = mknod(name, (int) hstat.st_mode, (int) hstat.st_rdev);
 		if (check != 0) {
-			if (make_dirs(skipcrud + current_file_name))
+			if (make_dirs(name))
 				goto make_node;
-			msg_perror("Could not make %s",
-				   current_file_name + skipcrud);
+			msg_perror("Could not make %s", name);
 			break;
 		};
 		goto set_filestat;
@@ -587,13 +577,11 @@
 	/* If local system doesn't support FIFOs, use default case */
 	case LF_FIFO:
 	make_fifo:
-		check = mkfifo(current_file_name + skipcrud,
-			       (int) hstat.st_mode);
+		check = mkfifo(name, (int) hstat.st_mode);
 		if (check != 0) {
-		  if (make_dirs(current_file_name + skipcrud))
+		  if (make_dirs(name))
 		    goto make_fifo;
-		  msg_perror("Could not make %s",
-			     skipcrud + current_file_name);
+		  msg_perror("Could not make %s", name);
 		  break;
 		};
 		 goto set_filestat;
@@ -601,12 +589,11 @@
 
 	case LF_DIR:
 	case LF_DUMPDIR:
-		 namelen = strlen(current_file_name) + skipcrud - 1;
+		 namelen = strlen(name) - 1;
 	really_dir:
 		/* Check for trailing /, and zap as many as we find. */
-		while (namelen
-		       && current_file_name[skipcrud+namelen] == '/')
-		  current_file_name[skipcrud+namelen--] = '\0';
+		while (namelen && name[namelen] == '/')
+		  name[namelen--] = '\0';
 		if(f_gnudump) {		/* Read the entry and delete files
 					   that aren't listed in the archive */
 			gnu_restore(skipcrud);
@@ -616,23 +603,22 @@
 
 	
 	again_dir:
-		check = mkdir(skipcrud+current_file_name,
+		check = mkdir(name,
 			      (we_are_root ? 0 : 0300) | (int)hstat.st_mode);
 		if (check != 0) {
 			struct stat st1;
 
-			if (make_dirs(skipcrud+current_file_name))
+			if (make_dirs(name))
 				goto again_dir;
 			/* If we're trying to create '.', let it be. */
-			if (current_file_name[skipcrud+namelen] == '.' && 
-			    (namelen==0 ||
-			     current_file_name[skipcrud+namelen-1]=='/'))
+			if (name[namelen] == '.' && 
+			    (namelen==0 || name[namelen-1]=='/'))
 				goto check_perms;
 			if(   errno==EEXIST
- 			   && stat(skipcrud+current_file_name,&st1)==0
+ 			   && stat(name,&st1)==0
  			   && (S_ISDIR(st1.st_mode)))
 				break;
-			msg_perror("Could not create directory %s",skipcrud+current_file_name);
+			msg_perror("Could not create directory %s",name);
 			break;
 		}
 		
@@ -640,14 +626,14 @@
 		if (!we_are_root && 0300 != (0300 & (int) hstat.st_mode)) {
 			hstat.st_mode |= 0300;
 			msg("Added write and execute permission to directory %s",
-			  skipcrud+current_file_name);
+			  name);
 		}
 
 		if (f_modified)
 		  goto set_filestat;
 		tmp = (struct saved_dir_info *) malloc (sizeof (struct saved_dir_info));
-		tmp->path = malloc (strlen (skipcrud + current_file_name) + 1);
-		strcpy (tmp->path, skipcrud + current_file_name);
+		tmp->path = malloc (strlen (name) + 1);
+		strcpy (tmp->path, name);
 		tmp->mode = hstat.st_mode;
 		tmp->atime = hstat.st_atime;
 		tmp->mtime = hstat.st_mtime;
@@ -655,7 +641,7 @@
 		saved_dir_info_head = tmp;
 	case LF_VOLHDR:
 		if(f_verbose) {
-			printf("Reading %s\n", current_file_name);
+			printf("Reading %s\n", name);
 		}
 		break;
 
@@ -664,7 +650,7 @@
 		break;
 
 	case LF_MULTIVOL:
-		msg("Can't extract '%s'--file is continued from another volume\n",current_file_name);
+		msg("Can't extract '%s'--file is continued from another volume\n",name);
 		skip_file((long)hstat.st_size);
 		break;
 
@@ -677,6 +663,7 @@
 	
 	/* We don't need to save it any longer. */
 	saverec((union record **) 0);	/* Unsave it */
+	free(name);
 }
 
 /*

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