compress 4.1 file deletion fixes

[David J. MacKenzie]

> This new version of compress seems to have the old problem with zcat
> somtimes deleting the compressed file when interrupted.  I thought
> this bug was fixed long ago.

To be precise, comp.sources.misc "v06i066: compress 4.0 bug fixes"
submitted by res at cbnews.ATT.COM (Robert E. Stampfli) contains that
fix.  It drops in to 4.1 with only a few small changes.  Below, I have
adapted Robert's fixes for compress 4.1.  I also fixed a problem with
declaring signal handlers in the wrong place, which prevented compress
from compiling with gcc.  And I fixed the problem that the error
messages that compress prints #ifdef SHORTNAMES when it can't tack on
a .Z only mentioned the last component of the pathname.  This happened
both in Robert's patch and in the stock code, when creating the output
file.


--- compress.c.dist	Tue Jun 25 17:36:59 1991
+++ compress.c	Thu Jun 27 02:19:55 1991
@@ -373,6 +373,7 @@
 #define	CLEAR	256	/* table clear output code */
 
 int force = 0;
+int valid = 0;		/* set when signal can remove ofname */
 char ofname [100];
 #ifdef DEBUG
 int verbose = 0;
@@ -429,18 +430,18 @@
 
 int overwrite = 0;	/* Do not overwrite unless given -f flag */
 int recursive = 0;  /* compress directories */
+extern onintr(), oops();
 main( argc, argv )
 register int argc; char **argv;
 {
     char **filelist, **fileptr;
     char *cp, *rindex(), *malloc();
-    extern onintr(), oops();
 
 
     if ( (bgnd_flag = signal ( SIGINT, SIG_IGN )) != SIG_IGN ) {
 	signal ( SIGINT, onintr );
-	signal ( SIGSEGV, oops );
     }
+    signal ( SIGSEGV, oops );
 
 #ifdef COMPATIBLE
     nomagic = 1;	/* Original didn't have a magic number */
@@ -615,6 +616,14 @@
 	      ** directory, but it shouldn't do any harm.
 	      */
 	      if (strcmp(tempname + strlen(tempname) - 2, ".Z") != 0) {
+#ifdef SHORTNAMES
+		    if ((cp=rindex(tempname,'/')) != NULL)	cp++;
+		    else					cp = tempname;
+		    if (strlen(cp) > 12) {
+			fprintf(stderr,"%s.Z: No such file or directory\n",tempname);
+			return;
+		    }
+#endif  /* SHORTNAMES */
 		strcat(tempname,".Z");
 		errno = 0;
 #ifdef	BSD4
@@ -732,7 +741,7 @@
 		if ((cp=rindex(ofname,'/')) != NULL)	cp++;
 		else					cp = ofname;
 		if (strlen(cp) > 12) {
-		    fprintf(stderr,"%s: filename too long to tack on .Z\n",cp);
+		    fprintf(stderr,"%s: filename too long to tack on .Z\n",ofname);
 		    signal(SIGINT,onintr);
 		    return;
 		}
@@ -746,8 +755,7 @@
 		    response[0] = 'n';
 		    fprintf(stderr, "%s already exists;", ofname);
 		    if (foreground()) {
-			fprintf(stderr, " do you wish to overwrite %s (y or n)? ",
-			ofname);
+			fprintf(stderr, " OK to overwrite (y or n)? ");
 			fflush(stderr);
 			read(2, response, 2);
 			while (response[1] != '\n') {
@@ -765,6 +773,7 @@
 	    }
 	    signal(SIGINT,onintr);
 	    if(zcat_flg == 0) {		/* Open output file */
+	        valid = 1;
 		if (freopen(ofname, "w", stdout) == NULL) {
 		    perror(ofname);
 			return;
@@ -1400,7 +1409,8 @@
 writeerr()
 {
     perror ( ofname );
-    unlink ( ofname );
+    if (valid)
+	unlink ( ofname );
     exit ( 1 );
 }
 
@@ -1439,6 +1449,7 @@
 	timep[0] = statbuf.st_atime;
 	timep[1] = statbuf.st_mtime;
 	utime(ofname, timep);	/* Update last accessed and modified times */
+	valid = 0;		/* prevent latent ofname removal */
 	if (unlink(ifname))	/* Remove input file */
 	    perror(ifname);
 	if(!quiet)
@@ -1469,7 +1480,8 @@
 
 onintr ( )
 {
-    unlink ( ofname );
+    if (valid)
+	unlink ( ofname );
     exit ( 1 );
 }
 
@@ -1477,7 +1489,8 @@
 {
     if ( do_decomp == 1 ) 
     	fprintf ( stderr, "uncompress: corrupt input\n" );
-    unlink ( ofname );
+    if (valid)
+	unlink ( ofname );
     exit ( 1 );
 }
 
--
David J. MacKenzie <djm at eng.umd.edu> <djm at ai.mit.edu>