From: krw <krw@openbsd.org>
Date: Thu, 12 Jul 2018 16:53:09 +0000 (+0000)
Subject: Cleanup and clarify the has_overlap() logic so it can be read by
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=0f1cd5a253df1badb4620617126d54ef9db08a93;p=openbsd

Cleanup and clarify the has_overlap() logic so it can be read by
normal people and is more efficient to boot.

The only intentional functional change was to use mergesort()
instead of heapsort() so that partitions with the same offset
retain their order in the emitted verbiage.

Looked good to tb@, ok kn@
---

diff --git a/sbin/disklabel/editor.c b/sbin/disklabel/editor.c
index b66345425ac..0f587356af0 100644
--- a/sbin/disklabel/editor.c
+++ b/sbin/disklabel/editor.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: editor.c,v 1.338 2018/07/07 09:59:34 krw Exp $	*/
+/*	$OpenBSD: editor.c,v 1.339 2018/07/12 16:53:09 krw Exp $	*/
 
 /*
  * Copyright (c) 1997-2000 Todd C. Miller <Todd.Miller@courtesan.com>
@@ -1296,56 +1296,46 @@ int
 has_overlap(struct disklabel *lp)
 {
 	struct partition **spp;
-	int c, i, j;
-	char buf[BUFSIZ];
+	int i, p1, p2;
+	char *line = NULL;
+	size_t linesize = 0;
+	ssize_t linelen;
 
-	/* Get a sorted list of the in-use partitions. */
-	spp = sort_partitions(lp);
-
-	/* If there are less than two partitions in use, there is no overlap. */
-	if (spp[1] == NULL)
-		return (0);
-
-	/* Now that we have things sorted by starting sector check overlap */
-	for (i = 0; spp[i] != NULL; i++) {
-		for (j = i + 1; spp[j] != NULL; j++) {
-			/* `if last_sec_in_part + 1 > first_sec_in_next_part' */
+	for (;;) {
+		spp = sort_partitions(lp);
+		for (i = 0; spp[i+1] != NULL; i++) {
 			if (DL_GETPOFFSET(spp[i]) + DL_GETPSIZE(spp[i]) >
-			    DL_GETPOFFSET(spp[j])) {
-				/* Overlap!  Convert to real part numbers. */
-				i = ((char *)spp[i] - (char *)lp->d_partitions)
-				    / sizeof(**spp);
-				j = ((char *)spp[j] - (char *)lp->d_partitions)
-				    / sizeof(**spp);
-				printf("\nError, partitions %c and %c overlap:"
-				    "\n", 'a' + i, 'a' + j);
-				printf("#    %16.16s %16.16s  fstype "
-				    "[fsize bsize    cpg]\n", "size", "offset");
-				display_partition(stdout, lp, i, 0);
-				display_partition(stdout, lp, j, 0);
-
-				/* Get partition to disable or ^D */
-				do {
-					printf("Disable which one? "
-					    "(^D to abort) [%c %c] ",
-					    'a' + i, 'a' + j);
-					buf[0] = '\0';
-					if (!fgets(buf, sizeof(buf), stdin)) {
-						putchar('\n');
-						return (1);	/* ^D */
-					}
-					c = buf[0] - 'a';
-				} while (buf[1] != '\n' && buf[1] != '\0' &&
-				    c != i && c != j);
+			    DL_GETPOFFSET(spp[i+1]))
+				break;
+		}
+		if (spp[i+1] == NULL) {
+			free(line);
+			return (0);
+		}
 
-				/* Mark the selected one as unused */
-				lp->d_partitions[c].p_fstype = FS_UNUSED;
-				return (has_overlap(lp));
-			}
+		p1 = 'a' + (spp[i] - lp->d_partitions);
+		p2 = 'a' + (spp[i+1] - lp->d_partitions);
+		printf("\nError, partitions %c and %c overlap:\n", p1, p2);
+		printf("#    %16.16s %16.16s  fstype [fsize bsize    cpg]\n",
+		    "size", "offset");
+		display_partition(stdout, lp, p1 - 'a', 0);
+		display_partition(stdout, lp, p2 - 'a', 0);
+
+		for (;;) {
+			printf("Disable which one? (%c %c) ", p1, p2);
+			linelen = getline(&line, &linesize, stdin);
+			if (linelen == -1)
+				goto done;
+			if (linelen == 2 && (line[0] == p1 || line[0] == p2))
+				break;
 		}
+		lp->d_partitions[line[0] - 'a'].p_fstype = FS_UNUSED;
 	}
 
-	return (0);
+done:
+	putchar('\n');
+	free(line);
+	return (1);
 }
 
 void
@@ -1514,7 +1504,7 @@ sort_partitions(struct disklabel *lp)
 	 * This is safe because we guarantee no overlap.
 	 */
 	if (npartitions > 1)
-		if (heapsort((void *)spp, npartitions, sizeof(spp[0]),
+		if (mergesort((void *)spp, npartitions, sizeof(spp[0]),
 		    partition_cmp))
 			err(4, "failed to sort partition table");