man/patches/man-1.6c-cut-duplicate-manpaths.patch

http://bugs.gentoo.org/90186

If we have entries in MANPATH that are really symlinks to other entries,
then many man functions will yield duplicate entries.

Without this patch, we see this behavior:
$ echo $MANPATH
/usr/share/man:/usr/man
$ man --path
/usr/share/man:/usr/man
$ ls -ld /usr/share/man /usr/man
lrwxrwxrwx  1 /usr/man -> /usr/share/man
drwxr-xr-x 36 /usr/share/man
$ man -k passwd
passwd               (1)  - change user password
passwd               (1)  - change user password

With this patch, we get:
$ echo $MANPATH
/usr/share/man:/usr/man
$ man --path
/usr/share/man
$ ls -ld /usr/share/man /usr/man
lrwxrwxrwx  1 /usr/man -> /usr/share/man
drwxr-xr-x 36 /usr/share/man
$ man -k passwd
passwd               (1)  - change user password

--- man-1.6c/src/manpath.c
+++ man-1.6c/src/manpath.c
@@ -380,6 +380,44 @@
      }
 }
 
+void trim_symlinked_manpaths (void);
+void
+trim_symlinked_manpaths () {
+	/*
+	 * Skip symlinks to other entries in path.
+	 * Do this after we've built the entire list.
+	 */
+	struct stat *stat_cache;
+	size_t i, j, size;
+
+	if (!mandirlist)
+		return;
+
+	for (size = 0; mandirlist[size]; ++size)
+		/* count # of elements */;
+	if (size == 0)
+		return;
+	/* cache stat information for every element */
+	stat_cache = (struct stat *) my_malloc (size * sizeof(*stat_cache));
+	for (i = 0; i < size; ++i)
+		stat(mandirlist[i], &stat_cache[i]);
+
+#define EQU_STAT(s,d) ((s).st_dev == (d).st_dev && (s).st_ino == (d).st_ino)
+	for (i = 0; i < size; ++i) {
+		for (j = i+1; j < size; ++j) {
+			if (EQU_STAT(stat_cache[i], stat_cache[j])) {
+				/* these two entries are the same, so cut out the second one */
+				memmove(mandirlist+j, mandirlist+j+1, (size-j)*sizeof(*mandirlist));
+				memmove(stat_cache+j, stat_cache+j+1, (size-j)*sizeof(*stat_cache));
+				mandirlist[--size] = NULL;
+				--j;
+			}
+		}
+	}
+
+	free(stat_cache);
+}
+
 void
 init_manpath () {
      static int done = 0;
@@ -391,6 +431,7 @@
               (manp = getenv ("MANPATH")) == NULL)
 	       manp = "";		/* default path */
 	  split (manp, to_mandirlist, 0);
+	  trim_symlinked_manpaths ();
 	  done = 1;
      }
 }
1	http://bugs.gentoo.org/90186
2
3	If we have entries in MANPATH that are really symlinks to other entries,
4	then many man functions will yield duplicate entries.
5
6	Without this patch, we see this behavior:
7	$ echo $MANPATH
8	/usr/share/man:/usr/man
9	$ man --path
10	/usr/share/man:/usr/man
11	$ ls -ld /usr/share/man /usr/man
12	lrwxrwxrwx 1 /usr/man -> /usr/share/man
13	drwxr-xr-x 36 /usr/share/man
14	$ man -k passwd
15	passwd (1) - change user password
16	passwd (1) - change user password
17
18	With this patch, we get:
19	$ echo $MANPATH
20	/usr/share/man:/usr/man
21	$ man --path
22	/usr/share/man
23	$ ls -ld /usr/share/man /usr/man
24	lrwxrwxrwx 1 /usr/man -> /usr/share/man
25	drwxr-xr-x 36 /usr/share/man
26	$ man -k passwd
27	passwd (1) - change user password
28
29	--- man-1.6c/src/manpath.c
30	+++ man-1.6c/src/manpath.c
31	@@ -380,6 +380,44 @@
32	}
33	}
34
35	+void trim_symlinked_manpaths (void);
36	+void
37	+trim_symlinked_manpaths () {
38	+ /*
39	+ * Skip symlinks to other entries in path.
40	+ * Do this after we've built the entire list.
41	+ */
42	+ struct stat *stat_cache;
43	+ size_t i, j, size;
44	+
45	+ if (!mandirlist)
46	+ return;
47	+
48	+ for (size = 0; mandirlist[size]; ++size)
49	+ /* count # of elements */;
50	+ if (size == 0)
51	+ return;
52	+ /* cache stat information for every element */
53	+ stat_cache = (struct stat ) my_malloc (size sizeof(*stat_cache));
54	+ for (i = 0; i < size; ++i)
55	+ stat(mandirlist[i], &stat_cache[i]);
56	+
57	+#define EQU_STAT(s,d) ((s).st_dev == (d).st_dev && (s).st_ino == (d).st_ino)
58	+ for (i = 0; i < size; ++i) {
59	+ for (j = i+1; j < size; ++j) {
60	+ if (EQU_STAT(stat_cache[i], stat_cache[j])) {
61	+ /* these two entries are the same, so cut out the second one */
62	+ memmove(mandirlist+j, mandirlist+j+1, (size-j)sizeof(mandirlist));
63	+ memmove(stat_cache+j, stat_cache+j+1, (size-j)sizeof(stat_cache));
64	+ mandirlist[--size] = NULL;
65	+ --j;
66	+ }
67	+ }
68	+ }
69	+
70	+ free(stat_cache);
71	+}
72	+
73	void
74	init_manpath () {
75	static int done = 0;
76	@@ -391,6 +431,7 @@
77	(manp = getenv ("MANPATH")) == NULL)
78	manp = ""; /* default path */
79	split (manp, to_mandirlist, 0);
80	+ trim_symlinked_manpaths ();
81	done = 1;
82	}
83	}