chmod: Remove -HLP flags, and ignore symlinks during traversal

These flags are non-POSIX and not useful since the mode of symlinks
is not used for anything.

This prevents a failure when a dangling symlink is encountered
during a recursive chmod.

chmod.1

@@ -1,4 +1,4 @@
-.Dd 2015-10-08
+.Dd 2019-12-21
 .Dt CHMOD 1
 .Os sbase
 .Sh NAME
@@ -6,10 +6,7 @@
 .Nd change file modes
 .Sh SYNOPSIS
 .Nm
-.Oo
-.Fl R
-.Op Fl H | L | P
-.Oc
+.Op Fl R
 .Ar mode
 .Ar file ...
 .Sh DESCRIPTION
@@ -58,19 +55,13 @@ read | write | execute | setuid and setgid | sticky
 .It X
 execute, if directory or at least one execute bit is already set
 .El
+.Pp
+Symbolic links are followed if they are passed as operands, and ignored
+if they are encountered during directory traversal.
 .Sh OPTIONS
 .Bl -tag -width Ds
 .It Fl R
 Change modes recursively.
-.It Fl H
-Dereference
-.Ar file
-if it is a symbolic link.
-.It Fl L
-Dereference all symbolic links.
-.It Fl P
-Preserve symbolic links.
-This is the default.
 .El
 .Sh SEE ALSO
 .Xr chgrp 1 ,

chmod.c

@@ -14,7 +14,7 @@ chmodr(const char *path, struct stat *st, void *data, struct recursor *r)
 	mode_t m;
 
 	m = parsemode(modestr, st->st_mode, mask);
-	if (chmod(path, m) < 0) {
+	if (!S_ISLNK(st->st_mode) && chmod(path, m) < 0) {
 		weprintf("chmod %s:", path);
 		ret = 1;
 	} else if (S_ISDIR(st->st_mode)) {
@@ -25,14 +25,14 @@ chmodr(const char *path, struct stat *st, void *data, struct recursor *r)
 static void
 usage(void)
 {
-	eprintf("usage: %s [-R [-H | -L | -P]] mode file ...\n", argv0);
+	eprintf("usage: %s [-R] mode file ...\n", argv0);
 }
 
 int
 main(int argc, char *argv[])
 {
 	struct recursor r = { .fn = chmodr, .hist = NULL, .depth = 0, .maxdepth = 1,
-	                      .follow = 'P', .flags = DIRFIRST };
+	                      .follow = 'H', .flags = DIRFIRST };
 	size_t i;
 
 	argv0 = *argv, argv0 ? (argc--, argv++) : (void *)0;
@@ -45,11 +45,6 @@ main(int argc, char *argv[])
 			case 'R':
 				r.maxdepth = 0;
 				break;
-			case 'H':
-			case 'L':
-			case 'P':
-				r.follow = (*argv)[i];
-				break;
 			case 'r': case 'w': case 'x': case 'X': case 's': case 't':
 				/* -[rwxXst] are valid modes, so we're done */
 				if (i == 1)