From 31f49e7968db5d0d569513992baa6d25dde8aa58 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Sat, 21 Jul 2012 22:45:05 -0500
Subject: Make chmod +w respect umask, implement +s and +t, fix ls to show
 suid/sgid/stid without x bit.

---
 lib/lib.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

(limited to 'lib')

diff --git a/lib/lib.c b/lib/lib.c
index 2b321099..69029a2c 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -983,16 +983,20 @@ mode_t string_to_mode(char *modestr, mode_t mode)
 
 	// Gaze into the bin of permission...
 	for (;;) {
-		int i, j, dowho, dohow, dowhat;
+		int i, j, dowho, dohow, dowhat, amask;
 
-		dowho = dohow = dowhat = 0;
+		dowho = dohow = dowhat = amask = 0;
 
 		// Find the who, how, and what stanzas, in that order
 		while (*str && (s = strchr(whos, *str))) {
 			dowho |= 1<<(s-whos);
 			str++;
 		}
-		if (!dowho) dowho = 8;
+		// If who isn't specified, like "a" but honoring umask.
+		if (!dowho) {
+			dowho = 8;
+			umask(amask=umask(0));
+		}
 		if (!*str || !(s = strchr(hows, *str))) goto barf;
 		dohow = *(str++);
 
@@ -1018,19 +1022,26 @@ mode_t string_to_mode(char *modestr, mode_t mode)
 		for (i=0; i<4; i++) {
 			for (j=0; j<3; j++) {
 				mode_t bit = 0;
+				int where = 1<<((3*i)+j);
+
+				if (amask & where) continue;
 
 				// Figure out new value at this location
 				if (i == 3) {
-				} else if (dowhat&(1<<j)) bit++;
+					// suid/sticky bit.
+					if (j) {
+						if ((dowhat & 8) && (dowho&(8|(1<<i)))) bit++;
+					} else if (dowhat & 16) bit++;
+				} else {
+					if (!(dowho&(8|(1<<i)))) continue;
+					if (dowhat&(1<<j)) bit++;
+				}
 
 				// When selection active, modify bit
-				if (dowho&(8|(1<<i))) {
-					int where = 1<<((3*i)+j);
 
-					if (dohow == '=' || (bit && dohow == '-'))
-						mode &= ~where;
-					if (bit && dohow != '-') mode |= where;
-				}
+				if (dohow == '=' || (bit && dohow == '-'))
+					mode &= ~where;
+				if (bit && dohow != '-') mode |= where;
 			}
 		}
 
-- 
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