From 6c346b88e1134f09024879a85f358ea4992023dd Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Mon, 16 Sep 2013 18:01:07 +0200
Subject: [PATCH] passwd: Add option -d to delete a user's password

---
 src/bin/multiuser/passwd.cpp | 124 ++++++++++++++++++++++++-----------
 1 file changed, 87 insertions(+), 37 deletions(-)

diff --git a/src/bin/multiuser/passwd.cpp b/src/bin/multiuser/passwd.cpp
index 58d86208b7..bd12bec15d 100644
--- a/src/bin/multiuser/passwd.cpp
+++ b/src/bin/multiuser/passwd.cpp
@@ -1,9 +1,10 @@
 /*
- * Copyright 2008, Ingo Weinhold, ingo_weinhold@gmx.de. All Rights Reserved.
+ * Copyright 2008-2013, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
 
 #include <errno.h>
+#include <getopt.h>
 #include <pwd.h>
 #include <shadow.h>
 #include <stdio.h>
@@ -28,8 +29,15 @@ extern const char *__progname;
 
 
 static const char* kUsage =
-"Usage: %s [ <user name> ]\n"
-;
+	"Usage: %s [ <options> ] [ <user name> ]\n"
+	"Deletes the specified user.\n"
+	"\n"
+	"Options:\n"
+	"  -d\n"
+	"    Delete the password for the specified user.\n"
+	"  -h, --help\n"
+	"    Print usage info.\n"
+	;
 
 static void
 print_usage_and_exit(bool error)
@@ -42,12 +50,39 @@ print_usage_and_exit(bool error)
 int
 main(int argc, const char* const* argv)
 {
-	if (argc > 2)
+	bool deletePassword = false;;
+
+	while (true) {
+		static struct option sLongOptions[] = {
+			{ "help", no_argument, 0, 'h' },
+			{ 0, 0, 0, 0 }
+		};
+
+		opterr = 0; // don't print errors
+		int c = getopt_long(argc, (char**)argv, "dh", sLongOptions, NULL);
+		if (c == -1)
+			break;
+
+	
+		switch (c) {
+			case 'd':
+				deletePassword = true;
+				break;
+
+			case 'h':
+				print_usage_and_exit(false);
+				break;
+
+			default:
+				print_usage_and_exit(true);
+				break;
+		}
+	}
+
+	if (optind + 1 < argc)
 		print_usage_and_exit(true);
 
-	const char* user = NULL;
-	if (argc == 2)
-		user = argv[1];
+	const char* user = optind < argc ? argv[optind] : NULL;
 
 	if (geteuid() != 0) {
 		fprintf(stderr, "Error: You need to be root.\n");
@@ -57,6 +92,18 @@ main(int argc, const char* const* argv)
 	// this is a set-uid tool -- get the real UID
 	uid_t uid = getuid();
 
+	if (deletePassword) {
+		if (uid != 0) {
+			fprintf(stderr, "Error: Only root can delete users' passwords.\n");
+			exit(1);
+		}
+
+		if (user == NULL) {
+			fprintf(stderr, "Error: A user must be specified.\n");
+			exit(1);
+		}
+	}
+
 	// get the passwd entry
 	struct passwd* passwd;
 	if (user != NULL) {
@@ -90,40 +137,43 @@ main(int argc, const char* const* argv)
 		}
 	}
 
-	// read new password
 	char password[LINE_MAX];
-	if (read_password("new password: ", password, sizeof(password), false)
-			!= B_OK) {
-		exit(1);
-	}
-
-	if (strlen(password) >= MAX_SHADOW_PWD_PASSWORD_LEN) {
-		fprintf(stderr, "Error: The password is too long.\n");
-		exit(1);
-	}
-
-	// read password again
-	char repeatedPassword[LINE_MAX];
-	if (read_password("repeat new password: ", repeatedPassword,
-			sizeof(repeatedPassword), false) != B_OK) {
-		exit(1);
-	}
-
-	// passwords need to match
-	if (strcmp(password, repeatedPassword) != 0) {
-		fprintf(stderr, "Error: passwords don't match\n");
-		exit(1);
-	}
-
-	memset(repeatedPassword, 0, sizeof(repeatedPassword));
-
-	// crypt it
 	char* encryptedPassword;
-	if (strlen(password) > 0) {
+
+	if (deletePassword) {
+		password[0] = '\0';
+		encryptedPassword = password;
+	} else {
+		// read new password
+		if (read_password("new password: ", password, sizeof(password), false)
+				!= B_OK) {
+			exit(1);
+		}
+
+		if (strlen(password) >= MAX_SHADOW_PWD_PASSWORD_LEN) {
+			fprintf(stderr, "Error: The password is too long.\n");
+			exit(1);
+		}
+
+		// read password again
+		char repeatedPassword[LINE_MAX];
+		if (read_password("repeat new password: ", repeatedPassword,
+				sizeof(repeatedPassword), false) != B_OK) {
+			exit(1);
+		}
+
+		// passwords need to match
+		if (strcmp(password, repeatedPassword) != 0) {
+			fprintf(stderr, "Error: passwords don't match\n");
+			exit(1);
+		}
+
+		memset(repeatedPassword, 0, sizeof(repeatedPassword));
+
+		// crypt it
 		encryptedPassword = crypt(password, user);
 		memset(password, 0, sizeof(password));
-	} else
-		encryptedPassword = password;
+	}
 
 	// prepare request for the registrar
 	KMessage message(BPrivate::B_REG_UPDATE_USER);