Fold mkpasswd applet into cryptpw.

mkpasswd is in Debian, OTOH cryptpw was added to busybox earlier.
Trying to make both camps happy by making those two applets just aliases.
They are command-line compatible. We can decide whether we want to drop one
(and which one) later.

function                                             old     new   delta
cryptpw_main                                         183     314    +131
static.methods                                        21       -     -21
packed_usage                                       25707   25648     -59
mkpasswd_main                                        307       -    -307
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 1/1 up/down: 131/-387)         Total: -256 bytes

4 files changed, 95 insertions, 137 deletions

diff --git a/loginutils/Config.in b/loginutils/Config.in
index 6efca7edf..ddd0c8015 100644
--- a/loginutils/Config.in
+++ b/loginutils/Config.in
@@ -242,22 +242,16 @@ config CRYPTPW
 	bool "cryptpw"
 	default n
 	help
-	  Applet for crypting a string.
+	  Encrypts the given password with the crypt(3) libc function
+	  using the given salt. Debian has this utility under mkpasswd
+	  name. Busybox provides mkpasswd as an alias for cryptpw.
 
 config CHPASSWD
 	bool "chpasswd"
 	default n
 	help
-	  chpasswd reads a file of user name and password pairs from
-	  standard input and uses this information to update a group of
-	  existing users.
-
-config MKPASSWD
-	bool "mkpasswd"
-	default n
-	help
-	  mkpasswd encrypts the given password with the crypt(3) libc function
-	  using the given salt.
+	  Reads a file of user name and password pairs from standard input
+	  and uses this information to update a group of existing users.
 
 config SU
 	bool "su"
diff --git a/loginutils/Kbuild b/loginutils/Kbuild
index 616d97721..3d0d777e8 100644
--- a/loginutils/Kbuild
+++ b/loginutils/Kbuild
@@ -11,7 +11,6 @@ lib-$(CONFIG_CRYPTPW)	+= cryptpw.o
 lib-$(CONFIG_CHPASSWD)	+= chpasswd.o
 lib-$(CONFIG_GETTY)	+= getty.o
 lib-$(CONFIG_LOGIN)	+= login.o
-lib-$(CONFIG_MKPASSWD)	+= mkpasswd.o
 lib-$(CONFIG_PASSWD)	+= passwd.o
 lib-$(CONFIG_SU)	+= su.o
 lib-$(CONFIG_SULOGIN)	+= sulogin.o
diff --git a/loginutils/cryptpw.c b/loginutils/cryptpw.c
index 0c1a9a0db..c179e35cf 100644
--- a/loginutils/cryptpw.c
+++ b/loginutils/cryptpw.c
@@ -3,75 +3,111 @@
  * cryptpw.c
  *
  * Cooked from passwd.c by Thomas Lundquist <thomasez@zelow.no>
+ * mkpasswd compatible options added by Bernhard Reutner-Fischer
  */
 
 #include "libbb.h"
 
-#define TESTING 0
+/* Debian has 'mkpasswd' utility, manpage says:
 
-/*
-set TESTING to 1 and pipe some file through this script
-if you played with bbox's crypt implementation.
+NAME
+    mkpasswd - Overfeatured front end to crypt(3)
+SYNOPSIS
+    mkpasswd PASSWORD SALT
+...
+OPTIONS
+-S, --salt=STRING
+    Use the STRING as salt. It must not  contain  prefixes  such  as
+    $1$.
+-R, --rounds=NUMBER
+    Use NUMBER rounds. This argument is ignored if the method
+    choosen does not support variable rounds. For the OpenBSD Blowfish
+    method this is the logarithm of the number of rounds.
+-m, --method=TYPE
+    Compute the password using the TYPE method. If TYPE is 'help'
+    then the available methods are printed.
+-P, --password-fd=NUM
+    Read the password from file descriptor NUM instead of using getpass(3).
+    If the file descriptor is not connected to a tty then
+    no other message than the hashed password is printed on stdout.
+-s, --stdin
+    Like --password-fd=0.
+ENVIRONMENT
+    $MKPASSWD_OPTIONS
+    A list of options which will be evaluated before the ones
+    specified on the command line.
+BUGS
+    This programs suffers of a bad case of featuritis.
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-while read line; do
-	n=`./busybox cryptpw -a des -- "$line"`
-	o=`./busybox_org cryptpw -a des -- "$line"`
-	test "$n" != "$o" && {
-		echo n="$n"
-		echo o="$o"
-		exit
-	}
-	n=`./busybox cryptpw -- "$line"`
-	o=`./busybox_org cryptpw -- "$line"`
-	test "$n" != "$o" && {
-		echo n="$n"
-		echo o="$o"
-		exit
-	}
-done
- */
+Very true...
+
+cryptpw was in bbox before this gem, so we retain it, and alias mkpasswd
+to cryptpw. -a option (alias for -m) came from cryptpw.
+*/
 
 int cryptpw_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int cryptpw_main(int argc UNUSED_PARAM, char **argv)
 {
-	char salt[sizeof("$N$") + 16 + TESTING*100];
-	char *opt_a;
-	int opts;
-
-	opts = getopt32(argv, "a:", &opt_a);
+	/* $N$ + sha_salt_16_bytes + NUL */
+	char salt[3 + 16 + 1];
+	char *salt_ptr;
+	const char *opt_m, *opt_S;
+	int len;
+	int fd;
 
-	if (opts && opt_a[0] == 'd') {
-		crypt_make_salt(salt, 2/2, 0);     /* des */
-#if TESTING
-		strcpy(salt, "a.");
+#if ENABLE_GETOPT_LONG
+	static const char mkpasswd_longopts[] ALIGN1 =
+		"stdin\0"       No_argument       "s"
+		"password-fd\0" Required_argument "P"
+		"salt\0"        Required_argument "S"
+		"method\0"      Required_argument "m"
+	;
+	applet_long_options = mkpasswd_longopts;
 #endif
-	} else {
-		salt[0] = '$';
-		salt[1] = '1';
-		salt[2] = '$';
+	fd = STDIN_FILENO;
+	opt_m = "d";
+	opt_S = NULL;
+	/* at most two non-option arguments; -P NUM */
+	opt_complementary = "?2:P+";
+	getopt32(argv, "sP:S:m:a:", &fd, &opt_S, &opt_m, &opt_m);
+	argv += optind;
+
+	/* have no idea how to handle -s... */
+
+	if (argv[0] && !opt_S)
+		opt_S = argv[1];
+
+	len = 2/2;
+	salt_ptr = salt;
+	if (opt_m[0] != 'd') { /* not des */
+		len = 8/2; /* so far assuming md5 */
+		*salt_ptr++ = '$';
+		*salt_ptr++ = '1';
+		*salt_ptr++ = '$';
 #if !ENABLE_USE_BB_CRYPT || ENABLE_USE_BB_CRYPT_SHA
-		if (opts && opt_a[0] == 's') {
-			salt[1] = '5' + (strcmp(opt_a, "sha512") == 0);
-			crypt_make_salt(salt + 3, 16/2, 0); /* sha */
-#if TESTING
-			strcpy(salt, "$5$rounds=5000$toolongsaltstring");
-			// with "This is just a test" as password, should produce:
-			// "$5$rounds=5000$toolongsaltstrin$Un/5jzAHMgOGZ5.mWJpuVolil07guHPvOW8mGRcvxa5"
-			strcpy(salt, "$6$rounds=5000$toolongsaltstring");
-			// with "This is just a test" as password, should produce:
-			// "$6$rounds=5000$toolongsaltstrin$lQ8jolhgVRVhY4b5pZKaysCLi0QBxGoNeKQzQ3glMhwllF7oGDZxUhx1yxdYcz/e1JSbq3y6JMxxl8audkUEm0"
-#endif
-		} else
-#endif
-		{
-			crypt_make_salt(salt + 3, 8/2, 0); /* md5 */
-#if TESTING
-			strcpy(salt + 3, "ajg./bcf");
-#endif
+		if (opt_m[0] == 's') { /* sha */
+			salt[1] = '5' + (strcmp(opt_m, "sha512") == 0);
+			len = 16/2;
 		}
+#endif
 	}
+	if (opt_S)
+		safe_strncpy(salt_ptr, opt_S, sizeof(salt) - 3);
+	else
+		crypt_make_salt(salt_ptr, len, 0);
+
+	xmove_fd(fd, STDIN_FILENO);
 
-	puts(pw_encrypt(argv[optind] ? argv[optind] : xmalloc_fgetline(stdin), salt, 1));
+	puts(pw_encrypt(
+		argv[0]	? argv[0] : (
+			/* Only mkpasswd, and only from tty, prompts.
+			 * Otherwise it is a plain read. */
+			(isatty(0) && applet_name[0] == 'm')
+			? bb_ask(STDIN_FILENO, 0, "Password: ")
+			: xmalloc_fgetline(stdin)
+		),
+		salt, 1));
 
-	return 0;
+	return EXIT_SUCCESS;
 }
diff --git a/loginutils/mkpasswd.c b/loginutils/mkpasswd.c
deleted file mode 100644
index 442738e03..000000000
--- a/loginutils/mkpasswd.c
+++ /dev/null
@@ -1,71 +0,0 @@
-/* vi: set sw=4 ts=4 sts=4: */
-/*
- * mkpasswd - Overfeatured front end to crypt(3)
- * Copyright (c) 2008 Bernhard Reutner-Fischer
- *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
- */
-
-#include "libbb.h"
-
-int mkpasswd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int mkpasswd_main(int argc UNUSED_PARAM, char **argv)
-{
-	char *chp = NULL, *method = NULL, *salt = NULL;
-	char *encrypted;
-	int fd = STDIN_FILENO;
-	enum {
-		OPT_P = (1 << 0),
-		OPT_s = (1 << 1),
-		OPT_m = (1 << 2),
-		OPT_S = (1 << 3)
-	};
-	static const char methods[] ALIGN1 =
-		/*"des\0"*/"md5\0""sha-256\0""sha-512\0";
-	enum { TYPE_des, TYPE_md5, TYPE_sha256, TYPE_sha512 };
-	unsigned algo = TYPE_des, algobits = 1;
-#if ENABLE_GETOPT_LONG
-	static const char mkpasswd_longopts[] ALIGN1 =
-		"password-fd\0"	Required_argument "P"
-		"stdin\0"		No_argument "s"
-		"method\0"		Required_argument "m"
-		"salt\0"		Required_argument "S"
-	;
-	applet_long_options = mkpasswd_longopts;
-#endif
-	opt_complementary = "?1"; /* at most one non-option argument */
-	getopt32(argv, "P:sm:S:", &chp, &method, &salt);
-	argv += optind;
-	if (option_mask32 & OPT_P)
-		fd = xatoi_u(chp);
-	if (option_mask32 & OPT_m)
-		algo = index_in_strings(methods, method) + 1;
-	if (*argv) /* we have a cleartext passwd */
-		chp = *argv;
-	else
-		chp = bb_ask(fd, 0, "Password: ");
-	if (!salt)
-		salt = xmalloc(128);
-
-	if (algo) {
-		char foo[2];
-		foo[0] = foo[2] = '$';
-		algobits = 4;
-		/* MD5 == "$1$", SHA-256 == "$5$", SHA-512 == "$6$" */
-		if (algo > 1) {
-			algo += 3;
-			algobits = 8;
-		}
-		foo[1] = '0' + (algo);
-		strcpy(salt, foo);
-	}
-	/* The opt_complementary adds a bit of additional noise, which is good
-	   but not strictly needed.  */
-	crypt_make_salt(salt + ((!!algo) * 3), algobits, (int)&opt_complementary);
-	encrypted = pw_encrypt(chp, salt, 1);
-	puts(encrypted);
-	if (ENABLE_FEATURE_CLEAN_UP) {
-		free(encrypted);
-	}
-	return EXIT_SUCCESS;
-}