add setarch/linux32/linux64 applet

include/applets.h

@@ -378,6 +378,10 @@
 #ifdef CONFIG_FEATURE_INITRD
 	APPLET_NOUSAGE("linuxrc", init_main, _BB_DIR_ROOT, _BB_SUID_NEVER)
 #endif
+#ifdef CONFIG_SETARCH
+	APPLET_NOUSAGE("linux32", setarch_main, _BB_DIR_BIN, _BB_SUID_NEVER)
+	APPLET_NOUSAGE("linux64", setarch_main, _BB_DIR_BIN, _BB_SUID_NEVER)
+#endif
 #ifdef CONFIG_LN
 	APPLET(ln, ln_main, _BB_DIR_BIN, _BB_SUID_NEVER)
 #endif
@@ -586,6 +590,9 @@
 #ifdef CONFIG_SEQ
 	APPLET(seq, seq_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER)
 #endif
+#ifdef CONFIG_SETARCH
+	APPLET(setarch, setarch_main, _BB_DIR_BIN, _BB_SUID_NEVER)
+#endif
 #ifdef CONFIG_SETCONSOLE
 	APPLET(setconsole, setconsole_main, _BB_DIR_SBIN, _BB_SUID_NEVER)
 #endif

include/usage.h

@@ -1626,6 +1626,13 @@
 	"\t\treached.\n" \
 	"\t-h, -?\tDisplay this help message\n"
 
+#define setarch_trivial_usage \
+	"<personality> <program> [args ...]"
+#define setarch_full_usage \
+	"Personality may be:\n" \
+	"\tlinux32\tSet 32bit uname emulation\n" \
+	"\tlinux64\tSet 64bit uname emulation"
+
 #define ln_trivial_usage \
 	"[OPTION] TARGET... LINK_NAME|DIRECTORY"
 #define ln_full_usage \

util-linux/Config.in

@@ -354,6 +354,15 @@ config CONFIG_READPROFILE
 	help
 	  This allows you to parse /proc/profile for basic profiling.
 
+config CONFIG_SETARCH
+	bool "setarch"
+	default n
+	help
+	  The linux32 utility is used to create a 32bit environment for the
+	  specified program (usually a shell).  It only makes sense to have
+	  this util on a system that supports both 64bit and 32bit userland
+	  (like amd64/x86, ppc64/ppc, sparc64/sparc, etc...).
+
 config CONFIG_SWAPONOFF
 	bool "swaponoff"
 	default n

util-linux/Makefile.in

@@ -33,6 +33,7 @@ UTILLINUX-$(CONFIG_FEATURE_MOUNT_NFS)	+=nfsmount.o
 UTILLINUX-$(CONFIG_PIVOT_ROOT)    +=pivot_root.o
 UTILLINUX-$(CONFIG_RDATE)         +=rdate.o
 UTILLINUX-$(CONFIG_READPROFILE)   +=readprofile.o
+UTILLINUX-$(CONFIG_SETARCH)       +=setarch.o
 UTILLINUX-$(CONFIG_SWAPONOFF)     +=swaponoff.o
 UTILLINUX-$(CONFIG_SWITCH_ROOT)   +=switch_root.o
 UTILLINUX-$(CONFIG_UMOUNT)        +=umount.o

util-linux/setarch.c

@@ -0,0 +1,54 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Linux32/linux64 allows for changing uname emulation.
+ *
+ * Copyright 2002 Andi Kleen, SuSE Labs.
+ * This file is subject to the GNU General Public License v2 
+ *
+ * Licensed under GPL v2 or later, see file License for details.
+*/
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+#include <sys/personality.h>
+
+#include "busybox.h"
+
+int setarch_main(int argc, char **argv)
+{
+	int pers = -1;
+
+	/* Figure out what personality we are supposed to switch to ...
+	 * we can be invoked as either:
+	 * argv[0],argv[1] -> "setarch","personality"
+	 * argv[0]         -> "personality"
+	 */
+retry:
+	if (!strcmp(argv[0], "linux64"))
+		pers = PER_LINUX;
+	else if (!strcmp(argv[0], "linux32"))
+		pers = PER_LINUX32;
+	else if (pers == -1 && argv[1] != NULL) {
+		pers = PER_LINUX32;
+		++argv;
+		goto retry;
+	}
+
+	/* make user actually gave us something to do */
+	++argv;
+	if (argv[0] == NULL)
+		bb_show_usage();
+
+	/* Try to set personality */
+	if (personality(pers) < 0)
+		goto failure;
+
+	/* Try to execute the program */
+	execvp(argv[0], argv);
+
+failure:
+	bb_perror_msg_and_die(argv[0]);
+}