diff --git a/Makefile.target b/Makefile.target
index 33dc285..07047c1 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -259,7 +259,7 @@
 endif
 
 ifdef CONFIG_LINUX_USER
-OBJS= main.o syscall.o mmap.o signal.o path.o osdep.o thunk.o \
+OBJS= main.o syscall.o strace.o mmap.o signal.o path.o osdep.o thunk.o \
       elfload.o linuxload.o
 LIBS+= $(AIOLIBS)
 ifdef TARGET_HAS_BFLT
diff --git a/linux-user/main.c b/linux-user/main.c
index 88a2e48..6a026b0 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -1980,6 +1980,10 @@
     env = cpu_init();
     global_env = env;
 
+    if(getenv("QEMU_STRACE") ){
+      do_strace=1;
+    }
+
     wrk = environ;
     while (*(wrk++))
         environ_count++;
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index e92db6e..22a4fec 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -153,10 +153,18 @@
 void cpu_loop(CPUState *env);
 void init_paths(const char *prefix);
 const char *path(const char *pathname);
+char *target_strerror(int err);
 
 extern int loglevel;
 extern FILE *logfile;
 
+/* strace.c */
+void print_syscall(int num,
+                   target_long arg1, target_long arg2, target_long arg3,
+                   target_long arg4, target_long arg5, target_long arg6);
+void print_syscall_ret(int num, target_long arg1);
+extern int do_strace;
+
 /* signal.c */
 void process_pending_signals(void *cpu_env);
 void signal_init(void);
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 6d1997e..07e84d9 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -251,11 +251,18 @@
 extern int getresgid(gid_t *, gid_t *, gid_t *);
 extern int setgroups(int, gid_t *);
 
+#define ERRNO_TABLE_SIZE 1200
+
+/* target_to_host_errno_table[] is initialized from
+ * host_to_target_errno_table[] in syscall_init(). */
+static uint16_t target_to_host_errno_table[ERRNO_TABLE_SIZE] = {
+};
+
 /*
  * This list is the union of errno values overridden in asm-<arch>/errno.h
  * minus the errnos that are not actually generic to all archs.
  */
-static uint16_t host_to_target_errno_table[1200] = {
+static uint16_t host_to_target_errno_table[ERRNO_TABLE_SIZE] = {
     [EIDRM]		= TARGET_EIDRM,
     [ECHRNG]		= TARGET_ECHRNG,
     [EL2NSYNC]		= TARGET_EL2NSYNC,
@@ -361,7 +368,7 @@
 #ifdef ENOTRECOVERABLE
     [ENOTRECOVERABLE]	= TARGET_ENOTRECOVERABLE,
 #endif
-	};
+};
 
 static inline int host_to_target_errno(int err)
 {
@@ -370,6 +377,13 @@
     return err;
 }
 
+static inline int target_to_host_errno(int err)
+{
+    if (target_to_host_errno_table[err])
+        return target_to_host_errno_table[err];
+    return err;
+}
+
 static inline abi_long get_errno(abi_long ret)
 {
     if (ret == -1)
@@ -383,6 +397,11 @@
     return (abi_ulong)ret >= (abi_ulong)(-4096);
 }
 
+char *target_strerror(int err)
+{
+    return strerror(target_to_host_errno(err));
+}
+
 static abi_ulong target_brk;
 static abi_ulong target_original_brk;
 
@@ -2465,6 +2484,7 @@
     IOCTLEntry *ie;
     const argtype *arg_type;
     int size;
+    int i;
 
 #define STRUCT(name, list...) thunk_register_struct(STRUCT_ ## name, #name, struct_ ## name ## _def);
 #define STRUCT_SPECIAL(name) thunk_register_struct_direct(STRUCT_ ## name, #name, &struct_ ## name ## _def);
@@ -2490,6 +2510,12 @@
                               ~(TARGET_IOC_SIZEMASK << TARGET_IOC_SIZESHIFT)) |
                 (size << TARGET_IOC_SIZESHIFT);
         }
+
+        /* Build target_to_host_errno_table[] table from
+         * host_to_target_errno_table[]. */
+        for (i=0; i < ERRNO_TABLE_SIZE; i++)
+                target_to_host_errno_table[host_to_target_errno_table[i]] = i;
+
         /* automatic consistency check if same arch */
 #if defined(__i386__) && defined(TARGET_I386)
         if (ie->target_cmd != ie->host_cmd) {
@@ -2588,6 +2614,9 @@
 #ifdef DEBUG
     gemu_log("syscall %d", num);
 #endif
+    if(do_strace)
+        print_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
+
     switch(num) {
     case TARGET_NR_exit:
 #ifdef HAVE_GPROF
@@ -5025,5 +5054,7 @@
 #ifdef DEBUG
     gemu_log(" = %ld\n", ret);
 #endif
+    if(do_strace)
+        print_syscall_ret(num, ret);
     return ret;
 }