Split out the non-ARM specific portions of SYS_SYSTEM to a
reusable function.  This doesn't use GuestFD, but it does
reuse validate_strlen() from semihost_sys_open.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/semihosting/guestfd.h |  3 +++
 semihosting/arm-compat-semi.c | 12 +----------
 semihosting/guestfd.c         | 40 +++++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/include/semihosting/guestfd.h b/include/semihosting/guestfd.h
index 2bdf02429b..a6d34e8141 100644
--- a/include/semihosting/guestfd.h
+++ b/include/semihosting/guestfd.h
@@ -79,4 +79,7 @@ void semihost_sys_rename(CPUState *cs, gdb_syscall_complete_cb complete,
                          target_ulong oname, target_ulong oname_len,
                          target_ulong nname, target_ulong nname_len);
 
+void semihost_sys_system(CPUState *cs, gdb_syscall_complete_cb complete,
+                         target_ulong cmd, target_ulong cmd_len);
+
 #endif /* SEMIHOSTING_GUESTFD_H */
diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index 143c8689f5..61e8dede8d 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -495,17 +495,7 @@ void do_common_semihosting(CPUState *cs)
     case TARGET_SYS_SYSTEM:
         GET_ARG(0);
         GET_ARG(1);
-        if (use_gdb_syscalls()) {
-            gdb_do_syscall(common_semi_cb, "system,%s", arg0, (int)arg1 + 1);
-            break;
-        }
-        s = lock_user_string(arg0);
-        if (!s) {
-            goto do_fault;
-        }
-        ret = system(s);
-        unlock_user(s, arg0, 0);
-        common_semi_cb(cs, ret, ret == -1 ? errno : 0);
+        semihost_sys_system(cs, common_semi_cb, arg0, arg1 + 1);
         break;
 
     case TARGET_SYS_ERRNO:
diff --git a/semihosting/guestfd.c b/semihosting/guestfd.c
index 03e516535a..9176ddd301 100644
--- a/semihosting/guestfd.c
+++ b/semihosting/guestfd.c
@@ -714,3 +714,43 @@ void semihost_sys_rename(CPUState *cs, gdb_syscall_complete_cb complete,
         host_rename(cs, complete, oname, oname_len, nname, nname_len);
     }
 }
+
+static void gdb_system(CPUState *cs, gdb_syscall_complete_cb complete,
+                       target_ulong cmd, target_ulong cmd_len)
+{
+    int len = validate_strlen(cs, cmd, cmd_len);
+    if (len < 0) {
+        complete(cs, -1, -len);
+        return;
+    }
+
+    gdb_do_syscall(complete, "system,%s", cmd, len);
+}
+
+static void host_system(CPUState *cs, gdb_syscall_complete_cb complete,
+                        target_ulong cmd, target_ulong cmd_len)
+{
+    CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+    char *p;
+    int ret;
+
+    ret = validate_lock_user_string(&p, cs, cmd, cmd_len);
+    if (ret < 0) {
+        complete(cs, -1, -ret);
+        return;
+    }
+
+    ret = system(p);
+    complete(cs, ret, ret == -1 ? errno : 0);
+    unlock_user(p, cmd, 0);
+}
+
+void semihost_sys_system(CPUState *cs, gdb_syscall_complete_cb complete,
+                         target_ulong cmd, target_ulong cmd_len)
+{
+    if (use_gdb_syscalls()) {
+        gdb_system(cs, complete, cmd, cmd_len);
+    } else {
+        host_system(cs, complete, cmd, cmd_len);
+    }
+}
-- 
2.34.1