[Qemu-devel] [PATCH v2 12/16] linux-user: support {name_to, open_by}_handle_at syscalls

[Paul Burton <paul@archlinuxmips.org>]

Implement support for the name_to_handle_at and open_by_handle_at
syscalls, allowing their use by the target program.

Signed-off-by: Paul Burton <paul@archlinuxmips.org>
---
Changes in v2:
  - None.
---
 linux-user/strace.c    | 30 ++++++++++++++++++++++++++++++
 linux-user/strace.list |  6 ++++++
 linux-user/syscall.c   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)

diff --git a/linux-user/strace.c b/linux-user/strace.c
index ea6c1d2..c20ddf1 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -1552,6 +1552,36 @@ print_kill(const struct syscallname *name,
 }
 #endif
 
+#ifdef TARGET_NR_name_to_handle_at
+static void
+print_name_to_handle_at(const struct syscallname *name,
+    abi_long arg0, abi_long arg1, abi_long arg2,
+    abi_long arg3, abi_long arg4, abi_long arg5)
+{
+    print_syscall_prologue(name);
+    print_at_dirfd(arg0, 0);
+    print_string(arg1, 0);
+    print_pointer(arg2, 0);
+    print_pointer(arg3, 0);
+    print_raw_param("0x%x", arg4, 1);
+    print_syscall_epilogue(name);
+}
+#endif
+
+#ifdef TARGET_NR_open_by_handle_at
+static void
+print_open_by_handle_at(const struct syscallname *name,
+    abi_long arg0, abi_long arg1, abi_long arg2,
+    abi_long arg3, abi_long arg4, abi_long arg5)
+{
+    print_syscall_prologue(name);
+    print_raw_param("%d", arg0, 0);
+    print_pointer(arg2, 0);
+    print_open_flags(arg3, 1);
+    print_syscall_epilogue(name);
+}
+#endif
+
 /*
  * An array of all of the syscalls we know about
  */
diff --git a/linux-user/strace.list b/linux-user/strace.list
index 8de972a..147f579 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -582,6 +582,9 @@
 #ifdef TARGET_NR_munmap
 { TARGET_NR_munmap, "munmap" , NULL, print_munmap, NULL },
 #endif
+#ifdef TARGET_NR_name_to_handle_at
+{ TARGET_NR_name_to_handle_at, "name_to_handle_at" , NULL, print_name_to_handle_at, NULL },
+#endif
 #ifdef TARGET_NR_nanosleep
 { TARGET_NR_nanosleep, "nanosleep" , NULL, NULL, NULL },
 #endif
@@ -624,6 +627,9 @@
 #ifdef TARGET_NR_openat
 { TARGET_NR_openat, "openat" , NULL, print_openat, NULL },
 #endif
+#ifdef TARGET_NR_open_by_handle_at
+{ TARGET_NR_open_by_handle_at, "open_by_handle_at" , NULL, print_open_by_handle_at, NULL },
+#endif
 #ifdef TARGET_NR_osf_adjtime
 { TARGET_NR_osf_adjtime, "osf_adjtime" , NULL, NULL, NULL },
 #endif
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index fb36f46..0495781 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5347,6 +5347,56 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         unlock_user(p, arg2, 0);
         break;
 #endif
+#ifdef TARGET_NR_name_to_handle_at
+    case TARGET_NR_name_to_handle_at:
+        {
+            struct file_handle *fh;
+            uint32_t sz;
+            int mount_id;
+
+            if (!(p = lock_user_string(arg2)))
+                goto efault;
+
+            if (get_user_u32(sz, arg3)) {
+                unlock_user(p, arg2, 0);
+                goto efault;
+            }
+
+            if (!(fh = lock_user(VERIFY_WRITE, arg3, sizeof(*fh) + sz, 1))) {
+                unlock_user(p, arg2, 0);
+                goto efault;
+            }
+
+            ret = get_errno(name_to_handle_at(arg1, path(p), fh,
+                                              &mount_id, arg5));
+
+            unlock_user(p, arg2, 0);
+            unlock_user(p, arg3, sizeof(*fh) + sz);
+
+            if (put_user_s32(mount_id, arg4))
+                goto efault;
+        }
+        break;
+#endif
+#ifdef TARGET_NR_open_by_handle_at
+    case TARGET_NR_open_by_handle_at:
+        {
+            struct file_handle *fh;
+            uint32_t sz;
+
+            if (get_user_u32(sz, arg2))
+                goto efault;
+
+            if (!(fh = lock_user(VERIFY_WRITE, arg2, sizeof(*fh) + sz, 1)))
+                goto efault;
+
+            ret = get_errno(open_by_handle_at(arg1, fh,
+                    target_to_host_bitmask(arg3, fcntl_flags_tbl)));
+
+            unlock_user(p, arg2, sizeof(*fh) + sz);
+        }
+        break;
+#endif
     case TARGET_NR_close:
         ret = get_errno(close(arg1));
         break;
-- 
2.0.0