[Qemu-devel] [PULL v2 08/23] linux-user: support {name_to, open_by}_handle_at syscalls

[riku.voipio@linaro.org]

From: Riku Voipio <riku.voipio@linaro.org>

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

Modified by Riku - move syscalls to functions and put behind
the already existing CONFIG_OPEN_BY_HANDLE to avoid build failure
with old glibc's.

Signed-off-by: Paul Burton <paul@archlinuxmips.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
---
 linux-user/strace.c    | 30 ++++++++++++++++++++++
 linux-user/strace.list |  6 +++++
 linux-user/syscall.c   | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 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 f1c182b..74c5d49 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5362,6 +5362,66 @@ static int do_openat(void *cpu_env, int dirfd, const char *pathname, int flags,
 
     return get_errno(sys_openat(dirfd, path(pathname), flags, mode));
 }
+#if defined(TARGET_NR_name_to_handle_at) && defined(CONFIG_OPEN_BY_HANDLE)
+static abi_long do_name_to_handle_at(abi_long arg1, abi_long arg2,
+        abi_long arg3, abi_long arg4, abi_long arg5)
+{
+    struct file_handle *fh;
+    uint32_t sz;
+    int mount_id;
+    abi_long ret;
+    char *p;
+
+    if (get_user_u32(sz, arg3)) {
+        return -TARGET_EFAULT;
+    }
+
+    p = lock_user_string(arg2);
+    if (!p) {
+        return -TARGET_EFAULT;
+    }
+
+    fh = lock_user(VERIFY_WRITE, arg3, sizeof(*fh) + sz, 1);
+    if (!fh) {
+        unlock_user(p, arg2, 0);
+        return -TARGET_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)) {
+        return -TARGET_EFAULT;
+    }
+    return ret;
+
+}
+#endif
+#if defined(TARGET_NR_open_by_handle_at) && defined(CONFIG_OPEN_BY_HANDLE)
+static abi_long do_open_by_handle_at(abi_long arg1, abi_long arg2, abi_long arg3)
+{
+    struct file_handle *fh;
+    uint32_t sz;
+    abi_long ret;
+    char *p;
+
+    if (get_user_u32(sz, arg2)) {
+        return -TARGET_EFAULT;
+    }
+
+    fh = lock_user(VERIFY_WRITE, arg2, sizeof(*fh) + sz, 1);
+    if (!fh) {
+        return -TARGET_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);
+    return ret;
+}
+#endif
 
 /* do_syscall() should always have a single exit point at the end so
    that actions, such as logging of syscall results, can be performed.
@@ -5448,6 +5508,16 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                                   arg4));
         unlock_user(p, arg2, 0);
         break;
+#if defined(TARGET_NR_name_to_handle_at) && defined(CONFIG_OPEN_BY_HANDLE)
+    case TARGET_NR_name_to_handle_at:
+        ret = do_name_to_handle_at(arg1, arg2, arg3, arg4, arg5);
+        break;
+#endif
+#if defined(TARGET_NR_open_by_handle_at) && defined(CONFIG_OPEN_BY_HANDLE)
+    case TARGET_NR_open_by_handle_at:
+        ret = do_open_by_handle_at(arg1, arg2, arg3);
+        break;
+#endif
     case TARGET_NR_close:
         ret = get_errno(close(arg1));
         break;
-- 
2.0.1