[Qemu-devel] [PATCH 01/16] linux-user: translate the result of getsockopt SO_TYPE

[Paul Burton <paul@archlinuxmips.org>]

QEMU previously passed the result of the host syscall directly to the
target program. This is a problem if the host & target have different
representations of socket types, as is the case when running a MIPS
target program on an x86 host. Introduce a host_to_target_sock_type
helper function mirroring the existing target_to_host_sock_type, and
call it to translate the value provided by getsockopt when called for
the SO_TYPE option.

Signed-off-by: Paul Burton <paul@archlinuxmips.org>
---
 linux-user/syscall.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 6efeeff..3921cff 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -592,6 +592,35 @@ char *target_strerror(int err)
     return strerror(target_to_host_errno(err));
 }
 
+static inline int host_to_target_sock_type(int host_type)
+{
+    int target_type;
+
+    switch (host_type & 0xf /* SOCK_TYPE_MASK */) {
+    case SOCK_DGRAM:
+        target_type = TARGET_SOCK_DGRAM;
+        break;
+    case SOCK_STREAM:
+        target_type = TARGET_SOCK_STREAM;
+        break;
+    default:
+        target_type = host_type & 0xf /* SOCK_TYPE_MASK */;
+        break;
+    }
+
+#if defined(SOCK_CLOEXEC)
+    if (host_type & SOCK_CLOEXEC)
+        target_type |= TARGET_SOCK_CLOEXEC;
+#endif
+
+#if defined(SOCK_NONBLOCK)
+    if (host_type & SOCK_NONBLOCK)
+        target_type |= TARGET_SOCK_NONBLOCK;
+#endif
+
+    return target_type;
+}
+
 static abi_ulong target_brk;
 static abi_ulong target_original_brk;
 static abi_ulong brk_page;
@@ -1526,6 +1555,7 @@ static abi_long do_getsockopt(int sockfd, int level, int optname,
     abi_long ret;
     int len, val;
     socklen_t lv;
+    int (*translate_result)(int val) = NULL;
 
     switch(level) {
     case TARGET_SOL_SOCKET:
@@ -1578,6 +1608,7 @@ static abi_long do_getsockopt(int sockfd, int level, int optname,
             optname = SO_REUSEADDR;
             goto int_case;
         case TARGET_SO_TYPE:
+            translate_result = host_to_target_sock_type;
             optname = SO_TYPE;
             goto int_case;
         case TARGET_SO_ERROR:
@@ -1636,6 +1667,8 @@ static abi_long do_getsockopt(int sockfd, int level, int optname,
         ret = get_errno(getsockopt(sockfd, level, optname, &val, &lv));
         if (ret < 0)
             return ret;
+        if (translate_result)
+            val = translate_result(val);
         if (len > lv)
             len = lv;
         if (len == 4) {
-- 
2.0.0