[Qemu-devel] [PATCH v7 42/74] linux-user: Split out dup, dup2, dup3

[Richard Henderson <richard.henderson@linaro.org>]

Note that dup3 is universally available for guests.
Implement host support with syscall when !CONFIG_DUP3.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/syscall-defs.h     |  5 +++++
 linux-user/syscall-file.inc.c | 42 +++++++++++++++++++++++++++++++++++
 linux-user/syscall.c          | 33 +++------------------------
 linux-user/strace.list        |  6 -----
 4 files changed, 50 insertions(+), 36 deletions(-)

diff --git a/linux-user/syscall-defs.h b/linux-user/syscall-defs.h
index 8b6d8f75ff..062adddd75 100644
--- a/linux-user/syscall-defs.h
+++ b/linux-user/syscall-defs.h
@@ -34,6 +34,11 @@ SYSCALL_DEF(close, ARG_DEC);
 #ifdef TARGET_NR_creat
 SYSCALL_DEF(creat, ARG_STR, ARG_MODEFLAG);
 #endif
+SYSCALL_DEF(dup, ARG_DEC);
+#ifdef TARGET_NR_dup2
+SYSCALL_DEF(dup2, ARG_DEC, ARG_DEC);
+#endif
+SYSCALL_DEF(dup3, ARG_DEC, ARG_DEC, ARG_OPENFLAG);
 SYSCALL_DEF(exit, ARG_DEC);
 SYSCALL_DEF(execve, ARG_STR, ARG_PTR, ARG_PTR);
 SYSCALL_DEF(execveat, ARG_ATDIRFD, ARG_STR, ARG_PTR, ARG_PTR, ARG_ATFLAG);
diff --git a/linux-user/syscall-file.inc.c b/linux-user/syscall-file.inc.c
index 5ed8b78c79..7d97dd1ec1 100644
--- a/linux-user/syscall-file.inc.c
+++ b/linux-user/syscall-file.inc.c
@@ -94,6 +94,48 @@ SYSCALL_IMPL(creat)
 }
 #endif
 
+SYSCALL_IMPL(dup)
+{
+    abi_long ret = get_errno(dup(arg1));
+    if (ret >= 0) {
+        fd_trans_dup(arg1, ret);
+    }
+    return ret;
+}
+
+#ifdef TARGET_NR_dup2
+SYSCALL_IMPL(dup2)
+{
+    abi_long ret = get_errno(dup2(arg1, arg2));
+    if (ret >= 0) {
+        fd_trans_dup(arg1, arg2);
+    }
+    return ret;
+}
+#endif
+
+SYSCALL_IMPL(dup3)
+{
+    int ofd = arg1;
+    int nfd = arg2;
+    int host_flags = target_to_host_bitmask(arg3, fcntl_flags_tbl);
+    abi_long ret;
+
+#ifdef CONFIG_DUP3
+    ret = dup3(ofd, nfd, host_flags);
+#else
+    if (host_flags == 0) {
+        if (ofd == nfd) {
+            return -TARGET_EINVAL;
+        }
+        ret = dup2(ofd, nfd);
+    } else {
+        ret = syscall(__NR_dup3, ofd, nfd, host_flags);
+    }
+#endif
+    return get_errno(ret);
+}
+
 SYSCALL_IMPL(faccessat)
 {
     return do_faccessat(arg1, arg2, arg3);
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 0d6a9b7a6c..bab9a57ee0 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -204,6 +204,9 @@ _syscall0(int, sys_gettid)
  * Performing a bogus syscall is easier than boilerplating
  * the replacement functions here in C.
  */
+#ifndef __NR_dup3
+#define __NR_dup3  -1
+#endif
 #ifndef __NR_syncfs
 #define __NR_syncfs  -1
 #endif
@@ -5373,12 +5376,6 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
     void *p;
 
     switch(num) {
-    case TARGET_NR_dup:
-        ret = get_errno(dup(arg1));
-        if (ret >= 0) {
-            fd_trans_dup(arg1, ret);
-        }
-        return ret;
 #ifdef TARGET_NR_pipe
     case TARGET_NR_pipe:
         return do_pipe(cpu_env, arg1, 0, 0);
@@ -5433,30 +5430,6 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
         ret = get_errno(chroot(p));
         unlock_user(p, arg1, 0);
         return ret;
-#ifdef TARGET_NR_dup2
-    case TARGET_NR_dup2:
-        ret = get_errno(dup2(arg1, arg2));
-        if (ret >= 0) {
-            fd_trans_dup(arg1, arg2);
-        }
-        return ret;
-#endif
-#if defined(CONFIG_DUP3) && defined(TARGET_NR_dup3)
-    case TARGET_NR_dup3:
-    {
-        int host_flags;
-
-        if ((arg3 & ~TARGET_O_CLOEXEC) != 0) {
-            return -EINVAL;
-        }
-        host_flags = target_to_host_bitmask(arg3, fcntl_flags_tbl);
-        ret = get_errno(dup3(arg1, arg2, host_flags));
-        if (ret >= 0) {
-            fd_trans_dup(arg1, arg2);
-        }
-        return ret;
-    }
-#endif
 #ifdef TARGET_NR_getpgrp
     case TARGET_NR_getpgrp:
         return get_errno(getpgrp());
diff --git a/linux-user/strace.list b/linux-user/strace.list
index cdbc59bffd..2f78f4685b 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -91,12 +91,6 @@
 #ifdef TARGET_NR_dipc
 { TARGET_NR_dipc, "dipc" , NULL, NULL, NULL },
 #endif
-#ifdef TARGET_NR_dup
-{ TARGET_NR_dup, "dup" , NULL, NULL, NULL },
-#endif
-#ifdef TARGET_NR_dup2
-{ TARGET_NR_dup2, "dup2" , NULL, NULL, NULL },
-#endif
 #ifdef TARGET_NR_epoll_create
 { TARGET_NR_epoll_create, "epoll_create" , NULL, NULL, NULL },
 #endif
-- 
2.17.1