[Valgrind-developers] [valgrind] Mark returned descriptor as valid when CLONE_PIDFD is used

[Tom H. <tom...@so...>]

https://sourceware.org/git/gitweb.cgi?p=valgrind.git;h=22aa8640e6c44c78c228ffa726cfacf918455343

commit 22aa8640e6c44c78c228ffa726cfacf918455343
Author: Tom Hughes <to...@co...>
Date:   Thu Feb 20 09:18:17 2020 +0000

    Mark returned descriptor as valid when CLONE_PIDFD is used
    
    When CLONE_PIDFD is set the descriptor is returned via the
    argument otherwise used for the parent thread id.

Diff:
---
 coregrind/m_syswrap/syswrap-linux.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/coregrind/m_syswrap/syswrap-linux.c b/coregrind/m_syswrap/syswrap-linux.c
index a4c106f..87334c9 100644
--- a/coregrind/m_syswrap/syswrap-linux.c
+++ b/coregrind/m_syswrap/syswrap-linux.c
@@ -852,7 +852,7 @@ PRE(sys_clone)
       PRA_CHILD_STACK("clone",  void *, child_stack);
    }
 
-   if (ARG_FLAGS & VKI_CLONE_PARENT_SETTID) {
+   if (ARG_FLAGS & (VKI_CLONE_PARENT_SETTID | VKI_CLONE_PIDFD)) {
       if (VG_(tdict).track_pre_reg_read) {
          PRA3("clone", int *, parent_tidptr);
       }
@@ -941,10 +941,20 @@ PRE(sys_clone)
    }
 
    if (SUCCESS) {
-      if (ARG_FLAGS & VKI_CLONE_PARENT_SETTID)
+      if (ARG_FLAGS & (VKI_CLONE_PARENT_SETTID | VKI_CLONE_PIDFD))
          POST_MEM_WRITE(ARG3, sizeof(Int));
       if (ARG_FLAGS & (VKI_CLONE_CHILD_SETTID | VKI_CLONE_CHILD_CLEARTID))
          POST_MEM_WRITE(ARG_CHILD_TIDPTR, sizeof(Int));
+      if (ARG_FLAGS & VKI_CLONE_PIDFD) {
+         Int fd = *(Int*)(Addr)ARG3;
+         if (!ML_(fd_allowed)(fd, "clone", tid, True)) {
+            VG_(close)(fd);
+            SET_STATUS_Failure( VKI_EMFILE );
+         } else {
+            if (VG_(clo_track_fds))
+               ML_(record_fd_open_nameless) (tid, fd);
+         }
+      }
 
       /* Thread creation was successful; let the child have the chance
          to run */