From: Joel Sing <joel@sing.id.au>
Date: Sat, 29 May 2021 15:46:19 +0000 (+1000)
Subject: syscall: use correct type for TIOCSPGRP/TIOCGPGRP
X-Git-Tag: go1.18beta1~1788
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=3d679c6554;p=gostls13.git

syscall: use correct type for TIOCSPGRP/TIOCGPGRP

These ioctls take a pid_t (generally a C integer aka int32) and not an int64 - we
currently get away with this on little endian 64 bit platforms, since the bytes
fall into the correct place, however this breaks on big endian 64 bit platforms
(like openbsd/mips64).

This is the same fix as CL 267605, however for libc based exec.

Updates #36435

Change-Id: I01ae4905cba5e1f8725fa6cb8c35403c511534b2
Reviewed-on: https://go-review.googlesource.com/c/go/+/334881
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Mui <cherryyz@google.com>
---

diff --git a/src/syscall/exec_libc2.go b/src/syscall/exec_libc2.go
index b999754c2e..bd98109d07 100644
--- a/src/syscall/exec_libc2.go
+++ b/src/syscall/exec_libc2.go
@@ -117,14 +117,15 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
 	}
 
 	if sys.Foreground {
-		pgrp := sys.Pgid
+		// This should really be pid_t, however _C_int (aka int32) is
+		// generally equivalent.
+		pgrp := _C_int(sys.Pgid)
 		if pgrp == 0 {
 			r1, _, err1 = rawSyscall(abi.FuncPCABI0(libc_getpid_trampoline), 0, 0, 0)
 			if err1 != 0 {
 				goto childerror
 			}
-
-			pgrp = int(r1)
+			pgrp = _C_int(r1)
 		}
 
 		// Place process group in foreground.