pkg_install-macos-posix_spawn.diff

diff --git a/pkgtools/pkg_install/files/lib/fexec.c b/pkgtools/pkg_install/files/lib/fexec.c
index 540159863aa..592bd51f886 100644
--- a/pkgtools/pkg_install/files/lib/fexec.c
+++ b/pkgtools/pkg_install/files/lib/fexec.c
@@ -59,6 +59,16 @@
 
 #include "lib.h"
 
+/*
+ * Newer macOS releases are not able to correctly handle vfork() when the
+ * underlying file is changed or removed, but posix_spawn() seems to still
+ * work ok.
+ */
+#ifdef __APPLE__
+#include <spawn.h>
+extern char **environ;
+#endif
+
 __RCSID("$NetBSD: fexec.c,v 1.12 2009/08/02 17:56:45 joerg Exp $");
 
 static int	vfcexec(const char *, int, const char *, va_list);
@@ -67,6 +77,8 @@ static int	vfcexec(const char *, int, const char *, va_list);
  * fork, then change current working directory to path and
  * execute the command and arguments in the argv array.
  * wait for the command to finish, then return the exit status.
+ *
+ * macOS uses posix_spawn() instead due to reasons explained above.
  */
 int
 pfcexec(const char *path, const char *file, const char **argv)
@@ -74,6 +86,29 @@ pfcexec(const char *path, const char *file, const char **argv)
 	pid_t			child;
 	int			status;
 
+#ifdef __APPLE__
+	char oldcwd[PATH_MAX];
+
+	if (getcwd(oldcwd, sizeof(oldcwd)) == NULL) {
+		warn("getcwd failed");
+		return -1;
+	}
+
+	if ((path != NULL) && (chdir(path) < 0)) {
+		warn("chdir failed");
+		return -1;
+	}
+
+	if (posix_spawn(&child, file, NULL, NULL, argv, environ) < 0) {
+		warn("posix_spawn failed");
+		return -1;
+	}
+
+	if (chdir(oldcwd) < 0) {
+		warn("chdir failed");
+		return -1;
+	}
+#else
 	child = vfork();
 	switch (child) {
 	case 0:
@@ -86,6 +121,7 @@ pfcexec(const char *path, const char *file, const char **argv)
 	case -1:
 		return -1;
 	}
+#endif
 
 	while (waitpid(child, &status, 0) < 0) {
 		if (errno != EINTR)