From: Clément Léger <cleger@rivosinc.com>
Date: Fri, 2 Aug 2024 14:54:21 +0000 (+0200)
Subject: net/tap: Use qemu_close_all_open_fd()
X-Git-Tag: qemu-xen-4.20.0~34^2
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=9996a35c6433c0e019a1c05791299db5e63a5db7;p=qemu-xen.git

net/tap: Use qemu_close_all_open_fd()

Instead of using a slow implementation to close all open fd after
forking, use qemu_close_all_open_fd().

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240802145423.3232974-6-cleger@rivosinc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---

diff --git a/net/tap.c b/net/tap.c
index 7b2d5d5703..3f90022c0b 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -387,13 +387,20 @@ static TAPState *net_tap_fd_init(NetClientState *peer,
 
 static void close_all_fds_after_fork(int excluded_fd)
 {
-    int open_max = sysconf(_SC_OPEN_MAX), i;
+    const int skip_fd[] = {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO,
+                           excluded_fd};
+    unsigned int nskip = ARRAY_SIZE(skip_fd);
 
-    for (i = 3; i < open_max; i++) {
-        if (i != excluded_fd) {
-            close(i);
-        }
+    /*
+     * skip_fd must be an ordered array of distinct fds, exclude
+     * excluded_fd if already included in the [STDIN_FILENO - STDERR_FILENO]
+     * range
+     */
+    if (excluded_fd <= STDERR_FILENO) {
+        nskip--;
     }
+
+    qemu_close_all_open_fd(skip_fd, nskip);
 }
 
 static void launch_script(const char *setup_script, const char *ifname,