[v6,5/5] net/tap: Use qemu_close_all_open_fd()

Commit Message

Clément Léger July 30, 2024, 12:24 p.m. UTC

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

Signed-off-by: Clément Léger <[e-mail]>
---
 net/tap.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

Comments

Richard Henderson July 31, 2024, 2:06 a.m. UTC | #1

On 7/30/24 22:24, Clément Léger wrote:
> Instead of using a slow implementation to close all open fd after
> forking, use qemu_close_all_open_fd().
> 
> Signed-off-by: Clément Léger<[e-mail]>
> ---
>   net/tap.c | 17 ++++++++++++-----
>   1 file changed, 12 insertions(+), 5 deletions(-)

Reviewed-by: Richard Henderson <[e-mail]>

r~

Patch

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,