The branch main has been updated by christos:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=e5c0d7020f3d040b28dc7ca0cda9926e07e5aaf4

commit e5c0d7020f3d040b28dc7ca0cda9926e07e5aaf4
Author:     Christos Margiolis <[email protected]>
AuthorDate: 2025-11-11 12:07:44 +0000
Commit:     Christos Margiolis <[email protected]>
CommitDate: 2025-11-11 12:07:44 +0000

    virtual_oss(8): Improve hw.snd.basename_clone handling
    
    If we request a /dev/dsp virtual_oss(8) device, we have to replace the
    sound(4) one by first disabling hw.snd.basename_clone. This sysctl tells
    sound(4) to not create the /dev/dsp alias for the default device. There
    are currently two issues with the way this is handled by virtual_oss(8),
    however:
    
    1. It uses system(3) instead of sysctlbyname(3).
    2. It does not restore hw.snd.basename_clone to its original value, so
       if prior to virtual_oss(8) running, hw.snd.basename_clone was enabled
       (which is the case by default), and it is closed at some point,
       hw.snd.basename_clone stays disabled, which is annoying, because
       users have to manually restore it, otherwise applications that open
       the default device (i.e., most) will not work.
    
    Fix both issues.
    
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Reviewed by:    markj
    Differential Revision:  https://reviews.freebsd.org/D53621
---
 usr.sbin/virtual_oss/virtual_oss/main.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/usr.sbin/virtual_oss/virtual_oss/main.c 
b/usr.sbin/virtual_oss/virtual_oss/main.c
index f2fd085664ed..28095880c201 100644
--- a/usr.sbin/virtual_oss/virtual_oss/main.c
+++ b/usr.sbin/virtual_oss/virtual_oss/main.c
@@ -31,6 +31,7 @@
 #include <sys/nv.h>
 #include <sys/sndstat.h>
 #include <sys/soundcard.h>
+#include <sys/sysctl.h>
 
 #include <dlfcn.h>
 #include <errno.h>
@@ -52,6 +53,8 @@
 #include "int.h"
 #include "virtual_oss.h"
 
+#define SYSCTL_BASECLONE       "hw.snd.basename_clone"
+
 pthread_mutex_t atomic_mtx;
 pthread_cond_t atomic_cv;
 
@@ -1617,6 +1620,7 @@ volatile sig_atomic_t voss_exit = 0;
 
 static int voss_dsp_perm = 0666;
 static int voss_do_background;
+static int voss_baseclone = 0;
 static const char *voss_pid_path;
 
 uint32_t voss_dsp_rx_refresh;
@@ -1739,6 +1743,20 @@ usage(void)
        exit(EX_USAGE);
 }
 
+/*
+ * Restore hw.snd.basename_clone if it was disabled by us.
+ */
+static void
+restore_baseclone(void)
+{
+       if (voss_baseclone) {
+               if (sysctlbyname(SYSCTL_BASECLONE, NULL, NULL, &voss_baseclone,
+                   sizeof(int)) < 0)
+                       warn("Could not enable " SYSCTL_BASECLONE);
+               printf(SYSCTL_BASECLONE ": 0 -> %d\n", voss_baseclone);
+       }
+}
+
 static void
 init_compressor(struct virtual_profile *pvp)
 {
@@ -1883,8 +1901,18 @@ dup_profile(vprofile_t *pvp, int *pamp, int pol, int 
rx_mute,
                 * Detect /dev/dsp creation and try to disable system
                 * basename cloning automatically:
                 */
-               if (strcmp(ptr->oss_name, "dsp") == 0)
-                       system("sysctl hw.snd.basename_clone=0");
+               if (strcmp(ptr->oss_name, "dsp") == 0) {
+                       size_t size;
+
+                       x = 0;
+                       size = sizeof(int);
+                       if (sysctlbyname(SYSCTL_BASECLONE, &voss_baseclone,
+                           &size, &x, size) < 0)
+                               return ("Could not disable " SYSCTL_BASECLONE);
+                       printf(SYSCTL_BASECLONE ": %d -> 0\n", voss_baseclone);
+                       if (atexit(restore_baseclone) < 0)
+                               return ("Could not set atexit callback");
+               }
 
                /* create DSP character device */
                pdev = cuse_dev_create(&vclient_oss_methods, ptr, NULL,

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