bsd-user: Implement getpriority(2) and setpriority(2).

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20230925182425.3163-19-kariem.taha2.7@gmail.com>

bsd-user/bsd-proc.h

@@ -390,4 +390,28 @@ static inline abi_long do_bsd_ptrace(abi_long arg1, abi_long arg2,
     return -TARGET_ENOSYS;
 }
 
+/* getpriority(2) */
+static inline abi_long do_bsd_getpriority(abi_long which, abi_long who)
+{
+    abi_long ret;
+    /*
+     * Note that negative values are valid for getpriority, so we must
+     * differentiate based on errno settings.
+     */
+    errno = 0;
+    ret = getpriority(which, who);
+    if (ret == -1 && errno != 0) {
+        return -host_to_target_errno(errno);
+    }
+
+    return ret;
+}
+
+/* setpriority(2) */
+static inline abi_long do_bsd_setpriority(abi_long which, abi_long who,
+                                          abi_long prio)
+{
+    return get_errno(setpriority(which, who, prio));
+}
+
 #endif /* !BSD_PROC_H_ */

bsd-user/freebsd/os-syscall.c

@@ -359,6 +359,14 @@ static abi_long freebsd_syscall(void *cpu_env, int num, abi_long arg1,
         ret = do_bsd_ptrace(arg1, arg2, arg3, arg4);
         break;
 
+    case TARGET_FREEBSD_NR_getpriority: /* getpriority(2) */
+        ret = do_bsd_getpriority(arg1, arg2);
+        break;
+
+    case TARGET_FREEBSD_NR_setpriority: /* setpriority(2) */
+        ret = do_bsd_setpriority(arg1, arg2, arg3);
+        break;
+
 
         /*
          * File system calls.