X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f
X-Recipient: djgpp AT delorie DOT com
X-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20221208; t=1687968671; x=1690560671;
        h=content-transfer-encoding:in-reply-to:references:cc:to:from
         :content-language:subject:user-agent:mime-version:date:message-id
         :from:to:cc:subject:date:message-id:reply-to;
        bh=ePWi3XA5FoSz6hVCHCYpY6KKzU5ia5TdtAvy6kK10N0=;
        b=NXWKCrcTuGj5kWpVbSWYgmnhCJHZx9lHHAdfA1ubO5SfzKMIlrha/74iK0ozCJJmSO
         kWdiK2YApRG37l/uO1gZ0IzCYRbWssGhbBguP3Mgd/F2hr8Vu8F7reC2s2thvkIMnXf2
         AwkwajP24gmxId6RFijGLUoW2Q4u8GJfJATCM9tndyqMlRyQaCsQtwcIP8t2kUfvI8HH
         GqE0/ozzMZAQ1eHGRvAznNrU3fGLLXlSI5dAbDGBgRvxZ84XR6ObVuIRtfVpkLhbwlBt
         TZ8I+PyQzKhXxCTeBCCF5XxLHJpqCZysIANasC7hvGgshKYQQjtqPcp72P7eXtmnY7qr
         NYpA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20221208; t=1687968671; x=1690560671;
        h=content-transfer-encoding:in-reply-to:references:cc:to:from
         :content-language:subject:user-agent:mime-version:date:message-id
         :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to;
        bh=ePWi3XA5FoSz6hVCHCYpY6KKzU5ia5TdtAvy6kK10N0=;
        b=YE3yWX1l8kWbuTfeeEYNHlOG5D9FOHKKZTAtoc1YkINYGXWFa3LsuiN7OwdKmyjA0v
         V1SZOhIFVGXIIeVYYGFUQQpm7qVm69WTCfpjlNudm+Y1VWHcHQi/TinVjt3+rF0QTCxF
         vSP3W67z6YwJzgsitxMH/EsCmbXL8D5ST08rdDzz07r7HIkC6uxy2HPHOszB5ovX4WS5
         CSA1r0g5+1deXjYdFvXSfzoLOxVWMjBkOjnaHkulyJqYalxsew3RKZp0hWBEGPAspCs6
         FKxWx8xwoC8cuYIn1G7mxQA/IjRCyTbWp5nM9+7IoX74TLQJQ3Yjdg6lQpfJF5ATcZUZ
         +BRw==
X-Gm-Message-State: AC+VfDweQKQqdlJ8uDFNnu4trGDsUEFmJmxaLti1oQExEeu9t0Qy4/n1
	nPsvXG4J2kuaHOn+7BEmJW4uk5FROpM=
X-Google-Smtp-Source: ACHHUZ4UZK59NoMe+3Q6Yil4KRcw4RBtO1kT4U4KHU+A3+hQyoto05av8ETFWsAAjIr1X+MMM+PlUg==
X-Received: by 2002:a2e:7819:0:b0:2b4:7fc5:21ab with SMTP id t25-20020a2e7819000000b002b47fc521abmr19062650ljc.51.1687968671333;
        Wed, 28 Jun 2023 09:11:11 -0700 (PDT)
Message-ID: <5a7896dd-2f76-d043-bcd3-a40526766465@gmail.com>
Date: Wed, 28 Jun 2023 18:11:10 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.12.0
Subject: Re: fcntl() fails to pass option flags to fs-ext handler
Content-Language: en-US
From: "J.W. Jagersma (jwjagersma AT gmail DOT com) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
To: djgpp AT delorie DOT com
Cc: gvanem AT yahoo DOT no
References: <7cb7c635-4f9f-6904-6171-264266ef4fb6 AT gmail DOT com>
In-Reply-To: <7cb7c635-4f9f-6904-6171-264266ef4fb6@gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Reply-To: djgpp AT delorie DOT com

On 2023-06-28 17:04, J.W. Jagersma wrote:
> Hi all,
> 
> I was trying to make a non-blocking socket in Watt32 via:
> 
>     fcntl(sock, F_SETFL, O_NONBLOCK);
> 
> To my surprise, it did nothing.  Replacing fcntl() with fcntlsocket() does set
> the flag correctly, but that's not a portable solution.
> 
> Looking at the libc code, I see the fsext handler is invoked via:
> 
>     int
>     fcntl(int fd, int cmd, ...)
>     {
>     
>     /* ...  */
>     
>       func = __FSEXT_get_function(fd);
>       if (func)
>       {
>         int rv;
>         if (__FSEXT_func_wrapper(func, __FSEXT_fcntl, &rv, fd, cmd))
>           return rv;
>       }
>     
>     /* ...  */
>     
>     }
> 
> From what I can tell, the flags (in va_list) are never passed through to the
> fsext handler.  Has this ever worked?  It seems like a bug to me.

I see ioctl() suffers from the same issue (and doesn't even pass cmd).

If I may propose a patch:

diff --git a/src/libc/compat/ioctl/ioctl.c b/src/libc/compat/ioctl/ioctl.c
index f4382755..182be1a6 100644
--- a/src/libc/compat/ioctl/ioctl.c
+++ b/src/libc/compat/ioctl/ioctl.c
@@ -336,8 +336,17 @@ int ioctl(int fd, int cmd, ...)
    ** see if this is a file system extension file
    **
    */
-  if (func && __FSEXT_func_wrapper(func, __FSEXT_ioctl, &rv, fd))
-    return rv;
+  if (func)
+  {
+    char *arg;
+
+    va_start(args, cmd);
+    arg = va_arg(args, char *);
+    va_end(args);
+
+    if (__FSEXT_func_wrapper(func, __FSEXT_ioctl, &rv, fd, cmd, arg))
+      return rv;
+  }
 
   va_start(args, cmd);
 
diff --git a/src/libc/posix/fcntl/fcntl.c b/src/libc/posix/fcntl/fcntl.c
index e08ffe2b..1d43c0ff 100644
--- a/src/libc/posix/fcntl/fcntl.c
+++ b/src/libc/posix/fcntl/fcntl.c
@@ -281,8 +281,13 @@ fcntl(int fd, int cmd, ...)
   func = __FSEXT_get_function(fd);
   if (func)
   {
-    int rv;
-    if (__FSEXT_func_wrapper(func, __FSEXT_fcntl, &rv, fd, cmd))
+    int rv, arg;
+
+    va_start(ap, cmd);
+    arg = va_arg(ap, int);
+    va_end(ap);
+
+    if (__FSEXT_func_wrapper(func, __FSEXT_fcntl, &rv, fd, cmd, arg))
       return rv;
   }