From owner-freebsd-hackers@freebsd.org Tue Dec 18 19:14:04 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 09146133BA15 for ; Tue, 18 Dec 2018 19:14:04 +0000 (UTC) (envelope-from rysto32@gmail.com) Received: from mail-lj1-x22f.google.com (mail-lj1-x22f.google.com [IPv6:2a00:1450:4864:20::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 5E62E83481 for ; Tue, 18 Dec 2018 19:14:03 +0000 (UTC) (envelope-from rysto32@gmail.com) Received: by mail-lj1-x22f.google.com with SMTP id q2-v6so4062270lji.10 for ; Tue, 18 Dec 2018 11:14:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9vQEPuYbisMfvbHxibgoaWHmagpRfLIafJ+18tE4IMg=; b=NZ9jIFlWpPYQrrkpVHo8gbedmxNemXTnuHs0rsIJ8otjbdjnsrb/n54zavtJV8X91v WpZEotBZLSY/DASNzNR/SUphutsnTLlS181IKyniKeG4ogzMYFU//TQmlUilm6bk/FoH TRMD87SPLKScZNnBoT1PT4jLTU2a2b50FKIqVhCWBIReXtTcLFt3pWDNxoCvFVUQOl0o kCaOn5Onusw+ZmyOh8CarcDRcLNJi9r1C/jKpXyzsH7fyRvbhRxChZNeauc6xG2L0r3x +fO+NLU/4hmlipaqjAbPIhHUwoq+/rqm8D8QRln2h/+iAOHgbtv1+P/oM2ukzKeo/kSv yZbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=9vQEPuYbisMfvbHxibgoaWHmagpRfLIafJ+18tE4IMg=; b=q02317OfJbWDIFwfVCUl5/rM9Z8NZVt6535W4SSe37raBQg0LYI84z3Uhd3vOJSgya 0XH09uIXRJZwnJxUVa1AKzgeQxaSbDJX3Ju39zv4tRwSQ8sMw4nCgepCC8kiHDuTFt7s XnEehFuDOnxMdy4ntbqunOlrk2Fn1gWx7gGpiV06vLZrnG+qLHjx/XU5crUJIXXxo7k1 N5mi3kfZpCpaBMMayrGXm6zowLhQJYnfJhy0NRB1nbuzTxVIGwmlZJS7L8P3ab5W2qCQ GRj2wiVntsj6vieMj4/BzCvhVwtjPXl51Gm/515K7w8Y3WZhzcX31EEw9ntPttRFOHLl MSDg== X-Gm-Message-State: AA+aEWYV8LpfagGyQLcZ+bv61f2awc1zaJaXNrX4a6NJiwqrvyFQbcAT nruOQ5usChSfuTD2PDXSymqxStaF4BrsYD/DZ2A= X-Google-Smtp-Source: AFSGD/XNYA3H1jUXS9vWYt9ym1njMBXnD92c0OQlpjLq/z4yVSeSxPatjQ4MrgSmZyNUhHi27BDiV6pDhDYkzQUrAYY= X-Received: by 2002:a2e:5555:: with SMTP id j82-v6mr12263089ljb.69.1545160441955; Tue, 18 Dec 2018 11:14:01 -0800 (PST) MIME-Version: 1.0 References: <861s6fpyua.fsf@triplebuff.com> In-Reply-To: <861s6fpyua.fsf@triplebuff.com> From: Ryan Stone Date: Tue, 18 Dec 2018 14:13:50 -0500 Message-ID: Subject: Re: ENOMEM when calling sysctl_handle_int from custom handler To: Austin Shafer Cc: freebsd-hackers@freebsd.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 5E62E83481 X-Spamd-Bar: ------ Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=NZ9jIFlW; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of rysto32@gmail.com designates 2a00:1450:4864:20::22f as permitted sender) smtp.mailfrom=rysto32@gmail.com X-Spamd-Result: default: False [-6.36 / 15.00]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36]; FREEMAIL_FROM(0.00)[gmail.com]; DKIM_TRACE(0.00)[gmail.com:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; MX_GOOD(-0.01)[cached: alt3.gmail-smtp-in.l.google.com]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_LAST(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; DWL_DNSWL_NONE(0.00)[gmail.com.dwl.dnswl.org : 127.0.5.0]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_SHORT(-0.84)[-0.840,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[f.2.2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.5.4.1.0.0.a.2.list.dnswl.org : 127.0.5.0]; IP_SCORE(-2.51)[ip: (-9.51), ipnet: 2a00:1450::/32(-1.57), asn: 15169(-1.37), country: US(-0.08)]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Dec 2018 19:14:04 -0000 You should not pass arg1 and arg2 to sysctl_handle_int(). You instead need to pass a pointer to a local value containing the value you want to return to the sysctl caller. After sysctl_handle_int returns, if it returned 0 and req->newptr is non-NULL, then the integer value will contain the new value that was passed to you from userland. You want something that looks like this: int my_sysctl_handler(SYSCTL_HANDLER_ARGS) { int val, error; val = 5; /* Or whatever value you want to return from userland. */ error = sysctl_handle_int(oidp, &val, 0, req); if (error != 0 || req->newptr == NULL) return (error); /* val contains the value set by the caller, so do something interesting with it here. */ return (0); }