From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E417FFF8875 for ; Wed, 29 Apr 2026 21:22:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Xc2oiP7pp0P8+LSVJw9z98TCpWpEve1jI7g9J2HlvNI=; b=HypdYBo/pWeWvTWEU7REzLllmw UP7m28sXhuAH+Sk/03wFp77FJVjewlsyyL1soR8h4ysHPlexxQKP+ZZGazFKhcijYMtI365Me4QTX m5vO+jFAdLrjftnBp4Pf83SN3gUslHXfhhseL+RYBmtJuD7BwNWAOGFt56fBUQIGx4tbdNtNbsqBo 2mNvsUs2DHf6GSioqXr4utUbzzexHgbky+8wQp8XM28dCqNstymkMEFcND8km18PfOgnHwfpjK7kB prkn0FbB7yfru6d9V5s6UPpXTaqdS9wi8R3ESkxccdmNqYZCTjxATyeI15VS3/72WjAhnmPmiZFwt VB9RWv4Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wICMe-00000004EPQ-1omE; Wed, 29 Apr 2026 21:22:36 +0000 Received: from mail-wm1-x336.google.com ([2a00:1450:4864:20::336]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wICMa-00000004EMg-2ftL for kexec@lists.infradead.org; Wed, 29 Apr 2026 21:22:33 +0000 Received: by mail-wm1-x336.google.com with SMTP id 5b1f17b1804b1-488e1a8ac40so2016435e9.2 for ; Wed, 29 Apr 2026 14:22:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777497750; x=1778102550; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Xc2oiP7pp0P8+LSVJw9z98TCpWpEve1jI7g9J2HlvNI=; b=g4kocMwPzu6Er5pTuvH95CgseWbKT6fQKM44K7ifyPOUAXQmtbTIExHLKK6CbqWVlz LayYpKM4KfaQc5ww2736CvCAyXo+iIXmNb0ngP9OzebKC1n56W/TJtGYnLubx8LcAGiC HaNMFeqcDuurCt4iosn/SI/xt4/0DWTYVI/FWgKDlR1Kx3ZDriPCyDC5rObsQdO3PEfh 28UXKZ7POB3BLLTkmfujjLRFI+cF/SvneB4N0yUNn5yjtoR1ASQA9vODP4v+DaRZO+c2 68X2678cEs890cPMHLDZMqeCshMDBzSLomevKKy+YXQ+e+4T6d/qbBBIhRDIQj4IAHxN VyyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777497750; x=1778102550; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=Xc2oiP7pp0P8+LSVJw9z98TCpWpEve1jI7g9J2HlvNI=; b=YdwjN8lfOVp/9li7q9X/2qqD5A+5KIQG2QOjhpRRlxx0z9tcvxFcZ1/U/qVrn0EGiT tC3F/ygiAI1r8Be5Rdt/ub+677d5yG1E5hSqtRoO6wi8vjJPmBsZxtkr8g0pk/DmIw/F LB59vWNLi9rF3LNZcpndObB5dW7sZ1p0b6ixMNq+86UVm2l9hcMuEcNdjiUW+PZTFg6Q Nf3ahnRxpFZgHXZJmofPDiqaG7C4T2mH+KLr/xos3ZSqFn14I1nKrI8H1t1uKBggT+X5 p5yqyCwGe/I+krTVRcsB/B77GX87Fjsjy8iEWniAVm8UlaZNuYnLeQvQORnvLU5AUjqv HlnA== X-Gm-Message-State: AOJu0YxWmGUMlm6ZrOcXlyTM5cMK4IF8DgP1ylMTyWAovCGvWickN1Ei Up+GDuSTnGLugJvEyP1f+obGJq3GIkup5IipITFtAaZzX1uJ+EQ6fdxKLTtiQA== X-Gm-Gg: AeBDieth4dyUpv58MX4yYYkZSF3WQiNjFqt4tqcnOJoNDCHGSJ2udywiaYT0h2hNTOG qMq+/z+em04BNSxOrScPOKb7bjpqpBQJG23+B4lZ3kB4lbpKrAuIyWeH6wDAIJjfeJRfZOBigHF kdV8MgmsldjsCbSSdW8vfIlpS0Fco0OQfX2tu+fVwovMy5oXXGVLY7re2tH1GVfeVJVKgAaV4Aw Vwju+KsehpfPtl/DI0YKF+yvTZFH5n10SQvfoJuIqKNUnJaAzvhMsc++JyAWgvhZHj8mblTLi4k Eef11ChcLYYAGo/WgAEkIeurPZnx33Cw4bVlmumzXqscDhhSZuoHdEBW/dlZSO9QuXICKkJqz3n /5LTVc0547n0gVbALoXu+hdYVMpE2rt71dL2tAriFg42vjBzIO5SIBI0LvSQ0HMLLjXIPx6tY6T XWMa0KQoG8MAzDiL7W0BuhNBE8NmzHMeIt3rB+0Ys= X-Received: by 2002:a05:600c:19c9:b0:48a:7a10:4f17 with SMTP id 5b1f17b1804b1-48a83d66b9emr4530045e9.6.1777497750288; Wed, 29 Apr 2026 14:22:30 -0700 (PDT) Received: from localhost ([2a01:4b00:d036:ae00:8fc7:44bf:8aca:ebae]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-48a822d4b57sm45365325e9.15.2026.04.29.14.22.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Apr 2026 14:22:29 -0700 (PDT) From: luca.boccassi@gmail.com To: kexec@lists.infradead.org Cc: linux-mm@kvack.org, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, linux-kernel@vger.kernel.org, Luca Boccassi Subject: [PATCH v11 3/4] liveupdate: add LIVEUPDATE_SESSION_GET_NAME ioctl Date: Wed, 29 Apr 2026 22:21:16 +0100 Message-ID: <20260429212221.814107-4-luca.boccassi@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260429212221.814107-1-luca.boccassi@gmail.com> References: <20260429212221.814107-1-luca.boccassi@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260429_142232_691382_FEEC08C8 X-CRM114-Status: GOOD ( 17.88 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org From: Luca Boccassi Userspace when requesting a session via the ioctl specifies a name and gets a FD, but then there is no ioctl to go back the other way and get the name given a LUO session FD. This is problematic especially when there is a userspace orchestrator that wants to check what FDs it is handling for clients without having to do manual string scraping of procfs, or without procfs at all. Add a ioctl to simply get the name from an FD. Signed-off-by: Luca Boccassi Reviewed-by: Pasha Tatashin Reviewed-by: Pratyush Yadav --- include/uapi/linux/liveupdate.h | 21 +++++++++++++++++++++ kernel/liveupdate/luo_session.c | 16 ++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/include/uapi/linux/liveupdate.h b/include/uapi/linux/liveupdate.h index 30bc66ee9436..3a9ff53b02e0 100644 --- a/include/uapi/linux/liveupdate.h +++ b/include/uapi/linux/liveupdate.h @@ -59,6 +59,7 @@ enum { LIVEUPDATE_CMD_SESSION_PRESERVE_FD = LIVEUPDATE_CMD_SESSION_BASE, LIVEUPDATE_CMD_SESSION_RETRIEVE_FD = 0x41, LIVEUPDATE_CMD_SESSION_FINISH = 0x42, + LIVEUPDATE_CMD_SESSION_GET_NAME = 0x43, }; /** @@ -213,4 +214,24 @@ struct liveupdate_session_finish { #define LIVEUPDATE_SESSION_FINISH \ _IO(LIVEUPDATE_IOCTL_TYPE, LIVEUPDATE_CMD_SESSION_FINISH) +/** + * struct liveupdate_session_get_name - ioctl(LIVEUPDATE_SESSION_GET_NAME) + * @size: Input; sizeof(struct liveupdate_session_get_name) + * @reserved: Input; Must be zero. Reserved for future use. + * @name: Output; A null-terminated string with the full session name. + * + * Retrieves the full name of the session associated with this file descriptor. + * This is useful because the kernel may truncate the name shown in /proc. + * + * Return: 0 on success, negative error code on failure. + */ +struct liveupdate_session_get_name { + __u32 size; + __u32 reserved; + __u8 name[LIVEUPDATE_SESSION_NAME_LENGTH]; +}; + +#define LIVEUPDATE_SESSION_GET_NAME \ + _IO(LIVEUPDATE_IOCTL_TYPE, LIVEUPDATE_CMD_SESSION_GET_NAME) + #endif /* _UAPI_LIVEUPDATE_H */ diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c index 24b4f381d3c8..1caaa7886ec6 100644 --- a/kernel/liveupdate/luo_session.c +++ b/kernel/liveupdate/luo_session.c @@ -289,10 +289,24 @@ static int luo_session_finish(struct luo_session *session, return luo_ucmd_respond(ucmd, sizeof(*argp)); } +static int luo_session_get_name(struct luo_session *session, + struct luo_ucmd *ucmd) +{ + struct liveupdate_session_get_name *argp = ucmd->cmd; + + if (argp->reserved != 0) + return -EINVAL; + + strscpy((char *)argp->name, session->name, sizeof(argp->name)); + + return luo_ucmd_respond(ucmd, sizeof(*argp)); +} + union ucmd_buffer { struct liveupdate_session_finish finish; struct liveupdate_session_preserve_fd preserve; struct liveupdate_session_retrieve_fd retrieve; + struct liveupdate_session_get_name get_name; }; struct luo_ioctl_op { @@ -319,6 +333,8 @@ static const struct luo_ioctl_op luo_session_ioctl_ops[] = { struct liveupdate_session_preserve_fd, token), IOCTL_OP(LIVEUPDATE_SESSION_RETRIEVE_FD, luo_session_retrieve_fd, struct liveupdate_session_retrieve_fd, token), + IOCTL_OP(LIVEUPDATE_SESSION_GET_NAME, luo_session_get_name, + struct liveupdate_session_get_name, name), }; static long luo_session_ioctl(struct file *filep, unsigned int cmd, -- 2.47.3