From patchwork Thu Feb 8 16:55:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 13550091 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 AF317C48260 for ; Thu, 8 Feb 2024 16:56:10 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.678352.1055540 (Exim 4.92) (envelope-from ) id 1rY7gw-00067W-Ub; Thu, 08 Feb 2024 16:56:02 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 678352.1055540; Thu, 08 Feb 2024 16:56:02 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rY7gw-00067P-RW; Thu, 08 Feb 2024 16:56:02 +0000 Received: by outflank-mailman (input) for mailman id 678352; Thu, 08 Feb 2024 16:56:01 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rY7gv-0005bD-Hl for xen-devel@lists.xenproject.org; Thu, 08 Feb 2024 16:56:01 +0000 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id efe0cf8d-c6a2-11ee-8a4a-1f161083a0e0; Thu, 08 Feb 2024 17:56:00 +0100 (CET) Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 8D35C21F60; Thu, 8 Feb 2024 16:56:00 +0000 (UTC) Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 580A21326D; Thu, 8 Feb 2024 16:56:00 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id RjUNFKAHxWWtEwAAD6G6ig (envelope-from ); Thu, 08 Feb 2024 16:56:00 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: efe0cf8d-c6a2-11ee-8a4a-1f161083a0e0 From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Wei Liu , Anthony PERARD , Jason Andryuk , Andrew Cooper Subject: [PATCH v5 02/22] tools: add a new xen 9pfs daemon Date: Thu, 8 Feb 2024 17:55:26 +0100 Message-Id: <20240208165546.5715-3-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20240208165546.5715-1-jgross@suse.com> References: <20240208165546.5715-1-jgross@suse.com> MIME-Version: 1.0 Authentication-Results: smtp-out1.suse.de; none X-Spamd-Result: default: False [-4.00 / 50.00]; REPLY(-4.00)[] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 8D35C21F60 Add "xen-9pfsd", a new 9pfs daemon meant to support infrastructure domains (e.g. xenstore-stubdom) to access files in dom0. For now only add the code needed for starting the daemon and registering it with Xenstore via a new "libxl/xen-9pfs/state" node by writing the "running" state to it. Signed-off-by: Juergen Gross Reviewed-by: Jason Andryuk Acked-by: Andrew Cooper Acked-by: Anthony PERARD --- V2: - rename from xenlogd to xen-9pfsd (Andrew Cooper) - use a backend domain local Xenstore node (Jason Andryuk) - use "volatile" for stop_me (Andrew Cooper) V3: - fix SPDX Identifier (Andrew Cooper) V4: - add strerror() test to error logging (Andrew Cooper) - don't handle "daemon already running" as error (Anthony Perard) V5: - rename source directory to tools/9pfsd (Andrew Cooper) --- tools/9pfsd/.gitignore | 1 + tools/9pfsd/Makefile | 38 +++++++++++ tools/9pfsd/xen-9pfsd.c | 147 ++++++++++++++++++++++++++++++++++++++++ tools/Makefile | 1 + 4 files changed, 187 insertions(+) create mode 100644 tools/9pfsd/.gitignore create mode 100644 tools/9pfsd/Makefile create mode 100644 tools/9pfsd/xen-9pfsd.c diff --git a/tools/9pfsd/.gitignore b/tools/9pfsd/.gitignore new file mode 100644 index 0000000000..d0c2d223ef --- /dev/null +++ b/tools/9pfsd/.gitignore @@ -0,0 +1 @@ +/xen-9pfsd diff --git a/tools/9pfsd/Makefile b/tools/9pfsd/Makefile new file mode 100644 index 0000000000..089cf5ae24 --- /dev/null +++ b/tools/9pfsd/Makefile @@ -0,0 +1,38 @@ +# +# tools/9pfsd/Makefile +# + +XEN_ROOT = $(CURDIR)/../.. +include $(XEN_ROOT)/tools/Rules.mk + +CFLAGS += $(PTHREAD_CFLAGS) +LDFLAGS += $(PTHREAD_LDFLAGS) + +TARGETS := xen-9pfsd + +XEN-9PFSD_OBJS = xen-9pfsd.o +$(XEN-9PFSD_OBJS): CFLAGS += $(CFLAGS_libxenstore) +$(XEN-9PFSD_OBJS): CFLAGS += $(CFLAGS_libxenevtchn) +$(XEN-9PFSD_OBJS): CFLAGS += $(CFLAGS_libxengnttab) +xen-9pfsd: LDLIBS += $(call xenlibs-ldlibs,store evtchn gnttab) + +.PHONY: all +all: $(TARGETS) + +xen-9pfsd: $(XEN-9PFSD_OBJS) + $(CC) $(LDFLAGS) -o $@ $(XEN-9PFSD_OBJS) $(LDLIBS) $(APPEND_LDFLAGS) + +.PHONY: install +install: all + $(INSTALL_DIR) $(DESTDIR)$(LIBEXEC_BIN) + for i in $(TARGETS); do $(INSTALL_PROG) $$i $(DESTDIR)$(LIBEXEC_BIN); done + +.PHONY: uninstall +uninstall: + for i in $(TARGETS); do rm -f $(DESTDIR)$(LIBEXEC_BIN)/$$i; done + +.PHONY: clean +clean: + $(RM) *.o $(TARGETS) $(DEPS_RM) + +distclean: clean diff --git a/tools/9pfsd/xen-9pfsd.c b/tools/9pfsd/xen-9pfsd.c new file mode 100644 index 0000000000..6939d01574 --- /dev/null +++ b/tools/9pfsd/xen-9pfsd.c @@ -0,0 +1,147 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +/* + * xen-9pfsd - Xen 9pfs daemon + * + * Copyright (C) 2024 Juergen Gross + * + * Daemon to enable guests to access a directory of the dom0 file system. + * Access is made via the 9pfs protocol (xen-9pfsd acts as a PV 9pfs backend). + * + * Usage: xen-9pfsd + * + * xen-9pfsd does NOT support writing any links (neither soft links nor hard + * links), and it is accepting only canonicalized file paths in order to + * avoid the possibility to "escape" from the guest specific directory. + * + * The backend device string is "xen_9pfs", the tag used for mounting the + * 9pfs device is "Xen". + * + * As an additional security measure the maximum file space used by the guest + * can be limited by the backend Xenstore node "max-size" specifying the size + * in MBytes. This size includes the size of the root directory of the guest. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static volatile bool stop_me; +static bool daemon_running; +static struct xs_handle *xs; +static xengnttab_handle *xg; +static xenevtchn_handle *xe; + +static void handle_stop(int sig) +{ + stop_me = true; +} + +static void close_all(void) +{ + if ( daemon_running ) + xs_rm(xs, XBT_NULL, "libxl/xen-9pfs"); + if ( xe ) + xenevtchn_close(xe); + if ( xg ) + xengnttab_close(xg); + if ( xs ) + xs_close(xs); + closelog(); +} + +static void do_err(const char *msg) +{ + syslog(LOG_ALERT, "%s, errno = %d, %s", msg, errno, strerror(errno)); + close_all(); + exit(1); +} + +static void xen_connect(void) +{ + xs_transaction_t t; + char *val; + unsigned int len; + + xs = xs_open(0); + if ( xs == NULL ) + do_err("xs_open() failed"); + + xg = xengnttab_open(NULL, 0); + if ( xg == NULL ) + do_err("xengnttab_open() failed"); + + xe = xenevtchn_open(NULL, 0); + if ( xe == NULL ) + do_err("xenevtchn_open() failed"); + + while ( true ) + { + t = xs_transaction_start(xs); + if ( t == XBT_NULL ) + do_err("xs_transaction_start() failed"); + + val = xs_read(xs, t, "libxl/xen-9pfs/state", &len); + if ( val ) + { + free(val); + xs_transaction_end(xs, t, true); + syslog(LOG_INFO, "daemon already running"); + close_all(); + exit(0); + } + + if ( !xs_write(xs, t, "libxl/xen-9pfs/state", "running", + strlen("running")) ) + { + xs_transaction_end(xs, t, true); + do_err("xs_write() failed writing state"); + } + + if ( xs_transaction_end(xs, t, false) ) + break; + if ( errno != EAGAIN ) + do_err("xs_transaction_end() failed"); + } + + daemon_running = true; +} + +int main(int argc, char *argv[]) +{ + struct sigaction act = { .sa_handler = handle_stop, }; + int syslog_mask = LOG_MASK(LOG_WARNING) | LOG_MASK(LOG_ERR) | + LOG_MASK(LOG_CRIT) | LOG_MASK(LOG_ALERT) | + LOG_MASK(LOG_EMERG); + + umask(027); + if ( getenv("XEN_9PFSD_VERBOSE") ) + syslog_mask |= LOG_MASK(LOG_NOTICE) | LOG_MASK(LOG_INFO); + openlog("xen-9pfsd", LOG_CONS, LOG_DAEMON); + setlogmask(syslog_mask); + + sigemptyset(&act.sa_mask); + sigaction(SIGHUP, &act, NULL); + + xen_connect(); + + while ( !stop_me ) + { + sleep(60); + } + + close_all(); + + return 0; +} diff --git a/tools/Makefile b/tools/Makefile index 3a510663a0..7d17211782 100644 --- a/tools/Makefile +++ b/tools/Makefile @@ -32,6 +32,7 @@ SUBDIRS-y += xenpmd SUBDIRS-$(CONFIG_GOLANG) += golang SUBDIRS-y += xl SUBDIRS-y += helpers +SUBDIRS-y += 9pfsd SUBDIRS-$(CONFIG_X86) += xenpaging SUBDIRS-$(CONFIG_X86) += debugger SUBDIRS-$(CONFIG_TESTS) += tests