From nobody Sat May 30 17:31:18 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=cyano.uk ARC-Seal: i=1; a=rsa-sha256; t=1780037663; cv=none; d=zohomail.com; s=zohoarc; b=iNcLjMAxJykZzRS3Tw0XVDJwP987TAqFhnIa+N4DZjjDnB92d+ho5WDJfYQJIQ1JT1+JSafgrvU9AcSO0+6xqiDeTagE9RhC9VlR6VNT9CryauLqtwv/FZI3pM+3/hTNOvqGOi+40hCX7E+R6lrT9Vr6AZTs6M2YucY2Zou30HI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1780037663; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=cBFZXZ5VBBd96EmFFpngfIH0I1YowUTAx0q99subMTA=; b=YIipiqYun4h7nBeBPEIBPkQXdY67RFQtJR6qcdSU9ZNtL1UUpCpk4X9wuzzrKA2lBpuaOYSyoPQgXmxcd+lDdsFy9raoXM31aPrtjSRQs9l+UoGD9XxJ3Ck194mDSTVijpATsFpLlikB6Lfr2dsWS5LZPpm8tDr86HIYCRE49ZY= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1780037663761998.4138543858776; Thu, 28 May 2026 23:54:23 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wSr6L-0006d2-7l; Fri, 29 May 2026 02:53:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wSr6J-0006ci-B6 for qemu-devel@nongnu.org; Fri, 29 May 2026 02:53:47 -0400 Received: from jupiter.guys.cyano.uk ([45.63.120.176]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wSr6H-0005MJ-JV for qemu-devel@nongnu.org; Fri, 29 May 2026 02:53:47 -0400 From: Xinhui Yang DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cyano.uk; s=dkim; t=1780037622; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cBFZXZ5VBBd96EmFFpngfIH0I1YowUTAx0q99subMTA=; b=Xy+cf3OOO9dIPb8ZIqOo3+SZ062u1KUR9vgiaXNEg9ntfzZkBtrvwGYwsB3NWAvWlTyajV r+KRar6eBxug05yAIipLSxLWkm5rLjzyfMO9qfEtZuSWFlXTIads6bK4C3UFHY6d9+qTSl Jv6lTD0kK94ppBxkhBkAtGou6ETkfZqPEvYfHKI2f6VfdIDH93hO1wYviHUlIFsM/W5hf5 rrHzIFstdi9g++RZi11w+bACPgUHtM8eW8gVVPhB0ayRULt5TUhmtOJX5ub7hy/mqw2yVc k4CGwxv61Jk/7Oj8RBtEKefdgKGuFlFo4ilto3wiPy9XdL6d/JVL3hhD0xmY+w== Authentication-Results: jupiter.guys.cyano.uk; auth=pass smtp.mailfrom=cyan@cyano.uk To: qemu-devel@nongnu.org Cc: Laurent Vivier , Helge Deller , Pierrick Bouvier , Mingcong Bai , Xinhui Yang Subject: [PATCH v3 1/2] linux-user: implement fsmount(2) series of syscalls Date: Fri, 29 May 2026 14:53:20 +0800 Message-ID: <193e73f7745a086b99ba68e28b665f9f22444b06.1780036891.git.cyan@cyano.uk> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Spamd-Bar: -- Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists1p.gnu.org; Received-SPF: pass client-ip=45.63.120.176; envelope-from=cyan@cyano.uk; helo=jupiter.guys.cyano.uk X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @cyano.uk) X-ZM-MESSAGEID: 1780037665794158500 Content-Type: text/plain; charset="utf-8" This series of syscalls replaces the old mount(2) syscall with a series of syscalls that operates around a filesystem context. This series of syscalls is available since Linux 5.2 and glibc 2.36+. Their users include systemd since v259 and libmount from util-linux, and possibly other widely used projects. Preliminary checks are implemented to ensure the validity of the interface. Signed-off-by: Xinhui Yang Reviewed-by: Pierrick Bouvier --- linux-user/syscall.c | 91 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 7d7a7b489c..c5c2aa80ec 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -14412,6 +14412,97 @@ static abi_long do_syscall1(CPUArchState *cpu_env,= int num, abi_long arg1, return do_map_shadow_stack(cpu_env, arg1, arg2, arg3); #endif =20 +#if defined(TARGET_NR_fsopen) + case TARGET_NR_fsopen: + { + p =3D lock_user_string(arg1); + if (!p) { + return -TARGET_EFAULT; + } + ret =3D get_errno(fsopen(p, arg2)); + unlock_user(p, arg1, 0); + } + return ret; + case TARGET_NR_fsconfig: + { + /* + * fsconfig(int, int, char *, void *, int) + * NOTE: p4 is nullable and its type might not be a string. + */ + void *p3, *p4; + int cmd =3D (int) arg2; + switch (cmd) { + case FSCONFIG_SET_BINARY: + case FSCONFIG_SET_STRING: + case FSCONFIG_SET_PATH: + case FSCONFIG_SET_PATH_EMPTY: + p3 =3D lock_user_string(arg3); + if (!p3) { + return -TARGET_EFAULT; + } + if (cmd !=3D FSCONFIG_SET_BINARY) { + /* key and value must be strings. */ + p4 =3D lock_user_string(arg4); + } else { + /* + * Otherwise the value must be a raw buffer with its + * length specified in arg5 (aux). + */ + p4 =3D lock_user(VERIFY_READ, arg4, arg5, 1); + } + if (!p4) { + unlock_user(p3, arg3, 0); + return -TARGET_EFAULT; + } + ret =3D get_errno(fsconfig(arg1, arg2, p3, p4, arg5)); + unlock_user(p3, arg3, 0); + unlock_user(p4, arg4, 0); + break; + + case FSCONFIG_SET_FLAG: + case FSCONFIG_SET_FD: + /* arg4 (value) must be NULL. */ + if (arg4) { + return -TARGET_EFAULT; + } + p3 =3D lock_user_string(arg3); + if (!p3) { + return -TARGET_EFAULT; + } + ret =3D get_errno(fsconfig(arg1, arg2, p3, NULL, arg5)); + unlock_user(p3, arg3, 0); + break; + case FSCONFIG_CMD_CREATE: + case FSCONFIG_CMD_RECONFIGURE: +#ifdef FSCONFIG_CMD_CREATE_EXCL + /* + * FSCONFIG_CMD_CREATE_EXCL is only available since Linux + * 6.6. Guarding it to allow building with pre-6.6 headers. + */ + case FSCONFIG_CMD_CREATE_EXCL: +#endif + /* key and value must be NULL, aux must be 0. */ + if (arg3 || arg4 || arg5) { + return -TARGET_EFAULT; + } + ret =3D get_errno(fsconfig(arg1, arg2, NULL, NULL, 0)); + break; + default: + return -TARGET_EFAULT; + } + } + return ret; + case TARGET_NR_fsmount: + ret =3D get_errno(fsmount(arg1, arg2, arg3)); + return ret; + case TARGET_NR_fspick: + { + p =3D lock_user_string(arg2); + ret =3D get_errno(fspick(arg1, p, arg3)); + unlock_user(p, arg2, 0); + } + return ret; +#endif default: qemu_log_mask(LOG_UNIMP, "Unsupported syscall: %d\n", num); return -TARGET_ENOSYS; --=20 2.52.0 From nobody Sat May 30 17:31:18 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=cyano.uk ARC-Seal: i=1; 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dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1780037663270736.4288229700566; Thu, 28 May 2026 23:54:23 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wSr6Q-0006e0-K8; Fri, 29 May 2026 02:53:54 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wSr6O-0006dX-Ab for qemu-devel@nongnu.org; Fri, 29 May 2026 02:53:52 -0400 Received: from jupiter.guys.cyano.uk ([45.63.120.176]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wSr6M-0005Mo-BY for qemu-devel@nongnu.org; Fri, 29 May 2026 02:53:51 -0400 From: Xinhui Yang DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cyano.uk; s=dkim; t=1780037627; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=m6jV25Ug5h7ljt+EAAlQsjavXhHvXlFYCOfQhYtHD6g=; b=srvXLxB6AOAS5kKGDav+dy5IfsN7UJTi6FAs14bo9T+AvqRmjk5rpnozCUx6+V4kVIAmvh gekb3SCRxAthyBUzPFI8rlQl1ATap3qK2eOBoeNc/CVF2bqDY0T9kydQIBr13FOaX3n9RQ VsVnZwYXwa0eVsTLGB0SVKw997oK55B+s2OKCzlZTX8W0Lb3FWoy2nEPGklo8Hzx+j40Jl ulxfaDjMWaxPwl+pymI+qTpUVeuVLGY/cAYIMBTPskFiUFJyrbDzvT+2FaAZE1WKRzw7ho wfwD+7btkrTH7KgLgpzuJq60Ikveix65w6otb7UXSoUphl7rxUCjuPBu77uLRQ== Authentication-Results: jupiter.guys.cyano.uk; auth=pass smtp.mailfrom=cyan@cyano.uk To: qemu-devel@nongnu.org Cc: Laurent Vivier , Helge Deller , Pierrick Bouvier , Mingcong Bai , Xinhui Yang Subject: [PATCH v3 2/2] linux-user/strace: add fsmount series of syscalls Date: Fri, 29 May 2026 14:53:21 +0800 Message-ID: <6fdae25aea6001375bcf78a80c3a6369a9a587ca.1780036891.git.cyan@cyano.uk> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Spamd-Bar: -- Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists1p.gnu.org; Received-SPF: pass client-ip=45.63.120.176; envelope-from=cyan@cyano.uk; helo=jupiter.guys.cyano.uk X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @cyano.uk) X-ZM-MESSAGEID: 1780037664370158500 Content-Type: text/plain; charset="utf-8" Following the addition of fsmount(2) series of syscalls in the syscall handler, strace support is added, with a dedicated function to print the parameters of fsconfig(2), which contains parameters that can be interpreted as multiple types. Snippet of the strace dump when running `mount -t tmpfs tmpfs /media`: 18 fsopen(tmpfs,1) =3D 3 18 read(3,0x407fcf1c,8191) =3D -1 errno=3D61 (No data available) 18 fsconfig(3,FSCONFIG_SET_STRING,"source","tmpfs",0) =3D 0 18 read(3,0x407fce3c,8191) =3D -1 errno=3D61 (No data available) 18 fsconfig(3,FSCONFIG_CMD_CREATE,NULL,NULL,0) =3D 0 18 read(3,0x407fce3c,8191) =3D -1 errno=3D61 (No data available) 18 fsmount(3,1,0) =3D 4 18 read(3,0x407fce3c,8191) =3D -1 errno=3D61 (No data available) 18 statx(4,"",AT_EMPTY_PATH|AT_STATX_SYNC_AS_STAT,0x1000,0x407fee98) =3D 0 18 move_mount(4,,-100,/media,4) =3D 0 18 read(3,0x407fcfcc,8191) =3D -1 errno=3D61 (No data available) 18 close(3) =3D 0 18 close(4) =3D 0 Signed-off-by: Xinhui Yang Reviewed-by: Pierrick Bouvier --- linux-user/strace.c | 105 +++++++++++++++++++++++++++++++++++++++++ linux-user/strace.list | 15 ++++++ 2 files changed, 120 insertions(+) diff --git a/linux-user/strace.c b/linux-user/strace.c index 2cbaf94c89..d861f311f6 100644 --- a/linux-user/strace.c +++ b/linux-user/strace.c @@ -4344,6 +4344,111 @@ print_statx(CPUArchState *cpu_env, const struct sys= callname *name, } #endif =20 +#ifdef TARGET_NR_fsconfig +static void +print_fsconfig_cmd_name(int cmd) +{ + switch (cmd) { + case FSCONFIG_SET_FLAG: + qemu_log("%s%s", "FSCONFIG_SET_FLAG", get_comma(0)); + break; + case FSCONFIG_SET_STRING: + qemu_log("%s%s", "FSCONFIG_SET_STRING", get_comma(0)); + break; + case FSCONFIG_SET_BINARY: + qemu_log("%s%s", "FSCONFIG_SET_BINARY", get_comma(0)); + break; + case FSCONFIG_SET_PATH: + qemu_log("%s%s", "FSCONFIG_SET_PATH", get_comma(0)); + break; + case FSCONFIG_SET_PATH_EMPTY: + qemu_log("%s%s", "FSCONFIG_SET_PATH_EMPTY", get_comma(0)); + break; + case FSCONFIG_SET_FD: + qemu_log("%s%s", "FSCONFIG_SET_FD", get_comma(0)); + break; + case FSCONFIG_CMD_CREATE: + qemu_log("%s%s", "FSCONFIG_CMD_CREATE", get_comma(0)); + break; + case FSCONFIG_CMD_RECONFIGURE: + qemu_log("%s%s", "FSCONFIG_CMD_RECONFIGURE", get_comma(0)); + break; +#ifdef FSCONFIG_CMD_CREATE_EXCL + case FSCONFIG_CMD_CREATE_EXCL: + /* Only available since Linux 6.6. */ + qemu_log("%s%s", "FSCONFIG_CMD_CREATE_EXCL", get_comma(0)); + break; +#endif + default: + qemu_log("%s (%d)%s", "UNKNOWN_CMD", cmd, get_comma(0)); + break; + } +} + +static void +print_fsconfig(CPUArchState *cpu_env, const struct syscallname *name, + abi_long arg0, abi_long arg1, abi_long arg2, + abi_long arg3, abi_long arg4, abi_long arg5) +{ + /* + * fsconfig(int fd, int cmd, char* key, void* value, int aux) + * Where: + * fd: file descriptor returned by fsopen(). + * cmd: integer constant specifying a command. + * key: a string, can be NULL on certain commands. + * value: any data in a buffer, can be NULL, raw buffer or a string. + * aux: axillary values such as flags for FSCONFIG_SET_PATH. + */ + int cmd =3D (int) arg1; + print_syscall_prologue(name); + print_raw_param("%d", arg0, 0); + print_fsconfig_cmd_name(cmd); + /* Process arg2 (key). */ + switch (cmd) { + case FSCONFIG_SET_FLAG: + case FSCONFIG_SET_STRING: + case FSCONFIG_SET_BINARY: + case FSCONFIG_SET_PATH: + case FSCONFIG_SET_PATH_EMPTY: + case FSCONFIG_SET_FD: + print_string(arg2, 0); + break; + default: + print_pointer(arg2, 0); + break; + } + /* Process arg3 (value). */ + switch (cmd) { + case FSCONFIG_SET_STRING: + case FSCONFIG_SET_PATH: + case FSCONFIG_SET_PATH_EMPTY: + print_string(arg3, 0); + break; + default: + print_pointer(arg3, 0); + break; + } + /* + * Process arg4 (aux). + * On FSCONFIG_SET_PATH and FSCONFIG_SET_PATH_EMPTY, aux can + * be either 0 or AT_FDCWD. + * On FSCONFIG_SET_BINARY, aux is an integer to state the length + * of the buffer pointed by arg3. + * Otherwise, it must be 0. + */ + switch (cmd) { + case FSCONFIG_SET_PATH: + case FSCONFIG_SET_PATH_EMPTY: + print_at_dirfd(arg4, 1); + break; + default: + print_raw_param("%d", arg4, 1); + break; + } + print_syscall_epilogue(name); +} +#endif + #ifdef TARGET_NR_ioctl static void print_ioctl(CPUArchState *cpu_env, const struct syscallname *name, diff --git a/linux-user/strace.list b/linux-user/strace.list index 6162a407f9..3a366b8cac 100644 --- a/linux-user/strace.list +++ b/linux-user/strace.list @@ -1722,3 +1722,18 @@ #ifdef TARGET_NR_rseq { TARGET_NR_rseq, "rseq" , "%s(%p,%u,%d,%#x)", NULL, NULL }, #endif +#ifdef TARGET_NR_fsopen +{ TARGET_NR_fsopen, "fsopen", "%s(%s,%d)", NULL, NULL }, +#endif +#ifdef TARGET_NR_fsconfig +{ TARGET_NR_fsconfig, "fsconfig", NULL, print_fsconfig, NULL }, +#endif +#ifdef TARGET_NR_fsmount +{ TARGET_NR_fsmount, "fsmount", "%s(%d,%d,%d)", NULL, NULL }, +#endif +#ifdef TARGET_NR_move_mount +{ TARGET_NR_move_mount, "move_mount", "%s(%d,%s,%d,%s,%d)", NULL, NULL }, +#endif +#ifdef TARGET_NR_fspick +{ TARGET_NR_fspick, "fspick", "%s(%d,%s,%d)", NULL, NULL }, +#endif --=20 2.52.0