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Fri, 26 May 2023 11:50:49 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EE14820043; Fri, 26 May 2023 11:50:48 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 380CA20049; Fri, 26 May 2023 11:50:48 +0000 (GMT) Received: from heavy.boeblingen.de.ibm.com (unknown [9.171.55.92]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 26 May 2023 11:50:48 +0000 (GMT) From: Ilya Leoshkevich To: =?utf-8?q?Alex_Benn=C3=A9e?= , =?utf-8?q?Philipp?= =?utf-8?q?e_Mathieu-Daud=C3=A9?= , Laurent Vivier Cc: "Dominik 'Disconnect3d' Czarnota" , Christian Borntraeger , Andreas Arnez , qemu-devel@nongnu.org, Ilya Leoshkevich Subject: [PATCH v2 1/6] linux-user: Expose do_guest_openat() and do_guest_readlink() Date: Fri, 26 May 2023 13:50:36 +0200 Message-Id: <20230526115041.1362009-2-iii@linux.ibm.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230526115041.1362009-1-iii@linux.ibm.com> References: <20230526115041.1362009-1-iii@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: txxqMOXILxCdO81Bzt1dADRadIN1pCh9 X-Proofpoint-ORIG-GUID: poX16zjlvQNw27WbqDQROSgHZ1rR9I-V X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.573,FMLib:17.11.176.26 definitions=2023-05-26_01,2023-05-25_03,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 suspectscore=0 impostorscore=0 spamscore=0 lowpriorityscore=0 phishscore=0 mlxlogscore=999 malwarescore=0 mlxscore=0 priorityscore=1501 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2304280000 definitions=main-2305260099 Received-SPF: pass client-ip=148.163.158.5; envelope-from=iii@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org These functions will be required by the GDB stub in order to provide the guest view of /proc to GDB. Reviewed-by: Alex Bennée Signed-off-by: Ilya Leoshkevich --- linux-user/qemu.h | 3 +++ linux-user/syscall.c | 54 ++++++++++++++++++++++++++++---------------- 2 files changed, 38 insertions(+), 19 deletions(-) diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 92f9f5af41c..a5830ec2396 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -165,6 +165,9 @@ typedef struct TaskState { } TaskState; abi_long do_brk(abi_ulong new_brk); +int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname, + int flags, mode_t mode); +ssize_t do_guest_readlink(const char *pathname, char *buf, size_t bufsiz); /* user access */ diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 89b58b386b1..3e6ed51ce62 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8347,7 +8347,8 @@ static int open_hardware(CPUArchState *cpu_env, int fd) } #endif -static int do_openat(CPUArchState *cpu_env, int dirfd, const char *pathname, int flags, mode_t mode) +int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname, + int flags, mode_t mode) { struct fake_open { const char *filename; @@ -8418,6 +8419,36 @@ static int do_openat(CPUArchState *cpu_env, int dirfd, const char *pathname, int return safe_openat(dirfd, path(pathname), flags, mode); } +ssize_t do_guest_readlink(const char *pathname, char *buf, size_t bufsiz) +{ + ssize_t ret; + + if (!pathname || !buf) { + errno = EFAULT; + return -1; + } + + if (!bufsiz) { + /* Short circuit this for the magic exe check. */ + errno = EINVAL; + return -1; + } + + if (is_proc_myself((const char *)pathname, "exe")) { + /* + * Don't worry about sign mismatch as earlier mapping + * logic would have thrown a bad address error. + */ + ret = MIN(strlen(exec_path), bufsiz); + /* We cannot NUL terminate the string. */ + memcpy(buf, exec_path, ret); + } else { + ret = readlink(path(pathname), buf, bufsiz); + } + + return ret; +} + static int do_execveat(CPUArchState *cpu_env, int dirfd, abi_long pathname, abi_long guest_argp, abi_long guest_envp, int flags) @@ -8892,7 +8923,7 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1, case TARGET_NR_open: if (!(p = lock_user_string(arg1))) return -TARGET_EFAULT; - ret = get_errno(do_openat(cpu_env, AT_FDCWD, p, + ret = get_errno(do_guest_openat(cpu_env, AT_FDCWD, p, target_to_host_bitmask(arg2, fcntl_flags_tbl), arg3)); fd_trans_unregister(ret); @@ -8902,7 +8933,7 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1, case TARGET_NR_openat: if (!(p = lock_user_string(arg2))) return -TARGET_EFAULT; - ret = get_errno(do_openat(cpu_env, arg1, p, + ret = get_errno(do_guest_openat(cpu_env, arg1, p, target_to_host_bitmask(arg3, fcntl_flags_tbl), arg4)); fd_trans_unregister(ret); @@ -10127,22 +10158,7 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1, void *p2; p = lock_user_string(arg1); p2 = lock_user(VERIFY_WRITE, arg2, arg3, 0); - if (!p || !p2) { - ret = -TARGET_EFAULT; - } else if (!arg3) { - /* Short circuit this for the magic exe check. */ - ret = -TARGET_EINVAL; - } else if (is_proc_myself((const char *)p, "exe")) { - /* - * Don't worry about sign mismatch as earlier mapping - * logic would have thrown a bad address error. - */ - ret = MIN(strlen(exec_path), arg3); - /* We cannot NUL terminate the string. */ - memcpy(p2, exec_path, ret); - } else { - ret = get_errno(readlink(path(p), p2, arg3)); - } + ret = get_errno(do_guest_readlink(p, p2, arg3)); unlock_user(p2, arg2, ret); unlock_user(p, arg1, 0); }