From patchwork Fri Feb 3 14:49:16 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Riku Voipio X-Patchwork-Id: 139396 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C637C104792 for ; Sat, 4 Feb 2012 02:23:26 +1100 (EST) Received: from localhost ([::1]:41672 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RtKTT-0001fO-Ce for incoming@patchwork.ozlabs.org; Fri, 03 Feb 2012 09:50:51 -0500 Received: from eggs.gnu.org ([140.186.70.92]:46190) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RtKSL-0007tn-7A for qemu-devel@nongnu.org; Fri, 03 Feb 2012 09:49:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RtKSE-0001TN-8r for qemu-devel@nongnu.org; Fri, 03 Feb 2012 09:49:41 -0500 Received: from afflict.kos.to ([92.243.29.197]:49779) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RtKSE-0001RF-05 for qemu-devel@nongnu.org; Fri, 03 Feb 2012 09:49:34 -0500 Received: by afflict.kos.to (Postfix, from userid 1000) id 3103426530; Fri, 3 Feb 2012 14:49:32 +0000 (UTC) From: riku.voipio@linaro.org To: qemu-devel@nongnu.org Date: Fri, 3 Feb 2012 16:49:16 +0200 Message-Id: <3be14d05d45774b67398debe42e3bb5524998f4f.1328280144.git.riku.voipio@linaro.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 92.243.29.197 Cc: Alexander Graf Subject: [Qemu-devel] [PATCH 03/19] linux-user: add open() hijack infrastructure X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Alexander Graf There are a number of files in /proc that expose host information to the guest program. This patch adds infrastructure to override the open() syscall for guest programs to enable us to on the fly generate guest sensible files. Signed-off-by: Alexander Graf Signed-off-by: Riku Voipio --- linux-user/syscall.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 49 insertions(+), 3 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 2bf9e7e..e100025 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -4600,6 +4600,52 @@ int get_osversion(void) return osversion; } +static int do_open(void *cpu_env, const char *pathname, int flags, mode_t mode) +{ + struct fake_open { + const char *filename; + int (*fill)(void *cpu_env, int fd); + }; + const struct fake_open *fake_open; + static const struct fake_open fakes[] = { + { NULL, NULL } + }; + + for (fake_open = fakes; fake_open->filename; fake_open++) { + if (!strncmp(pathname, fake_open->filename, + strlen(fake_open->filename))) { + break; + } + } + + if (fake_open->filename) { + const char *tmpdir; + char filename[PATH_MAX]; + int fd, r; + + /* create temporary file to map stat to */ + tmpdir = getenv("TMPDIR"); + if (!tmpdir) + tmpdir = "/tmp"; + snprintf(filename, sizeof(filename), "%s/qemu-open.XXXXXX", tmpdir); + fd = mkstemp(filename); + if (fd < 0) { + return fd; + } + unlink(filename); + + if ((r = fake_open->fill(cpu_env, fd))) { + close(fd); + return r; + } + lseek(fd, 0, SEEK_SET); + + return fd; + } + + return get_errno(open(path(pathname), flags, mode)); +} + /* do_syscall() should always have a single exit point at the end so that actions, such as logging of syscall results, can be performed. All errnos that do_syscall() returns must be -TARGET_. */ @@ -4685,9 +4731,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, case TARGET_NR_open: if (!(p = lock_user_string(arg1))) goto efault; - ret = get_errno(open(path(p), - target_to_host_bitmask(arg2, fcntl_flags_tbl), - arg3)); + ret = get_errno(do_open(cpu_env, p, + target_to_host_bitmask(arg2, fcntl_flags_tbl), + arg3)); unlock_user(p, arg1, 0); break; #if defined(TARGET_NR_openat) && defined(__NR_openat)