From patchwork Sat Aug 15 18:26:01 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Stefan_Br=C3=BCns?= X-Patchwork-Id: 507643 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 2090014018C for ; Sun, 16 Aug 2015 04:53:31 +1000 (AEST) Received: from localhost ([::1]:50617 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZQga9-0004hV-9x for incoming@patchwork.ozlabs.org; Sat, 15 Aug 2015 14:53:29 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34452) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZQgA1-0005Jt-5L for qemu-devel@nongnu.org; Sat, 15 Aug 2015 14:26:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZQg9x-0008Gm-Pz for qemu-devel@nongnu.org; Sat, 15 Aug 2015 14:26:29 -0400 Received: from mx-out-1.rwth-aachen.de ([134.130.5.186]:18247) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZQg9x-0008GS-Bq for qemu-devel@nongnu.org; Sat, 15 Aug 2015 14:26:25 -0400 X-IronPort-AV: E=Sophos;i="5.15,685,1432591200"; d="scan'208";a="475780826" Received: from hub2.rwth-ad.de (HELO mail.rwth-aachen.de) ([134.130.26.143]) by mx-1.rz.rwth-aachen.de with ESMTP; 15 Aug 2015 20:26:24 +0200 Received: from pebbles.fritz.box (78.49.107.181) by mail.rwth-aachen.de (134.130.26.143) with Microsoft SMTP Server (TLS) id 14.3.248.2; Sat, 15 Aug 2015 20:26:19 +0200 From: =?UTF-8?q?Stefan=20Br=C3=BCns?= To: Date: Sat, 15 Aug 2015 20:26:01 +0200 X-Mailer: git-send-email 2.1.4 In-Reply-To: <1439663161-13070-1-git-send-email-stefan.bruens@rwth-aachen.de> References: <1439663161-13070-1-git-send-email-stefan.bruens@rwth-aachen.de> MIME-Version: 1.0 X-PMWin-Version: 3.1.3.0, Antivirus-Engine: 3.60.0, Antivirus-Data: 5.17 Message-ID: <2931c2a6-414b-4193-bd6b-38c38c858677@HUB2.rwth-ad.de> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.130.5.186 X-Mailman-Approved-At: Sat, 15 Aug 2015 14:53:07 -0400 Cc: Riku Voipio , =?UTF-8?q?Stefan=20Br=C3=BCns?= Subject: [Qemu-devel] [PATCH] linux-user: remove MAX_ARG_PAGES, allow dynamic growth of env/argv space 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 qemu currently limits the space for the evironment and arguments to 32 * PAGE_SIZE. Linux limits the argument space to 1/4 of the stack size. A program trying to detect this with a getrlimit(RLIMIT_STACK) syscall will typically get a much larger limit than qemus current 128kB. The current limit causes "Argument list too long" errors. Signed-off-by: Stefan Brüns --- linux-user/elfload.c | 29 ++++++++++++++++++----------- linux-user/linuxload.c | 7 ++++--- linux-user/qemu.h | 11 ++--------- linux-user/syscall.c | 4 ++++ 4 files changed, 28 insertions(+), 23 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 1788368..be8f4d6 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1365,11 +1365,13 @@ static bool elf_check_ehdr(struct elfhdr *ehdr) * to be put directly into the top of new user memory. * */ -static abi_ulong copy_elf_strings(int argc,char ** argv, void **page, - abi_ulong p) +static abi_ulong copy_elf_strings(int argc,char ** argv, + struct linux_binprm *bprm) { char *tmp, *tmp1, *pag = NULL; int len, offset = 0; + void **page = bprm->page; + abi_ulong p = bprm->p; if (!p) { return 0; /* bullet-proofing */ @@ -1383,8 +1385,13 @@ static abi_ulong copy_elf_strings(int argc,char ** argv, void **page, tmp1 = tmp; while (*tmp++); len = tmp - tmp1; - if (p < len) { /* this shouldn't happen - 128kB */ - return 0; + if (p < len) { + bprm->page = (void**)calloc(bprm->n_arg_pages + 32, sizeof(void*)); + memcpy(&bprm->page[32], page, sizeof(void*) * bprm->n_arg_pages); + free(page); + page = bprm->page; + bprm->n_arg_pages += 32; + p += 32 * TARGET_PAGE_SIZE; } while (len) { --p; --tmp; --len; @@ -1423,8 +1430,8 @@ static abi_ulong setup_arg_pages(abi_ulong p, struct linux_binprm *bprm, /* Create enough stack to hold everything. If we don't use it for args, we'll use it for something else. */ size = guest_stack_size; - if (size < MAX_ARG_PAGES*TARGET_PAGE_SIZE) { - size = MAX_ARG_PAGES*TARGET_PAGE_SIZE; + if (size < bprm->n_arg_pages * TARGET_PAGE_SIZE) { + size = bprm->n_arg_pages * TARGET_PAGE_SIZE; } guard = TARGET_PAGE_SIZE; if (guard < qemu_real_host_page_size) { @@ -1442,10 +1449,10 @@ static abi_ulong setup_arg_pages(abi_ulong p, struct linux_binprm *bprm, target_mprotect(error, guard, PROT_NONE); info->stack_limit = error + guard; - stack_base = info->stack_limit + size - MAX_ARG_PAGES*TARGET_PAGE_SIZE; + stack_base = info->stack_limit + size - bprm->n_arg_pages * TARGET_PAGE_SIZE; p += stack_base; - for (i = 0 ; i < MAX_ARG_PAGES ; i++) { + for (i = 0; i < bprm->n_arg_pages; i++) { if (bprm->page[i]) { info->rss++; /* FIXME - check return value of memcpy_to_target() for failure */ @@ -2211,9 +2218,9 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) when we load the interpreter. */ elf_ex = *(struct elfhdr *)bprm->buf; - bprm->p = copy_elf_strings(1, &bprm->filename, bprm->page, bprm->p); - bprm->p = copy_elf_strings(bprm->envc,bprm->envp,bprm->page,bprm->p); - bprm->p = copy_elf_strings(bprm->argc,bprm->argv,bprm->page,bprm->p); + bprm->p = copy_elf_strings(1, &bprm->filename, bprm); + bprm->p = copy_elf_strings(bprm->envc, bprm->envp, bprm); + bprm->p = copy_elf_strings(bprm->argc, bprm->argv, bprm); if (!bprm->p) { fprintf(stderr, "%s: %s\n", bprm->filename, strerror(E2BIG)); exit(-1); diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c index 506e837..59943ea 100644 --- a/linux-user/linuxload.c +++ b/linux-user/linuxload.c @@ -137,8 +137,9 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, int retval; int i; - bprm->p = TARGET_PAGE_SIZE*MAX_ARG_PAGES-sizeof(unsigned int); - memset(bprm->page, 0, sizeof(bprm->page)); + bprm->n_arg_pages = 32; + bprm->p = bprm->n_arg_pages * TARGET_PAGE_SIZE - sizeof(unsigned int); + bprm->page = (void**)calloc(bprm->n_arg_pages, sizeof(void*)); bprm->fd = fdexec; bprm->filename = (char *)filename; bprm->argc = count(argv); @@ -173,7 +174,7 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, } /* Something went wrong, return the inode and free the argument pages*/ - for (i=0 ; in_arg_pages; i++) { g_free(bprm->page[i]); } return(retval); diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 8012cc2..cf4aa73 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -144,14 +144,6 @@ void stop_all_tasks(void); extern const char *qemu_uname_release; extern unsigned long mmap_min_addr; -/* ??? See if we can avoid exposing so much of the loader internals. */ -/* - * MAX_ARG_PAGES defines the number of pages allocated for arguments - * and envelope for the new program. 32 should suffice, this gives - * a maximum env+arg of 128kB w/4KB pages! - */ -#define MAX_ARG_PAGES 33 - /* Read a good amount of data initially, to hopefully get all the program headers loaded. */ #define BPRM_BUF_SIZE 1024 @@ -162,7 +154,8 @@ extern unsigned long mmap_min_addr; */ struct linux_binprm { char buf[BPRM_BUF_SIZE] __attribute__((aligned)); - void *page[MAX_ARG_PAGES]; + void **page; + int n_arg_pages; abi_ulong p; int fd; int e_uid, e_gid; diff --git a/linux-user/syscall.c b/linux-user/syscall.c index f62c698..6fa5fb4 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -5799,12 +5799,16 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, } *q = NULL; +/* This check is bogus. MAX_ARG_PAGES is a thing of the past. Trust the host +execve to set errno appropriately */ +#if 0 /* This case will not be caught by the host's execve() if its page size is bigger than the target's. */ if (total_size > MAX_ARG_PAGES * TARGET_PAGE_SIZE) { ret = -TARGET_E2BIG; goto execve_end; } +#endif if (!(p = lock_user_string(arg1))) goto execve_efault; ret = get_errno(execve(p, argp, envp));