[mirror_ubuntu-artful-kernel.git] / arch / um / os-Linux / start_up.c

/*
 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 */

#include <stdio.h>
#include <stddef.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sched.h>
#include <fcntl.h>
#include <errno.h>
#include <setjmp.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <asm/unistd.h>
#include <asm/page.h>
#include <sys/types.h>
#include "user_util.h"
#include "kern_util.h"
#include "user.h"
#include "signal_kern.h"
#include "signal_user.h"
#include "sysdep/ptrace.h"
#include "sysdep/sigcontext.h"
#include "irq_user.h"
#include "ptrace_user.h"
#include "mem_user.h"
#include "time_user.h"
#include "init.h"
#include "os.h"
#include "uml-config.h"
#include "choose-mode.h"
#include "mode.h"
#include "tempfile.h"
#include "kern_constants.h"

#ifdef UML_CONFIG_MODE_SKAS
#include "skas.h"
#include "skas_ptrace.h"
#include "registers.h"
#endif

static int ptrace_child(void *arg)
{
	int ret;
	int pid = os_getpid(), ppid = getppid();
	int sc_result;

	if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
		perror("ptrace");
		os_kill_process(pid, 0);
	}
	os_stop_process(pid);

	/*This syscall will be intercepted by the parent. Don't call more than
	 * once, please.*/
	sc_result = os_getpid();

	if (sc_result == pid)
		ret = 1; /*Nothing modified by the parent, we are running
			   normally.*/
	else if (sc_result == ppid)
		ret = 0; /*Expected in check_ptrace and check_sysemu when they
			   succeed in modifying the stack frame*/
	else
		ret = 2; /*Serious trouble! This could be caused by a bug in
			   host 2.6 SKAS3/2.6 patch before release -V6, together
			   with a bug in the UML code itself.*/
	_exit(ret);
}

static int start_ptraced_child(void **stack_out)
{
	void *stack;
	unsigned long sp;
	int pid, n, status;

	stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
		     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	if(stack == MAP_FAILED)
		panic("check_ptrace : mmap failed, errno = %d", errno);
	sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
	if(pid < 0)
		panic("start_ptraced_child : clone failed, errno = %d", errno);
	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	if(n < 0)
		panic("check_ptrace : clone failed, errno = %d", errno);
	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
		panic("check_ptrace : expected SIGSTOP, got status = %d",
		      status);

	*stack_out = stack;
	return(pid);
}

/* When testing for SYSEMU support, if it is one of the broken versions, we
 * must just avoid using sysemu, not panic, but only if SYSEMU features are
 * broken.
 * So only for SYSEMU features we test mustpanic, while normal host features
 * must work anyway!
 */
static int stop_ptraced_child(int pid, void *stack, int exitcode,
			      int mustpanic)
{
	int status, n, ret = 0;

	if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
		panic("check_ptrace : ptrace failed, errno = %d", errno);
	CATCH_EINTR(n = waitpid(pid, &status, 0));
	if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
		int exit_with = WEXITSTATUS(status);
		if (exit_with == 2)
			printk("check_ptrace : child exited with status 2. "
			       "Serious trouble happening! Try updating your "
			       "host skas patch!\nDisabling SYSEMU support.");
		printk("check_ptrace : child exited with exitcode %d, while "
		      "expecting %d; status 0x%x", exit_with,
		      exitcode, status);
		if (mustpanic)
			panic("\n");
		else
			printk("\n");
		ret = -1;
	}

	if(munmap(stack, PAGE_SIZE) < 0)
		panic("check_ptrace : munmap failed, errno = %d", errno);
	return ret;
}

int ptrace_faultinfo = 1;
int proc_mm = 1;

static int __init skas0_cmd_param(char *str, int* add)
{
	ptrace_faultinfo = proc_mm = 0;
	return 0;
}

/* The two __uml_setup would conflict, without this stupid alias. */

static int __init mode_skas0_cmd_param(char *str, int* add)
	__attribute__((alias("skas0_cmd_param")));

__uml_setup("skas0", skas0_cmd_param,
		"skas0\n"
		"    Disables SKAS3 usage, so that SKAS0 is used, unless \n"
	        "    you specify mode=tt.\n\n");

__uml_setup("mode=skas0", mode_skas0_cmd_param,
		"mode=skas0\n"
		"    Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
		"    specify mode=tt. Note that this was recently added - on \n"
		"    older kernels you must use simply \"skas0\".\n\n");

static int force_sysemu_disabled = 0;

static int __init nosysemu_cmd_param(char *str, int* add)
{
	force_sysemu_disabled = 1;
	return 0;
}

__uml_setup("nosysemu", nosysemu_cmd_param,
"nosysemu\n"
"    Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
"    SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
"    behaviour of ptrace() and helps reducing host context switch rate.\n"
"    To make it working, you need a kernel patch for your host, too.\n"
"    See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
"    information.\n\n");

static void __init check_sysemu(void)
{
	void *stack;
 	int pid, n, status, count=0;

	printk("Checking syscall emulation patch for ptrace...");
	sysemu_supported = 0;
	pid = start_ptraced_child(&stack);

	if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
		goto fail;

	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	if (n < 0)
		panic("check_sysemu : wait failed, errno = %d", errno);
	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
		panic("check_sysemu : expected SIGTRAP, "
		      "got status = %d", status);

	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
		   os_getpid());
	if(n < 0)
		panic("check_sysemu : failed to modify system "
		      "call return, errno = %d", errno);

	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
		goto fail_stopped;

	sysemu_supported = 1;
	printk("OK\n");
	set_using_sysemu(!force_sysemu_disabled);

	printk("Checking advanced syscall emulation patch for ptrace...");
	pid = start_ptraced_child(&stack);

	if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
		  (void *) PTRACE_O_TRACESYSGOOD) < 0)
		panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d",
		      errno);

	while(1){
		count++;
		if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
			goto fail;
		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
		if(n < 0)
			panic("check_ptrace : wait failed, errno = %d", errno);
		if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))){
			if (!count)
				panic("check_ptrace : SYSEMU_SINGLESTEP "
				      "doesn't singlestep");
			n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
				   os_getpid());
			if(n < 0)
				panic("check_sysemu : failed to modify system "
				      "call return, errno = %d", errno);
			break;
		}
		else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
			count++;
		else
			panic("check_ptrace : expected SIGTRAP or "
			      "(SIGTRAP|0x80), got status = %d", status);
	}
	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
		goto fail_stopped;

	sysemu_supported = 2;
	printk("OK\n");

	if ( !force_sysemu_disabled )
		set_using_sysemu(sysemu_supported);
	return;

fail:
	stop_ptraced_child(pid, stack, 1, 0);
fail_stopped:
	printk("missing\n");
}

static void __init check_ptrace(void)
{
	void *stack;
	int pid, syscall, n, status;

	printk("Checking that ptrace can change system call numbers...");
	pid = start_ptraced_child(&stack);

	if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
		panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d", errno);

	while(1){
		if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
			panic("check_ptrace : ptrace failed, errno = %d",
			      errno);
		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
		if(n < 0)
			panic("check_ptrace : wait failed, errno = %d", errno);
		if(!WIFSTOPPED(status) || (WSTOPSIG(status) != (SIGTRAP|0x80)))
			panic("check_ptrace : expected (SIGTRAP|0x80), "
			      "got status = %d", status);

		syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
				 0);
		if(syscall == __NR_getpid){
			n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
				   __NR_getppid);
			if(n < 0)
				panic("check_ptrace : failed to modify system "
				      "call, errno = %d", errno);
			break;
		}
	}
	stop_ptraced_child(pid, stack, 0, 1);
	printk("OK\n");
	check_sysemu();
}

extern int create_tmp_file(unsigned long len);

static void check_tmpexec(void)
{
	void *addr;
	int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);

	addr = mmap(NULL, UM_KERN_PAGE_SIZE,
		    PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
	printf("Checking PROT_EXEC mmap in /tmp...");
	fflush(stdout);
	if(addr == MAP_FAILED){
		err = errno;
		perror("failed");
		if(err == EPERM)
			printf("/tmp must be not mounted noexec\n");
		exit(1);
	}
	printf("OK\n");
	munmap(addr, UM_KERN_PAGE_SIZE);

	close(fd);
}

void os_early_checks(void)
{
	check_ptrace();

	/* Need to check this early because mmapping happens before the
	 * kernel is running.
	 */
	check_tmpexec();
}

static int __init noprocmm_cmd_param(char *str, int* add)
{
	proc_mm = 0;
	return 0;
}

__uml_setup("noprocmm", noprocmm_cmd_param,
"noprocmm\n"
"    Turns off usage of /proc/mm, even if host supports it.\n"
"    To support /proc/mm, the host needs to be patched using\n"
"    the current skas3 patch.\n\n");

static int __init noptracefaultinfo_cmd_param(char *str, int* add)
{
	ptrace_faultinfo = 0;
	return 0;
}

__uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
"noptracefaultinfo\n"
"    Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
"    it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
"    using the current skas3 patch.\n\n");

#ifdef UML_CONFIG_MODE_SKAS
static inline void check_skas3_ptrace_support(void)
{
	struct ptrace_faultinfo fi;
	void *stack;
	int pid, n;

	printf("Checking for the skas3 patch in the host...");
	pid = start_ptraced_child(&stack);

	n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
	if (n < 0) {
		ptrace_faultinfo = 0;
		if(errno == EIO)
			printf("not found\n");
		else
			perror("not found");
	}
	else {
		if (!ptrace_faultinfo)
			printf("found but disabled on command line\n");
		else
			printf("found\n");
	}

	init_registers(pid);
	stop_ptraced_child(pid, stack, 1, 1);
}

int can_do_skas(void)
{
	printf("Checking for /proc/mm...");
	if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
 		proc_mm = 0;
		printf("not found\n");
	}
	else {
		if (!proc_mm)
			printf("found but disabled on command line\n");
		else
			printf("found\n");
	}

	check_skas3_ptrace_support();
	return 1;
}
#else
int can_do_skas(void)
{
	return(0);
}
#endif

int have_devanon = 0;

void check_devanon(void)
{
	int fd;

	printk("Checking for /dev/anon on the host...");
	fd = open("/dev/anon", O_RDWR);
	if(fd < 0){
		printk("Not available (open failed with errno %d)\n", errno);
		return;
	}

	printk("OK\n");
	have_devanon = 1;
}

int __init parse_iomem(char *str, int *add)
{
	struct iomem_region *new;
	struct uml_stat buf;
	char *file, *driver;
	int fd, err, size;

	driver = str;
	file = strchr(str,',');
	if(file == NULL){
		printf("parse_iomem : failed to parse iomem\n");
		goto out;
	}
	*file = '\0';
	file++;
	fd = os_open_file(file, of_rdwr(OPENFLAGS()), 0);
	if(fd < 0){
		os_print_error(fd, "parse_iomem - Couldn't open io file");
		goto out;
	}

	err = os_stat_fd(fd, &buf);
	if(err < 0){
		os_print_error(err, "parse_iomem - cannot stat_fd file");
		goto out_close;
	}

	new = malloc(sizeof(*new));
	if(new == NULL){
		perror("Couldn't allocate iomem_region struct");
		goto out_close;
	}

	size = (buf.ust_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);

	*new = ((struct iomem_region) { .next		= iomem_regions,
					.driver		= driver,
					.fd		= fd,
					.size		= size,
					.phys		= 0,
					.virt		= 0 });
	iomem_regions = new;
	iomem_size += new->size + UM_KERN_PAGE_SIZE;

	return(0);
 out_close:
	os_close_file(fd);
 out:
	return(1);
}
Commit	Line	Data
60d339f6	1	/*
1da177e4 LT	2	* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
	3	* Licensed under the GPL
	4	*/
	5
	6	#include <stdio.h>
0f80bc85 JD	7	#include <stddef.h>
	8	#include <stdarg.h>
	9	#include <stdlib.h>
	10	#include <string.h>
1da177e4 LT	11	#include <unistd.h>
	12	#include <signal.h>
	13	#include <sched.h>
0f80bc85	14	#include <fcntl.h>
1da177e4	15	#include <errno.h>
1da177e4 LT	16	#include <setjmp.h>
	17	#include <sys/time.h>
	18	#include <sys/wait.h>
	19	#include <sys/mman.h>
	20	#include <asm/unistd.h>
	21	#include <asm/page.h>
0f80bc85	22	#include <sys/types.h>
1da177e4 LT	23	#include "user_util.h"
	24	#include "kern_util.h"
	25	#include "user.h"
1da177e4 LT	26	#include "signal_kern.h"
	27	#include "signal_user.h"
	28	#include "sysdep/ptrace.h"
	29	#include "sysdep/sigcontext.h"
	30	#include "irq_user.h"
	31	#include "ptrace_user.h"
0f80bc85	32	#include "mem_user.h"
1da177e4 LT	33	#include "time_user.h"
	34	#include "init.h"
	35	#include "os.h"
	36	#include "uml-config.h"
1da177e4 LT	37	#include "choose-mode.h"
1da177e4 LT	38	#include "mode.h"
d67b569f	39	#include "tempfile.h"
0f80bc85 JD	40	#include "kern_constants.h"
0f80bc85 JD	41
1da177e4 LT	42	#ifdef UML_CONFIG_MODE_SKAS
	43	#include "skas.h"
	44	#include "skas_ptrace.h"
	45	#include "registers.h"
	46	#endif
	47
b85e9680	48	static int ptrace_child(void *arg)
1da177e4 LT	49	{
	50	int ret;
	51	int pid = os_getpid(), ppid = getppid();
	52	int sc_result;
	53
	54	if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
	55	perror("ptrace");
	56	os_kill_process(pid, 0);
	57	}
	58	os_stop_process(pid);
	59
	60	/*This syscall will be intercepted by the parent. Don't call more than
	61	* once, please.*/
	62	sc_result = os_getpid();
	63
	64	if (sc_result == pid)
	65	ret = 1; /*Nothing modified by the parent, we are running
	66	normally.*/
	67	else if (sc_result == ppid)
	68	ret = 0; /*Expected in check_ptrace and check_sysemu when they
	69	succeed in modifying the stack frame*/
	70	else
	71	ret = 2; /*Serious trouble! This could be caused by a bug in
	72	host 2.6 SKAS3/2.6 patch before release -V6, together
	73	with a bug in the UML code itself.*/
	74	_exit(ret);
	75	}
	76
b85e9680	77	static int start_ptraced_child(void **stack_out)
1da177e4	78	{
b85e9680 JD	79	void *stack;
b85e9680 JD	80	unsigned long sp;
1da177e4	81	int pid, n, status;
60d339f6	82
b85e9680 JD	83	stack = mmap(NULL, PAGE_SIZE, PROT_READ \| PROT_WRITE \| PROT_EXEC,
	84	MAP_PRIVATE \| MAP_ANONYMOUS, -1, 0);
	85	if(stack == MAP_FAILED)
	86	panic("check_ptrace : mmap failed, errno = %d", errno);
	87	sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
	88	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
1da177e4	89	if(pid < 0)
60d339f6	90	panic("start_ptraced_child : clone failed, errno = %d", errno);
1da177e4 LT	91	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
1da177e4 LT	92	if(n < 0)
60d339f6	93	panic("check_ptrace : clone failed, errno = %d", errno);
1da177e4 LT	94	if(!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != SIGSTOP))
	95	panic("check_ptrace : expected SIGSTOP, got status = %d",
	96	status);
	97
b85e9680	98	*stack_out = stack;
1da177e4 LT	99	return(pid);
	100	}
	101
60d339f6 GS	102	/* When testing for SYSEMU support, if it is one of the broken versions, we
	103	* must just avoid using sysemu, not panic, but only if SYSEMU features are
	104	* broken.
1da177e4	105	* So only for SYSEMU features we test mustpanic, while normal host features
60d339f6 GS	106	* must work anyway!
	107	*/
	108	static int stop_ptraced_child(int pid, void *stack, int exitcode,
	109	int mustpanic)
1da177e4 LT	110	{
	111	int status, n, ret = 0;
	112
	113	if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
b85e9680	114	panic("check_ptrace : ptrace failed, errno = %d", errno);
1da177e4 LT	115	CATCH_EINTR(n = waitpid(pid, &status, 0));
	116	if(!WIFEXITED(status) \|\| (WEXITSTATUS(status) != exitcode)) {
	117	int exit_with = WEXITSTATUS(status);
	118	if (exit_with == 2)
	119	printk("check_ptrace : child exited with status 2. "
	120	"Serious trouble happening! Try updating your "
	121	"host skas patch!\nDisabling SYSEMU support.");
	122	printk("check_ptrace : child exited with exitcode %d, while "
	123	"expecting %d; status 0x%x", exit_with,
	124	exitcode, status);
b85e9680	125	if (mustpanic)
1da177e4 LT	126	panic("\n");
	127	else
	128	printk("\n");
	129	ret = -1;
	130	}
	131
b85e9680 JD	132	if(munmap(stack, PAGE_SIZE) < 0)
b85e9680 JD	133	panic("check_ptrace : munmap failed, errno = %d", errno);
1da177e4 LT	134	return ret;
	135	}
	136
cb66504d PBG	137	int ptrace_faultinfo = 1;
	138	int proc_mm = 1;
	139
	140	static int __init skas0_cmd_param(char str, int add)
	141	{
	142	ptrace_faultinfo = proc_mm = 0;
	143	return 0;
	144	}
	145
9e3d862e PBG	146	/* The two __uml_setup would conflict, without this stupid alias. */
	147
	148	static int __init mode_skas0_cmd_param(char str, int add)
	149	__attribute__((alias("skas0_cmd_param")));
	150
60d339f6 GS	151	__uml_setup("skas0", skas0_cmd_param,
	152	"skas0\n"
	153	" Disables SKAS3 usage, so that SKAS0 is used, unless \n"
	154	" you specify mode=tt.\n\n");
	155
9e3d862e PBG	156	__uml_setup("mode=skas0", mode_skas0_cmd_param,
	157	"mode=skas0\n"
	158	" Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
	159	" specify mode=tt. Note that this was recently added - on \n"
	160	" older kernels you must use simply \"skas0\".\n\n");
	161
60d339f6 GS	162	static int force_sysemu_disabled = 0;
60d339f6 GS	163
1da177e4 LT	164	static int __init nosysemu_cmd_param(char str, int add)
	165	{
	166	force_sysemu_disabled = 1;
	167	return 0;
	168	}
	169
	170	__uml_setup("nosysemu", nosysemu_cmd_param,
60d339f6 GS	171	"nosysemu\n"
	172	" Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
	173	" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
	174	" behaviour of ptrace() and helps reducing host context switch rate.\n"
	175	" To make it working, you need a kernel patch for your host, too.\n"
	176	" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
	177	" information.\n\n");
1da177e4 LT	178
	179	static void __init check_sysemu(void)
	180	{
b85e9680	181	void *stack;
f9dfefe4	182	int pid, n, status, count=0;
1da177e4 LT	183
	184	printk("Checking syscall emulation patch for ptrace...");
	185	sysemu_supported = 0;
b85e9680	186	pid = start_ptraced_child(&stack);
1da177e4 LT	187
	188	if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
	189	goto fail;
	190
	191	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	192	if (n < 0)
	193	panic("check_sysemu : wait failed, errno = %d", errno);
	194	if(!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != SIGTRAP))
	195	panic("check_sysemu : expected SIGTRAP, "
	196	"got status = %d", status);
	197
	198	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
	199	os_getpid());
	200	if(n < 0)
	201	panic("check_sysemu : failed to modify system "
	202	"call return, errno = %d", errno);
	203
b85e9680	204	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
1da177e4 LT	205	goto fail_stopped;
	206
	207	sysemu_supported = 1;
	208	printk("OK\n");
	209	set_using_sysemu(!force_sysemu_disabled);
	210
	211	printk("Checking advanced syscall emulation patch for ptrace...");
b85e9680	212	pid = start_ptraced_child(&stack);
f9dfefe4 BS	213
	214	if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
	215	(void *) PTRACE_O_TRACESYSGOOD) < 0)
	216	panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d",
	217	errno);
	218
1da177e4 LT	219	while(1){
	220	count++;
	221	if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
	222	goto fail;
	223	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	224	if(n < 0)
	225	panic("check_ptrace : wait failed, errno = %d", errno);
f9dfefe4	226	if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP\|0x80))){
1da177e4	227	if (!count)
f9dfefe4 BS	228	panic("check_ptrace : SYSEMU_SINGLESTEP "
f9dfefe4 BS	229	"doesn't singlestep");
1da177e4 LT	230	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
	231	os_getpid());
	232	if(n < 0)
	233	panic("check_sysemu : failed to modify system "
	234	"call return, errno = %d", errno);
	235	break;
	236	}
f9dfefe4 BS	237	else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
	238	count++;
	239	else
	240	panic("check_ptrace : expected SIGTRAP or "
	241	"(SIGTRAP\|0x80), got status = %d", status);
1da177e4	242	}
b85e9680	243	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
1da177e4 LT	244	goto fail_stopped;
	245
	246	sysemu_supported = 2;
	247	printk("OK\n");
	248
	249	if ( !force_sysemu_disabled )
	250	set_using_sysemu(sysemu_supported);
	251	return;
	252
	253	fail:
b85e9680	254	stop_ptraced_child(pid, stack, 1, 0);
1da177e4 LT	255	fail_stopped:
	256	printk("missing\n");
	257	}
	258
60d339f6	259	static void __init check_ptrace(void)
1da177e4	260	{
b85e9680	261	void *stack;
1da177e4 LT	262	int pid, syscall, n, status;
	263
	264	printk("Checking that ptrace can change system call numbers...");
b85e9680	265	pid = start_ptraced_child(&stack);
1da177e4	266
60d339f6 GS	267	if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
60d339f6 GS	268	panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d", errno);
1da177e4 LT	269
	270	while(1){
	271	if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
60d339f6	272	panic("check_ptrace : ptrace failed, errno = %d",
1da177e4 LT	273	errno);
	274	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	275	if(n < 0)
	276	panic("check_ptrace : wait failed, errno = %d", errno);
f9dfefe4 BS	277	if(!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != (SIGTRAP\|0x80)))
f9dfefe4 BS	278	panic("check_ptrace : expected (SIGTRAP\|0x80), "
1da177e4	279	"got status = %d", status);
60d339f6	280
1da177e4 LT	281	syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
	282	0);
	283	if(syscall == __NR_getpid){
	284	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
	285	__NR_getppid);
	286	if(n < 0)
	287	panic("check_ptrace : failed to modify system "
	288	"call, errno = %d", errno);
	289	break;
	290	}
	291	}
b85e9680	292	stop_ptraced_child(pid, stack, 0, 1);
1da177e4 LT	293	printk("OK\n");
	294	check_sysemu();
	295	}
	296
0f80bc85 JD	297	extern int create_tmp_file(unsigned long len);
	298
	299	static void check_tmpexec(void)
	300	{
	301	void *addr;
	302	int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
	303
	304	addr = mmap(NULL, UM_KERN_PAGE_SIZE,
	305	PROT_READ \| PROT_WRITE \| PROT_EXEC, MAP_PRIVATE, fd, 0);
	306	printf("Checking PROT_EXEC mmap in /tmp...");
	307	fflush(stdout);
	308	if(addr == MAP_FAILED){
	309	err = errno;
	310	perror("failed");
	311	if(err == EPERM)
	312	printf("/tmp must be not mounted noexec\n");
	313	exit(1);
	314	}
	315	printf("OK\n");
	316	munmap(addr, UM_KERN_PAGE_SIZE);
	317
	318	close(fd);
	319	}
	320
60d339f6	321	void os_early_checks(void)
1da177e4	322	{
60d339f6	323	check_ptrace();
0f80bc85 JD	324
	325	/* Need to check this early because mmapping happens before the
	326	* kernel is running.
	327	*/
	328	check_tmpexec();
1da177e4 LT	329	}
1da177e4 LT	330
d9838d86 BS	331	static int __init noprocmm_cmd_param(char str, int add)
	332	{
	333	proc_mm = 0;
	334	return 0;
	335	}
	336
	337	__uml_setup("noprocmm", noprocmm_cmd_param,
	338	"noprocmm\n"
	339	" Turns off usage of /proc/mm, even if host supports it.\n"
	340	" To support /proc/mm, the host needs to be patched using\n"
	341	" the current skas3 patch.\n\n");
	342
	343	static int __init noptracefaultinfo_cmd_param(char str, int add)
	344	{
	345	ptrace_faultinfo = 0;
	346	return 0;
	347	}
	348
	349	__uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
	350	"noptracefaultinfo\n"
	351	" Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
	352	" it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
	353	" using the current skas3 patch.\n\n");
	354
1da177e4	355	#ifdef UML_CONFIG_MODE_SKAS
d67b569f	356	static inline void check_skas3_ptrace_support(void)
1da177e4 LT	357	{
1da177e4 LT	358	struct ptrace_faultinfo fi;
b85e9680	359	void *stack;
d67b569f	360	int pid, n;
1da177e4 LT	361
1da177e4 LT	362	printf("Checking for the skas3 patch in the host...");
b85e9680	363	pid = start_ptraced_child(&stack);
1da177e4 LT	364
	365	n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
	366	if (n < 0) {
cb66504d	367	ptrace_faultinfo = 0;
1da177e4 LT	368	if(errno == EIO)
1da177e4 LT	369	printf("not found\n");
60d339f6	370	else
1da177e4	371	perror("not found");
d67b569f JD	372	}
d67b569f JD	373	else {
cb66504d PBG	374	if (!ptrace_faultinfo)
	375	printf("found but disabled on command line\n");
	376	else
	377	printf("found\n");
1da177e4 LT	378	}
	379
	380	init_registers(pid);
b85e9680	381	stop_ptraced_child(pid, stack, 1, 1);
1da177e4 LT	382	}
	383
	384	int can_do_skas(void)
	385	{
1da177e4 LT	386	printf("Checking for /proc/mm...");
1da177e4 LT	387	if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
60d339f6	388	proc_mm = 0;
1da177e4	389	printf("not found\n");
60d339f6 GS	390	}
60d339f6 GS	391	else {
cb66504d PBG	392	if (!proc_mm)
	393	printf("found but disabled on command line\n");
	394	else
	395	printf("found\n");
1da177e4 LT	396	}
1da177e4 LT	397
d67b569f JD	398	check_skas3_ptrace_support();
d67b569f JD	399	return 1;
1da177e4 LT	400	}
	401	#else
	402	int can_do_skas(void)
	403	{
	404	return(0);
	405	}
	406	#endif
0f80bc85 JD	407
	408	int have_devanon = 0;
	409
	410	void check_devanon(void)
	411	{
	412	int fd;
	413
	414	printk("Checking for /dev/anon on the host...");
	415	fd = open("/dev/anon", O_RDWR);
	416	if(fd < 0){
	417	printk("Not available (open failed with errno %d)\n", errno);
	418	return;
	419	}
	420
	421	printk("OK\n");
	422	have_devanon = 1;
	423	}
	424
	425	int __init parse_iomem(char str, int add)
	426	{
	427	struct iomem_region *new;
	428	struct uml_stat buf;
	429	char file, driver;
	430	int fd, err, size;
	431
	432	driver = str;
	433	file = strchr(str,',');
	434	if(file == NULL){
	435	printf("parse_iomem : failed to parse iomem\n");
	436	goto out;
	437	}
	438	*file = '\0';
	439	file++;
	440	fd = os_open_file(file, of_rdwr(OPENFLAGS()), 0);
	441	if(fd < 0){
	442	os_print_error(fd, "parse_iomem - Couldn't open io file");
	443	goto out;
	444	}
	445
	446	err = os_stat_fd(fd, &buf);
	447	if(err < 0){
	448	os_print_error(err, "parse_iomem - cannot stat_fd file");
	449	goto out_close;
	450	}
	451
	452	new = malloc(sizeof(*new));
	453	if(new == NULL){
	454	perror("Couldn't allocate iomem_region struct");
	455	goto out_close;
	456	}
	457
	458	size = (buf.ust_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
	459
	460	*new = ((struct iomem_region) { .next = iomem_regions,
	461	.driver = driver,
	462	.fd = fd,
	463	.size = size,
	464	.phys = 0,
	465	.virt = 0 });
	466	iomem_regions = new;
	467	iomem_size += new->size + UM_KERN_PAGE_SIZE;
	468
	469	return(0);
	470	out_close:
471	os_close_file(fd);
472	out:
473	return(1);
474	}
475