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

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

#include <pty.h>
#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 <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 "sysdep/ptrace.h"
#include "sysdep/sigcontext.h"
#include "irq_user.h"
#include "ptrace_user.h"
#include "mem_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;

	change_sig(SIGWINCH, 0);
	if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
		perror("ptrace");
		os_kill_process(pid, 0);
	}
	kill(pid, SIGSTOP);

	/*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 void fatal_perror(char *str)
{
	perror(str);
	exit(1);
}

static void fatal(char *fmt, ...)
{
	va_list list;

	va_start(list, fmt);
	vprintf(fmt, list);
	va_end(list);
	fflush(stdout);

	exit(1);
}

static void non_fatal(char *fmt, ...)
{
	va_list list;

	va_start(list, fmt);
	vprintf(fmt, list);
	va_end(list);
	fflush(stdout);
}

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)
		fatal_perror("check_ptrace : mmap failed");
	sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
	if(pid < 0)
		fatal_perror("start_ptraced_child : clone failed");
	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	if(n < 0)
		fatal_perror("check_ptrace : clone failed");
	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
		fatal("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 mustexit)
{
	int status, n, ret = 0;

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

	if(munmap(stack, PAGE_SIZE) < 0)
		fatal_perror("check_ptrace : munmap failed");
	return ret;
}

/* Changed only during early boot */
int ptrace_faultinfo = 1;
int ptrace_ldt = 1;
int proc_mm = 1;
int skas_needs_stub = 0;

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");

/* Changed only during early boot */
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;

	non_fatal("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)
		fatal_perror("check_sysemu : wait failed");
	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
		fatal("check_sysemu : expected SIGTRAP, got status = %d",
		      status);

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

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

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

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

	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
		   (void *) PTRACE_O_TRACESYSGOOD) < 0))
		fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");

	while(1){
		count++;
		if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
			goto fail;
		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
		if(n < 0)
			fatal_perror("check_ptrace : wait failed");

		if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))){
			if (!count)
				fatal("check_ptrace : SYSEMU_SINGLESTEP "
				      "doesn't singlestep");
			n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
				   os_getpid());
			if(n < 0)
				fatal_perror("check_sysemu : failed to modify "
					     "system call return");
			break;
		}
		else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
			count++;
		else
			fatal("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;
	non_fatal("OK\n");

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

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

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

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

	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
		   (void *) PTRACE_O_TRACESYSGOOD) < 0))
		fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");

	while(1){
		if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
			fatal_perror("check_ptrace : ptrace failed");

		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
		if(n < 0)
			fatal_perror("check_ptrace : wait failed");

		if(!WIFSTOPPED(status) ||
		   (WSTOPSIG(status) != (SIGTRAP | 0x80)))
			fatal("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)
				fatal_perror("check_ptrace : failed to modify "
					     "system call");
			break;
		}
	}
	stop_ptraced_child(pid, stack, 0, 1);
	non_fatal("OK\n");
	check_sysemu();
}

extern void check_tmpexec(void);

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");

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

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

#ifdef UML_CONFIG_MODE_SKAS
static inline void check_skas3_ptrace_faultinfo(void)
{
	struct ptrace_faultinfo fi;
	void *stack;
	int pid, n;

	non_fatal("  - PTRACE_FAULTINFO...");
	pid = start_ptraced_child(&stack);

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

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

static inline void check_skas3_ptrace_ldt(void)
{
#ifdef PTRACE_LDT
	void *stack;
	int pid, n;
	unsigned char ldtbuf[40];
	struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
		.func = 2, /* read default ldt */
		.ptr = ldtbuf,
		.bytecount = sizeof(ldtbuf)};

	non_fatal("  - PTRACE_LDT...");
	pid = start_ptraced_child(&stack);

	n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
	if (n < 0) {
		if(errno == EIO)
			non_fatal("not found\n");
		else {
			perror("not found");
		}
		ptrace_ldt = 0;
	}
	else {
		if(ptrace_ldt)
			non_fatal("found\n");
		else
			non_fatal("found, but use is disabled\n");
	}

	stop_ptraced_child(pid, stack, 1, 1);
#else
	/* PTRACE_LDT might be disabled via cmdline option.
	 * We want to override this, else we might use the stub
	 * without real need
	 */
	ptrace_ldt = 1;
#endif
}

static inline void check_skas3_proc_mm(void)
{
	non_fatal("  - /proc/mm...");
	if (access("/proc/mm", W_OK) < 0) {
		proc_mm = 0;
		perror("not found");
	}
	else {
		if (!proc_mm)
			non_fatal("found but disabled on command line\n");
		else
			non_fatal("found\n");
	}
}

int can_do_skas(void)
{
	non_fatal("Checking for the skas3 patch in the host:\n");

	check_skas3_proc_mm();
	check_skas3_ptrace_faultinfo();
	check_skas3_ptrace_ldt();

	if(!proc_mm || !ptrace_faultinfo || !ptrace_ldt)
		skas_needs_stub = 1;

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

int __init parse_iomem(char *str, int *add)
{
	struct iomem_region *new;
	struct stat64 buf;
	char *file, *driver;
	int fd, size;

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

	if(fstat64(fd, &buf) < 0){
		perror("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.st_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:
	close(fd);
 out:
	return 1;
}


/* Changed during early boot */
int pty_output_sigio = 0;
int pty_close_sigio = 0;

/* Used as a flag during SIGIO testing early in boot */
static volatile int got_sigio = 0;

static void __init handler(int sig)
{
	got_sigio = 1;
}

struct openpty_arg {
	int master;
	int slave;
	int err;
};

static void openpty_cb(void *arg)
{
	struct openpty_arg *info = arg;

	info->err = 0;
	if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
		info->err = -errno;
}

static int async_pty(int master, int slave)
{
	int flags;

	flags = fcntl(master, F_GETFL);
	if(flags < 0)
		return -errno;

	if((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
	   (fcntl(master, F_SETOWN, os_getpid()) < 0))
		return -errno;

	if((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
		return -errno;

	return(0);
}

static void __init check_one_sigio(void (*proc)(int, int))
{
	struct sigaction old, new;
	struct openpty_arg pty = { .master = -1, .slave = -1 };
	int master, slave, err;

	initial_thread_cb(openpty_cb, &pty);
	if(pty.err){
		printk("openpty failed, errno = %d\n", -pty.err);
		return;
	}

	master = pty.master;
	slave = pty.slave;

	if((master == -1) || (slave == -1)){
		printk("openpty failed to allocate a pty\n");
		return;
	}

	/* Not now, but complain so we now where we failed. */
	err = raw(master);
	if (err < 0)
		panic("check_sigio : __raw failed, errno = %d\n", -err);

	err = async_pty(master, slave);
	if(err < 0)
		panic("tty_fds : sigio_async failed, err = %d\n", -err);

	if(sigaction(SIGIO, NULL, &old) < 0)
		panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
	new = old;
	new.sa_handler = handler;
	if(sigaction(SIGIO, &new, NULL) < 0)
		panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);

	got_sigio = 0;
	(*proc)(master, slave);

	close(master);
	close(slave);

	if(sigaction(SIGIO, &old, NULL) < 0)
		panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
}

static void tty_output(int master, int slave)
{
	int n;
	char buf[512];

	printk("Checking that host ptys support output SIGIO...");

	memset(buf, 0, sizeof(buf));

	while(os_write_file(master, buf, sizeof(buf)) > 0) ;
	if(errno != EAGAIN)
		panic("check_sigio : write failed, errno = %d\n", errno);
	while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;

	if(got_sigio){
		printk("Yes\n");
		pty_output_sigio = 1;
	}
	else if(n == -EAGAIN) printk("No, enabling workaround\n");
	else panic("check_sigio : read failed, err = %d\n", n);
}

static void tty_close(int master, int slave)
{
	printk("Checking that host ptys support SIGIO on close...");

	close(slave);
	if(got_sigio){
		printk("Yes\n");
		pty_close_sigio = 1;
	}
	else printk("No, enabling workaround\n");
}

void __init check_sigio(void)
{
	if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
	   (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
		printk("No pseudo-terminals available - skipping pty SIGIO "
		       "check\n");
		return;
	}
	check_one_sigio(tty_output);
	check_one_sigio(tty_close);
}

void os_check_bugs(void)
{
	check_ptrace();
	check_sigio();
}
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
8e367065	6	#include <pty.h>
1da177e4	7	#include <stdio.h>
0f80bc85 JD	8	#include <stddef.h>
	9	#include <stdarg.h>
	10	#include <stdlib.h>
	11	#include <string.h>
1da177e4 LT	12	#include <unistd.h>
	13	#include <signal.h>
	14	#include <sched.h>
0f80bc85	15	#include <fcntl.h>
1da177e4	16	#include <errno.h>
1da177e4 LT	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	26	#include "signal_kern.h"
1da177e4 LT	27	#include "sysdep/ptrace.h"
	28	#include "sysdep/sigcontext.h"
	29	#include "irq_user.h"
	30	#include "ptrace_user.h"
0f80bc85	31	#include "mem_user.h"
1da177e4 LT	32	#include "init.h"
	33	#include "os.h"
	34	#include "uml-config.h"
1da177e4 LT	35	#include "choose-mode.h"
1da177e4 LT	36	#include "mode.h"
d67b569f	37	#include "tempfile.h"
0f80bc85 JD	38	#include "kern_constants.h"
0f80bc85 JD	39
1da177e4 LT	40	#ifdef UML_CONFIG_MODE_SKAS
	41	#include "skas.h"
	42	#include "skas_ptrace.h"
	43	#include "registers.h"
	44	#endif
	45
b85e9680	46	static int ptrace_child(void *arg)
1da177e4 LT	47	{
	48	int ret;
	49	int pid = os_getpid(), ppid = getppid();
	50	int sc_result;
	51
43b00fdb	52	change_sig(SIGWINCH, 0);
1da177e4 LT	53	if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
	54	perror("ptrace");
	55	os_kill_process(pid, 0);
	56	}
73c8f444	57	kill(pid, SIGSTOP);
1da177e4 LT	58
	59	/*This syscall will be intercepted by the parent. Don't call more than
	60	* once, please.*/
	61	sc_result = os_getpid();
	62
	63	if (sc_result == pid)
	64	ret = 1; /*Nothing modified by the parent, we are running
	65	normally.*/
	66	else if (sc_result == ppid)
	67	ret = 0; /*Expected in check_ptrace and check_sysemu when they
	68	succeed in modifying the stack frame*/
	69	else
	70	ret = 2; /*Serious trouble! This could be caused by a bug in
	71	host 2.6 SKAS3/2.6 patch before release -V6, together
	72	with a bug in the UML code itself.*/
	73	_exit(ret);
	74	}
	75
3a150e1d JD	76	static void fatal_perror(char *str)
	77	{
	78	perror(str);
	79	exit(1);
	80	}
	81
	82	static void fatal(char *fmt, ...)
	83	{
	84	va_list list;
	85
	86	va_start(list, fmt);
	87	vprintf(fmt, list);
	88	va_end(list);
	89	fflush(stdout);
	90
	91	exit(1);
	92	}
	93
	94	static void non_fatal(char *fmt, ...)
	95	{
	96	va_list list;
	97
	98	va_start(list, fmt);
	99	vprintf(fmt, list);
	100	va_end(list);
	101	fflush(stdout);
	102	}
	103
b85e9680	104	static int start_ptraced_child(void **stack_out)
1da177e4	105	{
b85e9680 JD	106	void *stack;
b85e9680 JD	107	unsigned long sp;
1da177e4	108	int pid, n, status;
60d339f6	109
b85e9680 JD	110	stack = mmap(NULL, PAGE_SIZE, PROT_READ \| PROT_WRITE \| PROT_EXEC,
	111	MAP_PRIVATE \| MAP_ANONYMOUS, -1, 0);
	112	if(stack == MAP_FAILED)
3a150e1d	113	fatal_perror("check_ptrace : mmap failed");
b85e9680 JD	114	sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
b85e9680 JD	115	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
1da177e4	116	if(pid < 0)
3a150e1d	117	fatal_perror("start_ptraced_child : clone failed");
1da177e4 LT	118	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
1da177e4 LT	119	if(n < 0)
3a150e1d	120	fatal_perror("check_ptrace : clone failed");
1da177e4	121	if(!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != SIGSTOP))
3a150e1d	122	fatal("check_ptrace : expected SIGSTOP, got status = %d",
1da177e4 LT	123	status);
1da177e4 LT	124
b85e9680	125	*stack_out = stack;
9eae9b13	126	return pid;
1da177e4 LT	127	}
1da177e4 LT	128
60d339f6 GS	129	/* When testing for SYSEMU support, if it is one of the broken versions, we
	130	* must just avoid using sysemu, not panic, but only if SYSEMU features are
	131	* broken.
1da177e4	132	* So only for SYSEMU features we test mustpanic, while normal host features
60d339f6 GS	133	* must work anyway!
	134	*/
	135	static int stop_ptraced_child(int pid, void *stack, int exitcode,
3a150e1d	136	int mustexit)
1da177e4 LT	137	{
	138	int status, n, ret = 0;
	139
	140	if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
3a150e1d	141	fatal_perror("stop_ptraced_child : ptrace failed");
1da177e4 LT	142	CATCH_EINTR(n = waitpid(pid, &status, 0));
	143	if(!WIFEXITED(status) \|\| (WEXITSTATUS(status) != exitcode)) {
	144	int exit_with = WEXITSTATUS(status);
	145	if (exit_with == 2)
3a150e1d JD	146	non_fatal("check_ptrace : child exited with status 2. "
	147	"Serious trouble happening! Try updating "
	148	"your host skas patch!\nDisabling SYSEMU "
	149	"support.");
	150	non_fatal("check_ptrace : child exited with exitcode %d, while "
	151	"expecting %d; status 0x%x\n", exit_with,
	152	exitcode, status);
	153	if (mustexit)
	154	exit(1);
1da177e4 LT	155	ret = -1;
	156	}
	157
b85e9680	158	if(munmap(stack, PAGE_SIZE) < 0)
3a150e1d	159	fatal_perror("check_ptrace : munmap failed");
1da177e4 LT	160	return ret;
	161	}
	162
7242a400	163	/* Changed only during early boot */
cb66504d	164	int ptrace_faultinfo = 1;
858259cf	165	int ptrace_ldt = 1;
cb66504d	166	int proc_mm = 1;
858259cf	167	int skas_needs_stub = 0;
cb66504d PBG	168
	169	static int __init skas0_cmd_param(char str, int add)
	170	{
	171	ptrace_faultinfo = proc_mm = 0;
	172	return 0;
	173	}
	174
9e3d862e PBG	175	/* The two __uml_setup would conflict, without this stupid alias. */
	176
	177	static int __init mode_skas0_cmd_param(char str, int add)
	178	__attribute__((alias("skas0_cmd_param")));
	179
60d339f6 GS	180	__uml_setup("skas0", skas0_cmd_param,
	181	"skas0\n"
	182	" Disables SKAS3 usage, so that SKAS0 is used, unless \n"
	183	" you specify mode=tt.\n\n");
	184
9e3d862e PBG	185	__uml_setup("mode=skas0", mode_skas0_cmd_param,
	186	"mode=skas0\n"
	187	" Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
	188	" specify mode=tt. Note that this was recently added - on \n"
	189	" older kernels you must use simply \"skas0\".\n\n");
	190
7242a400	191	/* Changed only during early boot */
60d339f6 GS	192	static int force_sysemu_disabled = 0;
60d339f6 GS	193
1da177e4 LT	194	static int __init nosysemu_cmd_param(char str, int add)
	195	{
	196	force_sysemu_disabled = 1;
	197	return 0;
	198	}
	199
	200	__uml_setup("nosysemu", nosysemu_cmd_param,
60d339f6 GS	201	"nosysemu\n"
	202	" Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
	203	" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
	204	" behaviour of ptrace() and helps reducing host context switch rate.\n"
	205	" To make it working, you need a kernel patch for your host, too.\n"
	206	" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
	207	" information.\n\n");
1da177e4 LT	208
	209	static void __init check_sysemu(void)
	210	{
b85e9680	211	void *stack;
9eae9b13	212	int pid, n, status, count=0;
1da177e4	213
3a150e1d	214	non_fatal("Checking syscall emulation patch for ptrace...");
1da177e4	215	sysemu_supported = 0;
b85e9680	216	pid = start_ptraced_child(&stack);
1da177e4 LT	217
	218	if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
	219	goto fail;
	220
	221	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	222	if (n < 0)
3a150e1d	223	fatal_perror("check_sysemu : wait failed");
1da177e4	224	if(!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != SIGTRAP))
3a150e1d JD	225	fatal("check_sysemu : expected SIGTRAP, got status = %d",
3a150e1d JD	226	status);
1da177e4 LT	227
	228	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
	229	os_getpid());
	230	if(n < 0)
3a150e1d JD	231	fatal_perror("check_sysemu : failed to modify system call "
3a150e1d JD	232	"return");
1da177e4	233
b85e9680	234	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
1da177e4 LT	235	goto fail_stopped;
	236
	237	sysemu_supported = 1;
3a150e1d	238	non_fatal("OK\n");
1da177e4 LT	239	set_using_sysemu(!force_sysemu_disabled);
1da177e4 LT	240
3a150e1d	241	non_fatal("Checking advanced syscall emulation patch for ptrace...");
b85e9680	242	pid = start_ptraced_child(&stack);
f9dfefe4	243
3a150e1d JD	244	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
	245	(void *) PTRACE_O_TRACESYSGOOD) < 0))
	246	fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
f9dfefe4	247
1da177e4 LT	248	while(1){
	249	count++;
	250	if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
	251	goto fail;
	252	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	253	if(n < 0)
3a150e1d JD	254	fatal_perror("check_ptrace : wait failed");
3a150e1d JD	255
f9dfefe4	256	if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP\|0x80))){
1da177e4	257	if (!count)
3a150e1d	258	fatal("check_ptrace : SYSEMU_SINGLESTEP "
f9dfefe4	259	"doesn't singlestep");
1da177e4 LT	260	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
	261	os_getpid());
	262	if(n < 0)
3a150e1d JD	263	fatal_perror("check_sysemu : failed to modify "
3a150e1d JD	264	"system call return");
1da177e4 LT	265	break;
1da177e4 LT	266	}
f9dfefe4 BS	267	else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
	268	count++;
	269	else
3a150e1d JD	270	fatal("check_ptrace : expected SIGTRAP or "
3a150e1d JD	271	"(SIGTRAP \| 0x80), got status = %d", status);
1da177e4	272	}
b85e9680	273	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
1da177e4 LT	274	goto fail_stopped;
	275
	276	sysemu_supported = 2;
3a150e1d	277	non_fatal("OK\n");
1da177e4 LT	278
	279	if ( !force_sysemu_disabled )
	280	set_using_sysemu(sysemu_supported);
	281	return;
	282
	283	fail:
b85e9680	284	stop_ptraced_child(pid, stack, 1, 0);
1da177e4	285	fail_stopped:
3a150e1d	286	non_fatal("missing\n");
1da177e4 LT	287	}
1da177e4 LT	288
60d339f6	289	static void __init check_ptrace(void)
1da177e4	290	{
b85e9680	291	void *stack;
1da177e4 LT	292	int pid, syscall, n, status;
1da177e4 LT	293
3a150e1d	294	non_fatal("Checking that ptrace can change system call numbers...");
b85e9680	295	pid = start_ptraced_child(&stack);
1da177e4	296
3a150e1d JD	297	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
	298	(void *) PTRACE_O_TRACESYSGOOD) < 0))
	299	fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
1da177e4 LT	300
	301	while(1){
	302	if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
3a150e1d JD	303	fatal_perror("check_ptrace : ptrace failed");
3a150e1d JD	304
1da177e4 LT	305	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
1da177e4 LT	306	if(n < 0)
3a150e1d JD	307	fatal_perror("check_ptrace : wait failed");
	308
	309	if(!WIFSTOPPED(status) \|\|
	310	(WSTOPSIG(status) != (SIGTRAP \| 0x80)))
	311	fatal("check_ptrace : expected (SIGTRAP\|0x80), "
	312	"got status = %d", status);
60d339f6	313
1da177e4 LT	314	syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
	315	0);
	316	if(syscall == __NR_getpid){
	317	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
	318	__NR_getppid);
	319	if(n < 0)
3a150e1d JD	320	fatal_perror("check_ptrace : failed to modify "
3a150e1d JD	321	"system call");
1da177e4 LT	322	break;
	323	}
	324	}
b85e9680	325	stop_ptraced_child(pid, stack, 0, 1);
3a150e1d	326	non_fatal("OK\n");
1da177e4 LT	327	check_sysemu();
	328	}
	329
966a082f	330	extern void check_tmpexec(void);
0f80bc85	331
60d339f6	332	void os_early_checks(void)
1da177e4	333	{
60d339f6	334	check_ptrace();
0f80bc85 JD	335
	336	/* Need to check this early because mmapping happens before the
	337	* kernel is running.
	338	*/
	339	check_tmpexec();
1da177e4 LT	340	}
1da177e4 LT	341
d9838d86 BS	342	static int __init noprocmm_cmd_param(char str, int add)
	343	{
	344	proc_mm = 0;
	345	return 0;
	346	}
	347
	348	__uml_setup("noprocmm", noprocmm_cmd_param,
	349	"noprocmm\n"
	350	" Turns off usage of /proc/mm, even if host supports it.\n"
	351	" To support /proc/mm, the host needs to be patched using\n"
	352	" the current skas3 patch.\n\n");
	353
	354	static int __init noptracefaultinfo_cmd_param(char str, int add)
	355	{
	356	ptrace_faultinfo = 0;
	357	return 0;
	358	}
	359
	360	__uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
	361	"noptracefaultinfo\n"
	362	" Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
	363	" it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
	364	" using the current skas3 patch.\n\n");
	365
858259cf BS	366	static int __init noptraceldt_cmd_param(char str, int add)
	367	{
	368	ptrace_ldt = 0;
	369	return 0;
	370	}
	371
	372	__uml_setup("noptraceldt", noptraceldt_cmd_param,
	373	"noptraceldt\n"
	374	" Turns off usage of PTRACE_LDT, even if host supports it.\n"
	375	" To support PTRACE_LDT, the host needs to be patched using\n"
	376	" the current skas3 patch.\n\n");
	377
1da177e4	378	#ifdef UML_CONFIG_MODE_SKAS
858259cf	379	static inline void check_skas3_ptrace_faultinfo(void)
1da177e4 LT	380	{
1da177e4 LT	381	struct ptrace_faultinfo fi;
b85e9680	382	void *stack;
d67b569f	383	int pid, n;
1da177e4	384
3a150e1d	385	non_fatal(" - PTRACE_FAULTINFO...");
b85e9680	386	pid = start_ptraced_child(&stack);
1da177e4 LT	387
	388	n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
	389	if (n < 0) {
cb66504d	390	ptrace_faultinfo = 0;
1da177e4	391	if(errno == EIO)
3a150e1d	392	non_fatal("not found\n");
60d339f6	393	else
1da177e4	394	perror("not found");
d67b569f JD	395	}
d67b569f JD	396	else {
cb66504d	397	if (!ptrace_faultinfo)
3a150e1d	398	non_fatal("found but disabled on command line\n");
cb66504d	399	else
3a150e1d	400	non_fatal("found\n");
1da177e4 LT	401	}
	402
	403	init_registers(pid);
b85e9680	404	stop_ptraced_child(pid, stack, 1, 1);
1da177e4 LT	405	}
1da177e4 LT	406
858259cf BS	407	static inline void check_skas3_ptrace_ldt(void)
	408	{
	409	#ifdef PTRACE_LDT
	410	void *stack;
	411	int pid, n;
	412	unsigned char ldtbuf[40];
	413	struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
	414	.func = 2, /* read default ldt */
	415	.ptr = ldtbuf,
	416	.bytecount = sizeof(ldtbuf)};
	417
3a150e1d	418	non_fatal(" - PTRACE_LDT...");
858259cf BS	419	pid = start_ptraced_child(&stack);
	420
	421	n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
	422	if (n < 0) {
	423	if(errno == EIO)
3a150e1d	424	non_fatal("not found\n");
858259cf BS	425	else {
	426	perror("not found");
	427	}
	428	ptrace_ldt = 0;
	429	}
	430	else {
	431	if(ptrace_ldt)
3a150e1d	432	non_fatal("found\n");
858259cf	433	else
3a150e1d	434	non_fatal("found, but use is disabled\n");
858259cf BS	435	}
	436
	437	stop_ptraced_child(pid, stack, 1, 1);
	438	#else
	439	/* PTRACE_LDT might be disabled via cmdline option.
	440	* We want to override this, else we might use the stub
	441	* without real need
	442	*/
	443	ptrace_ldt = 1;
	444	#endif
	445	}
	446
	447	static inline void check_skas3_proc_mm(void)
1da177e4	448	{
3a150e1d	449	non_fatal(" - /proc/mm...");
73c8f444	450	if (access("/proc/mm", W_OK) < 0) {
9eae9b13	451	proc_mm = 0;
3a150e1d	452	perror("not found");
60d339f6 GS	453	}
60d339f6 GS	454	else {
cb66504d	455	if (!proc_mm)
3a150e1d	456	non_fatal("found but disabled on command line\n");
cb66504d	457	else
3a150e1d	458	non_fatal("found\n");
1da177e4	459	}
858259cf BS	460	}
	461
	462	int can_do_skas(void)
	463	{
3a150e1d	464	non_fatal("Checking for the skas3 patch in the host:\n");
858259cf BS	465
	466	check_skas3_proc_mm();
	467	check_skas3_ptrace_faultinfo();
	468	check_skas3_ptrace_ldt();
	469
	470	if(!proc_mm \|\| !ptrace_faultinfo \|\| !ptrace_ldt)
	471	skas_needs_stub = 1;
1da177e4	472
d67b569f	473	return 1;
1da177e4 LT	474	}
	475	#else
	476	int can_do_skas(void)
	477	{
9eae9b13	478	return 0;
1da177e4 LT	479	}
1da177e4 LT	480	#endif
0f80bc85	481
0f80bc85 JD	482	int __init parse_iomem(char str, int add)
	483	{
	484	struct iomem_region *new;
73c8f444	485	struct stat64 buf;
0f80bc85	486	char file, driver;
73c8f444	487	int fd, size;
0f80bc85 JD	488
	489	driver = str;
	490	file = strchr(str,',');
	491	if(file == NULL){
	492	printf("parse_iomem : failed to parse iomem\n");
	493	goto out;
	494	}
	495	*file = '\0';
	496	file++;
73c8f444	497	fd = open(file, O_RDWR, 0);
0f80bc85 JD	498	if(fd < 0){
	499	os_print_error(fd, "parse_iomem - Couldn't open io file");
	500	goto out;
	501	}
	502
73c8f444 JD	503	if(fstat64(fd, &buf) < 0){
73c8f444 JD	504	perror("parse_iomem - cannot stat_fd file");
0f80bc85 JD	505	goto out_close;
	506	}
	507
	508	new = malloc(sizeof(*new));
	509	if(new == NULL){
	510	perror("Couldn't allocate iomem_region struct");
	511	goto out_close;
	512	}
	513
73c8f444	514	size = (buf.st_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
0f80bc85 JD	515
	516	*new = ((struct iomem_region) { .next = iomem_regions,
	517	.driver = driver,
	518	.fd = fd,
	519	.size = size,
	520	.phys = 0,
	521	.virt = 0 });
	522	iomem_regions = new;
	523	iomem_size += new->size + UM_KERN_PAGE_SIZE;
	524
9eae9b13	525	return 0;
0f80bc85	526	out_close:
73c8f444	527	close(fd);
0f80bc85	528	out:
9eae9b13	529	return 1;
0f80bc85 JD	530	}
0f80bc85 JD	531
8e367065 JD	532
	533	/* Changed during early boot */
	534	int pty_output_sigio = 0;
	535	int pty_close_sigio = 0;
	536
	537	/* Used as a flag during SIGIO testing early in boot */
	538	static volatile int got_sigio = 0;
	539
	540	static void __init handler(int sig)
	541	{
	542	got_sigio = 1;
	543	}
	544
	545	struct openpty_arg {
	546	int master;
	547	int slave;
	548	int err;
	549	};
	550
	551	static void openpty_cb(void *arg)
	552	{
	553	struct openpty_arg *info = arg;
	554
	555	info->err = 0;
	556	if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
	557	info->err = -errno;
	558	}
	559
73c8f444 JD	560	static int async_pty(int master, int slave)
	561	{
	562	int flags;
	563
	564	flags = fcntl(master, F_GETFL);
	565	if(flags < 0)
	566	return -errno;
	567
	568	if((fcntl(master, F_SETFL, flags \| O_NONBLOCK \| O_ASYNC) < 0) \|\|
	569	(fcntl(master, F_SETOWN, os_getpid()) < 0))
	570	return -errno;
	571
	572	if((fcntl(slave, F_SETFL, flags \| O_NONBLOCK) < 0))
	573	return -errno;
	574
	575	return(0);
	576	}
	577
8e367065 JD	578	static void __init check_one_sigio(void (*proc)(int, int))
	579	{
	580	struct sigaction old, new;
	581	struct openpty_arg pty = { .master = -1, .slave = -1 };
	582	int master, slave, err;
	583
	584	initial_thread_cb(openpty_cb, &pty);
	585	if(pty.err){
	586	printk("openpty failed, errno = %d\n", -pty.err);
	587	return;
	588	}
	589
	590	master = pty.master;
	591	slave = pty.slave;
	592
	593	if((master == -1) \|\| (slave == -1)){
	594	printk("openpty failed to allocate a pty\n");
	595	return;
	596	}
	597
	598	/* Not now, but complain so we now where we failed. */
	599	err = raw(master);
	600	if (err < 0)
	601	panic("check_sigio : __raw failed, errno = %d\n", -err);
	602
73c8f444	603	err = async_pty(master, slave);
8e367065 JD	604	if(err < 0)
	605	panic("tty_fds : sigio_async failed, err = %d\n", -err);
	606
	607	if(sigaction(SIGIO, NULL, &old) < 0)
	608	panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
	609	new = old;
	610	new.sa_handler = handler;
	611	if(sigaction(SIGIO, &new, NULL) < 0)
	612	panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
	613
	614	got_sigio = 0;
	615	(*proc)(master, slave);
	616
	617	close(master);
	618	close(slave);
	619
	620	if(sigaction(SIGIO, &old, NULL) < 0)
	621	panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
	622	}
	623
	624	static void tty_output(int master, int slave)
	625	{
	626	int n;
	627	char buf[512];
	628
	629	printk("Checking that host ptys support output SIGIO...");
	630
	631	memset(buf, 0, sizeof(buf));
	632
	633	while(os_write_file(master, buf, sizeof(buf)) > 0) ;
	634	if(errno != EAGAIN)
	635	panic("check_sigio : write failed, errno = %d\n", errno);
	636	while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
	637
	638	if(got_sigio){
	639	printk("Yes\n");
	640	pty_output_sigio = 1;
	641	}
	642	else if(n == -EAGAIN) printk("No, enabling workaround\n");
	643	else panic("check_sigio : read failed, err = %d\n", n);
	644	}
	645
	646	static void tty_close(int master, int slave)
	647	{
	648	printk("Checking that host ptys support SIGIO on close...");
	649
	650	close(slave);
	651	if(got_sigio){
	652	printk("Yes\n");
	653	pty_close_sigio = 1;
	654	}
	655	else printk("No, enabling workaround\n");
	656	}
	657
	658	void __init check_sigio(void)
	659	{
	660	if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
	661	(os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
	662	printk("No pseudo-terminals available - skipping pty SIGIO "
	663	"check\n");
	664	return;
	665	}
	666	check_one_sigio(tty_output);
	667	check_one_sigio(tty_close);
668	}
669
670	void os_check_bugs(void)
671	{
672	check_ptrace();
673	check_sigio();
8e367065 JD	674	}
8e367065 JD	675