arch/um/os-Linux/start_up.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include <unistd.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sched.h>
 #include <signal.h>
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <sys/time.h>
 #include <sys/resource.h>
 #include <asm/unistd.h>
 #include <init.h>
 #include <os.h>
 #include <mem_user.h>
 #include <ptrace_user.h>
 #include <registers.h>
 #include <skas.h>

 static void ptrace_child(void)
 {
 	int ret;
 	/* Calling os_getpid because some libcs cached getpid incorrectly */
 	int pid = os_getpid(), ppid = getppid();
 	int sc_result;

 	if (change_sig(SIGWINCH, 0) < 0 ||
 	    ptrace(PTRACE_TRACEME, 0, 0, 0) < 0) {
 		perror("ptrace");
 		kill(pid, SIGKILL);
 	}
 	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)
 		/* Nothing modified by the parent, we are running normally. */
 		ret = 1;
 	else if (sc_result == ppid)
 		/*
 		 * Expected in check_ptrace and check_sysemu when they succeed
 		 * in modifying the stack frame
 		 */
 		ret = 0;
 	else
 		/* 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.
 		 */
 		ret = 2;

 	exit(ret);
 }

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

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

 	va_start(list, fmt);
 	vfprintf(stderr, fmt, list);
 	va_end(list);

 	exit(1);
 }

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

 	va_start(list, fmt);
 	vfprintf(stderr, fmt, list);
 	va_end(list);
 }

 static int start_ptraced_child(void)
 {
 	int pid, n, status;

 	fflush(stdout);

 	pid = fork();
 	if (pid == 0)
 		ptrace_child();
 	else if (pid < 0)
 		fatal_perror("start_ptraced_child : fork failed");

 	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
 	if (n < 0)
 		fatal_perror("check_ptrace : waitpid failed");
 	if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
 		fatal("check_ptrace : expected SIGSTOP, got status = %d",
 		      status);

 	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, int exitcode, int mustexit)
 {
 	int status, n, ret = 0;

 	if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) {
 		perror("stop_ptraced_child : ptrace failed");
 		return -1;
 	}
 	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. "
 				  "\nDisabling SYSEMU support.\n");
 		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;
 	}

 	return ret;
 }

 /* 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)
 {
 	unsigned long regs[MAX_REG_NR];
 	int pid, n, status, count=0;

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

 	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\n",
 		      status);

 	if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
 		fatal_perror("check_sysemu : PTRACE_GETREGS failed");
 	if (PT_SYSCALL_NR(regs) != __NR_getpid) {
 		non_fatal("check_sysemu got system call number %d, "
 			  "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
 		goto fail;
 	}

 	n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
 	if (n < 0) {
 		non_fatal("check_sysemu : failed to modify system call "
 			  "return");
 		goto fail;
 	}

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

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

 	os_info("Checking advanced syscall emulation patch for ptrace...");
 	pid = start_ptraced_child();

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

 		if (WIFSTOPPED(status) &&
 		    (WSTOPSIG(status) == (SIGTRAP|0x80))) {
 			if (!count) {
 				non_fatal("check_sysemu: SYSEMU_SINGLESTEP "
 					  "doesn't singlestep");
 				goto fail;
 			}
 			n = ptrace(PTRACE_POKEUSER, 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 {
 			non_fatal("check_sysemu: expected SIGTRAP or "
 				  "(SIGTRAP | 0x80), got status = %d\n",
 				  status);
 			goto fail;
 		}
 	}
 	if (stop_ptraced_child(pid, 0, 0) < 0)
 		goto fail_stopped;

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

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

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

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

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

 	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_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
 				 0);
 		if (syscall == __NR_getpid) {
 			n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
 				   __NR_getppid);
 			if (n < 0)
 				fatal_perror("check_ptrace : failed to modify "
 					     "system call");
 			break;
 		}
 	}
 	stop_ptraced_child(pid, 0, 1);
 	os_info("OK\n");
 	check_sysemu();
 }

 extern void check_tmpexec(void);

 static void __init check_coredump_limit(void)
 {
 	struct rlimit lim;
 	int err = getrlimit(RLIMIT_CORE, &lim);

 	if (err) {
 		perror("Getting core dump limit");
 		return;
 	}

 	os_info("Core dump limits :\n\tsoft - ");
 	if (lim.rlim_cur == RLIM_INFINITY)
 		os_info("NONE\n");
 	else
 		os_info("%llu\n", (unsigned long long)lim.rlim_cur);

 	os_info("\thard - ");
 	if (lim.rlim_max == RLIM_INFINITY)
 		os_info("NONE\n");
 	else
 		os_info("%llu\n", (unsigned long long)lim.rlim_max);
 }

 void __init os_early_checks(void)
 {
 	int pid;

 	/* Print out the core dump limits early */
 	check_coredump_limit();

 	check_ptrace();

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

 	pid = start_ptraced_child();
 	if (init_registers(pid))
 		fatal("Failed to initialize default registers");
 	stop_ptraced_child(pid, 1, 1);
 }

 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) {
 		os_warn("parse_iomem : failed to parse iomem\n");
 		goto out;
 	}
 	*file = '\0';
 	file++;
 	fd = open(file, O_RDWR, 0);
 	if (fd < 0) {
 		perror("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;
 }
	/*
	* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
	* Licensed under the GPL
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <stdarg.h>
	#include <unistd.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <sched.h>
	#include <signal.h>
	#include <string.h>
	#include <sys/mman.h>
	#include <sys/stat.h>
	#include <sys/wait.h>
	#include <sys/time.h>
	#include <sys/resource.h>
	#include <asm/unistd.h>
	#include <init.h>
	#include <os.h>
	#include <mem_user.h>
	#include <ptrace_user.h>
	#include <registers.h>
	#include <skas.h>

	static void ptrace_child(void)
	{
	int ret;
	/* Calling os_getpid because some libcs cached getpid incorrectly */
	int pid = os_getpid(), ppid = getppid();
	int sc_result;

	if (change_sig(SIGWINCH, 0) < 0 \|\|
	ptrace(PTRACE_TRACEME, 0, 0, 0) < 0) {
	perror("ptrace");
	kill(pid, SIGKILL);
	}
	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)
	/* Nothing modified by the parent, we are running normally. */
	ret = 1;
	else if (sc_result == ppid)
	/*
	* Expected in check_ptrace and check_sysemu when they succeed
	* in modifying the stack frame
	*/
	ret = 0;
	else
	/* 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.
	*/
	ret = 2;

	exit(ret);
	}

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

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

	va_start(list, fmt);
	vfprintf(stderr, fmt, list);
	va_end(list);

	exit(1);
	}

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

	va_start(list, fmt);
	vfprintf(stderr, fmt, list);
	va_end(list);
	}

	static int start_ptraced_child(void)
	{
	int pid, n, status;

	fflush(stdout);

	pid = fork();
	if (pid == 0)
	ptrace_child();
	else if (pid < 0)
	fatal_perror("start_ptraced_child : fork failed");

	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	if (n < 0)
	fatal_perror("check_ptrace : waitpid failed");
	if (!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != SIGSTOP))
	fatal("check_ptrace : expected SIGSTOP, got status = %d",
	status);

	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, int exitcode, int mustexit)
	{
	int status, n, ret = 0;

	if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) {
	perror("stop_ptraced_child : ptrace failed");
	return -1;
	}
	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. "
	"\nDisabling SYSEMU support.\n");
	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;
	}

	return ret;
	}

	/* 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)
	{
	unsigned long regs[MAX_REG_NR];
	int pid, n, status, count=0;

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

	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\n",
	status);

	if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
	fatal_perror("check_sysemu : PTRACE_GETREGS failed");
	if (PT_SYSCALL_NR(regs) != __NR_getpid) {
	non_fatal("check_sysemu got system call number %d, "
	"expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
	goto fail;
	}

	n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
	if (n < 0) {
	non_fatal("check_sysemu : failed to modify system call "
	"return");
	goto fail;
	}

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

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

	os_info("Checking advanced syscall emulation patch for ptrace...");
	pid = start_ptraced_child();

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

	if (WIFSTOPPED(status) &&
	(WSTOPSIG(status) == (SIGTRAP\|0x80))) {
	if (!count) {
	non_fatal("check_sysemu: SYSEMU_SINGLESTEP "
	"doesn't singlestep");
	goto fail;
	}
	n = ptrace(PTRACE_POKEUSER, 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 {
	non_fatal("check_sysemu: expected SIGTRAP or "
	"(SIGTRAP \| 0x80), got status = %d\n",
	status);
	goto fail;
	}
	}
	if (stop_ptraced_child(pid, 0, 0) < 0)
	goto fail_stopped;

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

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

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

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

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

	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_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
	0);
	if (syscall == __NR_getpid) {
	n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
	__NR_getppid);
	if (n < 0)
	fatal_perror("check_ptrace : failed to modify "
	"system call");
	break;
	}
	}
	stop_ptraced_child(pid, 0, 1);
	os_info("OK\n");
	check_sysemu();
	}

	extern void check_tmpexec(void);

	static void __init check_coredump_limit(void)
	{
	struct rlimit lim;
	int err = getrlimit(RLIMIT_CORE, &lim);

	if (err) {
	perror("Getting core dump limit");
	return;
	}

	os_info("Core dump limits :\n\tsoft - ");
	if (lim.rlim_cur == RLIM_INFINITY)
	os_info("NONE\n");
	else
	os_info("%llu\n", (unsigned long long)lim.rlim_cur);

	os_info("\thard - ");
	if (lim.rlim_max == RLIM_INFINITY)
	os_info("NONE\n");
	else
	os_info("%llu\n", (unsigned long long)lim.rlim_max);
	}

	void __init os_early_checks(void)
	{
	int pid;

	/* Print out the core dump limits early */
	check_coredump_limit();

	check_ptrace();

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

	pid = start_ptraced_child();
	if (init_registers(pid))
	fatal("Failed to initialize default registers");
	stop_ptraced_child(pid, 1, 1);
	}

	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) {
	os_warn("parse_iomem : failed to parse iomem\n");
	goto out;
	}
	*file = '\0';
	file++;
	fd = open(file, O_RDWR, 0);
	if (fd < 0) {
	perror("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;
	}