#include <sched.h>
#include <errno.h>
#include <stdarg.h>
-#include <fcntl.h>
#include <stdlib.h>
#include <setjmp.h>
#include <sys/time.h>
-#include <sys/ptrace.h>
-#include <sys/ioctl.h>
#include <sys/wait.h>
#include <sys/mman.h>
-#include <asm/ptrace.h>
-#include <asm/sigcontext.h>
#include <asm/unistd.h>
#include <asm/page.h>
#include "user_util.h"
#ifdef UML_CONFIG_MODE_SKAS
#include "skas.h"
#include "skas_ptrace.h"
+#include "registers.h"
#endif
void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
int flags = 0, pages;
if(sig_stack != NULL){
- pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER) - 2;
+ pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
set_sigstack(sig_stack, pages * page_size());
flags = SA_ONSTACK;
}
SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
set_handler(SIGBUS, (__sighandler_t) sig_handler, flags,
SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
- set_handler(SIGWINCH, (__sighandler_t) sig_handler, flags,
- SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
set_handler(SIGUSR2, (__sighandler_t) sig_handler,
- SA_NOMASK | flags, -1);
- (void) CHOOSE_MODE(signal(SIGCHLD, SIG_IGN), (void *) 0);
+ flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
signal(SIGHUP, SIG_IGN);
init_irq_signals(altstack);
/* Start the process and wait for it to kill itself */
new_pid = clone(outer_tramp, (void *) sp, clone_flags, &arg);
- if(new_pid < 0) return(-errno);
- while((err = waitpid(new_pid, &status, 0) < 0) && (errno == EINTR)) ;
- if(err < 0) panic("Waiting for outer trampoline failed - errno = %d",
- errno);
- if(!WIFSIGNALED(status) || (WTERMSIG(status) != SIGKILL))
- panic("outer trampoline didn't exit with SIGKILL");
+ if(new_pid < 0)
+ return(new_pid);
- return(arg.pid);
-}
+ CATCH_EINTR(err = waitpid(new_pid, &status, 0));
+ if(err < 0)
+ panic("Waiting for outer trampoline failed - errno = %d",
+ errno);
-void suspend_new_thread(int fd)
-{
- char c;
-
- os_stop_process(os_getpid());
+ if(!WIFSIGNALED(status) || (WTERMSIG(status) != SIGKILL))
+ panic("outer trampoline didn't exit with SIGKILL, "
+ "status = %d", status);
- if(read(fd, &c, sizeof(c)) != sizeof(c))
- panic("read failed in suspend_new_thread");
+ return(arg.pid);
}
-static int ptrace_child(void *arg)
+static int ptrace_child(void)
{
- int pid = os_getpid();
+ 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);
- _exit(os_getpid() == 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)
+static int start_ptraced_child(void)
{
- 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);
+ pid = fork();
+ if(pid == 0)
+ ptrace_child();
+
if(pid < 0)
- panic("check_ptrace : clone failed, errno = %d", errno);
- n = waitpid(pid, &status, WUNTRACED);
+ panic("check_ptrace : fork 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) != SIGSTOP))
panic("check_ptrace : expected SIGSTOP, got status = %d",
status);
- *stack_out = stack;
return(pid);
}
-static void stop_ptraced_child(int pid, void *stack, int exitcode)
+/* 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;
+ int status, n, ret = 0;
if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
- panic("check_ptrace : ptrace failed, errno = %d", errno);
- n = waitpid(pid, &status, 0);
- if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode))
- panic("check_ptrace : child exited with status 0x%x", status);
+ panic("stop_ptraced_child : 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 (mustexit)
+ panic("\n");
+ else
+ printk("\n");
+ ret = -1;
+ }
+
+ return ret;
+}
+
+static int force_sysemu_disabled = 0;
- if(munmap(stack, PAGE_SIZE) < 0)
- panic("check_ptrace : munmap failed, errno = %d", errno);
+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 information.\n\n");
+
+static void __init check_sysemu(void)
+{
+ int pid, syscall, n, status, count=0;
+
+ printk("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)
+ 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, 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();
+ 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))
+ panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
+ "got status = %d", status);
+
+ syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
+ 0);
+ if(syscall == __NR_getpid){
+ 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;
+ }
+ }
+ if (stop_ptraced_child(pid, 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, 1, 0);
+fail_stopped:
+ printk("missing\n");
}
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);
+ pid = start_ptraced_child();
+
+ if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
+ panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d", errno);
while(1){
if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
panic("check_ptrace : ptrace failed, errno = %d",
errno);
- n = waitpid(pid, &status, WUNTRACED);
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
if(n < 0)
panic("check_ptrace : wait failed, errno = %d", errno);
- if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
- panic("check_ptrace : expected SIGTRAP, "
+ if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80))
+ panic("check_ptrace : expected SIGTRAP + 0x80, "
"got status = %d", status);
- syscall = ptrace(PTRACE_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
+ syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
0);
if(syscall == __NR_getpid){
- n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
+ n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
__NR_getppid);
if(n < 0)
panic("check_ptrace : failed to modify system "
break;
}
}
- stop_ptraced_child(pid, stack, 0);
+ stop_ptraced_child(pid, 0, 1);
printk("OK\n");
+ check_sysemu();
}
int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
{
- jmp_buf buf;
+ sigjmp_buf buf;
int n;
*jmp_ptr = &buf;
- n = setjmp(buf);
+ n = sigsetjmp(buf, 1);
if(n != 0)
return(n);
(*fn)(arg);
kill(target, SIGIO);
}
-int can_do_skas(void)
-{
#ifdef UML_CONFIG_MODE_SKAS
+static inline int check_skas3_ptrace_support(void)
+{
struct ptrace_faultinfo fi;
- void *stack;
int pid, n, ret = 1;
printf("Checking for the skas3 patch in the host...");
- pid = start_ptraced_child(&stack);
+ pid = start_ptraced_child();
n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
- if(n < 0){
+ if (n < 0) {
if(errno == EIO)
printf("not found\n");
- else printf("No (unexpected errno - %d)\n", errno);
+ else {
+ perror("not found");
+ }
ret = 0;
+ } else {
+ printf("found\n");
}
- else printf("found\n");
init_registers(pid);
- stop_ptraced_child(pid, stack, 1);
+ stop_ptraced_child(pid, 1, 1);
+
+ return(ret);
+}
+
+int can_do_skas(void)
+{
+ int ret = 1;
printf("Checking for /proc/mm...");
- if(access("/proc/mm", W_OK)){
+ if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
printf("not found\n");
ret = 0;
+ goto out;
+ } else {
+ printf("found\n");
}
- else printf("found\n");
- return(ret);
+ ret = check_skas3_ptrace_support();
+out:
+ return ret;
+}
#else
+int can_do_skas(void)
+{
return(0);
-#endif
}
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
+#endif
git://git.onelab.eu / linux-2.6.git / blobdiff