#include <setjmp.h>
#include <sys/time.h>
#include <sys/ptrace.h>
+
+/*Userspace header, must be after sys/ptrace.h, and both must be included. */
+#include <linux/ptrace.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 <asm/user.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/ptrace_user.h"
#include "sysdep/sigcontext.h"
#include "irq_user.h"
#include "ptrace_user.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))
static int ptrace_child(void *arg)
{
- 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)
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, void *stack, int exitcode, int mustpanic)
{
- int status, n;
+ 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))
- panic("check_ptrace : child exited with status 0x%x", status);
+ 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;
}
static int force_sysemu_disabled = 0;
" 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");
+ " See http://perso.wanadoo.fr/laurent.vivier/UML/ for further information.\n\n");
static void __init check_sysemu(void)
{
void *stack;
- int pid, n, status;
-
- if (mode_tt)
- return;
+ int pid, syscall, 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) {
- struct user_regs_struct regs;
+ 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_POKEUSER, 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);
+ while(1){
+ count++;
+ if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
+ goto fail;
CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
- if (n < 0)
+ if(n < 0)
panic("check_ptrace : wait failed, errno = %d", errno);
if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
- panic("check_ptrace : expected SIGTRAP, "
+ panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
"got status = %d", status);
- if (ptrace(PTRACE_GETREGS, pid, 0, ®s) < 0)
- panic("check_ptrace : failed to read child "
- "registers, errno = %d", errno);
- regs.orig_eax = pid;
- if (ptrace(PTRACE_SETREGS, pid, 0, ®s) < 0)
- panic("check_ptrace : failed to modify child "
- "registers, errno = %d", errno);
+ syscall = ptrace(PTRACE_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
+ 0);
+ if(syscall == __NR_getpid){
+ if (!count)
+ panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
+ n = ptrace(PTRACE_POKEUSER, 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, stack, 0, 0) < 0)
+ goto fail_stopped;
- stop_ptraced_child(pid, stack, 0);
+ sysemu_supported = 2;
+ printk("OK\n");
- sysemu_supported = 1;
- printk("found\n");
- }
- else
- {
- stop_ptraced_child(pid, stack, 1);
- sysemu_supported = 0;
- printk("missing\n");
- }
+ if ( !force_sysemu_disabled )
+ set_using_sysemu(sysemu_supported);
+ return;
- set_using_sysemu(!force_sysemu_disabled);
+fail:
+ stop_ptraced_child(pid, stack, 1, 0);
+fail_stopped:
+ printk("missing\n");
}
void __init check_ptrace(void)
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_SETOPTIONS failed, errno = %d", errno);
+
while(1){
if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
panic("check_ptrace : ptrace failed, errno = %d",
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,
break;
}
}
- stop_ptraced_child(pid, stack, 0);
+ stop_ptraced_child(pid, stack, 0, 1);
printk("OK\n");
check_sysemu();
}
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;
pid = start_ptraced_child(&stack);
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, stack, 1, 1);
+
+ return(ret);
+}
+
+int can_do_skas(void)
+{
+ int ret = 1;
printf("Checking for /proc/mm...");
- if(os_access("/proc/mm", OS_ACC_W_OK) < 0){
+ 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