2 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
17 #include <asm/unistd.h>
19 #include "user_util.h"
20 #include "kern_util.h"
23 #include "signal_kern.h"
24 #include "signal_user.h"
25 #include "sysdep/ptrace.h"
26 #include "sysdep/sigcontext.h"
28 #include "ptrace_user.h"
29 #include "time_user.h"
32 #include "uml-config.h"
33 #include "ptrace_user.h"
34 #include "choose-mode.h"
36 #ifdef UML_CONFIG_MODE_SKAS
38 #include "skas_ptrace.h"
39 #include "registers.h"
42 void init_new_thread_stack(void *sig_stack
, void (*usr1_handler
)(int))
46 if(sig_stack
!= NULL
){
47 pages
= (1 << UML_CONFIG_KERNEL_STACK_ORDER
);
48 set_sigstack(sig_stack
, pages
* page_size());
51 if(usr1_handler
) set_handler(SIGUSR1
, usr1_handler
, flags
, -1);
54 void init_new_thread_signals(int altstack
)
56 int flags
= altstack
? SA_ONSTACK
: 0;
58 set_handler(SIGSEGV
, (__sighandler_t
) sig_handler
, flags
,
59 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
60 set_handler(SIGTRAP
, (__sighandler_t
) sig_handler
, flags
,
61 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
62 set_handler(SIGFPE
, (__sighandler_t
) sig_handler
, flags
,
63 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
64 set_handler(SIGILL
, (__sighandler_t
) sig_handler
, flags
,
65 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
66 set_handler(SIGBUS
, (__sighandler_t
) sig_handler
, flags
,
67 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
68 set_handler(SIGUSR2
, (__sighandler_t
) sig_handler
,
69 flags
, SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
70 signal(SIGHUP
, SIG_IGN
);
72 init_irq_signals(altstack
);
78 unsigned long temp_stack
;
83 /* See above for why sigkill is here */
85 int sigkill
= SIGKILL
;
87 int outer_tramp(void *arg
)
93 t
->pid
= clone(t
->tramp
, (void *) t
->temp_stack
+ page_size()/2,
94 t
->flags
, t
->tramp_data
);
95 if(t
->pid
> 0) wait_for_stop(t
->pid
, SIGSTOP
, PTRACE_CONT
, NULL
);
96 kill(os_getpid(), sig
);
100 int start_fork_tramp(void *thread_arg
, unsigned long temp_stack
,
101 int clone_flags
, int (*tramp
)(void *))
105 int new_pid
, status
, err
;
107 /* The trampoline will run on the temporary stack */
108 sp
= stack_sp(temp_stack
);
110 clone_flags
|= CLONE_FILES
| SIGCHLD
;
113 arg
.tramp_data
= thread_arg
;
114 arg
.temp_stack
= temp_stack
;
115 arg
.flags
= clone_flags
;
117 /* Start the process and wait for it to kill itself */
118 new_pid
= clone(outer_tramp
, (void *) sp
, clone_flags
, &arg
);
122 CATCH_EINTR(err
= waitpid(new_pid
, &status
, 0));
124 panic("Waiting for outer trampoline failed - errno = %d",
127 if(!WIFSIGNALED(status
) || (WTERMSIG(status
) != SIGKILL
))
128 panic("outer trampoline didn't exit with SIGKILL, "
129 "status = %d", status
);
134 static int ptrace_child(void *arg
)
137 int pid
= os_getpid(), ppid
= getppid();
140 if(ptrace(PTRACE_TRACEME
, 0, 0, 0) < 0){
142 os_kill_process(pid
, 0);
144 os_stop_process(pid
);
146 /*This syscall will be intercepted by the parent. Don't call more than
148 sc_result
= os_getpid();
150 if (sc_result
== pid
)
151 ret
= 1; /*Nothing modified by the parent, we are running
153 else if (sc_result
== ppid
)
154 ret
= 0; /*Expected in check_ptrace and check_sysemu when they
155 succeed in modifying the stack frame*/
157 ret
= 2; /*Serious trouble! This could be caused by a bug in
158 host 2.6 SKAS3/2.6 patch before release -V6, together
159 with a bug in the UML code itself.*/
163 static int start_ptraced_child(void **stack_out
)
169 stack
= mmap(NULL
, PAGE_SIZE
, PROT_READ
| PROT_WRITE
| PROT_EXEC
,
170 MAP_PRIVATE
| MAP_ANONYMOUS
, -1, 0);
171 if(stack
== MAP_FAILED
)
172 panic("check_ptrace : mmap failed, errno = %d", errno
);
173 sp
= (unsigned long) stack
+ PAGE_SIZE
- sizeof(void *);
174 pid
= clone(ptrace_child
, (void *) sp
, SIGCHLD
, NULL
);
176 panic("check_ptrace : clone failed, errno = %d", errno
);
177 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
179 panic("check_ptrace : wait failed, errno = %d", errno
);
180 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGSTOP
))
181 panic("check_ptrace : expected SIGSTOP, got status = %d",
188 /* When testing for SYSEMU support, if it is one of the broken versions, we must
189 * just avoid using sysemu, not panic, but only if SYSEMU features are broken.
190 * So only for SYSEMU features we test mustpanic, while normal host features
191 * must work anyway!*/
192 static int stop_ptraced_child(int pid
, void *stack
, int exitcode
, int mustpanic
)
194 int status
, n
, ret
= 0;
196 if(ptrace(PTRACE_CONT
, pid
, 0, 0) < 0)
197 panic("check_ptrace : ptrace failed, errno = %d", errno
);
198 CATCH_EINTR(n
= waitpid(pid
, &status
, 0));
199 if(!WIFEXITED(status
) || (WEXITSTATUS(status
) != exitcode
)) {
200 int exit_with
= WEXITSTATUS(status
);
202 printk("check_ptrace : child exited with status 2. "
203 "Serious trouble happening! Try updating your "
204 "host skas patch!\nDisabling SYSEMU support.");
205 printk("check_ptrace : child exited with exitcode %d, while "
206 "expecting %d; status 0x%x", exit_with
,
215 if(munmap(stack
, PAGE_SIZE
) < 0)
216 panic("check_ptrace : munmap failed, errno = %d", errno
);
220 static int force_sysemu_disabled
= 0;
222 static int __init
nosysemu_cmd_param(char *str
, int* add
)
224 force_sysemu_disabled
= 1;
228 __uml_setup("nosysemu", nosysemu_cmd_param
,
230 " Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
231 " SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
232 " behaviour of ptrace() and helps reducing host context switch rate.\n"
233 " To make it working, you need a kernel patch for your host, too.\n"
234 " See http://perso.wanadoo.fr/laurent.vivier/UML/ for further information.\n\n");
236 static void __init
check_sysemu(void)
239 int pid
, syscall
, n
, status
, count
=0;
241 printk("Checking syscall emulation patch for ptrace...");
242 sysemu_supported
= 0;
243 pid
= start_ptraced_child(&stack
);
245 if(ptrace(PTRACE_SYSEMU
, pid
, 0, 0) < 0)
248 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
250 panic("check_sysemu : wait failed, errno = %d", errno
);
251 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGTRAP
))
252 panic("check_sysemu : expected SIGTRAP, "
253 "got status = %d", status
);
255 n
= ptrace(PTRACE_POKEUSR
, pid
, PT_SYSCALL_RET_OFFSET
,
258 panic("check_sysemu : failed to modify system "
259 "call return, errno = %d", errno
);
261 if (stop_ptraced_child(pid
, stack
, 0, 0) < 0)
264 sysemu_supported
= 1;
266 set_using_sysemu(!force_sysemu_disabled
);
268 printk("Checking advanced syscall emulation patch for ptrace...");
269 pid
= start_ptraced_child(&stack
);
272 if(ptrace(PTRACE_SYSEMU_SINGLESTEP
, pid
, 0, 0) < 0)
274 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
276 panic("check_ptrace : wait failed, errno = %d", errno
);
277 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGTRAP
))
278 panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
279 "got status = %d", status
);
281 syscall
= ptrace(PTRACE_PEEKUSR
, pid
, PT_SYSCALL_NR_OFFSET
,
283 if(syscall
== __NR_getpid
){
285 panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
286 n
= ptrace(PTRACE_POKEUSR
, pid
, PT_SYSCALL_RET_OFFSET
,
289 panic("check_sysemu : failed to modify system "
290 "call return, errno = %d", errno
);
294 if (stop_ptraced_child(pid
, stack
, 0, 0) < 0)
297 sysemu_supported
= 2;
300 if ( !force_sysemu_disabled
)
301 set_using_sysemu(sysemu_supported
);
305 stop_ptraced_child(pid
, stack
, 1, 0);
310 void __init
check_ptrace(void)
313 int pid
, syscall
, n
, status
;
315 printk("Checking that ptrace can change system call numbers...");
316 pid
= start_ptraced_child(&stack
);
318 if (ptrace(PTRACE_OLDSETOPTIONS
, pid
, 0, (void *)PTRACE_O_TRACESYSGOOD
) < 0)
319 panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d", errno
);
322 if(ptrace(PTRACE_SYSCALL
, pid
, 0, 0) < 0)
323 panic("check_ptrace : ptrace failed, errno = %d",
325 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
327 panic("check_ptrace : wait failed, errno = %d", errno
);
328 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGTRAP
+ 0x80))
329 panic("check_ptrace : expected SIGTRAP + 0x80, "
330 "got status = %d", status
);
332 syscall
= ptrace(PTRACE_PEEKUSR
, pid
, PT_SYSCALL_NR_OFFSET
,
334 if(syscall
== __NR_getpid
){
335 n
= ptrace(PTRACE_POKEUSR
, pid
, PT_SYSCALL_NR_OFFSET
,
338 panic("check_ptrace : failed to modify system "
339 "call, errno = %d", errno
);
343 stop_ptraced_child(pid
, stack
, 0, 1);
348 int run_kernel_thread(int (*fn
)(void *), void *arg
, void **jmp_ptr
)
354 n
= sigsetjmp(buf
, 1);
361 void forward_pending_sigio(int target
)
365 if(sigpending(&sigs
))
366 panic("forward_pending_sigio : sigpending failed");
367 if(sigismember(&sigs
, SIGIO
))
371 #ifdef UML_CONFIG_MODE_SKAS
372 static inline int check_skas3_ptrace_support(void)
374 struct ptrace_faultinfo fi
;
378 printf("Checking for the skas3 patch in the host...");
379 pid
= start_ptraced_child(&stack
);
381 n
= ptrace(PTRACE_FAULTINFO
, pid
, 0, &fi
);
384 printf("not found\n");
394 stop_ptraced_child(pid
, stack
, 1, 1);
399 int can_do_skas(void)
403 printf("Checking for /proc/mm...");
404 if (os_access("/proc/mm", OS_ACC_W_OK
) < 0) {
405 printf("not found\n");
412 ret
= check_skas3_ptrace_support();
417 int can_do_skas(void)