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(SIGWINCH, (__sighandler_t) sig_handler, flags,
69 SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
70 set_handler(SIGUSR2, (__sighandler_t) sig_handler,
71 flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
72 signal(SIGHUP, SIG_IGN);
74 init_irq_signals(altstack);
80 unsigned long temp_stack;
85 /* See above for why sigkill is here */
87 int sigkill = SIGKILL;
89 int outer_tramp(void *arg)
95 t->pid = clone(t->tramp, (void *) t->temp_stack + page_size()/2,
96 t->flags, t->tramp_data);
97 if(t->pid > 0) wait_for_stop(t->pid, SIGSTOP, PTRACE_CONT, NULL);
98 kill(os_getpid(), sig);
102 int start_fork_tramp(void *thread_arg, unsigned long temp_stack,
103 int clone_flags, int (*tramp)(void *))
107 int new_pid, status, err;
109 /* The trampoline will run on the temporary stack */
110 sp = stack_sp(temp_stack);
112 clone_flags |= CLONE_FILES | SIGCHLD;
115 arg.tramp_data = thread_arg;
116 arg.temp_stack = temp_stack;
117 arg.flags = clone_flags;
119 /* Start the process and wait for it to kill itself */
120 new_pid = clone(outer_tramp, (void *) sp, clone_flags, &arg);
124 CATCH_EINTR(err = waitpid(new_pid, &status, 0));
126 panic("Waiting for outer trampoline failed - errno = %d",
129 if(!WIFSIGNALED(status) || (WTERMSIG(status) != SIGKILL))
130 panic("outer trampoline didn't exit with SIGKILL, "
131 "status = %d", status);
136 static int ptrace_child(void *arg)
139 int pid = os_getpid(), ppid = getppid();
142 if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
144 os_kill_process(pid, 0);
146 os_stop_process(pid);
148 /*This syscall will be intercepted by the parent. Don't call more than
150 sc_result = os_getpid();
152 if (sc_result == pid)
153 ret = 1; /*Nothing modified by the parent, we are running
155 else if (sc_result == ppid)
156 ret = 0; /*Expected in check_ptrace and check_sysemu when they
157 succeed in modifying the stack frame*/
159 ret = 2; /*Serious trouble! This could be caused by a bug in
160 host 2.6 SKAS3/2.6 patch before release -V6, together
161 with a bug in the UML code itself.*/
165 static int start_ptraced_child(void **stack_out)
171 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
172 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
173 if(stack == MAP_FAILED)
174 panic("check_ptrace : mmap failed, errno = %d", errno);
175 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
176 pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
178 panic("check_ptrace : clone failed, errno = %d", errno);
179 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
181 panic("check_ptrace : wait failed, errno = %d", errno);
182 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
183 panic("check_ptrace : expected SIGSTOP, got status = %d",
190 /* When testing for SYSEMU support, if it is one of the broken versions, we must
191 * just avoid using sysemu, not panic, but only if SYSEMU features are broken.
192 * So only for SYSEMU features we test mustpanic, while normal host features
193 * must work anyway!*/
194 static int stop_ptraced_child(int pid, void *stack, int exitcode, int mustpanic)
196 int status, n, ret = 0;
198 if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
199 panic("check_ptrace : ptrace failed, errno = %d", errno);
200 CATCH_EINTR(n = waitpid(pid, &status, 0));
201 if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
202 int exit_with = WEXITSTATUS(status);
204 printk("check_ptrace : child exited with status 2. "
205 "Serious trouble happening! Try updating your "
206 "host skas patch!\nDisabling SYSEMU support.");
207 printk("check_ptrace : child exited with exitcode %d, while "
208 "expecting %d; status 0x%x", exit_with,
217 if(munmap(stack, PAGE_SIZE) < 0)
218 panic("check_ptrace : munmap failed, errno = %d", errno);
222 static int force_sysemu_disabled = 0;
224 static int __init nosysemu_cmd_param(char *str, int* add)
226 force_sysemu_disabled = 1;
230 __uml_setup("nosysemu", nosysemu_cmd_param,
232 " Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
233 " SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
234 " behaviour of ptrace() and helps reducing host context switch rate.\n"
235 " To make it working, you need a kernel patch for your host, too.\n"
236 " See http://perso.wanadoo.fr/laurent.vivier/UML/ for further information.\n\n");
238 static void __init check_sysemu(void)
241 int pid, syscall, n, status, count=0;
243 printk("Checking syscall emulation patch for ptrace...");
244 sysemu_supported = 0;
245 pid = start_ptraced_child(&stack);
247 if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
250 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
252 panic("check_sysemu : wait failed, errno = %d", errno);
253 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
254 panic("check_sysemu : expected SIGTRAP, "
255 "got status = %d", status);
257 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
260 panic("check_sysemu : failed to modify system "
261 "call return, errno = %d", errno);
263 if (stop_ptraced_child(pid, stack, 0, 0) < 0)
266 sysemu_supported = 1;
268 set_using_sysemu(!force_sysemu_disabled);
270 printk("Checking advanced syscall emulation patch for ptrace...");
271 pid = start_ptraced_child(&stack);
274 if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
276 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
278 panic("check_ptrace : wait failed, errno = %d", errno);
279 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
280 panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
281 "got status = %d", status);
283 syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
285 if(syscall == __NR_getpid){
287 panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
288 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
291 panic("check_sysemu : failed to modify system "
292 "call return, errno = %d", errno);
296 if (stop_ptraced_child(pid, stack, 0, 0) < 0)
299 sysemu_supported = 2;
302 if ( !force_sysemu_disabled )
303 set_using_sysemu(sysemu_supported);
307 stop_ptraced_child(pid, stack, 1, 0);
312 void __init check_ptrace(void)
315 int pid, syscall, n, status;
317 printk("Checking that ptrace can change system call numbers...");
318 pid = start_ptraced_child(&stack);
320 if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
321 panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d", errno);
324 if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
325 panic("check_ptrace : ptrace failed, errno = %d",
327 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
329 panic("check_ptrace : wait failed, errno = %d", errno);
330 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80))
331 panic("check_ptrace : expected SIGTRAP + 0x80, "
332 "got status = %d", status);
334 syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
336 if(syscall == __NR_getpid){
337 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
340 panic("check_ptrace : failed to modify system "
341 "call, errno = %d", errno);
345 stop_ptraced_child(pid, stack, 0, 1);
350 int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
356 n = sigsetjmp(buf, 1);
363 void forward_pending_sigio(int target)
367 if(sigpending(&sigs))
368 panic("forward_pending_sigio : sigpending failed");
369 if(sigismember(&sigs, SIGIO))
373 #ifdef UML_CONFIG_MODE_SKAS
374 static inline int check_skas3_ptrace_support(void)
376 struct ptrace_faultinfo fi;
380 printf("Checking for the skas3 patch in the host...");
381 pid = start_ptraced_child(&stack);
383 n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
386 printf("not found\n");
396 stop_ptraced_child(pid, stack, 1, 1);
401 int can_do_skas(void)
405 printf("Checking for /proc/mm...");
406 if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
407 printf("not found\n");
414 ret = check_skas3_ptrace_support();
419 int can_do_skas(void)