Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 | /* * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com) * Licensed under the GPL */ #include <stdio.h> #include <unistd.h> #include <signal.h> #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" #include "kern_util.h" #include "user.h" #include "process.h" #include "signal_kern.h" #include "signal_user.h" #include "sysdep/ptrace.h" #include "sysdep/sigcontext.h" #include "irq_user.h" #include "ptrace_user.h" #include "time_user.h" #include "init.h" #include "os.h" #include "uml-config.h" #include "choose-mode.h" #include "mode.h" #ifdef UML_CONFIG_MODE_SKAS #include "skas.h" #include "skas_ptrace.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; set_sigstack(sig_stack, pages * page_size()); flags = SA_ONSTACK; } if(usr1_handler) set_handler(SIGUSR1, usr1_handler, flags, -1); } void init_new_thread_signals(int altstack) { int flags = altstack ? SA_ONSTACK : 0; set_handler(SIGSEGV, (__sighandler_t) sig_handler, flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1); set_handler(SIGTRAP, (__sighandler_t) sig_handler, flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1); set_handler(SIGFPE, (__sighandler_t) sig_handler, flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1); set_handler(SIGILL, (__sighandler_t) sig_handler, flags, 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); signal(SIGHUP, SIG_IGN); init_irq_signals(altstack); } struct tramp { int (*tramp)(void *); void *tramp_data; unsigned long temp_stack; int flags; int pid; }; /* See above for why sigkill is here */ int sigkill = SIGKILL; int outer_tramp(void *arg) { struct tramp *t; int sig = sigkill; t = arg; t->pid = clone(t->tramp, (void *) t->temp_stack + page_size()/2, t->flags, t->tramp_data); if(t->pid > 0) wait_for_stop(t->pid, SIGSTOP, PTRACE_CONT, NULL); kill(os_getpid(), sig); _exit(0); } int start_fork_tramp(void *thread_arg, unsigned long temp_stack, int clone_flags, int (*tramp)(void *)) { struct tramp arg; unsigned long sp; int new_pid, status, err; /* The trampoline will run on the temporary stack */ sp = stack_sp(temp_stack); clone_flags |= CLONE_FILES | SIGCHLD; arg.tramp = tramp; arg.tramp_data = thread_arg; arg.temp_stack = temp_stack; arg.flags = clone_flags; /* 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"); return(arg.pid); } void suspend_new_thread(int fd) { char c; os_stop_process(os_getpid()); if(read(fd, &c, sizeof(c)) != sizeof(c)) panic("read failed in suspend_new_thread"); } static int ptrace_child(void *arg) { int pid = os_getpid(); if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){ perror("ptrace"); os_kill_process(pid, 0); } os_stop_process(pid); _exit(os_getpid() == pid); } static int start_ptraced_child(void **stack_out) { 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); if(pid < 0) panic("check_ptrace : clone failed, errno = %d", errno); 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) { int status, n; 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); if(munmap(stack, PAGE_SIZE) < 0) panic("check_ptrace : munmap failed, errno = %d", errno); } 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); while(1){ if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0) panic("check_ptrace : ptrace failed, errno = %d", errno); 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, " "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) panic("check_ptrace : failed to modify system " "call, errno = %d", errno); break; } } stop_ptraced_child(pid, stack, 0); printk("OK\n"); } int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr) { jmp_buf buf; int n; *jmp_ptr = &buf; n = setjmp(buf); if(n != 0) return(n); (*fn)(arg); return(0); } void forward_pending_sigio(int target) { sigset_t sigs; if(sigpending(&sigs)) panic("forward_pending_sigio : sigpending failed"); if(sigismember(&sigs, SIGIO)) kill(target, SIGIO); } int can_do_skas(void) { #ifdef UML_CONFIG_MODE_SKAS 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); n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); if(n < 0){ if(errno == EIO) printf("not found\n"); else printf("No (unexpected errno - %d)\n", errno); ret = 0; } else printf("found\n"); init_registers(pid); stop_ptraced_child(pid, stack, 1); printf("Checking for /proc/mm..."); if(access("/proc/mm", W_OK)){ printf("not found\n"); ret = 0; } else printf("found\n"); return(ret); #else 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: */ |