| /* |
| * 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 <stdlib.h> |
| #include <setjmp.h> |
| #include <sys/time.h> |
| #include <sys/wait.h> |
| #include <sys/mman.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 "ptrace_user.h" |
| #include "choose-mode.h" |
| #include "mode.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); |
| 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, |
| flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1); |
| 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(new_pid); |
| |
| CATCH_EINTR(err = waitpid(new_pid, &status, 0)); |
| 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, " |
| "status = %d", status); |
| |
| return(arg.pid); |
| } |
| |
| static int ptrace_child(void *arg) |
| { |
| 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); |
| |
| /*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) |
| { |
| 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); |
| 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); |
| } |
| |
| /* 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, 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)) { |
| 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; |
| |
| 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) |
| { |
| void *stack; |
| 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) |
| 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, 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) |
| 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, stack, 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, stack, 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); |
| |
| 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); |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| if(n < 0) |
| panic("check_ptrace : wait failed, errno = %d", errno); |
| if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80)) |
| panic("check_ptrace : expected SIGTRAP + 0x80, " |
| "got status = %d", status); |
| |
| syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET, |
| 0); |
| if(syscall == __NR_getpid){ |
| n = ptrace(PTRACE_POKEUSR, 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, 1); |
| printk("OK\n"); |
| check_sysemu(); |
| } |
| |
| int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr) |
| { |
| sigjmp_buf buf; |
| int n; |
| |
| *jmp_ptr = &buf; |
| n = sigsetjmp(buf, 1); |
| 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); |
| } |
| |
| #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); |
| |
| n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); |
| if (n < 0) { |
| if(errno == EIO) |
| printf("not found\n"); |
| else { |
| perror("not found"); |
| } |
| ret = 0; |
| } else { |
| printf("found\n"); |
| } |
| |
| init_registers(pid); |
| 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) { |
| printf("not found\n"); |
| ret = 0; |
| goto out; |
| } else { |
| printf("found\n"); |
| } |
| |
| ret = check_skas3_ptrace_support(); |
| out: |
| return ret; |
| } |
| #else |
| int can_do_skas(void) |
| { |
| return(0); |
| } |
| #endif |