/* ptrace.c */ /* By Ross Biro 1/23/92 */ /* edited by Linus Torvalds */ /* mangled further by Bob Manson (manson@santafe.edu) */ /* more mutilation by David Mosberger (davidm@azstarnet.com) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "proto.h" #define DEBUG DBG_MEM #undef DEBUG #ifdef DEBUG enum { DBG_MEM = (1<<0), DBG_BPT = (1<<1), DBG_MEM_ALL = (1<<2) }; #define DBG(fac,args) {if ((fac) & DEBUG) printk args;} #else #define DBG(fac,args) #endif #define BREAKINST 0x00000080 /* call_pal bpt */ /* * does not yet catch signals sent when the child dies. * in exit.c or in signal.c. */ /* * Processes always block with the following stack-layout: * * +================================+ <---- task + 2*PAGE_SIZE * | PALcode saved frame (ps, pc, | ^ * | gp, a0, a1, a2) | | * +================================+ | struct pt_regs * | | | * | frame generated by SAVE_ALL | | * | | v * +================================+ * | | ^ * | frame saved by do_switch_stack | | struct switch_stack * | | v * +================================+ */ /* * The following table maps a register index into the stack offset at * which the register is saved. Register indices are 0-31 for integer * regs, 32-63 for fp regs, and 64 for the pc. Notice that sp and * zero have no stack-slot and need to be treated specially (see * get_reg/put_reg below). */ enum { REG_R0 = 0, REG_F0 = 32, REG_FPCR = 63, REG_PC = 64 }; static int regoff[] = { PT_REG( r0), PT_REG( r1), PT_REG( r2), PT_REG( r3), PT_REG( r4), PT_REG( r5), PT_REG( r6), PT_REG( r7), PT_REG( r8), SW_REG( r9), SW_REG( r10), SW_REG( r11), SW_REG( r12), SW_REG( r13), SW_REG( r14), SW_REG( r15), PT_REG( r16), PT_REG( r17), PT_REG( r18), PT_REG( r19), PT_REG( r20), PT_REG( r21), PT_REG( r22), PT_REG( r23), PT_REG( r24), PT_REG( r25), PT_REG( r26), PT_REG( r27), PT_REG( r28), PT_REG( gp), -1, -1, SW_REG(fp[ 0]), SW_REG(fp[ 1]), SW_REG(fp[ 2]), SW_REG(fp[ 3]), SW_REG(fp[ 4]), SW_REG(fp[ 5]), SW_REG(fp[ 6]), SW_REG(fp[ 7]), SW_REG(fp[ 8]), SW_REG(fp[ 9]), SW_REG(fp[10]), SW_REG(fp[11]), SW_REG(fp[12]), SW_REG(fp[13]), SW_REG(fp[14]), SW_REG(fp[15]), SW_REG(fp[16]), SW_REG(fp[17]), SW_REG(fp[18]), SW_REG(fp[19]), SW_REG(fp[20]), SW_REG(fp[21]), SW_REG(fp[22]), SW_REG(fp[23]), SW_REG(fp[24]), SW_REG(fp[25]), SW_REG(fp[26]), SW_REG(fp[27]), SW_REG(fp[28]), SW_REG(fp[29]), SW_REG(fp[30]), SW_REG(fp[31]), PT_REG( pc) }; static unsigned long zero; /* * Get address of register REGNO in task TASK. */ static unsigned long * get_reg_addr(struct task_struct * task, unsigned long regno) { unsigned long *addr; if (regno == 30) { addr = &task->thread_info->pcb.usp; } else if (regno == 65) { addr = &task->thread_info->pcb.unique; } else if (regno == 31 || regno > 65) { zero = 0; addr = &zero; } else { addr = (void *)task->thread_info + regoff[regno]; } return addr; } /* * Get contents of register REGNO in task TASK. */ static unsigned long get_reg(struct task_struct * task, unsigned long regno) { /* Special hack for fpcr -- combine hardware and software bits. */ if (regno == 63) { unsigned long fpcr = *get_reg_addr(task, regno); unsigned long swcr = task->thread_info->ieee_state & IEEE_SW_MASK; swcr = swcr_update_status(swcr, fpcr); return fpcr | swcr; } return *get_reg_addr(task, regno); } /* * Write contents of register REGNO in task TASK. */ static int put_reg(struct task_struct *task, unsigned long regno, unsigned long data) { if (regno == 63) { task->thread_info->ieee_state = ((task->thread_info->ieee_state & ~IEEE_SW_MASK) | (data & IEEE_SW_MASK)); data = (data & FPCR_DYN_MASK) | ieee_swcr_to_fpcr(data); } *get_reg_addr(task, regno) = data; return 0; } static inline int read_int(struct task_struct *task, unsigned long addr, int * data) { int copied = access_process_vm(task, addr, data, sizeof(int), 0); return (copied == sizeof(int)) ? 0 : -EIO; } static inline int write_int(struct task_struct *task, unsigned long addr, int data) { int copied = access_process_vm(task, addr, &data, sizeof(int), 1); return (copied == sizeof(int)) ? 0 : -EIO; } /* * Set breakpoint. */ int ptrace_set_bpt(struct task_struct * child) { int displ, i, res, reg_b, nsaved = 0; unsigned int insn, op_code; unsigned long pc; pc = get_reg(child, REG_PC); res = read_int(child, pc, (int *) &insn); if (res < 0) return res; op_code = insn >> 26; if (op_code >= 0x30) { /* * It's a branch: instead of trying to figure out * whether the branch will be taken or not, we'll put * a breakpoint at either location. This is simpler, * more reliable, and probably not a whole lot slower * than the alternative approach of emulating the * branch (emulation can be tricky for fp branches). */ displ = ((s32)(insn << 11)) >> 9; child->thread_info->bpt_addr[nsaved++] = pc + 4; if (displ) /* guard against unoptimized code */ child->thread_info->bpt_addr[nsaved++] = pc + 4 + displ; DBG(DBG_BPT, ("execing branch\n")); } else if (op_code == 0x1a) { reg_b = (insn >> 16) & 0x1f; child->thread_info->bpt_addr[nsaved++] = get_reg(child, reg_b); DBG(DBG_BPT, ("execing jump\n")); } else { child->thread_info->bpt_addr[nsaved++] = pc + 4; DBG(DBG_BPT, ("execing normal insn\n")); } /* install breakpoints: */ for (i = 0; i < nsaved; ++i) { res = read_int(child, child->thread_info->bpt_addr[i], (int *) &insn); if (res < 0) return res; child->thread_info->bpt_insn[i] = insn; DBG(DBG_BPT, (" -> next_pc=%lx\n", child->thread_info->bpt_addr[i])); res = write_int(child, child->thread_info->bpt_addr[i], BREAKINST); if (res < 0) return res; } child->thread_info->bpt_nsaved = nsaved; return 0; } /* * Ensure no single-step breakpoint is pending. Returns non-zero * value if child was being single-stepped. */ int ptrace_cancel_bpt(struct task_struct * child) { int i, nsaved = child->thread_info->bpt_nsaved; child->thread_info->bpt_nsaved = 0; if (nsaved > 2) { printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved); nsaved = 2; } for (i = 0; i < nsaved; ++i) { write_int(child, child->thread_info->bpt_addr[i], child->thread_info->bpt_insn[i]); } return (nsaved != 0); } /* * Called by kernel/ptrace.c when detaching.. * * Make sure the single step bit is not set. */ void ptrace_disable(struct task_struct *child) { ptrace_cancel_bpt(child); } asmlinkage long do_sys_ptrace(long request, long pid, long addr, long data, struct pt_regs *regs) { struct task_struct *child; unsigned long tmp; size_t copied; long ret; lock_kernel(); DBG(DBG_MEM, ("request=%ld pid=%ld addr=0x%lx data=0x%lx\n", request, pid, addr, data)); ret = -EPERM; if (request == PTRACE_TRACEME) { /* are we already being traced? */ if (current->ptrace & PT_PTRACED) goto out_notsk; ret = security_ptrace(current->parent, current); if (ret) goto out_notsk; /* set the ptrace bit in the process ptrace flags. */ current->ptrace |= PT_PTRACED; ret = 0; goto out_notsk; } if (pid == 1) /* you may not mess with init */ goto out_notsk; ret = -ESRCH; read_lock(&tasklist_lock); child = find_task_by_pid(pid); if (child) get_task_struct(child); read_unlock(&tasklist_lock); if (!child) goto out_notsk; if (request == PTRACE_ATTACH) { ret = ptrace_attach(child); goto out; } ret = ptrace_check_attach(child, request == PTRACE_KILL); if (ret < 0) goto out; switch (request) { /* When I and D space are separate, these will need to be fixed. */ case PTRACE_PEEKTEXT: /* read word at location addr. */ case PTRACE_PEEKDATA: copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); ret = -EIO; if (copied != sizeof(tmp)) break; regs->r0 = 0; /* special return: no errors */ ret = tmp; break; /* Read register number ADDR. */ case PTRACE_PEEKUSR: regs->r0 = 0; /* special return: no errors */ ret = get_reg(child, addr); DBG(DBG_MEM, ("peek $%ld->%#lx\n", addr, ret)); break; /* When I and D space are separate, this will have to be fixed. */ case PTRACE_POKETEXT: /* write the word at location addr. */ case PTRACE_POKEDATA: tmp = data; copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1); ret = (copied == sizeof(tmp)) ? 0 : -EIO; break; case PTRACE_POKEUSR: /* write the specified register */ DBG(DBG_MEM, ("poke $%ld<-%#lx\n", addr, data)); ret = put_reg(child, addr, data); break; case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ case PTRACE_CONT: /* restart after signal. */ ret = -EIO; if (!valid_signal(data)) break; if (request == PTRACE_SYSCALL) set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); else clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); child->exit_code = data; /* make sure single-step breakpoint is gone. */ ptrace_cancel_bpt(child); wake_up_process(child); ret = 0; break; /* * Make the child exit. Best I can do is send it a sigkill. * perhaps it should be put in the status that it wants to * exit. */ case PTRACE_KILL: ret = 0; if (child->exit_state == EXIT_ZOMBIE) break; child->exit_code = SIGKILL; /* make sure single-step breakpoint is gone. */ ptrace_cancel_bpt(child); wake_up_process(child); goto out; case PTRACE_SINGLESTEP: /* execute single instruction. */ ret = -EIO; if (!valid_signal(data)) break; /* Mark single stepping. */ child->thread_info->bpt_nsaved = -1; clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); child->exit_code = data; wake_up_process(child); /* give it a chance to run. */ ret = 0; goto out; case PTRACE_DETACH: /* detach a process that was attached. */ ret = ptrace_detach(child, data); goto out; default: ret = ptrace_request(child, request, addr, data); goto out; } out: put_task_struct(child); out_notsk: unlock_kernel(); return ret; } asmlinkage void syscall_trace(void) { if (!test_thread_flag(TIF_SYSCALL_TRACE)) return; if (!(current->ptrace & PT_PTRACED)) return; /* The 0x80 provides a way for the tracing parent to distinguish between a syscall stop and SIGTRAP delivery */ ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); /* * This isn't the same as continuing with a signal, but it will do * for normal use. strace only continues with a signal if the * stopping signal is not SIGTRAP. -brl */ if (current->exit_code) { send_sig(current->exit_code, current, 1); current->exit_code = 0; } }