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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 | /* 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 <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/fpu.h>
#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
};
#define PT_REG(reg) \
(PAGE_SIZE*2 - sizeof(struct pt_regs) + offsetof(struct pt_regs, reg))
#define SW_REG(reg) \
(PAGE_SIZE*2 - sizeof(struct pt_regs) - sizeof(struct switch_stack) \
+ offsetof(struct switch_stack, reg))
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(task)->pcb.usp;
} else if (regno == 65) {
addr = &task_thread_info(task)->pcb.unique;
} else if (regno == 31 || regno > 65) {
zero = 0;
addr = &zero;
} else {
addr = task_stack_page(task) + 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(task)->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(task)->ieee_state
= ((task_thread_info(task)->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;
task_thread_info(child)->bpt_addr[nsaved++] = pc + 4;
if (displ) /* guard against unoptimized code */
task_thread_info(child)->bpt_addr[nsaved++]
= pc + 4 + displ;
DBG(DBG_BPT, ("execing branch\n"));
} else if (op_code == 0x1a) {
reg_b = (insn >> 16) & 0x1f;
task_thread_info(child)->bpt_addr[nsaved++] = get_reg(child, reg_b);
DBG(DBG_BPT, ("execing jump\n"));
} else {
task_thread_info(child)->bpt_addr[nsaved++] = pc + 4;
DBG(DBG_BPT, ("execing normal insn\n"));
}
/* install breakpoints: */
for (i = 0; i < nsaved; ++i) {
res = read_int(child, task_thread_info(child)->bpt_addr[i],
(int *) &insn);
if (res < 0)
return res;
task_thread_info(child)->bpt_insn[i] = insn;
DBG(DBG_BPT, (" -> next_pc=%lx\n",
task_thread_info(child)->bpt_addr[i]));
res = write_int(child, task_thread_info(child)->bpt_addr[i],
BREAKINST);
if (res < 0)
return res;
}
task_thread_info(child)->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 = task_thread_info(child)->bpt_nsaved;
task_thread_info(child)->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, task_thread_info(child)->bpt_addr[i],
task_thread_info(child)->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));
if (request == PTRACE_TRACEME) {
ret = ptrace_traceme();
goto out_notsk;
}
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(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. */
task_thread_info(child)->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;
}
}
|