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linux_ptrace.c revision 1.25
      1 /*	$NetBSD: linux_ptrace.c,v 1.24 2014/01/04 00:10:03 dsl Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Matthias Scheler and Emmanuel Dreyfus.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.24 2014/01/04 00:10:03 dsl Exp $");
     34 
     35 #include <sys/param.h>
     36 #include <sys/malloc.h>
     37 #include <sys/mount.h>
     38 #include <sys/proc.h>
     39 #include <sys/ptrace.h>
     40 #include <sys/systm.h>
     41 #include <sys/syscallargs.h>
     42 #include <uvm/uvm_extern.h>
     43 
     44 #include <machine/reg.h>
     45 
     46 #include <compat/linux/common/linux_types.h>
     47 #include <compat/linux/common/linux_ptrace.h>
     48 #include <compat/linux/common/linux_signal.h>
     49 
     50 #include <compat/linux/common/linux_util.h>
     51 #include <compat/linux/common/linux_machdep.h>
     52 #include <compat/linux/common/linux_emuldata.h>
     53 #include <compat/linux/common/linux_exec.h>	/* for emul_linux */
     54 
     55 #include <compat/linux/linux_syscallargs.h>
     56 
     57 #include <lib/libkern/libkern.h>	/* for offsetof() */
     58 
     59 /*
     60  * From Linux's include/asm-ppc/ptrace.h.
     61  * structure used for storing reg context:  defined in linux_machdep.h
     62  * structure used for storing floating point context:
     63  * Linux just uses a double fpr[32], no struct
     64  */
     65 
     66 /*
     67  * user struct for linux process - this is used for Linux ptrace emulation
     68  * most of it is junk only used by gdb
     69  *
     70  * From Linux's include/asm-ppc/user.h
     71  *
     72  * XXX u_ar0 was a struct reg in Linux/powerpc
     73  * Can't find out what a struct regs is for Linux/powerpc,
     74  * so we use a struct pt_regs instead. don't know if this is right.
     75  */
     76 
     77 struct linux_user {
     78 	struct linux_pt_regs regs;
     79 #define lusr_startgdb regs
     80 	size_t u_tsize;
     81 	size_t u_dsize;
     82 	size_t u_ssize;
     83 	unsigned long start_code;
     84 	unsigned long start_data;
     85 	unsigned long start_stack;
     86 	long int signal;
     87 	struct linux_pt_regs *u_ar0;		/* help gdb find registers */
     88 	unsigned long magic;
     89 	char u_comm[32];
     90 #define lu_comm_end u_comm[31]
     91 };
     92 
     93 #define LUSR_OFF(member) offsetof(struct linux_user, member)
     94 #define LUSR_REG_OFF(member) offsetof(struct linux_pt_regs, member)
     95 #define ISSET(t, f) ((t) & (f))
     96 
     97 int linux_ptrace_disabled = 1;	/* bitrotted */
     98 
     99 /* XXX Check me! (From NetBSD/i386) */
    100 int
    101 linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
    102     register_t *retval)
    103 {
    104 	/* {
    105 		syscallarg(int) request;
    106 		syscallarg(int) pid;
    107 		syscallarg(int) addr;
    108 		syscallarg(int) data;
    109 	} */
    110 	struct proc *p = l->l_proc, *t;
    111 	struct lwp *lt;
    112 	struct reg *regs = NULL;
    113 	struct fpreg *fpregs = NULL;
    114 	struct linux_pt_regs *linux_regs = NULL;
    115 	double *linux_fpreg = NULL;  /* it's an array, not a struct */
    116 	int request, error, addr, i;
    117 
    118 	if (linux_ptrace_disabled)
    119 		return ENOSYS;
    120 
    121 	error = 0;
    122 	request = SCARG(uap, request);
    123 
    124 	switch (request) {
    125 	case LINUX_PTRACE_PEEKUSR:
    126 	case LINUX_PTRACE_POKEUSR:
    127 		regs = kmem_alloc(sizeof(struct reg), KM_SLEEP);
    128 		break;
    129 	case LINUX_PTRACE_GETREGS:
    130 	case LINUX_PTRACE_SETREGS:
    131 		regs = kmem_alloc(sizeof(struct reg), KM_SLEEP);
    132 		linux_regs = kmem_alloc(sizeof(*linux_regs), KM_SLEEP);
    133 		if (request == LINUX_PTRACE_SETREGS) {
    134 			error = copyin((void *)SCARG(uap, data), linux_regs,
    135 			    sizeof(struct linux_pt_regs));
    136 			if (error) {
    137 				goto out;
    138 			}
    139 		}
    140 		break;
    141 	case LINUX_PTRACE_GETFPREGS:
    142 	case LINUX_PTRACE_SETFPREGS:
    143 		fpregs = kmem_alloc(sizeof(struct fpreg), KM_SLEEP);
    144 		linux_fpreg = kmem_alloc(32 * sizeof(double), KM_SLEEP);
    145 		if (request == LINUX_PTRACE_SETFPREGS) {
    146 			error = copyin((void *)SCARG(uap, data), linux_fpreg,
    147 			    32 * sizeof(double));
    148 			if (error) {
    149 				goto out;
    150 			}
    151 		}
    152 		break;
    153 	default:
    154 		error = EIO;
    155 		goto out;
    156 	}
    157 
    158 	/* Find the process we are supposed to be operating on. */
    159 	mutex_enter(proc_lock);
    160 	if ((t = proc_find(SCARG(uap, pid))) == NULL) {
    161 		mutex_exit(proc_lock);
    162 		return ESRCH;
    163 	}
    164 	mutex_enter(t->p_lock);
    165 	mutex_exit(proc_lock);
    166 
    167 	/*
    168 	 * You cannot do what you want to the process if:
    169 	 * 1. It is not being traced at all,
    170 	 */
    171 	if (!ISSET(t->p_slflag, PSL_TRACED)) {
    172 		mutex_exit(t->p_lock);
    173 		error = EPERM;
    174 		goto out;
    175 	}
    176 	/*
    177 	 * 2. It is being traced by procfs (which has different signal
    178 	 *    delivery semantics),
    179 	 * 3. It is not being traced by _you_, or
    180 	 * 4. It is not currently stopped.
    181 	 */
    182 	if (ISSET(t->p_slflag, PSL_FSTRACE) || t->p_pptr != p ||
    183 	    t->p_stat != SSTOP || !t->p_waited) {
    184 		mutex_exit(t->p_lock);
    185 		error = EBUSY;
    186 		goto out;
    187 	}
    188 	/* XXX: ptrace needs revamp for multi-threading support. */
    189 	if (t->p_nlwps > 1) {
    190 		mutex_exit(t->p_lock);
    191 		error = ENOSYS;
    192 		goto out;
    193 	}
    194 	lt = LIST_FIRST(&t->p_lwps);
    195 	*retval = 0;
    196 
    197 	switch (request) {
    198 	case LINUX_PTRACE_GETREGS:
    199 		error = process_read_regs(lt, regs);
    200 		mutex_exit(t->p_lock);
    201 		if (error) {
    202 			break;
    203 		}
    204 		for (i = 0; i <= 31; i++) {
    205 			linux_regs->lgpr[i] = regs->fixreg[i];
    206 		}
    207 		linux_regs->lnip = regs->pc;
    208 		linux_regs->lmsr = 0;
    209 		/* XXX Is that right? */
    210 		linux_regs->lorig_gpr3 = regs->fixreg[3];
    211 		linux_regs->lctr = regs->ctr;
    212 		linux_regs->llink = regs->lr;
    213 		linux_regs->lxer = regs->xer;
    214 		linux_regs->lccr = regs->cr;
    215 		linux_regs->lmq = 0;
    216 		linux_regs->ltrap = 0;
    217 		linux_regs->ldar = 0;
    218 		linux_regs->ldsisr = 0;
    219 		linux_regs->lresult = 0;
    220 
    221 		error = copyout(linux_regs, (void *)SCARG(uap, data),
    222 		    sizeof(struct linux_pt_regs));
    223 		break;
    224 
    225 	case LINUX_PTRACE_SETREGS:
    226 		for (i = 0; i <= 31; i++) {
    227 			regs->fixreg[i] = linux_regs->lgpr[i];
    228 		}
    229 		regs->lr = linux_regs->llink;
    230 		regs->cr = linux_regs->lccr;
    231 		regs->xer = linux_regs->lxer;
    232 		regs->ctr = linux_regs->lctr;
    233 		regs->pc = linux_regs->lnip; /* XXX */
    234 
    235 		error = process_write_regs(lt, regs);
    236 		mutex_exit(t->p_lock);
    237 		break;
    238 
    239 	case LINUX_PTRACE_GETFPREGS:
    240 		error = process_read_fpregs(lt, fpregs, NULL);
    241 		mutex_exit(t->p_lock);
    242 		if (error) {
    243 			break;
    244 		}
    245 		/* Zero the contents if NetBSD fpreg structure is smaller */
    246 		if (sizeof(struct fpreg) < (32 * sizeof(double))) {
    247 			memset(linux_fpreg, '\0', (32 * sizeof(double)));
    248 		}
    249 		memcpy(linux_fpreg, fpregs,
    250 		    min(32 * sizeof(double), sizeof(struct fpreg)));
    251 		error = copyout(linux_fpreg, (void *)SCARG(uap, data),
    252 		    32 * sizeof(double));
    253 		break;
    254 
    255 	case LINUX_PTRACE_SETFPREGS:
    256 		memset(fpregs, '\0', sizeof(struct fpreg));
    257 		memcpy(fpregs, linux_fpreg,
    258 		    min(32 * sizeof(double), sizeof(struct fpreg)));
    259 		error = process_write_fpregs(lt, fpregs, sizeof fpregs);
    260 		mutex_exit(t->p_lock);
    261 		break;
    262 
    263 	case LINUX_PTRACE_PEEKUSR:
    264 		addr = SCARG(uap, addr);
    265 		error = process_read_regs(lt, regs);
    266 		mutex_exit(t->p_lock);
    267 		if (error) {
    268 			break;
    269 		}
    270 		error = 0;
    271 		if ((addr < LUSR_OFF(lusr_startgdb)) ||
    272 		    (addr > LUSR_OFF(lu_comm_end)))
    273 		 	error = 1;
    274 		else if (addr == LUSR_OFF(u_tsize))
    275 			*retval = p->p_vmspace->vm_tsize;
    276 		else if (addr == LUSR_OFF(u_dsize))
    277 			*retval = p->p_vmspace->vm_dsize;
    278 		else if (addr == LUSR_OFF(u_ssize))
    279 			*retval = p->p_vmspace->vm_ssize;
    280 		else if (addr == LUSR_OFF(start_code))
    281 			*retval = (register_t) p->p_vmspace->vm_taddr;
    282 		else if (addr == LUSR_OFF(start_stack))
    283 			*retval = (register_t) p->p_vmspace->vm_minsaddr;
    284 		else if ((addr >= LUSR_REG_OFF(lpt_regs_fixreg_begin)) &&
    285 		    (addr <= LUSR_REG_OFF(lpt_regs_fixreg_end)))
    286 			*retval = regs->fixreg[addr / sizeof (register_t)];
    287 		else if (addr == LUSR_REG_OFF(lnip))
    288 			*retval = regs->pc;
    289 		else if (addr == LUSR_REG_OFF(lctr))
    290 			*retval = regs->ctr;
    291 		else if (addr == LUSR_REG_OFF(llink))
    292 			*retval = regs->lr;
    293 		else if (addr == LUSR_REG_OFF(lxer))
    294 			*retval = regs->xer;
    295 		else if (addr == LUSR_REG_OFF(lccr))
    296 			*retval = regs->cr;
    297 		else if (addr == LUSR_OFF(signal))
    298 			error = 1;
    299 		else if (addr == LUSR_OFF(magic))
    300 			error = 1;
    301 		else if (addr == LUSR_OFF(u_comm))
    302 			error = 1;
    303 		else {
    304 #ifdef DEBUG_LINUX
    305 			printf("linux_ptrace: unsupported address: %d\n", addr);
    306 #endif
    307 			error = 1;
    308 		}
    309 		if (error) {
    310 			break;
    311 		}
    312 		error = copyout (retval, (void *)SCARG(uap, data),
    313 		    sizeof(retval));
    314 		*retval = SCARG(uap, data);
    315 		break;
    316 
    317 	case  LINUX_PTRACE_POKEUSR: /* XXX Not tested */
    318 		addr = SCARG(uap, addr);
    319 		error = process_read_regs(lt, regs);
    320 		if (error) {
    321 			mutex_exit(t->p_lock);
    322 			break;
    323 		}
    324 		error = 0;
    325 		if ((addr < LUSR_OFF(lusr_startgdb)) ||
    326 		    (addr > LUSR_OFF(lu_comm_end)))
    327 		 	error = 1;
    328 		else if (addr == LUSR_OFF(u_tsize))
    329 			error = 1;
    330 		else if (addr == LUSR_OFF(u_dsize))
    331 			error = 1;
    332 		else if (addr == LUSR_OFF(u_ssize))
    333 			error = 1;
    334 		else if (addr == LUSR_OFF(start_code))
    335 			error = 1;
    336 		else if (addr == LUSR_OFF(start_stack))
    337 			error = 1;
    338 		else if ((addr >= LUSR_REG_OFF(lpt_regs_fixreg_begin)) &&
    339 		    (addr <= LUSR_REG_OFF(lpt_regs_fixreg_end)))
    340 			regs->fixreg[addr / sizeof (register_t)] =
    341 			    (register_t)SCARG(uap, data);
    342 		else if (addr == LUSR_REG_OFF(lnip))
    343 			regs->pc = (register_t)SCARG(uap, data);
    344 		else if (addr == LUSR_REG_OFF(lctr))
    345 			regs->ctr = (register_t)SCARG(uap, data);
    346 		else if (addr == LUSR_REG_OFF(llink))
    347 			regs->lr = (register_t)SCARG(uap, data);
    348 		else if (addr == LUSR_REG_OFF(lxer))
    349 			regs->xer = (register_t)SCARG(uap, data);
    350 		else if (addr == LUSR_REG_OFF(lccr))
    351 			regs->cr = (register_t)SCARG(uap, data);
    352 		else if (addr == LUSR_OFF(signal))
    353 			error = 1;
    354 		else if (addr == LUSR_OFF(magic))
    355 			error = 1;
    356 		else if (addr == LUSR_OFF(u_comm))
    357 			error = 1;
    358 		else {
    359 #ifdef DEBUG_LINUX
    360 			printf("linux_ptrace: unsupported address: %d\n", addr);
    361 #endif
    362 			error = 1;
    363 		}
    364 		error = process_write_regs(lt,regs);
    365 		mutex_exit(t->p_lock);
    366 		break;
    367 	default:
    368 		mutex_exit(t->p_lock);
    369 		break;
    370 	}
    371 out:
    372 	if (regs)
    373 		kmem_free(regs, sizeof(*regs));
    374 	if (fpregs)
    375 		kmem_free(fpregs, sizeof(*fpregs));
    376 	if (linux_regs)
    377 		kmem_free(linux_regs, sizeof(*linux_regs));
    378 	if (linux_fpreg)
    379 		kmem_free(linux_fpreg, sizeof(*linux_fpreg));
    380 	return error;
    381 }
    382