1 /* $NetBSD: linux_ptrace.c,v 1.30 2014/11/09 17:48:07 maxv Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 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. 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 1.30 2014/11/09 17:48:07 maxv Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/mount.h> 37 #include <sys/proc.h> 38 #include <sys/ptrace.h> 39 #include <sys/systm.h> 40 #include <sys/syscall.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 struct linux_reg { 60 long ebx; 61 long ecx; 62 long edx; 63 long esi; 64 long edi; 65 long ebp; 66 long eax; 67 long xds, xes; /* unsigned short ds, __ds, es, __es; */ 68 long __fs, __gs; /* unsigned short fs, __fs, gs, __gs; */ 69 long orig_eax; 70 long eip; 71 long xcs; /* unsigned short cs, __cs; */ 72 long eflags; 73 long esp; 74 long xss; /* unsigned short ss, __ss; */ 75 }; 76 77 /* structure used for storing floating point context */ 78 struct linux_fpctx { 79 long cwd; 80 long swd; 81 long twd; 82 long fip; 83 long fcs; 84 long foo; 85 long fos; 86 long st_space[20]; 87 }; 88 89 /* user struct for linux process - this is used for Linux ptrace emulation */ 90 /* most of it is junk only used by gdb */ 91 struct linux_user { 92 struct linux_reg regs; /* registers */ 93 int u_fpvalid; /* true if math co-processor being used. */ 94 struct linux_fpctx i387; /* Math Co-processor registers. */ 95 /* The rest of this junk is to help gdb figure out what goes where */ 96 #define lusr_startgdb u_tsize 97 unsigned long int u_tsize; /* Text segment size (pages). */ 98 unsigned long int u_dsize; /* Data segment size (pages). */ 99 unsigned long int u_ssize; /* Stack segment size (pages). */ 100 unsigned long start_code; /* Starting virtual address of text. */ 101 unsigned long start_stack; /* Starting virtual address of stack 102 area. This is actually the bottom of 103 the stack, the top of the stack is 104 always found in the esp register. */ 105 long int __signal; /* Signal that caused the core dump. */ 106 int __reserved; /* unused */ 107 void *u_ar0; /* Used by gdb to help find the values 108 for the registers. */ 109 struct linux_fpctx *u_fpstate; /* Math Co-processor pointer. */ 110 unsigned long __magic; /* To uniquely identify a core file */ 111 char u_comm[32]; /* User command that was responsible */ 112 int u_debugreg[8]; 113 #define u_debugreg_end u_debugreg[7] 114 }; 115 116 #define LUSR_OFF(member) offsetof(struct linux_user, member) 117 #define ISSET(t, f) ((t) & (f)) 118 119 int linux_ptrace_disabled = 1; /* bitrotted */ 120 121 int 122 linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap, 123 register_t *retval) 124 { 125 /* { 126 syscallarg(int) request; 127 syscallarg(int) pid; 128 syscallarg(int) addr; 129 syscallarg(int) data; 130 } */ 131 struct proc *p = l->l_proc, *t; 132 struct lwp *lt; 133 struct reg *regs = NULL; 134 struct fpreg *fpregs = NULL; 135 struct linux_reg *linux_regs = NULL; 136 struct linux_fpctx *linux_fpregs = NULL; 137 struct linux_emuldata *led; 138 int request, error, addr; 139 size_t fp_size; 140 141 if (linux_ptrace_disabled) 142 return ENOSYS; 143 144 error = 0; 145 request = SCARG(uap, request); 146 147 switch (request) { 148 case LINUX_PTRACE_PEEKUSR: 149 case LINUX_PTRACE_POKEUSR: 150 break; 151 case LINUX_PTRACE_GETREGS: 152 case LINUX_PTRACE_SETREGS: 153 regs = kmem_alloc(sizeof(struct reg), KM_SLEEP); 154 linux_regs = kmem_alloc(sizeof(struct linux_reg), KM_SLEEP); 155 if (request == LINUX_PTRACE_SETREGS) { 156 error = copyin((void *)SCARG(uap, data), linux_regs, 157 sizeof(struct linux_reg)); 158 if (error) { 159 goto out; 160 } 161 } 162 break; 163 case LINUX_PTRACE_GETFPREGS: 164 case LINUX_PTRACE_SETFPREGS: 165 fpregs = kmem_alloc(sizeof(struct fpreg), KM_SLEEP); 166 linux_fpregs = kmem_alloc(sizeof(struct linux_fpctx), KM_SLEEP); 167 if (request == LINUX_PTRACE_SETFPREGS) { 168 error = copyin((void *)SCARG(uap, data), linux_fpregs, 169 sizeof(struct linux_fpctx)); 170 if (error) { 171 goto out; 172 } 173 } 174 break; 175 default: 176 error = EIO; 177 goto out; 178 } 179 180 /* Find the process we are supposed to be operating on. */ 181 mutex_enter(proc_lock); 182 if ((t = proc_find(SCARG(uap, pid))) == NULL) { 183 mutex_exit(proc_lock); 184 error = ESRCH; 185 goto out; 186 } 187 mutex_enter(t->p_lock); 188 mutex_exit(proc_lock); 189 190 /* 191 * You cannot do what you want to the process if: 192 * 1. It is not being traced at all, 193 */ 194 if (!ISSET(t->p_slflag, PSL_TRACED)) { 195 mutex_exit(t->p_lock); 196 error = EPERM; 197 goto out; 198 } 199 /* 200 * 2. It is being traced by procfs (which has different signal 201 * delivery semantics), 202 * 3. It is not being traced by _you_, or 203 * 4. It is not currently stopped. 204 */ 205 if (ISSET(t->p_slflag, PSL_FSTRACE) || t->p_pptr != p || 206 t->p_stat != SSTOP || !t->p_waited) { 207 mutex_exit(t->p_lock); 208 error = EBUSY; 209 goto out; 210 } 211 /* XXX: ptrace needs revamp for multi-threading support. */ 212 if (t->p_nlwps > 1) { 213 mutex_exit(t->p_lock); 214 error = ENOSYS; 215 goto out; 216 } 217 lt = LIST_FIRST(&t->p_lwps); 218 *retval = 0; 219 220 switch (request) { 221 case LINUX_PTRACE_GETREGS: 222 error = process_read_regs(lt, regs); 223 mutex_exit(t->p_lock); 224 if (error) { 225 break; 226 } 227 linux_regs->ebx = regs->r_ebx; 228 linux_regs->ecx = regs->r_ecx; 229 linux_regs->edx = regs->r_edx; 230 linux_regs->esi = regs->r_esi; 231 linux_regs->edi = regs->r_edi; 232 linux_regs->ebp = regs->r_ebp; 233 linux_regs->eax = regs->r_eax; 234 linux_regs->xds = regs->r_ds; 235 linux_regs->xes = regs->r_es; 236 linux_regs->orig_eax = regs->r_eax; /* XXX is this correct? */ 237 linux_regs->eip = regs->r_cs + regs->r_eip; 238 linux_regs->xcs = regs->r_cs; 239 linux_regs->eflags = regs->r_eflags; 240 linux_regs->esp = regs->r_esp; 241 linux_regs->xss = regs->r_ss; 242 243 error = copyout(linux_regs, (void *)SCARG(uap, data), 244 sizeof(struct linux_reg)); 245 break; 246 247 case LINUX_PTRACE_SETREGS: 248 regs->r_ebx = linux_regs->ebx; 249 regs->r_ecx = linux_regs->ecx; 250 regs->r_edx = linux_regs->edx; 251 regs->r_esi = linux_regs->esi; 252 regs->r_edi = linux_regs->edi; 253 regs->r_ebp = linux_regs->ebp; 254 regs->r_eax = linux_regs->eax; 255 regs->r_ds = linux_regs->xds; 256 regs->r_es = linux_regs->xes; 257 regs->r_eip = linux_regs->eip - linux_regs->xcs; 258 regs->r_cs = linux_regs->xcs; 259 regs->r_eflags = linux_regs->eflags; 260 regs->r_esp = linux_regs->esp; 261 regs->r_ss = linux_regs->xss; 262 263 error = process_write_regs(lt, regs); 264 mutex_exit(t->p_lock); 265 break; 266 267 case LINUX_PTRACE_GETFPREGS: 268 fp_size = sizeof fpregs; 269 error = process_read_fpregs(lt, fpregs, &fp_size); 270 mutex_exit(t->p_lock); 271 if (error) { 272 break; 273 } 274 /* Zero the contents if NetBSD fpreg structure is smaller */ 275 if (fp_size < sizeof(struct linux_fpctx)) { 276 memset(linux_fpregs, '\0', sizeof(struct linux_fpctx)); 277 } 278 memcpy(linux_fpregs, fpregs, 279 min(sizeof(struct linux_fpctx), fp_size)); 280 error = copyout(linux_fpregs, (void *)SCARG(uap, data), 281 sizeof(struct linux_fpctx)); 282 break; 283 284 case LINUX_PTRACE_SETFPREGS: 285 memset(fpregs, '\0', sizeof(struct fpreg)); 286 memcpy(fpregs, linux_fpregs, 287 min(sizeof(struct linux_fpctx), sizeof(struct fpreg))); 288 error = process_write_regs(lt, regs); 289 mutex_exit(t->p_lock); 290 break; 291 292 case LINUX_PTRACE_PEEKUSR: 293 /* XXX locking */ 294 addr = SCARG(uap, addr); 295 296 error = 0; 297 if (addr < LUSR_OFF(lusr_startgdb)) { 298 /* XXX should provide appropriate register */ 299 error = ENOTSUP; 300 } else if (addr == LUSR_OFF(u_tsize)) 301 *retval = p->p_vmspace->vm_tsize; 302 else if (addr == LUSR_OFF(u_dsize)) 303 *retval = p->p_vmspace->vm_dsize; 304 else if (addr == LUSR_OFF(u_ssize)) 305 *retval = p->p_vmspace->vm_ssize; 306 else if (addr == LUSR_OFF(start_code)) 307 *retval = (register_t) p->p_vmspace->vm_taddr; 308 else if (addr == LUSR_OFF(start_stack)) 309 *retval = (register_t) p->p_vmspace->vm_minsaddr; 310 else if (addr == LUSR_OFF(u_ar0)) 311 *retval = LUSR_OFF(regs); 312 else if (addr >= LUSR_OFF(u_debugreg) 313 && addr <= LUSR_OFF(u_debugreg_end)) { 314 int off = (addr - LUSR_OFF(u_debugreg)) / sizeof(int); 315 316 /* only do this for Linux processes */ 317 if (t->p_emul != &emul_linux) { 318 mutex_exit(t->p_lock); 319 return EINVAL; 320 } 321 322 led = lt->l_emuldata; 323 *retval = led->led_debugreg[off]; 324 } else if (addr == LUSR_OFF(__signal)) { 325 error = ENOTSUP; 326 } else if (addr == LUSR_OFF(u_fpstate)) { 327 error = ENOTSUP; 328 } else if (addr == LUSR_OFF(__magic)) { 329 error = ENOTSUP; 330 } else if (addr == LUSR_OFF(u_comm)) { 331 error = ENOTSUP; 332 } else { 333 #ifdef DEBUG_LINUX 334 printf("linux_ptrace: unsupported address: %d\n", addr); 335 #endif 336 error = ENOTSUP; 337 } 338 mutex_exit(t->p_lock); 339 break; 340 341 case LINUX_PTRACE_POKEUSR: 342 /* we only support setting debugregs for now */ 343 addr = SCARG(uap, addr); 344 if (addr >= LUSR_OFF(u_debugreg) && 345 addr <= LUSR_OFF(u_debugreg_end)) { 346 int off = (addr - LUSR_OFF(u_debugreg)) / sizeof(int); 347 int data = SCARG(uap, data); 348 349 /* only do this for Linux processes */ 350 if (t->p_emul != &emul_linux) { 351 mutex_exit(t->p_lock); 352 return EINVAL; 353 } 354 led = lt->l_emuldata; 355 led->led_debugreg[off] = data; 356 } 357 mutex_exit(t->p_lock); 358 break; 359 360 default: 361 mutex_exit(t->p_lock); 362 break; 363 } 364 out: 365 if (regs) 366 kmem_free(regs, sizeof(*regs)); 367 if (linux_regs) 368 kmem_free(linux_regs, sizeof(*linux_regs)); 369 if (fpregs) 370 kmem_free(fpregs, sizeof(*fpregs)); 371 if (linux_fpregs) 372 kmem_free(linux_fpregs, sizeof(*linux_fpregs)); 373 374 return error; 375 } 376