arm-fbsd.c revision 278613
1/* 2 * Copyright 1997 Sean Eric Fagan 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. All advertising materials mentioning features or use of this software 13 * must display the following acknowledgement: 14 * This product includes software developed by Sean Eric Fagan 15 * 4. Neither the name of the author may be used to endorse or promote 16 * products derived from this software without specific prior written 17 * permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32/* 33 * FreeBSD/arm-specific system call handling. This is probably the most 34 * complex part of the entire truss program, although I've got lots of 35 * it handled relatively cleanly now. The system call names are generated 36 * automatically, thanks to /usr/src/sys/kern/syscalls.master. The 37 * names used for the various structures are confusing, I sadly admit. 38 */ 39 40#include <sys/cdefs.h> 41__FBSDID("$FreeBSD: stable/10/usr.bin/truss/arm-fbsd.c 278613 2015-02-12 03:50:33Z ian $"); 42#include <sys/types.h> 43#include <sys/ptrace.h> 44#include <sys/syscall.h> 45 46#include <machine/reg.h> 47#include <machine/armreg.h> 48#include <machine/ucontext.h> 49 50#include <errno.h> 51#include <fcntl.h> 52#include <signal.h> 53#include <stdio.h> 54#include <stdlib.h> 55#include <string.h> 56#include <time.h> 57#include <unistd.h> 58#include <err.h> 59 60#include "truss.h" 61#include "syscall.h" 62#include "extern.h" 63 64#include "syscalls.h" 65 66 67static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); 68 69/* 70 * This is what this particular file uses to keep track of a system call. 71 * It is probably not quite sufficient -- I can probably use the same 72 * structure for the various syscall personalities, and I also probably 73 * need to nest system calls (for signal handlers). 74 * 75 * 'struct syscall' describes the system call; it may be NULL, however, 76 * if we don't know about this particular system call yet. 77 */ 78struct freebsd_syscall { 79 struct syscall *sc; 80 const char *name; 81 int number; 82 unsigned long *args; 83 int nargs; /* number of arguments -- *not* number of words! */ 84 char **s_args; /* the printable arguments */ 85}; 86 87static struct freebsd_syscall * 88alloc_fsc(void) 89{ 90 91 return (malloc(sizeof(struct freebsd_syscall))); 92} 93 94/* Clear up and free parts of the fsc structure. */ 95static void 96free_fsc(struct freebsd_syscall *fsc) 97{ 98 int i; 99 100 free(fsc->args); 101 if (fsc->s_args) { 102 for (i = 0; i < fsc->nargs; i++) 103 free(fsc->s_args[i]); 104 free(fsc->s_args); 105 } 106 free(fsc); 107} 108 109/* 110 * Called when a process has entered a system call. nargs is the 111 * number of words, not number of arguments (a necessary distinction 112 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 113 * is ever changed these functions need to keep up. 114 */ 115 116void 117arm_syscall_entry(struct trussinfo *trussinfo, int nargs) 118{ 119 struct ptrace_io_desc iorequest; 120 struct reg regs; 121 struct freebsd_syscall *fsc; 122 struct syscall *sc; 123 lwpid_t tid; 124 int i, syscall_num; 125 register_t *ap; 126 127 tid = trussinfo->curthread->tid; 128 129 if (ptrace(PT_GETREGS, tid, (caddr_t)®s, 0) < 0) { 130 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 131 return; 132 } 133 ap = ®s.r[0]; 134 135 /* 136 * FreeBSD has two special kinds of system call redirctions -- 137 * SYS_syscall, and SYS___syscall. The former is the old syscall() 138 * routine, basically; the latter is for quad-aligned arguments. 139 */ 140#ifdef __ARM_EABI__ 141 syscall_num = regs.r[7]; 142#else 143 if ((syscall_num = ptrace(PT_READ_I, tid, 144 (caddr_t)(regs.r[_REG_PC] - INSN_SIZE), 0)) == -1) { 145 fprintf(trussinfo->outfile, "-- CANNOT READ PC --\n"); 146 return; 147 } 148 syscall_num = syscall_num & 0x000fffff; 149#endif 150 switch (syscall_num) { 151 case SYS_syscall: 152 syscall_num = *ap++; 153 nargs--; 154 break; 155 case SYS___syscall: 156 syscall_num = ap[_QUAD_LOWWORD]; 157 ap += 2; 158 nargs -= 2; 159 break; 160 } 161 162 fsc = alloc_fsc(); 163 if (fsc == NULL) 164 return; 165 fsc->number = syscall_num; 166 fsc->name = (syscall_num < 0 || syscall_num >= nsyscalls) ? 167 NULL : syscallnames[syscall_num]; 168 if (!fsc->name) { 169 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", 170 syscall_num); 171 } 172 173 if (fsc->name && (trussinfo->flags & FOLLOWFORKS) && 174 (strcmp(fsc->name, "fork") == 0 || 175 strcmp(fsc->name, "rfork") == 0 || 176 strcmp(fsc->name, "vfork") == 0)) 177 trussinfo->curthread->in_fork = 1; 178 179 if (nargs == 0) 180 return; 181 182 fsc->args = malloc((1 + nargs) * sizeof(unsigned long)); 183 switch (nargs) { 184 default: 185 /* 186 * The OS doesn't seem to allow more than 10 words of 187 * parameters (yay!). So we shouldn't be here. 188 */ 189 warn("More than 10 words (%d) of arguments!\n", nargs); 190 break; 191 case 10: 192 case 9: 193 case 8: 194 case 7: 195 case 6: 196 case 5: 197 /* 198 * If there are 7-10 words of arguments, they are placed 199 * on the stack, as is normal for other processors. 200 * The fall-through for all of these is deliberate!!! 201 */ 202 // XXX BAD constant used here 203 iorequest.piod_op = PIOD_READ_D; 204 iorequest.piod_offs = (void *)(regs.r[_REG_SP] + 205 4 * sizeof(uint32_t)); 206 iorequest.piod_addr = &fsc->args[4]; 207 iorequest.piod_len = (nargs - 4) * sizeof(fsc->args[0]); 208 ptrace(PT_IO, tid, (caddr_t)&iorequest, 0); 209 if (iorequest.piod_len == 0) 210 return; 211 case 4: fsc->args[3] = ap[3]; 212 case 3: fsc->args[2] = ap[2]; 213 case 2: fsc->args[1] = ap[1]; 214 case 1: fsc->args[0] = ap[0]; 215 case 0: break; 216 } 217 218 sc = NULL; 219 if (fsc->name) 220 sc = get_syscall(fsc->name); 221 if (sc) 222 fsc->nargs = sc->nargs; 223 else { 224#if DEBUG 225 fprintf(trussinfo->outfile, "unknown syscall %s -- setting " 226 "args to %d\n", fsc->name, nargs); 227#endif 228 fsc->nargs = nargs; 229 } 230 231 fsc->s_args = calloc(1, (1 + fsc->nargs) * sizeof(char *)); 232 fsc->sc = sc; 233 234 /* 235 * At this point, we set up the system call arguments. 236 * We ignore any OUT ones, however -- those are arguments that 237 * are set by the system call, and so are probably meaningless 238 * now. This doesn't currently support arguments that are 239 * passed in *and* out, however. 240 */ 241 242 if (fsc->name) { 243#if DEBUG 244 fprintf(stderr, "syscall %s(", fsc->name); 245#endif 246 for (i = 0; i < fsc->nargs; i++) { 247#if DEBUG 248 fprintf(stderr, "0x%x%s", sc ? 249 fsc->args[sc->args[i].offset] : fsc->args[i], 250 i < (fsc->nargs - 1) ? "," : ""); 251#endif 252 if (sc && !(sc->args[i].type & OUT)) { 253 fsc->s_args[i] = print_arg(&sc->args[i], 254 fsc->args, 0, trussinfo); 255 } 256 } 257#if DEBUG 258 fprintf(stderr, ")\n"); 259#endif 260 } 261 262#if DEBUG 263 fprintf(trussinfo->outfile, "\n"); 264#endif 265 266 if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 || 267 strcmp(fsc->name, "exit") == 0)) { 268 /* 269 * XXX 270 * This could be done in a more general 271 * manner but it still wouldn't be very pretty. 272 */ 273 if (strcmp(fsc->name, "execve") == 0) { 274 if ((trussinfo->flags & EXECVEARGS) == 0) { 275 if (fsc->s_args[1]) { 276 free(fsc->s_args[1]); 277 fsc->s_args[1] = NULL; 278 } 279 } 280 if ((trussinfo->flags & EXECVEENVS) == 0) { 281 if (fsc->s_args[2]) { 282 free(fsc->s_args[2]); 283 fsc->s_args[2] = NULL; 284 } 285 } 286 } 287 } 288 trussinfo->curthread->fsc = fsc; 289} 290 291/* 292 * And when the system call is done, we handle it here. 293 * Currently, no attempt is made to ensure that the system calls 294 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 295 * the system call number instead of, say, an error status). 296 */ 297 298long 299arm_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 300{ 301 struct reg regs; 302 struct freebsd_syscall *fsc; 303 struct syscall *sc; 304 lwpid_t tid; 305 long retval; 306 int errorp, i; 307 308 if (trussinfo->curthread->fsc == NULL) 309 return (-1); 310 311 tid = trussinfo->curthread->tid; 312 313 if (ptrace(PT_GETREGS, tid, (caddr_t)®s, 0) < 0) { 314 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 315 return (-1); 316 } 317 318 retval = regs.r[0]; 319 errorp = !!(regs.r_cpsr & PSR_C); 320 321 /* 322 * This code, while simpler than the initial versions I used, could 323 * stand some significant cleaning. 324 */ 325 326 fsc = trussinfo->curthread->fsc; 327 sc = fsc->sc; 328 if (!sc) { 329 for (i = 0; i < fsc->nargs; i++) 330 asprintf(&fsc->s_args[i], "0x%lx", fsc->args[i]); 331 } else { 332 /* 333 * Here, we only look for arguments that have OUT masked in -- 334 * otherwise, they were handled in the syscall_entry function. 335 */ 336 for (i = 0; i < sc->nargs; i++) { 337 char *temp; 338 if (sc->args[i].type & OUT) { 339 /* 340 * If an error occurred, then don't bother 341 * getting the data; it may not be valid. 342 */ 343 if (errorp) { 344 asprintf(&temp, "0x%lx", 345 fsc->args[sc->args[i].offset]); 346 } else { 347 temp = print_arg(&sc->args[i], 348 fsc->args, retval, trussinfo); 349 } 350 fsc->s_args[i] = temp; 351 } 352 } 353 } 354 355 if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 || 356 strcmp(fsc->name, "exit") == 0)) 357 trussinfo->curthread->in_syscall = 1; 358 359 /* 360 * It would probably be a good idea to merge the error handling, 361 * but that complicates things considerably. 362 */ 363 364 print_syscall_ret(trussinfo, fsc->name, fsc->nargs, fsc->s_args, errorp, 365 retval, fsc->sc); 366 free_fsc(fsc); 367 368 return (retval); 369} 370