arm-freebsd.c revision 286963
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: head/usr.bin/truss/arm-fbsd.c 286963 2015-08-20 14:51:11Z jhb $"); 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 = nitems(syscallnames); 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, "pdfork") == 0 || 176 strcmp(fsc->name, "rfork") == 0 || 177 strcmp(fsc->name, "vfork") == 0)) 178 trussinfo->curthread->in_fork = 1; 179 180 if (nargs == 0) 181 return; 182 183 fsc->args = malloc((1 + nargs) * sizeof(unsigned long)); 184 switch (nargs) { 185 default: 186 /* 187 * The OS doesn't seem to allow more than 10 words of 188 * parameters (yay!). So we shouldn't be here. 189 */ 190 warn("More than 10 words (%d) of arguments!\n", nargs); 191 break; 192 case 10: 193 case 9: 194 case 8: 195 case 7: 196 case 6: 197 case 5: 198 /* 199 * If there are 7-10 words of arguments, they are placed 200 * on the stack, as is normal for other processors. 201 * The fall-through for all of these is deliberate!!! 202 */ 203 // XXX BAD constant used here 204 iorequest.piod_op = PIOD_READ_D; 205 iorequest.piod_offs = (void *)(regs.r_sp + 206 4 * sizeof(uint32_t)); 207 iorequest.piod_addr = &fsc->args[4]; 208 iorequest.piod_len = (nargs - 4) * sizeof(fsc->args[0]); 209 ptrace(PT_IO, tid, (caddr_t)&iorequest, 0); 210 if (iorequest.piod_len == 0) 211 return; 212 case 4: fsc->args[3] = ap[3]; 213 case 3: fsc->args[2] = ap[2]; 214 case 2: fsc->args[1] = ap[1]; 215 case 1: fsc->args[0] = ap[0]; 216 case 0: break; 217 } 218 219 sc = NULL; 220 if (fsc->name) 221 sc = get_syscall(fsc->name); 222 if (sc) 223 fsc->nargs = sc->nargs; 224 else { 225#if DEBUG 226 fprintf(trussinfo->outfile, "unknown syscall %s -- setting " 227 "args to %d\n", fsc->name, nargs); 228#endif 229 fsc->nargs = nargs; 230 } 231 232 fsc->s_args = calloc(1, (1 + fsc->nargs) * sizeof(char *)); 233 fsc->sc = sc; 234 235 /* 236 * At this point, we set up the system call arguments. 237 * We ignore any OUT ones, however -- those are arguments that 238 * are set by the system call, and so are probably meaningless 239 * now. This doesn't currently support arguments that are 240 * passed in *and* out, however. 241 */ 242 243 if (fsc->name) { 244#if DEBUG 245 fprintf(stderr, "syscall %s(", fsc->name); 246#endif 247 for (i = 0; i < fsc->nargs; i++) { 248#if DEBUG 249 fprintf(stderr, "0x%x%s", sc ? 250 fsc->args[sc->args[i].offset] : fsc->args[i], 251 i < (fsc->nargs - 1) ? "," : ""); 252#endif 253 if (sc && !(sc->args[i].type & OUT)) { 254 fsc->s_args[i] = print_arg(&sc->args[i], 255 fsc->args, 0, trussinfo); 256 } 257 } 258#if DEBUG 259 fprintf(stderr, ")\n"); 260#endif 261 } 262 263#if DEBUG 264 fprintf(trussinfo->outfile, "\n"); 265#endif 266 267 trussinfo->curthread->fsc = fsc; 268} 269 270/* 271 * And when the system call is done, we handle it here. 272 * Currently, no attempt is made to ensure that the system calls 273 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 274 * the system call number instead of, say, an error status). 275 */ 276 277long 278arm_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 279{ 280 struct reg regs; 281 struct freebsd_syscall *fsc; 282 struct syscall *sc; 283 lwpid_t tid; 284 long retval; 285 int errorp, i; 286 287 if (trussinfo->curthread->fsc == NULL) 288 return (-1); 289 290 tid = trussinfo->curthread->tid; 291 292 if (ptrace(PT_GETREGS, tid, (caddr_t)®s, 0) < 0) { 293 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 294 return (-1); 295 } 296 297 retval = regs.r[0]; 298 errorp = !!(regs.r_cpsr & PSR_C); 299 300 /* 301 * This code, while simpler than the initial versions I used, could 302 * stand some significant cleaning. 303 */ 304 305 fsc = trussinfo->curthread->fsc; 306 sc = fsc->sc; 307 if (!sc) { 308 for (i = 0; i < fsc->nargs; i++) 309 asprintf(&fsc->s_args[i], "0x%lx", fsc->args[i]); 310 } else { 311 /* 312 * Here, we only look for arguments that have OUT masked in -- 313 * otherwise, they were handled in the syscall_entry function. 314 */ 315 for (i = 0; i < sc->nargs; i++) { 316 char *temp; 317 318 if (sc->args[i].type & OUT) { 319 /* 320 * If an error occurred, then don't bother 321 * getting the data; it may not be valid. 322 */ 323 if (errorp) { 324 asprintf(&temp, "0x%lx", 325 fsc->args[sc->args[i].offset]); 326 } else { 327 temp = print_arg(&sc->args[i], 328 fsc->args, retval, trussinfo); 329 } 330 fsc->s_args[i] = temp; 331 } 332 } 333 } 334 335 if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 || 336 strcmp(fsc->name, "exit") == 0)) 337 trussinfo->curthread->in_syscall = 1; 338 339 /* 340 * It would probably be a good idea to merge the error handling, 341 * but that complicates things considerably. 342 */ 343 344 print_syscall_ret(trussinfo, fsc->name, fsc->nargs, fsc->s_args, errorp, 345 retval, fsc->sc); 346 free_fsc(fsc); 347 348 return (retval); 349} 350