amd64-fbsd.c revision 286789
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#ifndef lint 33static const char rcsid[] = 34 "$FreeBSD: stable/10/usr.bin/truss/amd64-fbsd.c 286789 2015-08-14 21:44:42Z emaste $"; 35#endif /* not lint */ 36 37/* 38 * FreeBSD/amd64-specific system call handling. This is probably the most 39 * complex part of the entire truss program, although I've got lots of 40 * it handled relatively cleanly now. The system call names are generated 41 * automatically, thanks to /usr/src/sys/kern/syscalls.master. The 42 * names used for the various structures are confusing, I sadly admit. 43 */ 44 45#include <sys/types.h> 46#include <sys/ptrace.h> 47#include <sys/syscall.h> 48 49#include <machine/reg.h> 50#include <machine/psl.h> 51 52#include <errno.h> 53#include <fcntl.h> 54#include <signal.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#include <time.h> 59#include <unistd.h> 60 61#include "truss.h" 62#include "syscall.h" 63#include "extern.h" 64 65#include "syscalls.h" 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 amd64/amd64/trap.c 113 * is ever changed these functions need to keep up. 114 */ 115 116void 117amd64_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, reg, syscall_num; 125 126 tid = trussinfo->curthread->tid; 127 128 if (ptrace(PT_GETREGS, tid, (caddr_t)®s, 0) < 0) { 129 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 130 return; 131 } 132 133 /* 134 * FreeBSD has two special kinds of system call redirctions -- 135 * SYS_syscall, and SYS___syscall. The former is the old syscall() 136 * routine, basically; the latter is for quad-aligned arguments. 137 */ 138 reg = 0; 139 syscall_num = regs.r_rax; 140 switch (syscall_num) { 141 case SYS_syscall: 142 case SYS___syscall: 143 syscall_num = regs.r_rdi; 144 reg++; 145 break; 146 } 147 148 fsc = alloc_fsc(); 149 if (fsc == NULL) 150 return; 151 fsc->number = syscall_num; 152 fsc->name = (syscall_num < 0 || syscall_num >= nsyscalls) ? 153 NULL : syscallnames[syscall_num]; 154 if (!fsc->name) { 155 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", 156 syscall_num); 157 } 158 159 if (fsc->name && (trussinfo->flags & FOLLOWFORKS) && 160 (strcmp(fsc->name, "fork") == 0 || 161 strcmp(fsc->name, "pdfork") == 0 || 162 strcmp(fsc->name, "rfork") == 0 || 163 strcmp(fsc->name, "vfork") == 0)) 164 trussinfo->curthread->in_fork = 1; 165 166 if (nargs == 0) 167 return; 168 169 fsc->args = malloc((1 + nargs) * sizeof(unsigned long)); 170 for (i = 0; i < nargs && reg < 6; i++, reg++) { 171 switch (reg) { 172 case 0: fsc->args[i] = regs.r_rdi; break; 173 case 1: fsc->args[i] = regs.r_rsi; break; 174 case 2: fsc->args[i] = regs.r_rdx; break; 175 case 3: fsc->args[i] = regs.r_rcx; break; 176 case 4: fsc->args[i] = regs.r_r8; break; 177 case 5: fsc->args[i] = regs.r_r9; break; 178 } 179 } 180 if (nargs > i) { 181 iorequest.piod_op = PIOD_READ_D; 182 iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t)); 183 iorequest.piod_addr = &fsc->args[i]; 184 iorequest.piod_len = (nargs - i) * sizeof(register_t); 185 ptrace(PT_IO, tid, (caddr_t)&iorequest, 0); 186 if (iorequest.piod_len == 0) 187 return; 188 } 189 190 sc = get_syscall(fsc->name); 191 if (sc) 192 fsc->nargs = sc->nargs; 193 else { 194#if DEBUG 195 fprintf(trussinfo->outfile, "unknown syscall %s -- setting " 196 "args to %d\n", fsc->name, nargs); 197#endif 198 fsc->nargs = nargs; 199 } 200 201 fsc->s_args = calloc(1, (1 + fsc->nargs) * sizeof(char *)); 202 fsc->sc = sc; 203 204 /* 205 * At this point, we set up the system call arguments. 206 * We ignore any OUT ones, however -- those are arguments that 207 * are set by the system call, and so are probably meaningless 208 * now. This doesn't currently support arguments that are 209 * passed in *and* out, however. 210 */ 211 212 if (fsc->name) { 213#if DEBUG 214 fprintf(stderr, "syscall %s(", fsc->name); 215#endif 216 for (i = 0; i < fsc->nargs; i++) { 217#if DEBUG 218 fprintf(stderr, "0x%lx%s", sc ? 219 fsc->args[sc->args[i].offset] : fsc->args[i], 220 i < (fsc->nargs - 1) ? "," : ""); 221#endif 222 if (sc && !(sc->args[i].type & OUT)) { 223 fsc->s_args[i] = print_arg(&sc->args[i], 224 fsc->args, 0, trussinfo); 225 } 226 } 227#if DEBUG 228 fprintf(stderr, ")\n"); 229#endif 230 } 231 232#if DEBUG 233 fprintf(trussinfo->outfile, "\n"); 234#endif 235 236 if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 || 237 strcmp(fsc->name, "exit") == 0)) { 238 /* 239 * XXX 240 * This could be done in a more general 241 * manner but it still wouldn't be very pretty. 242 */ 243 if (strcmp(fsc->name, "execve") == 0) { 244 if ((trussinfo->flags & EXECVEARGS) == 0) { 245 if (fsc->s_args[1]) { 246 free(fsc->s_args[1]); 247 fsc->s_args[1] = NULL; 248 } 249 } 250 if ((trussinfo->flags & EXECVEENVS) == 0) { 251 if (fsc->s_args[2]) { 252 free(fsc->s_args[2]); 253 fsc->s_args[2] = NULL; 254 } 255 } 256 } 257 } 258 trussinfo->curthread->fsc = fsc; 259} 260 261/* 262 * And when the system call is done, we handle it here. 263 * Currently, no attempt is made to ensure that the system calls 264 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 265 * the system call number instead of, say, an error status). 266 */ 267 268long 269amd64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 270{ 271 struct reg regs; 272 struct freebsd_syscall *fsc; 273 struct syscall *sc; 274 lwpid_t tid; 275 long retval; 276 int errorp, i; 277 278 if (trussinfo->curthread->fsc == NULL) 279 return (-1); 280 281 tid = trussinfo->curthread->tid; 282 283 if (ptrace(PT_GETREGS, tid, (caddr_t)®s, 0) < 0) { 284 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 285 return (-1); 286 } 287 288 retval = regs.r_rax; 289 errorp = !!(regs.r_rflags & PSL_C); 290 291 /* 292 * This code, while simpler than the initial versions I used, could 293 * stand some significant cleaning. 294 */ 295 296 fsc = trussinfo->curthread->fsc; 297 sc = fsc->sc; 298 if (!sc) { 299 for (i = 0; i < fsc->nargs; i++) 300 asprintf(&fsc->s_args[i], "0x%lx", fsc->args[i]); 301 } else { 302 /* 303 * Here, we only look for arguments that have OUT masked in -- 304 * otherwise, they were handled in the syscall_entry function. 305 */ 306 for (i = 0; i < sc->nargs; i++) { 307 char *temp; 308 if (sc->args[i].type & OUT) { 309 /* 310 * If an error occurred, then don't bother 311 * getting the data; it may not be valid. 312 */ 313 if (errorp) { 314 asprintf(&temp, "0x%lx", 315 fsc->args[sc->args[i].offset]); 316 } else { 317 temp = print_arg(&sc->args[i], 318 fsc->args, retval, trussinfo); 319 } 320 fsc->s_args[i] = temp; 321 } 322 } 323 } 324 325 if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 || 326 strcmp(fsc->name, "exit") == 0)) 327 trussinfo->curthread->in_syscall = 1; 328 329 /* 330 * It would probably be a good idea to merge the error handling, 331 * but that complicates things considerably. 332 */ 333 334 print_syscall_ret(trussinfo, fsc->name, fsc->nargs, fsc->s_args, errorp, 335 retval, fsc->sc); 336 free_fsc(fsc); 337 338 return (retval); 339} 340