i386-fbsd.c revision 158630
1/* 2 * Copryight 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: head/usr.bin/truss/i386-fbsd.c 158630 2006-05-15 21:18:28Z pav $"; 35#endif /* not lint */ 36 37/* 38 * FreeBSD/i386-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/ioctl.h> 47#include <sys/pioctl.h> 48#include <sys/syscall.h> 49 50#include <machine/reg.h> 51#include <machine/psl.h> 52 53#include <errno.h> 54#include <fcntl.h> 55#include <signal.h> 56#include <stdio.h> 57#include <stdlib.h> 58#include <string.h> 59#include <time.h> 60#include <unistd.h> 61 62#include "truss.h" 63#include "syscall.h" 64#include "extern.h" 65 66static int fd = -1; 67static int cpid = -1; 68 69#include "syscalls.h" 70 71static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); 72 73/* 74 * This is what this particular file uses to keep track of a system call. 75 * It is probably not quite sufficient -- I can probably use the same 76 * structure for the various syscall personalities, and I also probably 77 * need to nest system calls (for signal handlers). 78 * 79 * 'struct syscall' describes the system call; it may be NULL, however, 80 * if we don't know about this particular system call yet. 81 */ 82static struct freebsd_syscall { 83 struct syscall *sc; 84 const char *name; 85 int number; 86 unsigned long *args; 87 int nargs; /* number of arguments -- *not* number of words! */ 88 char **s_args; /* the printable arguments */ 89} fsc; 90 91/* Clear up and free parts of the fsc structure. */ 92static __inline void 93clear_fsc(void) { 94 if (fsc.args) { 95 free(fsc.args); 96 } 97 if (fsc.s_args) { 98 int i; 99 for (i = 0; i < fsc.nargs; i++) 100 if (fsc.s_args[i]) 101 free(fsc.s_args[i]); 102 free(fsc.s_args); 103 } 104 memset(&fsc, 0, sizeof(fsc)); 105} 106 107/* 108 * Called when a process has entered a system call. nargs is the 109 * number of words, not number of arguments (a necessary distinction 110 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 111 * is ever changed these functions need to keep up. 112 */ 113 114void 115i386_syscall_entry(struct trussinfo *trussinfo, int nargs) { 116 char buf[32]; 117 struct reg regs; 118 int syscall_num; 119 int i; 120 unsigned int parm_offset; 121 struct syscall *sc; 122 123 if (fd == -1 || trussinfo->pid != cpid) { 124 sprintf(buf, "/proc/%d/regs", trussinfo->pid); 125 fd = open(buf, O_RDWR); 126 if (fd == -1) { 127 fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n"); 128 return; 129 } 130 cpid = trussinfo->pid; 131 } 132 133 clear_fsc(); 134 lseek(fd, 0L, 0); 135 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) { 136 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 137 return; 138 } 139 parm_offset = regs.r_esp + sizeof(int); 140 141 /* 142 * FreeBSD has two special kinds of system call redirctions -- 143 * SYS_syscall, and SYS___syscall. The former is the old syscall() 144 * routine, basicly; the latter is for quad-aligned arguments. 145 */ 146 syscall_num = regs.r_eax; 147 switch (syscall_num) { 148 case SYS_syscall: 149 lseek(Procfd, parm_offset, SEEK_SET); 150 read(Procfd, &syscall_num, sizeof(int)); 151 parm_offset += sizeof(int); 152 break; 153 case SYS___syscall: 154 lseek(Procfd, parm_offset, SEEK_SET); 155 read(Procfd, &syscall_num, sizeof(int)); 156 parm_offset += sizeof(quad_t); 157 break; 158 } 159 160 fsc.number = syscall_num; 161 fsc.name = 162 (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num]; 163 if (!fsc.name) { 164 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num); 165 } 166 167 if (fsc.name && (trussinfo->flags & FOLLOWFORKS) 168 && ((!strcmp(fsc.name, "fork") 169 || !strcmp(fsc.name, "rfork") 170 || !strcmp(fsc.name, "vfork")))) 171 { 172 trussinfo->in_fork = 1; 173 } 174 175 if (nargs == 0) 176 return; 177 178 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 179 lseek(Procfd, parm_offset, SEEK_SET); 180 if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1) 181 return; 182 183 if (fsc.name) 184 sc = get_syscall(fsc.name); 185 if (sc) { 186 fsc.nargs = sc->nargs; 187 } else { 188#if DEBUG 189 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", 190 fsc.name, nargs); 191#endif 192 fsc.nargs = nargs; 193 } 194 195 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 196 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); 197 fsc.sc = sc; 198 199 /* 200 * At this point, we set up the system call arguments. 201 * We ignore any OUT ones, however -- those are arguments that 202 * are set by the system call, and so are probably meaningless 203 * now. This doesn't currently support arguments that are 204 * passed in *and* out, however. 205 */ 206 207 if (fsc.name) { 208 209#if DEBUG 210 fprintf(stderr, "syscall %s(", fsc.name); 211#endif 212 for (i = 0; i < fsc.nargs; i++) { 213#if DEBUG 214 fprintf(stderr, "0x%x%s", 215 sc 216 ? fsc.args[sc->args[i].offset] 217 : fsc.args[i], 218 i < (fsc.nargs - 1) ? "," : ""); 219#endif 220 if (sc && !(sc->args[i].type & OUT)) { 221 fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args, 0, trussinfo); 222 } 223 } 224#if DEBUG 225 fprintf(stderr, ")\n"); 226#endif 227 } 228 229#if DEBUG 230 fprintf(trussinfo->outfile, "\n"); 231#endif 232 233 /* 234 * Some system calls should be printed out before they are done -- 235 * execve() and exit(), for example, never return. Possibly change 236 * this to work for any system call that doesn't have an OUT 237 * parameter? 238 */ 239 240 if (fsc.name != NULL && 241 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { 242 243 /* XXX 244 * This could be done in a more general 245 * manner but it still wouldn't be very pretty. 246 */ 247 if (!strcmp(fsc.name, "execve")) { 248 if ((trussinfo->flags & EXECVEARGS) == 0) 249 if (fsc.s_args[1]) { 250 free(fsc.s_args[1]); 251 fsc.s_args[1] = NULL; 252 } 253 if ((trussinfo->flags & EXECVEENVS) == 0) 254 if (fsc.s_args[2]) { 255 free(fsc.s_args[2]); 256 fsc.s_args[2] = NULL; 257 } 258 } 259 260 print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args); 261 fprintf(trussinfo->outfile, "\n"); 262 } 263 264 return; 265} 266 267/* 268 * And when the system call is done, we handle it here. 269 * Currently, no attempt is made to ensure that the system calls 270 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 271 * the sytem call number instead of, say, an error status). 272 */ 273 274long 275i386_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 276{ 277 char buf[32]; 278 struct reg regs; 279 long retval; 280 int i; 281 int errorp; 282 struct syscall *sc; 283 284 if (fd == -1 || trussinfo->pid != cpid) { 285 sprintf(buf, "/proc/%d/regs", trussinfo->pid); 286 fd = open(buf, O_RDONLY); 287 if (fd == -1) { 288 fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n"); 289 return (-1); 290 } 291 cpid = trussinfo->pid; 292 } 293 294 lseek(fd, 0L, 0); 295 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) { 296 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 297 return (-1); 298 } 299 retval = regs.r_eax; 300 errorp = !!(regs.r_eflags & PSL_C); 301 302 /* 303 * This code, while simpler than the initial versions I used, could 304 * stand some significant cleaning. 305 */ 306 307 sc = fsc.sc; 308 if (!sc) { 309 for (i = 0; i < fsc.nargs; i++) 310 asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]); 311 } else { 312 /* 313 * Here, we only look for arguments that have OUT masked in -- 314 * otherwise, they were handled in the syscall_entry function. 315 */ 316 for (i = 0; i < sc->nargs; i++) { 317 char *temp; 318 if (sc->args[i].type & OUT) { 319 /* 320 * If an error occurred, then don't bother getting the data; 321 * it may not be valid. 322 */ 323 if (errorp) 324 asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]); 325 else 326 temp = print_arg(Procfd, &sc->args[i], fsc.args, retval, trussinfo); 327 fsc.s_args[i] = temp; 328 } 329 } 330 } 331 332 /* 333 * The pipe syscall returns its fds in two registers and has assembly glue 334 * to provide the libc API, so it cannot be handled like regular syscalls. 335 * The nargs check is so we don't have to do yet another strcmp on every 336 * syscall. 337 */ 338 if (!errorp && fsc.nargs == 0 && fsc.name && strcmp(fsc.name, "pipe") == 0) { 339 fsc.nargs = 1; 340 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 341 asprintf(&fsc.s_args[0], "[%d,%d]", (int)retval, regs.r_edx); 342 retval = 0; 343 } 344 345 /* 346 * It would probably be a good idea to merge the error handling, 347 * but that complicates things considerably. 348 */ 349 350 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval); 351 clear_fsc(); 352 353 return (retval); 354} 355