i386-fbsd.c revision 106713
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 106713 2002-11-09 22:46:51Z dwmalone $"; 35#endif /* not lint */ 36 37/* 38 * FreeBSD/386-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; 68extern int Procfd; 69 70#include "syscalls.h" 71 72static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); 73 74/* 75 * This is what this particular file uses to keep track of a system call. 76 * It is probably not quite sufficient -- I can probably use the same 77 * structure for the various syscall personalities, and I also probably 78 * need to nest system calls (for signal handlers). 79 * 80 * 'struct syscall' describes the system call; it may be NULL, however, 81 * if we don't know about this particular system call yet. 82 */ 83static struct freebsd_syscall { 84 struct syscall *sc; 85 const char *name; 86 int number; 87 unsigned long *args; 88 int nargs; /* number of arguments -- *not* number of words! */ 89 char **s_args; /* the printable arguments */ 90} fsc; 91 92/* Clear up and free parts of the fsc structure. */ 93static __inline void 94clear_fsc(void) { 95 if (fsc.args) { 96 free(fsc.args); 97 } 98 if (fsc.s_args) { 99 int i; 100 for (i = 0; i < fsc.nargs; i++) 101 if (fsc.s_args[i]) 102 free(fsc.s_args[i]); 103 free(fsc.s_args); 104 } 105 memset(&fsc, 0, sizeof(fsc)); 106} 107 108/* 109 * Called when a process has entered a system call. nargs is the 110 * number of words, not number of arguments (a necessary distinction 111 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 112 * is ever changed these functions need to keep up. 113 */ 114 115void 116i386_syscall_entry(struct trussinfo *trussinfo, int nargs) { 117 char buf[32]; 118 struct reg regs; 119 int syscall_num; 120 int i; 121 unsigned int parm_offset; 122 struct syscall *sc; 123 124 if (fd == -1 || trussinfo->pid != cpid) { 125 sprintf(buf, "/proc/%d/regs", trussinfo->pid); 126 fd = open(buf, O_RDWR); 127 if (fd == -1) { 128 fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n"); 129 return; 130 } 131 cpid = trussinfo->pid; 132 } 133 134 clear_fsc(); 135 lseek(fd, 0L, 0); 136 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) { 137 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 138 return; 139 } 140 parm_offset = regs.r_esp + sizeof(int); 141 142 /* 143 * FreeBSD has two special kinds of system call redirctions -- 144 * SYS_syscall, and SYS___syscall. The former is the old syscall() 145 * routine, basicly; the latter is for quad-aligned arguments. 146 */ 147 syscall_num = regs.r_eax; 148 switch (syscall_num) { 149 case SYS_syscall: 150 lseek(Procfd, parm_offset, SEEK_SET); 151 read(Procfd, &syscall_num, sizeof(int)); 152 parm_offset += sizeof(int); 153 break; 154 case SYS___syscall: 155 lseek(Procfd, parm_offset, SEEK_SET); 156 read(Procfd, &syscall_num, sizeof(int)); 157 parm_offset += sizeof(quad_t); 158 break; 159 } 160 161 fsc.number = syscall_num; 162 fsc.name = 163 (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num]; 164 if (!fsc.name) { 165 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num); 166 } 167 168 if (fsc.name && (trussinfo->flags & FOLLOWFORKS) 169 && ((!strcmp(fsc.name, "fork") 170 || !strcmp(fsc.name, "rfork") 171 || !strcmp(fsc.name, "vfork")))) 172 { 173 trussinfo->in_fork = 1; 174 } 175 176 if (nargs == 0) 177 return; 178 179 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 180 lseek(Procfd, parm_offset, SEEK_SET); 181 if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1) 182 return; 183 184 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); 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 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) { 241 242 /* XXX 243 * This could be done in a more general 244 * manner but it still wouldn't be very pretty. 245 */ 246 if (!strcmp(fsc.name, "execve")) { 247 if ((trussinfo->flags & EXECVEARGS) == 0) 248 if (fsc.s_args[1]) { 249 free(fsc.s_args[1]); 250 fsc.s_args[1] = NULL; 251 } 252 if ((trussinfo->flags & EXECVEENVS) == 0) 253 if (fsc.s_args[2]) { 254 free(fsc.s_args[2]); 255 fsc.s_args[2] = NULL; 256 } 257 } 258 259 print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args); 260 fprintf(trussinfo->outfile, "\n"); 261 } 262 263 return; 264} 265 266/* 267 * And when the system call is done, we handle it here. 268 * Currently, no attempt is made to ensure that the system calls 269 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 270 * the sytem call number instead of, say, an error status). 271 */ 272 273int 274i386_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) { 275 char buf[32]; 276 struct reg regs; 277 int retval; 278 int i; 279 int errorp; 280 struct syscall *sc; 281 282 if (fd == -1 || trussinfo->pid != cpid) { 283 sprintf(buf, "/proc/%d/regs", trussinfo->pid); 284 fd = open(buf, O_RDONLY); 285 if (fd == -1) { 286 fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n"); 287 return (-1); 288 } 289 cpid = trussinfo->pid; 290 } 291 292 lseek(fd, 0L, 0); 293 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) { 294 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 295 return (-1); 296 } 297 retval = regs.r_eax; 298 errorp = !!(regs.r_eflags & PSL_C); 299 300 /* 301 * This code, while simpler than the initial versions I used, could 302 * stand some significant cleaning. 303 */ 304 305 sc = fsc.sc; 306 if (!sc) { 307 for (i = 0; i < fsc.nargs; i++) { 308 fsc.s_args[i] = malloc(12); 309 sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]); 310 } 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, than don't bothe getting the data; 321 * it may not be valid. 322 */ 323 if (errorp) { 324 temp = malloc(12); 325 sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]); 326 } else { 327 temp = print_arg(Procfd, &sc->args[i], fsc.args); 328 } 329 fsc.s_args[i] = temp; 330 } 331 } 332 } 333 334 /* 335 * It would probably be a good idea to merge the error handling, 336 * but that complicates things considerably. 337 */ 338 339 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval); 340 clear_fsc(); 341 342 return (retval); 343} 344