i386-fbsd.c revision 101309
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 101309 2002-08-04 10:57:41Z bde $"; 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#include <sys/time.h> 50 51#include <machine/reg.h> 52#include <machine/psl.h> 53 54#include <errno.h> 55#include <fcntl.h> 56#include <signal.h> 57#include <stdio.h> 58#include <stdlib.h> 59#include <string.h> 60#include <unistd.h> 61 62#include "truss.h" 63#include "syscall.h" 64 65static int fd = -1; 66static int cpid = -1; 67extern int Procfd; 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 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() { 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 = { 0 }; 118 int syscall; 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 READ REGISTERS --\n"); 128 return; 129 } 130 cpid = trussinfo->pid; 131 } 132 133 clear_fsc(); 134 lseek(fd, 0L, 0); 135 i = read(fd, ®s, sizeof(regs)); 136 parm_offset = regs.r_esp + sizeof(int); 137 138 /* 139 * FreeBSD has two special kinds of system call redirctions -- 140 * SYS_syscall, and SYS___syscall. The former is the old syscall() 141 * routine, basicly; the latter is for quad-aligned arguments. 142 */ 143 syscall = regs.r_eax; 144 switch (syscall) { 145 case SYS_syscall: 146 lseek(Procfd, parm_offset, SEEK_SET); 147 read(Procfd, &syscall, sizeof(int)); 148 parm_offset += sizeof(int); 149 break; 150 case SYS___syscall: 151 lseek(Procfd, parm_offset, SEEK_SET); 152 read(Procfd, &syscall, sizeof(int)); 153 parm_offset += sizeof(quad_t); 154 break; 155 } 156 157 fsc.number = syscall; 158 fsc.name = 159 (syscall < 0 || syscall > nsyscalls) ? NULL : syscallnames[syscall]; 160 if (!fsc.name) { 161 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall); 162 } 163 164 if (fsc.name && (trussinfo->flags & FOLLOWFORKS) 165 && ((!strcmp(fsc.name, "fork") 166 || !strcmp(fsc.name, "rfork") 167 || !strcmp(fsc.name, "vfork")))) 168 { 169 trussinfo->in_fork = 1; 170 } 171 172 if (nargs == 0) 173 return; 174 175 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 176 lseek(Procfd, parm_offset, SEEK_SET); 177 if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1) 178 return; 179 180 sc = get_syscall(fsc.name); 181 if (sc) { 182 fsc.nargs = sc->nargs; 183 } else { 184#if DEBUG 185 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", 186 fsc.name, nargs); 187#endif 188 fsc.nargs = nargs; 189 } 190 191 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 192 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); 193 fsc.sc = sc; 194 195 /* 196 * At this point, we set up the system call arguments. 197 * We ignore any OUT ones, however -- those are arguments that 198 * are set by the system call, and so are probably meaningless 199 * now. This doesn't currently support arguments that are 200 * passed in *and* out, however. 201 */ 202 203 if (fsc.name) { 204 205#if DEBUG 206 fprintf(stderr, "syscall %s(", fsc.name); 207#endif 208 for (i = 0; i < fsc.nargs; i++) { 209#if DEBUG 210 fprintf(stderr, "0x%x%s", 211 sc 212 ? fsc.args[sc->args[i].offset] 213 : fsc.args[i], 214 i < (fsc.nargs -1) ? "," : ""); 215#endif 216 if (sc && !(sc->args[i].type & OUT)) { 217 fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args); 218 } 219 } 220#if DEBUG 221 fprintf(stderr, ")\n"); 222#endif 223 } 224 225#if DEBUG 226 fprintf(trussinfo->outfile, "\n"); 227#endif 228 229 /* 230 * Some system calls should be printed out before they are done -- 231 * execve() and exit(), for example, never return. Possibly change 232 * this to work for any system call that doesn't have an OUT 233 * parameter? 234 */ 235 236 if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) { 237 238 /* XXX 239 * This could be done in a more general 240 * manner but it still wouldn't be very pretty. 241 */ 242 if (!strcmp(fsc.name, "execve")) { 243 if ((trussinfo->flags & EXECVEARGS) == 0) 244 if (fsc.s_args[1]) { 245 free(fsc.s_args[1]); 246 fsc.s_args[1] = NULL; 247 } 248 if ((trussinfo->flags & EXECVEENVS) == 0) 249 if (fsc.s_args[2]) { 250 free(fsc.s_args[2]); 251 fsc.s_args[2] = NULL; 252 } 253 } 254 255 print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args); 256 fprintf(trussinfo->outfile, "\n"); 257 } 258 259 return; 260} 261 262/* 263 * And when the system call is done, we handle it here. 264 * Currently, no attempt is made to ensure that the system calls 265 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 266 * the sytem call number instead of, say, an error status). 267 */ 268 269int 270i386_syscall_exit(struct trussinfo *trussinfo, int syscall) { 271 char buf[32]; 272 struct reg regs; 273 int retval; 274 int i; 275 int errorp; 276 struct syscall *sc; 277 278 if (fd == -1 || trussinfo->pid != cpid) { 279 sprintf(buf, "/proc/%d/regs", trussinfo->pid); 280 fd = open(buf, O_RDONLY); 281 if (fd == -1) { 282 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 283 return; 284 } 285 cpid = trussinfo->pid; 286 } 287 288 lseek(fd, 0L, 0); 289 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) { 290 fprintf(trussinfo->outfile, "\n"); 291 return; 292 } 293 retval = regs.r_eax; 294 errorp = !!(regs.r_eflags & PSL_C); 295 296 /* 297 * This code, while simpler than the initial versions I used, could 298 * stand some significant cleaning. 299 */ 300 301 sc = fsc.sc; 302 if (!sc) { 303 for (i = 0; i < fsc.nargs; i++) { 304 fsc.s_args[i] = malloc(12); 305 sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]); 306 } 307 } else { 308 /* 309 * Here, we only look for arguments that have OUT masked in -- 310 * otherwise, they were handled in the syscall_entry function. 311 */ 312 for (i = 0; i < sc->nargs; i++) { 313 char *temp; 314 if (sc->args[i].type & OUT) { 315 /* 316 * If an error occurred, than don't bothe getting the data; 317 * it may not be valid. 318 */ 319 if (errorp) { 320 temp = malloc(12); 321 sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]); 322 } else { 323 temp = print_arg(Procfd, &sc->args[i], fsc.args); 324 } 325 fsc.s_args[i] = temp; 326 } 327 } 328 } 329 330 /* 331 * It would probably be a good idea to merge the error handling, 332 * but that complicates things considerably. 333 */ 334 335 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval); 336 clear_fsc(); 337 338 return (retval); 339} 340