i386-fbsd.c revision 192153
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 192153 2009-05-15 19:41:10Z delphij $"; 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/syscall.h> 47#include <sys/ptrace.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 65static int cpid = -1; 66 67#include "syscalls.h" 68 69static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); 70 71/* 72 * This is what this particular file uses to keep track of a system call. 73 * It is probably not quite sufficient -- I can probably use the same 74 * structure for the various syscall personalities, and I also probably 75 * need to nest system calls (for signal handlers). 76 * 77 * 'struct syscall' describes the system call; it may be NULL, however, 78 * if we don't know about this particular system call yet. 79 */ 80static struct freebsd_syscall { 81 struct syscall *sc; 82 const char *name; 83 int number; 84 unsigned long *args; 85 int nargs; /* number of arguments -- *not* number of words! */ 86 char **s_args; /* the printable arguments */ 87} fsc; 88 89/* Clear up and free parts of the fsc structure. */ 90static __inline void 91clear_fsc(void) { 92 if (fsc.args) { 93 free(fsc.args); 94 } 95 if (fsc.s_args) { 96 int i; 97 for (i = 0; i < fsc.nargs; i++) 98 if (fsc.s_args[i]) 99 free(fsc.s_args[i]); 100 free(fsc.s_args); 101 } 102 memset(&fsc, 0, sizeof(fsc)); 103} 104 105/* 106 * Called when a process has entered a system call. nargs is the 107 * number of words, not number of arguments (a necessary distinction 108 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 109 * is ever changed these functions need to keep up. 110 */ 111 112void 113i386_syscall_entry(struct trussinfo *trussinfo, int nargs) { 114 struct reg regs; 115 int syscall_num; 116 int i; 117 unsigned int parm_offset; 118 struct syscall *sc = NULL; 119 struct ptrace_io_desc iorequest; 120 cpid = trussinfo->curthread->tid; 121 122 clear_fsc(); 123 124 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) 125 { 126 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 127 return; 128 } 129 parm_offset = regs.r_esp + sizeof(int); 130 131 /* 132 * FreeBSD has two special kinds of system call redirctions -- 133 * SYS_syscall, and SYS___syscall. The former is the old syscall() 134 * routine, basicly; the latter is for quad-aligned arguments. 135 */ 136 syscall_num = regs.r_eax; 137 switch (syscall_num) { 138 case SYS_syscall: 139 syscall_num = ptrace(PT_READ_D, cpid, (caddr_t)parm_offset, 0); 140 parm_offset += sizeof(int); 141 break; 142 case SYS___syscall: 143 syscall_num = ptrace(PT_READ_D, cpid, (caddr_t)parm_offset, 0); 144 parm_offset += sizeof(quad_t); 145 break; 146 } 147 148 fsc.number = syscall_num; 149 fsc.name = 150 (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num]; 151 if (!fsc.name) { 152 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num); 153 } 154 155 if (fsc.name && (trussinfo->flags & FOLLOWFORKS) 156 && ((!strcmp(fsc.name, "fork") 157 || !strcmp(fsc.name, "rfork") 158 || !strcmp(fsc.name, "vfork")))) 159 { 160 trussinfo->curthread->in_fork = 1; 161 } 162 163 if (nargs == 0) 164 return; 165 166 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 167 iorequest.piod_op = PIOD_READ_D; 168 iorequest.piod_offs = (void *)parm_offset; 169 iorequest.piod_addr = fsc.args; 170 iorequest.piod_len = (1+nargs) * sizeof(unsigned long); 171 ptrace(PT_IO, cpid, (caddr_t)&iorequest, 0); 172 if (iorequest.piod_len == 0) 173 return; 174 175 if (fsc.name) 176 sc = get_syscall(fsc.name); 177 if (sc) { 178 fsc.nargs = sc->nargs; 179 } else { 180#if DEBUG 181 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", 182 fsc.name, nargs); 183#endif 184 fsc.nargs = nargs; 185 } 186 187 fsc.s_args = calloc(1, (1+fsc.nargs) * sizeof(char*)); 188 fsc.sc = sc; 189 190 /* 191 * At this point, we set up the system call arguments. 192 * We ignore any OUT ones, however -- those are arguments that 193 * are set by the system call, and so are probably meaningless 194 * now. This doesn't currently support arguments that are 195 * passed in *and* out, however. 196 */ 197 198 if (fsc.name) { 199 200#if DEBUG 201 fprintf(stderr, "syscall %s(", fsc.name); 202#endif 203 for (i = 0; i < fsc.nargs; i++) { 204#if DEBUG 205 fprintf(stderr, "0x%x%s", 206 sc 207 ? fsc.args[sc->args[i].offset] 208 : fsc.args[i], 209 i < (fsc.nargs - 1) ? "," : ""); 210#endif 211 if (sc && !(sc->args[i].type & OUT)) { 212 fsc.s_args[i] = print_arg(&sc->args[i], fsc.args, 0, trussinfo); 213 } 214 } 215#if DEBUG 216 fprintf(stderr, ")\n"); 217#endif 218 } 219 220#if DEBUG 221 fprintf(trussinfo->outfile, "\n"); 222#endif 223 224 if (fsc.name != NULL && 225 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { 226 227 /* XXX 228 * This could be done in a more general 229 * manner but it still wouldn't be very pretty. 230 */ 231 if (!strcmp(fsc.name, "execve")) { 232 if ((trussinfo->flags & EXECVEARGS) == 0) 233 if (fsc.s_args[1]) { 234 free(fsc.s_args[1]); 235 fsc.s_args[1] = NULL; 236 } 237 if ((trussinfo->flags & EXECVEENVS) == 0) 238 if (fsc.s_args[2]) { 239 free(fsc.s_args[2]); 240 fsc.s_args[2] = NULL; 241 } 242 } 243 244 } 245 246 return; 247} 248 249/* 250 * And when the system call is done, we handle it here. 251 * Currently, no attempt is made to ensure that the system calls 252 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 253 * the sytem call number instead of, say, an error status). 254 */ 255 256long 257i386_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 258{ 259 struct reg regs; 260 long retval; 261 int i; 262 int errorp; 263 struct syscall *sc; 264 265 if (fsc.name == NULL) 266 return (-1); 267 cpid = trussinfo->curthread->tid; 268 269 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) 270 { 271 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 272 return (-1); 273 } 274 275 retval = regs.r_eax; 276 errorp = !!(regs.r_eflags & PSL_C); 277 278 /* 279 * This code, while simpler than the initial versions I used, could 280 * stand some significant cleaning. 281 */ 282 283 sc = fsc.sc; 284 if (!sc) { 285 for (i = 0; i < fsc.nargs; i++) 286 asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]); 287 } else { 288 /* 289 * Here, we only look for arguments that have OUT masked in -- 290 * otherwise, they were handled in the syscall_entry function. 291 */ 292 for (i = 0; i < sc->nargs; i++) { 293 char *temp; 294 if (sc->args[i].type & OUT) { 295 /* 296 * If an error occurred, then don't bother getting the data; 297 * it may not be valid. 298 */ 299 if (errorp) 300 asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]); 301 else 302 temp = print_arg(&sc->args[i], fsc.args, retval, trussinfo); 303 fsc.s_args[i] = temp; 304 } 305 } 306 } 307 308 /* 309 * The pipe syscall returns its fds in two registers and has assembly glue 310 * to provide the libc API, so it cannot be handled like regular syscalls. 311 * The nargs check is so we don't have to do yet another strcmp on every 312 * syscall. 313 */ 314 if (!errorp && fsc.nargs == 0 && fsc.name && strcmp(fsc.name, "pipe") == 0) { 315 fsc.nargs = 1; 316 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 317 asprintf(&fsc.s_args[0], "[%d,%d]", (int)retval, regs.r_edx); 318 retval = 0; 319 } 320 321 if (fsc.name != NULL && 322 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { 323 trussinfo->curthread->in_syscall = 1; 324 } 325 326 /* 327 * It would probably be a good idea to merge the error handling, 328 * but that complicates things considerably. 329 */ 330 331 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, 332 retval, fsc.sc); 333 clear_fsc(); 334 335 return (retval); 336} 337