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[] =
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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 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 amd64/amd64/trap.c 109 * is ever changed these functions need to keep up. 110 */ 111 112void 113amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) { 114 struct reg regs; 115 int syscall_num; 116 int i, reg; 117 struct syscall *sc; 118 119 cpid = trussinfo->curthread->tid; 120 121 clear_fsc(); 122 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) 123 { 124 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 125 return; 126 } 127 128 /* 129 * FreeBSD has two special kinds of system call redirctions -- 130 * SYS_syscall, and SYS___syscall. The former is the old syscall() 131 * routine, basicly; the latter is for quad-aligned arguments. 132 */ 133 reg = 0; 134 syscall_num = regs.r_rax; 135 switch (syscall_num) { 136 case SYS_syscall: 137 case SYS___syscall: 138 syscall_num = regs.r_rdi; 139 reg++; 140 break; 141 } 142 143 fsc.number = syscall_num; 144 fsc.name = 145 (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num]; 146 if (!fsc.name) { 147 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num); 148 } 149 150 if (fsc.name && (trussinfo->flags & FOLLOWFORKS) 151 && ((!strcmp(fsc.name, "fork") 152 || !strcmp(fsc.name, "rfork") 153 || !strcmp(fsc.name, "vfork")))) 154 { 155 trussinfo->curthread->in_fork = 1; 156 } 157 158 if (nargs == 0) 159 return; 160 161 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 162 for (i = 0; i < nargs && reg < 6; i++, reg++) { 163 switch (reg) { 164 case 0: fsc.args[i] = regs.r_rdi; break; 165 case 1: fsc.args[i] = regs.r_rsi; break; 166 case 2: fsc.args[i] = regs.r_rdx; break; 167 case 3: fsc.args[i] = regs.r_rcx; break; 168 case 4: fsc.args[i] = regs.r_r8; break; 169 case 5: fsc.args[i] = regs.r_r9; break; 170 } 171 } 172 if (nargs > i) { 173 struct ptrace_io_desc iorequest; 174 iorequest.piod_op = PIOD_READ_D; 175 iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t)); 176 iorequest.piod_addr = &fsc.args[i]; 177 iorequest.piod_len = (nargs - i) * sizeof(register_t); 178 ptrace(PT_IO, cpid, (caddr_t)&iorequest, 0); 179 if (iorequest.piod_len == 0) 180 return; 181 } 182 183 sc = get_syscall(fsc.name); 184 if (sc) { 185 fsc.nargs = sc->nargs; 186 } else { 187#if DEBUG 188 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", 189 fsc.name, nargs); 190#endif 191 fsc.nargs = nargs; 192 } 193 194 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 195 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); 196 fsc.sc = sc; 197 198 /* 199 * At this point, we set up the system call arguments. 200 * We ignore any OUT ones, however -- those are arguments that 201 * are set by the system call, and so are probably meaningless 202 * now. This doesn't currently support arguments that are 203 * passed in *and* out, however. 204 */ 205 206 if (fsc.name) { 207 208#if DEBUG 209 fprintf(stderr, "syscall %s(", fsc.name); 210#endif 211 for (i = 0; i < fsc.nargs; i++) { 212#if DEBUG 213 fprintf(stderr, "0x%lx%s", 214 sc 215 ? fsc.args[sc->args[i].offset] 216 : fsc.args[i], 217 i < (fsc.nargs - 1) ? "," : ""); 218#endif 219 if (sc && !(sc->args[i].type & OUT)) { 220 fsc.s_args[i] = print_arg(&sc->args[i], fsc.args, 0, trussinfo); 221 } 222 } 223#if DEBUG 224 fprintf(stderr, ")\n"); 225#endif 226 } 227 228#if DEBUG 229 fprintf(trussinfo->outfile, "\n"); 230#endif 231 232 if (fsc.name != NULL && 233 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { 234 235 /* XXX 236 * This could be done in a more general 237 * manner but it still wouldn't be very pretty. 238 */ 239 if (!strcmp(fsc.name, "execve")) { 240 if ((trussinfo->flags & EXECVEARGS) == 0) 241 if (fsc.s_args[1]) { 242 free(fsc.s_args[1]); 243 fsc.s_args[1] = NULL; 244 } 245 if ((trussinfo->flags & EXECVEENVS) == 0) 246 if (fsc.s_args[2]) { 247 free(fsc.s_args[2]); 248 fsc.s_args[2] = NULL; 249 } 250 } 251 252 } 253 254 return; 255} 256 257/* 258 * And when the system call is done, we handle it here. 259 * Currently, no attempt is made to ensure that the system calls 260 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 261 * the sytem call number instead of, say, an error status). 262 */ 263 264long 265amd64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 266{ 267 struct reg regs; 268 long retval; 269 int i; 270 int errorp; 271 struct syscall *sc; 272 273 if (fsc.name == NULL) 274 return (-1); 275 276 cpid = trussinfo->curthread->tid; 277 278 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) 279 { 280 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 281 return (-1); 282 } 283 retval = regs.r_rax; 284 errorp = !!(regs.r_rflags & PSL_C); 285 286 /* 287 * This code, while simpler than the initial versions I used, could 288 * stand some significant cleaning. 289 */ 290 291 sc = fsc.sc; 292 if (!sc) { 293 for (i = 0; i < fsc.nargs; i++) 294 asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]); 295 } else { 296 /* 297 * Here, we only look for arguments that have OUT masked in -- 298 * otherwise, they were handled in the syscall_entry function. 299 */ 300 for (i = 0; i < sc->nargs; i++) { 301 char *temp; 302 if (sc->args[i].type & OUT) { 303 /* 304 * If an error occurred, than don't bothe getting the data; 305 * it may not be valid. 306 */ 307 if (errorp) 308 asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]); 309 else 310 temp = print_arg(&sc->args[i], fsc.args, retval, trussinfo); 311 fsc.s_args[i] = temp; 312 } 313 } 314 } 315 316 if (fsc.name != NULL && 317 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { 318 trussinfo->curthread->in_syscall = 1; 319 } 320 321 /* 322 * It would probably be a good idea to merge the error handling, 323 * but that complicates things considerably. 324 */ 325
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