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 * $FreeBSD: src/usr.bin/truss/i386-fbsd.c,v 1.7.2.2 2001/10/29 20:12:56 des Exp $ 32 * $DragonFly: src/usr.bin/truss/i386-fbsd.c,v 1.5 2008/10/16 01:52:33 swildner Exp $ 33 */ 34 35 /* 36 * FreeBSD/x86_64-specific system call handling. This is probably the most 37 * complex part of the entire truss program, although I've got lots of 38 * it handled relatively cleanly now. The system call names are generated 39 * automatically, thanks to /usr/src/sys/kern/syscalls.master. The 40 * names used for the various structures are confusing, I sadly admit. 41 */ 42 43 #include <sys/types.h> 44 #include <sys/ioctl.h> 45 #include <sys/pioctl.h> 46 #include <sys/syscall.h> 47 48 #include <machine/reg.h> 49 #include <machine/psl.h> 50 51 #include <err.h> 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 <unistd.h> 59 60 #include "truss.h" 61 #include "extern.h" 62 #include "syscall.h" 63 64 static int fd = -1; 65 static int cpid = -1; 66 67 #include "syscalls.h" 68 69 static 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 */ 80 static 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. */ 90 static inline void 91 clear_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 */ 111 112 void 113 x86_64_syscall_entry(struct trussinfo *trussinfo, int nargs) { 114 char *buf; 115 struct reg regs = { .r_err = 0 }; 116 int syscall_num; 117 int i, reg; 118 struct syscall *sc; 119 120 if (fd == -1 || trussinfo->pid != cpid) { 121 asprintf(&buf, "%s/%d/regs", procfs_path, trussinfo->pid); 122 if (buf == NULL) 123 err(1, "Out of memory"); 124 fd = open(buf, O_RDWR); 125 free(buf); 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)); 136 137 /* 138 * FreeBSD has two special kinds of system call redirctions -- 139 * SYS_syscall, and SYS___syscall. The former is the old syscall() 140 * routine, basicly; the latter is for quad-aligned arguments. 141 */ 142 reg = 0; 143 syscall_num = regs.r_rax; 144 switch (syscall_num) { 145 case SYS_syscall: 146 case SYS___syscall: 147 syscall_num = regs.r_rdi; 148 reg++; 149 break; 150 } 151 152 fsc.number = syscall_num; 153 fsc.name = 154 (syscall_num < 0 || syscall_num >= nsyscalls) ? NULL : syscallnames[syscall_num]; 155 if (!fsc.name) { 156 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num); 157 } 158 159 if (nargs == 0) 160 return; 161 162 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 163 for (i = 0; i < nargs && reg < 6; i++, reg++) { 164 switch (reg) { 165 case 0: fsc.args[i] = regs.r_rdi; break; 166 case 1: fsc.args[i] = regs.r_rsi; break; 167 case 2: fsc.args[i] = regs.r_rdx; break; 168 case 3: fsc.args[i] = regs.r_rcx; break; 169 case 4: fsc.args[i] = regs.r_r8; break; 170 case 5: fsc.args[i] = regs.r_r9; break; 171 } 172 } 173 if (nargs > i) { 174 lseek(Procfd, regs.r_rsp + sizeof(register_t), SEEK_SET); 175 if (read(Procfd, &fsc.args[i], (nargs-i) * sizeof(register_t)) == -1) 176 return; 177 } 178 179 sc = fsc.name ? get_syscall(fsc.name) : NULL; 180 if (sc) { 181 fsc.nargs = sc->nargs; 182 } else { 183 #if DEBUG 184 fprintf(trussinfo->trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", 185 fsc.name, nargs); 186 #endif 187 fsc.nargs = nargs; 188 } 189 190 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 191 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); 192 fsc.sc = sc; 193 194 /* 195 * At this point, we set up the system call arguments. 196 * We ignore any OUT ones, however -- those are arguments that 197 * are set by the system call, and so are probably meaningless 198 * now. This doesn't currently support arguments that are 199 * passed in *and* out, however. 200 */ 201 202 if (fsc.name) { 203 204 #if DEBUG 205 fprintf(stderr, "syscall %s(", fsc.name); 206 #endif 207 for (i = 0; i < fsc.nargs; i++) { 208 #if DEBUG 209 fprintf(stderr, "0x%x%s", 210 sc 211 ? fsc.args[sc->args[i].offset] 212 : fsc.args[i], 213 i < (fsc.nargs -1) ? "," : ""); 214 #endif 215 if (sc && !(sc->args[i].type & OUT)) { 216 fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args); 217 } 218 } 219 #if DEBUG 220 fprintf(stderr, ")\n"); 221 #endif 222 } 223 224 #if DEBUG 225 fprintf(trussinfo->trussinfo->outfile, "\n"); 226 #endif 227 228 /* 229 * Some system calls should be printed out before they are done -- 230 * execve() and exit(), for example, never return. Possibly change 231 * this to work for any system call that doesn't have an OUT 232 * parameter? 233 */ 234 235 if (fsc.name != NULL && 236 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { 237 print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args); 238 } 239 240 return; 241 } 242 243 /* 244 * And when the system call is done, we handle it here. 245 * Currently, no attempt is made to ensure that the system calls 246 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 247 * the sytem call number instead of, say, an error status). 248 */ 249 250 int 251 x86_64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) { 252 char *buf; 253 struct reg regs; 254 int retval; 255 int i; 256 int errorp; 257 struct syscall *sc; 258 259 if (fsc.name == NULL) 260 return 0; 261 262 if (fd == -1 || trussinfo->pid != cpid) { 263 asprintf(&buf, "%s/%d/regs", procfs_path, trussinfo->pid); 264 if (buf == NULL) 265 err(1, "Out of memory"); 266 fd = open(buf, O_RDONLY); 267 free(buf); 268 if (fd == -1) { 269 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 270 return 0; 271 } 272 cpid = trussinfo->pid; 273 } 274 275 lseek(fd, 0L, 0); 276 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) { 277 fprintf(trussinfo->outfile, "\n"); 278 return 0; 279 } 280 retval = regs.r_rax; 281 errorp = !!(regs.r_rflags & PSL_C); 282 283 /* 284 * This code, while simpler than the initial versions I used, could 285 * stand some significant cleaning. 286 */ 287 288 sc = fsc.sc; 289 if (!sc) { 290 for (i = 0; i < fsc.nargs; i++) { 291 fsc.s_args[i] = malloc(12); 292 sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]); 293 } 294 } else { 295 /* 296 * Here, we only look for arguments that have OUT masked in -- 297 * otherwise, they were handled in the syscall_entry function. 298 */ 299 for (i = 0; i < sc->nargs; i++) { 300 char *temp; 301 if (sc->args[i].type & OUT) { 302 /* 303 * If an error occurred, than don't bothe getting the data; 304 * it may not be valid. 305 */ 306 if (errorp) { 307 temp = malloc(12); 308 sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]); 309 } else { 310 temp = print_arg(Procfd, &sc->args[i], fsc.args); 311 } 312 fsc.s_args[i] = temp; 313 } 314 } 315 } 316 317 /* 318 * It would probably be a good idea to merge the error handling, 319 * but that complicates things considerably. 320 */ 321 322 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval); 323 clear_fsc(); 324 325 return (retval); 326 } 327