i386-fbsd.c revision 31899
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 33/* 34 * FreeBSD/386-specific system call handling. This is probably the most 35 * complex part of the entire truss program, although I've got lots of 36 * it handled relatively cleanly now. The system call names are generated 37 * automatically, thanks to /usr/src/sys/kern/syscalls.master. The 38 * names used for the various structures are confusing, I sadly admit. 39 */ 40/* 41 * $Id: i386-fbsd.c,v 1.1 1997/12/06 05:22:50 sef Exp $ 42 */ 43 44#include <stdio.h> 45#include <stdlib.h> 46#include <string.h> 47#include <errno.h> 48#include <err.h> 49#include <signal.h> 50#include <fcntl.h> 51#include <unistd.h> 52#include <sys/ioctl.h> 53#include <sys/pioctl.h> 54#include <machine/reg.h> 55#include <machine/psl.h> 56#include <sys/syscall.h> 57 58#include "syscall.h" 59 60static int fd = -1; 61static int cpid = -1; 62extern int Procfd; 63 64extern FILE *outfile; 65#include "syscalls.h" 66 67static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); 68 69/* 70 * This is what this particular file uses to keep track of a system call. 71 * It is probably not quite sufficient -- I can probably use the same 72 * structure for the various syscall personalities, and I also probably 73 * need to nest system calls (for signal handlers). 74 * 75 * 'struct syscall' describes the system call; it may be NULL, however, 76 * if we don't know about this particular system call yet. 77 */ 78static struct freebsd_syscall { 79 struct syscall *sc; 80 char *name; 81 int number; 82 unsigned long *args; 83 int nargs; /* number of arguments -- *not* number of words! */ 84 char **s_args; /* the printable arguments */ 85} fsc; 86 87/* Clear up and free parts of the fsc structure. */ 88static inline void 89clear_fsc() { 90 if (fsc.args) { 91 free(fsc.args); 92 } 93 if (fsc.s_args) { 94 int i; 95 for (i = 0; i < fsc.nargs; i++) 96 if (fsc.s_args[i]) 97 free(fsc.s_args[i]); 98 free(fsc.s_args); 99 } 100 memset(&fsc, 0, sizeof(fsc)); 101} 102 103/* 104 * Called when a process has entered a system call. nargs is the 105 * number of words, not number of arguments (a necessary distinction 106 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 107 * is ever changed these functions need to keep up. 108 */ 109 110void 111i386_syscall_entry(int pid, int nargs) { 112 char buf[32]; 113 struct reg regs = { 0 }; 114 int syscall; 115 int i; 116 int memfd; 117 unsigned int parm_offset; 118 struct syscall *sc; 119 120 if (fd == -1 || pid != cpid) { 121 sprintf(buf, "/proc/%d/regs", pid); 122 fd = open(buf, O_RDWR); 123 if (fd == -1) { 124 fprintf(outfile, "-- CANNOT READ REGISTERS --\n"); 125 return; 126 } 127 cpid = pid; 128 } 129 130 clear_fsc(); 131 lseek(fd, 0L, 0); 132 i = read(fd, ®s, sizeof(regs)); 133 parm_offset = regs.r_esp + sizeof(int); 134 135 /* 136 * FreeBSD has two special kinds of system call redirctions -- 137 * SYS_syscall, and SYS___syscall. The former is the old syscall() 138 * routine, basicly; the latter is for quad-aligned arguments. 139 */ 140 syscall = regs.r_eax; 141 switch (syscall) { 142 case SYS_syscall: 143 lseek(Procfd, parm_offset, SEEK_SET); 144 read(Procfd, &syscall, sizeof(int)); 145 parm_offset += sizeof(int); 146 break; 147 case SYS___syscall: 148 lseek(Procfd, parm_offset, SEEK_SET); 149 read(Procfd, &syscall, sizeof(int)); 150 parm_offset += sizeof(quad_t); 151 break; 152 } 153 154 fsc.number = syscall; 155 fsc.name = 156 (syscall < 0 || syscall > nsyscalls) ? NULL : syscallnames[syscall]; 157 if (!fsc.name) { 158 fprintf(outfile, "-- UNKNOWN SYSCALL %d --\n", syscall); 159 } 160 161 if (nargs == 0) 162 return; 163 164 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 165 lseek(Procfd, parm_offset, SEEK_SET); 166 if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1) 167 return; 168 169 sc = get_syscall(fsc.name); 170 if (sc) { 171 fsc.nargs = sc->nargs; 172 } else { 173#if DEBUG 174 fprintf(outfile, "unknown syscall %s -- setting args to %d\n", 175 fsc.name, nargs); 176#endif 177 fsc.nargs = nargs; 178 } 179 180 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 181 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); 182 fsc.sc = sc; 183 184 /* 185 * At this point, we set up the system call arguments. 186 * We ignore any OUT ones, however -- those are arguments that 187 * are set by the system call, and so are probably meaningless 188 * now. This doesn't currently support arguments that are 189 * passed in *and* out, however. 190 */ 191 192 if (fsc.name) { 193 char *tmp; 194 195#if DEBUG 196 fprintf(stderr, "syscall %s(", fsc.name); 197#endif 198 for (i = 0; i < fsc.nargs; i++) { 199#if DEBUG 200 fprintf(stderr, "0x%x%s", 201 sc 202 ? fsc.args[sc->args[i].offset] 203 : fsc.args[i], 204 i < (fsc.nargs -1) ? "," : ""); 205#endif 206 if (sc && !(sc->args[i].type & OUT)) { 207 fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args); 208 } 209 } 210#if DEBUG 211 fprintf(stderr, ")\n"); 212#endif 213 } 214 215#if DEBUG 216 fprintf(outfile, "\n"); 217#endif 218 219 /* 220 * Some system calls should be printed out before they are done -- 221 * execve() and exit(), for example, never return. Possibly change 222 * this to work for any system call that doesn't have an OUT 223 * parameter? 224 */ 225 226 if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) { 227 print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args); 228 } 229 230 return; 231} 232 233/* 234 * And when the system call is done, we handle it here. 235 * Currently, no attempt is made to ensure that the system calls 236 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 237 * the sytem call number instead of, say, an error status). 238 */ 239 240void 241i386_syscall_exit(int pid, int syscall) { 242 char buf[32]; 243 struct reg regs; 244 int retval; 245 int i; 246 int errorp; 247 struct syscall *sc; 248 249 if (fd == -1 || pid != cpid) { 250 sprintf(buf, "/proc/%d/regs", pid); 251 fd = open(buf, O_RDONLY); 252 if (fd == -1) { 253 fprintf(outfile, "-- CANNOT READ REGISTERS --\n"); 254 return; 255 } 256 cpid = pid; 257 } 258 259 lseek(fd, 0L, 0); 260 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) 261 return; 262 retval = regs.r_eax; 263 errorp = !!(regs.r_eflags & PSL_C); 264 265 /* 266 * This code, while simpler than the initial versions I used, could 267 * stand some significant cleaning. 268 */ 269 270 sc = fsc.sc; 271 if (!sc) { 272 for (i = 0; i < fsc.nargs; i++) { 273 fsc.s_args[i] = malloc(12); 274 sprintf(fsc.s_args[i], "0x%x", fsc.args[i]); 275 } 276 } else { 277 /* 278 * Here, we only look for arguments that have OUT masked in -- 279 * otherwise, they were handled in the syscall_entry function. 280 */ 281 for (i = 0; i < sc->nargs; i++) { 282 char *temp; 283 if (sc->args[i].type & OUT) { 284 /* 285 * If an error occurred, than don't bothe getting the data; 286 * it may not be valid. 287 */ 288 if (errorp) { 289 temp = malloc(12); 290 sprintf(temp, "0x%x", fsc.args[sc->args[i].offset]); 291 } else { 292 temp = print_arg(Procfd, &sc->args[i], fsc.args); 293 } 294 fsc.s_args[i] = temp; 295 } 296 } 297 } 298 299 /* 300 * It would probably be a good idea to merge the error handling, 301 * but that complicates things considerably. 302 */ 303 304 print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args); 305 if (errorp) { 306 fprintf(outfile, "errno %d '%s'\n", retval, strerror(retval)); 307 } else { 308 fprintf(outfile, "returns %d (0x%x)\n", retval, retval); 309 } 310 clear_fsc(); 311 312 return; 313} 314