usr.bin/truss/x86_64-fbsd.c

   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, &regs, 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, &regs, 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 }