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  */
  33
  34 /*
  35  * FreeBSD/x86_64-specific system call handling.  This is probably the most
  36  * complex part of the entire truss program, although I've got lots of
  37  * it handled relatively cleanly now.  The system call names are generated
  38  * automatically, thanks to /usr/src/sys/kern/syscalls.master.  The
  39  * names used for the various structures are confusing, I sadly admit.
  40  */
  41
  42 #include <sys/types.h>
  43 #include <sys/ioctl.h>
  44 #include <sys/pioctl.h>
  45 #include <sys/syscall.h>
  46
  47 #include <machine/reg.h>
  48 #include <machine/psl.h>
  49
  50 #include <err.h>
  51 #include <errno.h>
  52 #include <fcntl.h>
  53 #include <signal.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58
  59 #include "truss.h"
  60 #include "extern.h"
  61 #include "syscall.h"
  62
  63 static int fd = -1;
  64 static int cpid = -1;
  65
  66 #include "syscalls.h"
  67
  68 static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
  69
  70 /*
  71  * This is what this particular file uses to keep track of a system call.
  72  * It is probably not quite sufficient -- I can probably use the same
  73  * structure for the various syscall personalities, and I also probably
  74  * need to nest system calls (for signal handlers).
  75  *
  76  * 'struct syscall' describes the system call; it may be NULL, however,
  77  * if we don't know about this particular system call yet.
  78  */
  79 static struct freebsd_syscall {
  80         struct syscall *sc;
  81         const char *name;
  82         int number;
  83         unsigned long *args;
  84         int nargs;      /* number of arguments -- *not* number of words! */
  85         char **s_args;  /* the printable arguments */
  86 } fsc;
  87
  88 /* Clear up and free parts of the fsc structure. */
  89 static inline void
  90 clear_fsc(void) {
  91   if (fsc.args) {
  92     free(fsc.args);
  93   }
  94   if (fsc.s_args) {
  95     int i;
  96     for (i = 0; i < fsc.nargs; i++)
  97       if (fsc.s_args[i])
  98         free(fsc.s_args[i]);
  99     free(fsc.s_args);
 100   }
 101   memset(&fsc, 0, sizeof(fsc));
 102 }
 103
 104 /*
 105  * Called when a process has entered a system call.  nargs is the
 106  * number of words, not number of arguments (a necessary distinction
 107  * in some cases).  Note that if the STOPEVENT() code in i386/i386/trap.c
 108  * is ever changed these functions need to keep up.
 109  */
 110
 111 void
 112 x86_64_syscall_entry(struct trussinfo *trussinfo, int nargs) {
 113   char *buf;
 114   struct reg regs = { .r_err = 0 };
 115   int syscall_num;
 116   int i, reg;
 117   struct syscall *sc;
 118
 119   if (fd == -1 || trussinfo->pid != cpid) {
 120     asprintf(&buf, "%s/%d/regs", procfs_path, trussinfo->pid);
 121     if (buf == NULL)
 122       err(1, "Out of memory");
 123     fd = open(buf, O_RDWR);
 124     free(buf);
 125     if (fd == -1) {
 126       fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
 127       return;
 128     }
 129     cpid = trussinfo->pid;
 130   }
 131
 132   clear_fsc();
 133   lseek(fd, 0L, 0);
 134   i = read(fd, &regs, sizeof(regs));
 135
 136   /*
 137    * FreeBSD has two special kinds of system call redirctions --
 138    * SYS_syscall, and SYS___syscall.  The former is the old syscall()
 139    * routine, basicly; the latter is for quad-aligned arguments.
 140    */
 141   reg = 0;
 142   syscall_num = regs.r_rax;
 143   switch (syscall_num) {
 144   case SYS_syscall:
 145   case SYS___syscall:
 146     syscall_num = regs.r_rdi;
 147     reg++;
 148     break;
 149   }
 150
 151   fsc.number = syscall_num;
 152   fsc.name =
 153     (syscall_num < 0 || syscall_num >= nsyscalls) ? NULL : syscallnames[syscall_num];
 154   if (!fsc.name) {
 155     fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num);
 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     lseek(Procfd, regs.r_rsp + sizeof(register_t), SEEK_SET);
 174     if (read(Procfd, &fsc.args[i], (nargs-i) * sizeof(register_t)) == -1)
 175       return;
 176   }
 177
 178   sc = fsc.name ? get_syscall(fsc.name) : NULL;
 179   if (sc) {
 180     fsc.nargs = sc->nargs;
 181   } else {
 182 #ifdef DEBUG
 183     fprintf(trussinfo->trussinfo->outfile, "unknown syscall %s -- setting args to %d\n",
 184            fsc.name, nargs);
 185 #endif
 186     fsc.nargs = nargs;
 187   }
 188
 189   fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
 190   memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
 191   fsc.sc = sc;
 192
 193   /*
 194    * At this point, we set up the system call arguments.
 195    * We ignore any OUT ones, however -- those are arguments that
 196    * are set by the system call, and so are probably meaningless
 197    * now.  This doesn't currently support arguments that are
 198    * passed in *and* out, however.
 199    */
 200
 201   if (fsc.name) {
 202
 203 #ifdef DEBUG
 204     fprintf(stderr, "syscall %s(", fsc.name);
 205 #endif
 206     for (i = 0; i < fsc.nargs; i++) {
 207 #ifdef DEBUG
 208       fprintf(stderr, "0x%x%s",
 209              sc
 210              ? fsc.args[sc->args[i].offset]
 211              : fsc.args[i],
 212              i < (fsc.nargs -1) ? "," : "");
 213 #endif
 214       if (sc && !(sc->args[i].type & OUT)) {
 215         fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args);
 216       }
 217     }
 218 #ifdef DEBUG
 219     fprintf(stderr, ")\n");
 220 #endif
 221   }
 222
 223 #ifdef DEBUG
 224   fprintf(trussinfo->trussinfo->outfile, "\n");
 225 #endif
 226
 227   /*
 228    * Some system calls should be printed out before they are done --
 229    * execve() and exit(), for example, never return.  Possibly change
 230    * this to work for any system call that doesn't have an OUT
 231    * parameter?
 232    */
 233
 234   if (fsc.name != NULL &&
 235       (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) {
 236     print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args);
 237   }
 238
 239   return;
 240 }
 241
 242 /*
 243  * And when the system call is done, we handle it here.
 244  * Currently, no attempt is made to ensure that the system calls
 245  * match -- this needs to be fixed (and is, in fact, why S_SCX includes
 246  * the sytem call number instead of, say, an error status).
 247  */
 248
 249 int
 250 x86_64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) {
 251   char *buf;
 252   struct reg regs;
 253   int retval;
 254   int i;
 255   int errorp;
 256   struct syscall *sc;
 257
 258   if (fsc.name == NULL)
 259     return 0;
 260
 261   if (fd == -1 || trussinfo->pid != cpid) {
 262     asprintf(&buf, "%s/%d/regs", procfs_path, trussinfo->pid);
 263     if (buf == NULL)
 264       err(1, "Out of memory");
 265     fd = open(buf, O_RDONLY);
 266     free(buf);
 267     if (fd == -1) {
 268       fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
 269       return 0;
 270     }
 271     cpid = trussinfo->pid;
 272   }
 273
 274   lseek(fd, 0L, 0);
 275   if (read(fd, &regs, sizeof(regs)) != sizeof(regs)) {
 276           fprintf(trussinfo->outfile, "\n");
 277           return 0;
 278   }
 279   retval = regs.r_rax;
 280   errorp = !!(regs.r_rflags & PSL_C);
 281
 282   /*
 283    * This code, while simpler than the initial versions I used, could
 284    * stand some significant cleaning.
 285    */
 286
 287   sc = fsc.sc;
 288   if (!sc) {
 289     for (i = 0; i < fsc.nargs; i++) {
 290       fsc.s_args[i] = malloc(12);
 291       sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]);
 292     }
 293   } else {
 294     /*
 295      * Here, we only look for arguments that have OUT masked in --
 296      * otherwise, they were handled in the syscall_entry function.
 297      */
 298     for (i = 0; i < sc->nargs; i++) {
 299       char *temp;
 300       if (sc->args[i].type & OUT) {
 301         /*
 302          * If an error occurred, than don't bothe getting the data;
 303          * it may not be valid.
 304          */
 305         if (errorp) {
 306           temp = malloc(12);
 307           sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]);
 308         } else {
 309           temp = print_arg(Procfd, &sc->args[i], fsc.args);
 310         }
 311         fsc.s_args[i] = temp;
 312       }
 313     }
 314   }
 315
 316   /*
 317    * It would probably be a good idea to merge the error handling,
 318    * but that complicates things considerably.
 319    */
 320
 321   print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval);
 322   clear_fsc();
 323
 324   return (retval);
 325 }