usr.bin/truss/i386-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/386-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 "extern.h"
  61 #include "syscall.h"
  62
  63 static int fd = -1;
  64 static int cpid = -1;
  65
  66 extern FILE *outfile;
  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 i386_syscall_entry(int pid, int nargs) {
 114   char *buf;
 115   struct reg regs = { .r_err = 0 };
 116   int syscall_num;
 117   int i;
 118   unsigned int parm_offset;
 119   struct syscall *sc;
 120
 121   if (fd == -1 || pid != cpid) {
 122     asprintf(&buf, "%s/%d/regs", procfs_path, pid);
 123     if (buf == NULL)
 124       err(1, "Out of memory");
 125     fd = open(buf, O_RDWR);
 126     free(buf);
 127     if (fd == -1) {
 128       fprintf(outfile, "-- CANNOT READ REGISTERS --\n");
 129       return;
 130     }
 131     cpid = pid;
 132   }
 133
 134   clear_fsc();
 135   lseek(fd, 0L, 0);
 136   i = read(fd, &regs, sizeof(regs));
 137   parm_offset = regs.r_esp + sizeof(int);
 138
 139   /*
 140    * FreeBSD has two special kinds of system call redirctions --
 141    * SYS_syscall, and SYS___syscall.  The former is the old syscall()
 142    * routine, basicly; the latter is for quad-aligned arguments.
 143    */
 144   syscall_num = regs.r_eax;
 145   switch (syscall_num) {
 146   case SYS_syscall:
 147     lseek(Procfd, parm_offset, SEEK_SET);
 148     read(Procfd, &syscall_num, sizeof(int));
 149     parm_offset += sizeof(int);
 150     break;
 151   case SYS___syscall:
 152     lseek(Procfd, parm_offset, SEEK_SET);
 153     read(Procfd, &syscall_num, sizeof(int));
 154     parm_offset += sizeof(quad_t);
 155     break;
 156   }
 157
 158   fsc.number = syscall_num;
 159   fsc.name =
 160     (syscall_num < 0 || syscall_num >= nsyscalls) ? NULL : syscallnames[syscall_num];
 161   if (!fsc.name) {
 162     fprintf(outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num);
 163   }
 164
 165   if (nargs == 0)
 166     return;
 167
 168   fsc.args = malloc((1+nargs) * sizeof(unsigned long));
 169   lseek(Procfd, parm_offset, SEEK_SET);
 170   if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1)
 171     return;
 172
 173   sc = get_syscall(fsc.name);
 174   if (sc) {
 175     fsc.nargs = sc->nargs;
 176   } else {
 177 #if DEBUG
 178     fprintf(outfile, "unknown syscall %s -- setting args to %d\n",
 179            fsc.name, nargs);
 180 #endif
 181     fsc.nargs = nargs;
 182   }
 183
 184   fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
 185   memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
 186   fsc.sc = sc;
 187
 188   /*
 189    * At this point, we set up the system call arguments.
 190    * We ignore any OUT ones, however -- those are arguments that
 191    * are set by the system call, and so are probably meaningless
 192    * now.  This doesn't currently support arguments that are
 193    * passed in *and* out, however.
 194    */
 195
 196   if (fsc.name) {
 197
 198 #if DEBUG
 199     fprintf(stderr, "syscall %s(", fsc.name);
 200 #endif
 201     for (i = 0; i < fsc.nargs; i++) {
 202 #if DEBUG
 203       fprintf(stderr, "0x%x%s",
 204              sc
 205              ? fsc.args[sc->args[i].offset]
 206              : fsc.args[i],
 207              i < (fsc.nargs -1) ? "," : "");
 208 #endif
 209       if (sc && !(sc->args[i].type & OUT)) {
 210         fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args);
 211       }
 212     }
 213 #if DEBUG
 214     fprintf(stderr, ")\n");
 215 #endif
 216   }
 217
 218 #if DEBUG
 219   fprintf(outfile, "\n");
 220 #endif
 221
 222   /*
 223    * Some system calls should be printed out before they are done --
 224    * execve() and exit(), for example, never return.  Possibly change
 225    * this to work for any system call that doesn't have an OUT
 226    * parameter?
 227    */
 228
 229   if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) {
 230     print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args);
 231   }
 232
 233   return;
 234 }
 235
 236 /*
 237  * And when the system call is done, we handle it here.
 238  * Currently, no attempt is made to ensure that the system calls
 239  * match -- this needs to be fixed (and is, in fact, why S_SCX includes
 240  * the sytem call number instead of, say, an error status).
 241  */
 242
 243 void
 244 i386_syscall_exit(int pid, int syscall_num __unused) {
 245   char *buf;
 246   struct reg regs;
 247   int retval;
 248   int i;
 249   int errorp;
 250   struct syscall *sc;
 251
 252   if (fd == -1 || pid != cpid) {
 253     asprintf(&buf, "%s/%d/regs", procfs_path, pid);
 254     if (buf == NULL)
 255       err(1, "Out of memory");
 256     fd = open(buf, O_RDONLY);
 257     free(buf);
 258     if (fd == -1) {
 259       fprintf(outfile, "-- CANNOT READ REGISTERS --\n");
 260       return;
 261     }
 262     cpid = pid;
 263   }
 264
 265   lseek(fd, 0L, 0);
 266   if (read(fd, &regs, sizeof(regs)) != sizeof(regs))
 267     return;
 268   retval = regs.r_eax;
 269   errorp = !!(regs.r_eflags & PSL_C);
 270
 271   /*
 272    * This code, while simpler than the initial versions I used, could
 273    * stand some significant cleaning.
 274    */
 275
 276   sc = fsc.sc;
 277   if (!sc) {
 278     for (i = 0; i < fsc.nargs; i++) {
 279       fsc.s_args[i] = malloc(12);
 280       sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]);
 281     }
 282   } else {
 283     /*
 284      * Here, we only look for arguments that have OUT masked in --
 285      * otherwise, they were handled in the syscall_entry function.
 286      */
 287     for (i = 0; i < sc->nargs; i++) {
 288       char *temp;
 289       if (sc->args[i].type & OUT) {
 290         /*
 291          * If an error occurred, than don't bothe getting the data;
 292          * it may not be valid.
 293          */
 294         if (errorp) {
 295           temp = malloc(12);
 296           sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]);
 297         } else {
 298           temp = print_arg(Procfd, &sc->args[i], fsc.args);
 299         }
 300         fsc.s_args[i] = temp;
 301       }
 302     }
 303   }
 304
 305   /*
 306    * It would probably be a good idea to merge the error handling,
 307    * but that complicates things considerably.
 308    */
 309
 310   print_syscall_ret(outfile, fsc.name, fsc.nargs, fsc.s_args, errorp, retval);
 311   clear_fsc();
 312
 313   return;
 314 }