usr.bin/truss/main.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
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 /*
  36  * The main module for truss.  Suprisingly simple, but, then, the other
  37  * files handle the bulk of the work.  And, of course, the kernel has to
  38  * do a lot of the work :).
  39  */
  40
  41 #include <sys/param.h>
  42 #include <sys/types.h>
  43 #include <sys/time.h>
  44 #include <sys/resource.h>
  45 #include <sys/sysctl.h>
  46
  47 #include <ctype.h>
  48 #include <err.h>
  49 #include <errno.h>
  50 #include <fcntl.h>
  51 #include <signal.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <time.h>
  56 #include <unistd.h>
  57
  58 #include "truss.h"
  59 #include "extern.h"
  60
  61 #define MAXARGS 6
  62
  63 static void
  64 usage(void)
  65 {
  66         fprintf(stderr, "%s\n%s\n",
  67             "usage: truss [-faedDS] [-o file] [-s strsize] -p pid",
  68             "       truss [-faedDS] [-o file] [-s strsize] command [args]");
  69         exit(1);
  70 }
  71
  72 /*
  73  * WARNING! "FreeBSD a.out" must be first, or set_etype will not
  74  * work correctly.
  75  */
  76 struct ex_types {
  77         const char *type;
  78         void (*enter_syscall)(struct trussinfo *, int);
  79         long (*exit_syscall)(struct trussinfo *, int);
  80 } ex_types[] = {
  81 #ifdef __alpha__
  82         { "FreeBSD ELF", alpha_syscall_entry, alpha_syscall_exit },
  83 #endif
  84 #ifdef __amd64__
  85         { "FreeBSD ELF64", amd64_syscall_entry, amd64_syscall_exit },
  86 #endif
  87 #ifdef __i386__
  88         { "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit },
  89         { "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit },
  90         { "FreeBSD ELF32", i386_syscall_entry, i386_syscall_exit },
  91         { "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit },
  92 #endif
  93 #ifdef __ia64__
  94         { "FreeBSD ELF64", ia64_syscall_entry, ia64_syscall_exit },
  95 #endif
  96 #ifdef __powerpc__
  97         { "FreeBSD ELF", powerpc_syscall_entry, powerpc_syscall_exit },
  98         { "FreeBSD ELF32", powerpc_syscall_entry, powerpc_syscall_exit },
  99 #endif
 100 #ifdef __sparc64__
 101         { "FreeBSD ELF64", sparc64_syscall_entry, sparc64_syscall_exit },
 102 #endif
 103         { 0, 0, 0 },
 104 };
 105
 106 /*
 107  * Set the execution type.  This is called after every exec, and when
 108  * a process is first monitored.
 109  */
 110
 111 static struct ex_types *
 112 set_etype(struct trussinfo *trussinfo)
 113 {
 114         struct ex_types *funcs;
 115         char progt[32];
 116
 117         size_t len = sizeof(progt);
 118         int mib[4];
 119         int error;
 120
 121         mib[0] = CTL_KERN;
 122         mib[1] = KERN_PROC;
 123         mib[2] = KERN_PROC_SV_NAME;
 124         mib[3] = trussinfo->pid;
 125         error = sysctl(mib, 4, progt, &len, NULL, 0);
 126         if (error != 0)
 127                 err(2, "can not get etype");
 128
 129         for (funcs = ex_types; funcs->type; funcs++)
 130                 if (!strcmp(funcs->type, progt))
 131                         break;
 132
 133         if (funcs->type == NULL) {
 134                 funcs = &ex_types[0];
 135                 warn("execution type %s is not supported -- using %s",
 136                     progt, funcs->type);
 137         }
 138         return (funcs);
 139 }
 140
 141 char *
 142 strsig(int sig)
 143 {
 144         char *ret;
 145
 146         ret = NULL;
 147         if (sig > 0 && sig < NSIG) {
 148                 int i;
 149                 asprintf(&ret, "sig%s", sys_signame[sig]);
 150                 if (ret == NULL)
 151                         return (NULL);
 152                 for (i = 0; ret[i] != '\0'; ++i)
 153                         ret[i] = toupper(ret[i]);
 154         }
 155         return (ret);
 156 }
 157
 158 int
 159 main(int ac, char **av)
 160 {
 161         int c;
 162         int i;
 163         char **command;
 164         struct ex_types *funcs;
 165         int initial_open;
 166         char *fname;
 167         struct trussinfo *trussinfo;
 168         char *signame;
 169
 170         fname = NULL;
 171         initial_open = 1;
 172
 173         /* Initialize the trussinfo struct */
 174         trussinfo = (struct trussinfo *)malloc(sizeof(struct trussinfo));
 175         if (trussinfo == NULL)
 176                 errx(1, "malloc() failed");
 177         bzero(trussinfo, sizeof(struct trussinfo));
 178
 179         trussinfo->outfile = stderr;
 180         trussinfo->strsize = 32;
 181         trussinfo->pr_why = S_NONE;
 182         trussinfo->curthread = NULL;
 183         SLIST_INIT(&trussinfo->threadlist);
 184         while ((c = getopt(ac, av, "p:o:faedDs:S")) != -1) {
 185                 switch (c) {
 186                 case 'p':       /* specified pid */
 187                         trussinfo->pid = atoi(optarg);
 188                         /* make sure i don't trace me */
 189                         if(trussinfo->pid == getpid()) {
 190                                 fprintf(stderr, "attempt to grab self.\n");
 191                                 exit(2);
 192                         }
 193                         break;
 194                 case 'f': /* Follow fork()'s */
 195                         trussinfo->flags |= FOLLOWFORKS;
 196                         break;
 197                 case 'a': /* Print execve() argument strings. */
 198                         trussinfo->flags |= EXECVEARGS;
 199                         break;
 200                 case 'e': /* Print execve() environment strings. */
 201                         trussinfo->flags |= EXECVEENVS;
 202                         break;
 203                 case 'd': /* Absolute timestamps */
 204                         trussinfo->flags |= ABSOLUTETIMESTAMPS;
 205                         break;
 206                 case 'D': /* Relative timestamps */
 207                         trussinfo->flags |= RELATIVETIMESTAMPS;
 208                         break;
 209                 case 'o':       /* Specified output file */
 210                         fname = optarg;
 211                         break;
 212                 case 's':       /* Specified string size */
 213                         trussinfo->strsize = atoi(optarg);
 214                         break;
 215                 case 'S':       /* Don't trace signals */
 216                         trussinfo->flags |= NOSIGS;
 217                         break;
 218                 default:
 219                         usage();
 220                 }
 221         }
 222
 223         ac -= optind; av += optind;
 224         if ((trussinfo->pid == 0 && ac == 0) ||
 225             (trussinfo->pid != 0 && ac != 0))
 226                 usage();
 227
 228         if (fname != NULL) { /* Use output file */
 229                 if ((trussinfo->outfile = fopen(fname, "w")) == NULL)
 230                         errx(1, "cannot open %s", fname);
 231         }
 232
 233         /*
 234          * If truss starts the process itself, it will ignore some signals --
 235          * they should be passed off to the process, which may or may not
 236          * exit.  If, however, we are examining an already-running process,
 237          * then we restore the event mask on these same signals.
 238          */
 239
 240         if (trussinfo->pid == 0) {      /* Start a command ourselves */
 241                 command = av;
 242                 trussinfo->pid = setup_and_wait(command);
 243                 signal(SIGINT, SIG_IGN);
 244                 signal(SIGTERM, SIG_IGN);
 245                 signal(SIGQUIT, SIG_IGN);
 246         } else {
 247                 start_tracing(trussinfo->pid);
 248                 signal(SIGINT, restore_proc);
 249                 signal(SIGTERM, restore_proc);
 250                 signal(SIGQUIT, restore_proc);
 251         }
 252
 253
 254         /*
 255          * At this point, if we started the process, it is stopped waiting to
 256          * be woken up, either in exit() or in execve().
 257          */
 258
 259 START_TRACE:
 260         funcs = set_etype(trussinfo);
 261
 262         initial_open = 0;
 263         /*
 264          * At this point, it's a simple loop, waiting for the process to
 265          * stop, finding out why, printing out why, and then continuing it.
 266          * All of the grunt work is done in the support routines.
 267          */
 268
 269         clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);
 270
 271         do {
 272                 struct timespec timediff;
 273                 waitevent(trussinfo);
 274
 275                 switch(i = trussinfo->pr_why) {
 276                 case S_SCE:
 277                         funcs->enter_syscall(trussinfo, MAXARGS);
 278                         clock_gettime(CLOCK_REALTIME,
 279                             &trussinfo->before);
 280                         break;
 281                 case S_SCX:
 282                         clock_gettime(CLOCK_REALTIME,
 283                             &trussinfo->after);
 284
 285                         if (trussinfo->curthread->in_fork &&
 286                             (trussinfo->flags & FOLLOWFORKS)) {
 287                                 int childpid;
 288
 289                                 trussinfo->curthread->in_fork = 0;
 290                                 childpid =
 291                                     funcs->exit_syscall(trussinfo,
 292                                         trussinfo->pr_data);
 293
 294                                 /*
 295                                  * Fork a new copy of ourself to trace
 296                                  * the child of the original traced
 297                                  * process.
 298                                  */
 299                                 if (fork() == 0) {
 300                                         trussinfo->pid = childpid;
 301                                         start_tracing(trussinfo->pid);
 302                                         goto START_TRACE;
 303                                 }
 304                                 break;
 305                         }
 306                         funcs->exit_syscall(trussinfo, MAXARGS);
 307                         break;
 308                 case S_SIG:
 309                         if (trussinfo->flags & NOSIGS)
 310                                 break;
 311                         if (trussinfo->flags & FOLLOWFORKS)
 312                                 fprintf(trussinfo->outfile, "%5d: ",
 313                                     trussinfo->pid);
 314                         if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
 315                                 timespecsubt(&trussinfo->after,
 316                                     &trussinfo->start_time, &timediff);
 317                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 318                                     (long)timediff.tv_sec,
 319                                     timediff.tv_nsec);
 320                         }
 321                         if (trussinfo->flags & RELATIVETIMESTAMPS) {
 322                                 timespecsubt(&trussinfo->after,
 323                                     &trussinfo->before, &timediff);
 324                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 325                                     (long)timediff.tv_sec,
 326                                     timediff.tv_nsec);
 327                         }
 328                         signame = strsig(trussinfo->pr_data);
 329                         fprintf(trussinfo->outfile,
 330                             "SIGNAL %u (%s)\n", trussinfo->pr_data,
 331                             signame == NULL ? "?" : signame);
 332                         free(signame);
 333                         break;
 334                 case S_EXIT:
 335                         if (trussinfo->flags & FOLLOWFORKS)
 336                                 fprintf(trussinfo->outfile, "%5d: ",
 337                                     trussinfo->pid);
 338                         if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
 339                                 timespecsubt(&trussinfo->after,
 340                                     &trussinfo->start_time, &timediff);
 341                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 342                                     (long)timediff.tv_sec,
 343                                     timediff.tv_nsec);
 344                         }
 345                         if (trussinfo->flags & RELATIVETIMESTAMPS) {
 346                           timespecsubt(&trussinfo->after,
 347                               &trussinfo->before, &timediff);
 348                           fprintf(trussinfo->outfile, "%ld.%09ld ",
 349                             (long)timediff.tv_sec, timediff.tv_nsec);
 350                         }
 351                         fprintf(trussinfo->outfile,
 352                             "process exit, rval = %u\n", trussinfo->pr_data);
 353                         break;
 354                 default:
 355                         break;
 356                 }
 357         } while (trussinfo->pr_why != S_EXIT);
 358         fflush(trussinfo->outfile);
 359
 360         return (0);
 361 }