usr.bin/truss/main.c

   1 /*-
   2  * Copyright 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.  Surprisingly 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 #include <sys/wait.h>
  47
  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 #include "syscall.h"
  61
  62 #define MAXARGS 6
  63
  64 static void
  65 usage(void)
  66 {
  67         fprintf(stderr, "%s\n%s\n",
  68             "usage: truss [-cfaedDS] [-o file] [-s strsize] -p pid",
  69             "       truss [-cfaedDS] [-o file] [-s strsize] command [args]");
  70         exit(1);
  71 }
  72
  73 /*
  74  * WARNING! "FreeBSD a.out" must be first, or set_etype will not
  75  * work correctly.
  76  */
  77 struct ex_types {
  78         const char *type;
  79         void (*enter_syscall)(struct trussinfo *, int);
  80         long (*exit_syscall)(struct trussinfo *, int);
  81 } ex_types[] = {
  82 #ifdef __amd64__
  83         { "FreeBSD ELF64", amd64_syscall_entry, amd64_syscall_exit },
  84         { "FreeBSD ELF32", amd64_fbsd32_syscall_entry, amd64_fbsd32_syscall_exit },
  85         { "Linux ELF32", amd64_linux32_syscall_entry, amd64_linux32_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 #ifdef __powerpc64__
 100         { "FreeBSD ELF64", powerpc64_syscall_entry, powerpc64_syscall_exit },
 101 #endif
 102 #endif
 103 #ifdef __sparc64__
 104         { "FreeBSD ELF64", sparc64_syscall_entry, sparc64_syscall_exit },
 105 #endif
 106 #ifdef __mips__
 107         { "FreeBSD ELF", mips_syscall_entry, mips_syscall_exit },
 108         { "FreeBSD ELF32", mips_syscall_entry, mips_syscall_exit },
 109         { "FreeBSD ELF64", mips_syscall_entry, mips_syscall_exit }, // XXX
 110 #endif
 111         { 0, 0, 0 },
 112 };
 113
 114 /*
 115  * Set the execution type.  This is called after every exec, and when
 116  * a process is first monitored.
 117  */
 118
 119 static struct ex_types *
 120 set_etype(struct trussinfo *trussinfo)
 121 {
 122         struct ex_types *funcs;
 123         char progt[32];
 124
 125         size_t len = sizeof(progt);
 126         int mib[4];
 127         int error;
 128
 129         mib[0] = CTL_KERN;
 130         mib[1] = KERN_PROC;
 131         mib[2] = KERN_PROC_SV_NAME;
 132         mib[3] = trussinfo->pid;
 133         error = sysctl(mib, 4, progt, &len, NULL, 0);
 134         if (error != 0)
 135                 err(2, "can not get etype");
 136
 137         for (funcs = ex_types; funcs->type; funcs++)
 138                 if (!strcmp(funcs->type, progt))
 139                         break;
 140
 141         if (funcs->type == NULL) {
 142                 funcs = &ex_types[0];
 143                 warn("execution type %s is not supported -- using %s",
 144                     progt, funcs->type);
 145         }
 146         return (funcs);
 147 }
 148
 149 char *
 150 strsig(int sig)
 151 {
 152         char *ret;
 153
 154         ret = NULL;
 155         if (sig > 0 && sig < NSIG) {
 156                 asprintf(&ret, "SIG%s", sys_signame[sig]);
 157                 if (ret == NULL)
 158                         return (NULL);
 159         }
 160         return (ret);
 161 }
 162
 163 int
 164 main(int ac, char **av)
 165 {
 166         int c;
 167         int i;
 168         pid_t childpid;
 169         int status;
 170         char **command;
 171         struct ex_types *funcs;
 172         int initial_open;
 173         char *fname;
 174         struct trussinfo *trussinfo;
 175         char *signame;
 176
 177         fname = NULL;
 178         initial_open = 1;
 179
 180         /* Initialize the trussinfo struct */
 181         trussinfo = (struct trussinfo *)calloc(1, sizeof(struct trussinfo));
 182         if (trussinfo == NULL)
 183                 errx(1, "calloc() failed");
 184
 185         trussinfo->outfile = stderr;
 186         trussinfo->strsize = 32;
 187         trussinfo->pr_why = S_NONE;
 188         trussinfo->curthread = NULL;
 189         SLIST_INIT(&trussinfo->threadlist);
 190         while ((c = getopt(ac, av, "p:o:facedDs:S")) != -1) {
 191                 switch (c) {
 192                 case 'p':       /* specified pid */
 193                         trussinfo->pid = atoi(optarg);
 194                         /* make sure i don't trace me */
 195                         if(trussinfo->pid == getpid()) {
 196                                 fprintf(stderr, "attempt to grab self.\n");
 197                                 exit(2);
 198                         }
 199                         break;
 200                 case 'f': /* Follow fork()'s */
 201                         trussinfo->flags |= FOLLOWFORKS;
 202                         break;
 203                 case 'a': /* Print execve() argument strings. */
 204                         trussinfo->flags |= EXECVEARGS;
 205                         break;
 206                 case 'c': /* Count number of system calls and time. */
 207                         trussinfo->flags |= COUNTONLY;
 208                         break;
 209                 case 'e': /* Print execve() environment strings. */
 210                         trussinfo->flags |= EXECVEENVS;
 211                         break;
 212                 case 'd': /* Absolute timestamps */
 213                         trussinfo->flags |= ABSOLUTETIMESTAMPS;
 214                         break;
 215                 case 'D': /* Relative timestamps */
 216                         trussinfo->flags |= RELATIVETIMESTAMPS;
 217                         break;
 218                 case 'o':       /* Specified output file */
 219                         fname = optarg;
 220                         break;
 221                 case 's':       /* Specified string size */
 222                         trussinfo->strsize = atoi(optarg);
 223                         break;
 224                 case 'S':       /* Don't trace signals */
 225                         trussinfo->flags |= NOSIGS;
 226                         break;
 227                 default:
 228                         usage();
 229                 }
 230         }
 231
 232         ac -= optind; av += optind;
 233         if ((trussinfo->pid == 0 && ac == 0) ||
 234             (trussinfo->pid != 0 && ac != 0))
 235                 usage();
 236
 237         if (fname != NULL) { /* Use output file */
 238                 if ((trussinfo->outfile = fopen(fname, "w")) == NULL)
 239                         errx(1, "cannot open %s", fname);
 240                 /*
 241                  * Set FD_CLOEXEC, so that the output file is not shared with
 242                  * the traced process.
 243                  */
 244                 if (fcntl(fileno(trussinfo->outfile), F_SETFD, FD_CLOEXEC) ==
 245                     -1)
 246                         warn("fcntl()");
 247         }
 248
 249         /*
 250          * If truss starts the process itself, it will ignore some signals --
 251          * they should be passed off to the process, which may or may not
 252          * exit.  If, however, we are examining an already-running process,
 253          * then we restore the event mask on these same signals.
 254          */
 255
 256         if (trussinfo->pid == 0) {      /* Start a command ourselves */
 257                 command = av;
 258                 trussinfo->pid = setup_and_wait(command);
 259                 signal(SIGINT, SIG_IGN);
 260                 signal(SIGTERM, SIG_IGN);
 261                 signal(SIGQUIT, SIG_IGN);
 262         } else {
 263                 start_tracing(trussinfo->pid);
 264                 signal(SIGINT, restore_proc);
 265                 signal(SIGTERM, restore_proc);
 266                 signal(SIGQUIT, restore_proc);
 267         }
 268
 269
 270         /*
 271          * At this point, if we started the process, it is stopped waiting to
 272          * be woken up, either in exit() or in execve().
 273          */
 274
 275 START_TRACE:
 276         funcs = set_etype(trussinfo);
 277
 278         initial_open = 0;
 279         /*
 280          * At this point, it's a simple loop, waiting for the process to
 281          * stop, finding out why, printing out why, and then continuing it.
 282          * All of the grunt work is done in the support routines.
 283          */
 284
 285         clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);
 286
 287         do {
 288                 struct timespec timediff;
 289                 waitevent(trussinfo);
 290
 291                 switch(i = trussinfo->pr_why) {
 292                 case S_SCE:
 293                         funcs->enter_syscall(trussinfo, MAXARGS);
 294                         clock_gettime(CLOCK_REALTIME,
 295                             &trussinfo->before);
 296                         break;
 297                 case S_SCX:
 298                         clock_gettime(CLOCK_REALTIME,
 299                             &trussinfo->after);
 300
 301                         if (trussinfo->curthread->in_fork &&
 302                             (trussinfo->flags & FOLLOWFORKS)) {
 303                                 trussinfo->curthread->in_fork = 0;
 304                                 childpid =
 305                                     funcs->exit_syscall(trussinfo,
 306                                         trussinfo->pr_data);
 307
 308                                 /*
 309                                  * Fork a new copy of ourself to trace
 310                                  * the child of the original traced
 311                                  * process.
 312                                  */
 313                                 if (fork() == 0) {
 314                                         trussinfo->pid = childpid;
 315                                         start_tracing(trussinfo->pid);
 316                                         goto START_TRACE;
 317                                 }
 318                                 break;
 319                         }
 320                         funcs->exit_syscall(trussinfo, MAXARGS);
 321                         break;
 322                 case S_SIG:
 323                         if (trussinfo->flags & NOSIGS)
 324                                 break;
 325                         if (trussinfo->flags & FOLLOWFORKS)
 326                                 fprintf(trussinfo->outfile, "%5d: ",
 327                                     trussinfo->pid);
 328                         if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
 329                                 timespecsubt(&trussinfo->after,
 330                                     &trussinfo->start_time, &timediff);
 331                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 332                                     (long)timediff.tv_sec,
 333                                     timediff.tv_nsec);
 334                         }
 335                         if (trussinfo->flags & RELATIVETIMESTAMPS) {
 336                                 timespecsubt(&trussinfo->after,
 337                                     &trussinfo->before, &timediff);
 338                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 339                                     (long)timediff.tv_sec,
 340                                     timediff.tv_nsec);
 341                         }
 342                         signame = strsig(trussinfo->pr_data);
 343                         fprintf(trussinfo->outfile,
 344                             "SIGNAL %u (%s)\n", trussinfo->pr_data,
 345                             signame == NULL ? "?" : signame);
 346                         free(signame);
 347                         break;
 348                 case S_EXIT:
 349                         if (trussinfo->flags & COUNTONLY)
 350                                 break;
 351                         if (trussinfo->flags & FOLLOWFORKS)
 352                                 fprintf(trussinfo->outfile, "%5d: ",
 353                                     trussinfo->pid);
 354                         if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
 355                                 timespecsubt(&trussinfo->after,
 356                                     &trussinfo->start_time, &timediff);
 357                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 358                                     (long)timediff.tv_sec,
 359                                     timediff.tv_nsec);
 360                         }
 361                         if (trussinfo->flags & RELATIVETIMESTAMPS) {
 362                           timespecsubt(&trussinfo->after,
 363                               &trussinfo->before, &timediff);
 364                           fprintf(trussinfo->outfile, "%ld.%09ld ",
 365                             (long)timediff.tv_sec, timediff.tv_nsec);
 366                         }
 367                         fprintf(trussinfo->outfile,
 368                             "process exit, rval = %u\n", trussinfo->pr_data);
 369                         break;
 370                 default:
 371                         break;
 372                 }
 373         } while (trussinfo->pr_why != S_EXIT);
 374
 375         if (trussinfo->flags & FOLLOWFORKS)
 376                 do {
 377                         childpid = wait(&status);
 378                 } while (childpid != -1);
 379
 380         if (trussinfo->flags & COUNTONLY)
 381                 print_summary(trussinfo);
 382
 383         fflush(trussinfo->outfile);
 384
 385         return (0);
 386 }