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 __amd64__
  82         { "FreeBSD ELF64", amd64_syscall_entry, amd64_syscall_exit },
  83         { "FreeBSD ELF32", amd64_fbsd32_syscall_entry, amd64_fbsd32_syscall_exit },
  84         { "Linux ELF32", amd64_linux32_syscall_entry, amd64_linux32_syscall_exit },
  85 #endif
  86 #ifdef __i386__
  87         { "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit },
  88         { "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit },
  89         { "FreeBSD ELF32", i386_syscall_entry, i386_syscall_exit },
  90         { "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit },
  91 #endif
  92 #ifdef __ia64__
  93         { "FreeBSD ELF64", ia64_syscall_entry, ia64_syscall_exit },
  94 #endif
  95 #ifdef __powerpc__
  96         { "FreeBSD ELF", powerpc_syscall_entry, powerpc_syscall_exit },
  97         { "FreeBSD ELF32", powerpc_syscall_entry, powerpc_syscall_exit },
  98 #endif
  99 #ifdef __sparc64__
 100         { "FreeBSD ELF64", sparc64_syscall_entry, sparc64_syscall_exit },
 101 #endif
 102         { 0, 0, 0 },
 103 };
 104
 105 /*
 106  * Set the execution type.  This is called after every exec, and when
 107  * a process is first monitored.
 108  */
 109
 110 static struct ex_types *
 111 set_etype(struct trussinfo *trussinfo)
 112 {
 113         struct ex_types *funcs;
 114         char progt[32];
 115
 116         size_t len = sizeof(progt);
 117         int mib[4];
 118         int error;
 119
 120         mib[0] = CTL_KERN;
 121         mib[1] = KERN_PROC;
 122         mib[2] = KERN_PROC_SV_NAME;
 123         mib[3] = trussinfo->pid;
 124         error = sysctl(mib, 4, progt, &len, NULL, 0);
 125         if (error != 0)
 126                 err(2, "can not get etype");
 127
 128         for (funcs = ex_types; funcs->type; funcs++)
 129                 if (!strcmp(funcs->type, progt))
 130                         break;
 131
 132         if (funcs->type == NULL) {
 133                 funcs = &ex_types[0];
 134                 warn("execution type %s is not supported -- using %s",
 135                     progt, funcs->type);
 136         }
 137         return (funcs);
 138 }
 139
 140 char *
 141 strsig(int sig)
 142 {
 143         char *ret;
 144
 145         ret = NULL;
 146         if (sig > 0 && sig < NSIG) {
 147                 int i;
 148                 asprintf(&ret, "sig%s", sys_signame[sig]);
 149                 if (ret == NULL)
 150                         return (NULL);
 151                 for (i = 0; ret[i] != '\0'; ++i)
 152                         ret[i] = toupper(ret[i]);
 153         }
 154         return (ret);
 155 }
 156
 157 int
 158 main(int ac, char **av)
 159 {
 160         int c;
 161         int i;
 162         char **command;
 163         struct ex_types *funcs;
 164         int initial_open;
 165         char *fname;
 166         struct trussinfo *trussinfo;
 167         char *signame;
 168
 169         fname = NULL;
 170         initial_open = 1;
 171
 172         /* Initialize the trussinfo struct */
 173         trussinfo = (struct trussinfo *)malloc(sizeof(struct trussinfo));
 174         if (trussinfo == NULL)
 175                 errx(1, "malloc() failed");
 176         bzero(trussinfo, sizeof(struct trussinfo));
 177
 178         trussinfo->outfile = stderr;
 179         trussinfo->strsize = 32;
 180         trussinfo->pr_why = S_NONE;
 181         trussinfo->curthread = NULL;
 182         SLIST_INIT(&trussinfo->threadlist);
 183         while ((c = getopt(ac, av, "p:o:faedDs:S")) != -1) {
 184                 switch (c) {
 185                 case 'p':       /* specified pid */
 186                         trussinfo->pid = atoi(optarg);
 187                         /* make sure i don't trace me */
 188                         if(trussinfo->pid == getpid()) {
 189                                 fprintf(stderr, "attempt to grab self.\n");
 190                                 exit(2);
 191                         }
 192                         break;
 193                 case 'f': /* Follow fork()'s */
 194                         trussinfo->flags |= FOLLOWFORKS;
 195                         break;
 196                 case 'a': /* Print execve() argument strings. */
 197                         trussinfo->flags |= EXECVEARGS;
 198                         break;
 199                 case 'e': /* Print execve() environment strings. */
 200                         trussinfo->flags |= EXECVEENVS;
 201                         break;
 202                 case 'd': /* Absolute timestamps */
 203                         trussinfo->flags |= ABSOLUTETIMESTAMPS;
 204                         break;
 205                 case 'D': /* Relative timestamps */
 206                         trussinfo->flags |= RELATIVETIMESTAMPS;
 207                         break;
 208                 case 'o':       /* Specified output file */
 209                         fname = optarg;
 210                         break;
 211                 case 's':       /* Specified string size */
 212                         trussinfo->strsize = atoi(optarg);
 213                         break;
 214                 case 'S':       /* Don't trace signals */
 215                         trussinfo->flags |= NOSIGS;
 216                         break;
 217                 default:
 218                         usage();
 219                 }
 220         }
 221
 222         ac -= optind; av += optind;
 223         if ((trussinfo->pid == 0 && ac == 0) ||
 224             (trussinfo->pid != 0 && ac != 0))
 225                 usage();
 226
 227         if (fname != NULL) { /* Use output file */
 228                 if ((trussinfo->outfile = fopen(fname, "w")) == NULL)
 229                         errx(1, "cannot open %s", fname);
 230         }
 231
 232         /*
 233          * If truss starts the process itself, it will ignore some signals --
 234          * they should be passed off to the process, which may or may not
 235          * exit.  If, however, we are examining an already-running process,
 236          * then we restore the event mask on these same signals.
 237          */
 238
 239         if (trussinfo->pid == 0) {      /* Start a command ourselves */
 240                 command = av;
 241                 trussinfo->pid = setup_and_wait(command);
 242                 signal(SIGINT, SIG_IGN);
 243                 signal(SIGTERM, SIG_IGN);
 244                 signal(SIGQUIT, SIG_IGN);
 245         } else {
 246                 start_tracing(trussinfo->pid);
 247                 signal(SIGINT, restore_proc);
 248                 signal(SIGTERM, restore_proc);
 249                 signal(SIGQUIT, restore_proc);
 250         }
 251
 252
 253         /*
 254          * At this point, if we started the process, it is stopped waiting to
 255          * be woken up, either in exit() or in execve().
 256          */
 257
 258 START_TRACE:
 259         funcs = set_etype(trussinfo);
 260
 261         initial_open = 0;
 262         /*
 263          * At this point, it's a simple loop, waiting for the process to
 264          * stop, finding out why, printing out why, and then continuing it.
 265          * All of the grunt work is done in the support routines.
 266          */
 267
 268         clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);
 269
 270         do {
 271                 struct timespec timediff;
 272                 waitevent(trussinfo);
 273
 274                 switch(i = trussinfo->pr_why) {
 275                 case S_SCE:
 276                         funcs->enter_syscall(trussinfo, MAXARGS);
 277                         clock_gettime(CLOCK_REALTIME,
 278                             &trussinfo->before);
 279                         break;
 280                 case S_SCX:
 281                         clock_gettime(CLOCK_REALTIME,
 282                             &trussinfo->after);
 283
 284                         if (trussinfo->curthread->in_fork &&
 285                             (trussinfo->flags & FOLLOWFORKS)) {
 286                                 int childpid;
 287
 288                                 trussinfo->curthread->in_fork = 0;
 289                                 childpid =
 290                                     funcs->exit_syscall(trussinfo,
 291                                         trussinfo->pr_data);
 292
 293                                 /*
 294                                  * Fork a new copy of ourself to trace
 295                                  * the child of the original traced
 296                                  * process.
 297                                  */
 298                                 if (fork() == 0) {
 299                                         trussinfo->pid = childpid;
 300                                         start_tracing(trussinfo->pid);
 301                                         goto START_TRACE;
 302                                 }
 303                                 break;
 304                         }
 305                         funcs->exit_syscall(trussinfo, MAXARGS);
 306                         break;
 307                 case S_SIG:
 308                         if (trussinfo->flags & NOSIGS)
 309                                 break;
 310                         if (trussinfo->flags & FOLLOWFORKS)
 311                                 fprintf(trussinfo->outfile, "%5d: ",
 312                                     trussinfo->pid);
 313                         if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
 314                                 timespecsubt(&trussinfo->after,
 315                                     &trussinfo->start_time, &timediff);
 316                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 317                                     (long)timediff.tv_sec,
 318                                     timediff.tv_nsec);
 319                         }
 320                         if (trussinfo->flags & RELATIVETIMESTAMPS) {
 321                                 timespecsubt(&trussinfo->after,
 322                                     &trussinfo->before, &timediff);
 323                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 324                                     (long)timediff.tv_sec,
 325                                     timediff.tv_nsec);
 326                         }
 327                         signame = strsig(trussinfo->pr_data);
 328                         fprintf(trussinfo->outfile,
 329                             "SIGNAL %u (%s)\n", trussinfo->pr_data,
 330                             signame == NULL ? "?" : signame);
 331                         free(signame);
 332                         break;
 333                 case S_EXIT:
 334                         if (trussinfo->flags & FOLLOWFORKS)
 335                                 fprintf(trussinfo->outfile, "%5d: ",
 336                                     trussinfo->pid);
 337                         if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
 338                                 timespecsubt(&trussinfo->after,
 339                                     &trussinfo->start_time, &timediff);
 340                                 fprintf(trussinfo->outfile, "%ld.%09ld ",
 341                                     (long)timediff.tv_sec,
 342                                     timediff.tv_nsec);
 343                         }
 344                         if (trussinfo->flags & RELATIVETIMESTAMPS) {
 345                           timespecsubt(&trussinfo->after,
 346                               &trussinfo->before, &timediff);
 347                           fprintf(trussinfo->outfile, "%ld.%09ld ",
 348                             (long)timediff.tv_sec, timediff.tv_nsec);
 349                         }
 350                         fprintf(trussinfo->outfile,
 351                             "process exit, rval = %u\n", trussinfo->pr_data);
 352                         break;
 353                 default:
 354                         break;
 355                 }
 356         } while (trussinfo->pr_why != S_EXIT);
 357         fflush(trussinfo->outfile);
 358
 359         return (0);
 360 }