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/main.c,v 1.15.2.3 2002/05/16 23:41:23 peter Exp $ 32 * $DragonFly: src/usr.bin/truss/main.c,v 1.4 2003/11/04 15:34:41 eirikn Exp $ 33 */ 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/ioctl.h> 43 #include <sys/pioctl.h> 44 #include <sys/ucred.h> 45 #include <sys/mount.h> 46 47 #include <err.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <signal.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 56 #include "extern.h" 57 58 /* 59 * These should really be parameterized -- I don't like having globals, 60 * but this is the easiest way, right now, to deal with them. 61 */ 62 63 int pid = 0; 64 int nosigs = 0; 65 FILE *outfile; 66 int Procfd; 67 68 static inline void 69 usage(void) 70 { 71 fprintf(stderr, "%s\n%s\n", 72 "usage: truss [-S] [-o file] -p pid", 73 " truss [-S] [-o file] command [args]"); 74 exit(1); 75 } 76 77 /* 78 * WARNING! "FreeBSD a.out" must be first, or set_etype will not 79 * work correctly. 80 */ 81 struct ex_types { 82 const char *type; 83 void (*enter_syscall)(int, int); 84 void (*exit_syscall)(int, int); 85 } ex_types[] = { 86 #ifdef __alpha__ 87 { "FreeBSD ELF", alpha_syscall_entry, alpha_syscall_exit }, 88 #endif 89 #ifdef __i386__ 90 { "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit }, 91 { "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit }, 92 { "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit }, 93 #endif 94 { 0, 0, 0 }, 95 }; 96 97 /* 98 * Set the execution type. This is called after every exec, and when 99 * a process is first monitored. The procfs pseudo-file "etype" has 100 * the execution module type -- see /proc/curproc/etype for an example. 101 */ 102 103 static struct ex_types * 104 set_etype(void) { 105 struct ex_types *funcs; 106 char *etype; 107 char progt[32]; 108 int fd; 109 110 asprintf(&etype, "%s/%d/etype", procfs_path, pid); 111 if (etype == NULL) 112 err(1, "Out of memory"); 113 if ((fd = open(etype, O_RDONLY)) == -1) { 114 strcpy(progt, "FreeBSD a.out"); 115 } else { 116 int len = read(fd, progt, sizeof(progt)); 117 progt[len-1] = '\0'; 118 close(fd); 119 } 120 free(etype); 121 122 for (funcs = ex_types; funcs->type; funcs++) 123 if (!strcmp(funcs->type, progt)) 124 break; 125 126 if (funcs->type == NULL) { 127 funcs = &ex_types[0]; 128 warn("Execution type %s is not supported -- using %s\n", 129 progt, funcs->type); 130 } 131 return funcs; 132 } 133 134 int 135 main(int ac, char **av) { 136 int c, i, mntsize; 137 char **command; 138 struct procfs_status pfs; 139 struct ex_types *funcs; 140 struct statfs *mntbuf; 141 int in_exec = 0; 142 char *fname = NULL; 143 int sigexit = 0; 144 145 /* Check where procfs is mounted if it is mounted */ 146 if ((mntsize = getmntinfo(&mntbuf, MNT_NOWAIT)) == 0) 147 err(1, "getmntinfo"); 148 for (i = 0; i < mntsize; i++) { 149 if (strcasecmp(mntbuf[i].f_mntfromname, "procfs") == 0) { 150 strlcpy(procfs_path, mntbuf[i].f_mntonname, sizeof(procfs_path)); 151 have_procfs = 1; 152 break; 153 } 154 } 155 if (!have_procfs) { 156 errno = 2; 157 err(1, "You must have a mounted procfs to use truss"); 158 } 159 160 outfile = stderr; 161 while ((c = getopt(ac, av, "p:o:S")) != -1) { 162 switch (c) { 163 case 'p': /* specified pid */ 164 pid = atoi(optarg); 165 if (pid == getpid()) { 166 /* make sure truss doesn't trace itself */ 167 fprintf(stderr, "truss: attempt to self trace: %d\n", pid); 168 exit(2); 169 } 170 break; 171 case 'o': /* Specified output file */ 172 fname = optarg; 173 break; 174 case 'S': /* Don't trace signals */ 175 nosigs = 1; 176 break; 177 default: 178 usage(); 179 } 180 } 181 182 ac -= optind; av += optind; 183 if ((pid == 0 && ac == 0) || (pid != 0 && ac != 0)) 184 usage(); 185 186 if (fname != NULL) { /* Use output file */ 187 if ((outfile = fopen(fname, "w")) == NULL) 188 errx(1, "cannot open %s", fname); 189 } 190 191 /* 192 * If truss starts the process itself, it will ignore some signals -- 193 * they should be passed off to the process, which may or may not 194 * exit. If, however, we are examining an already-running process, 195 * then we restore the event mask on these same signals. 196 */ 197 198 if (pid == 0) { /* Start a command ourselves */ 199 command = av; 200 pid = setup_and_wait(command); 201 signal(SIGINT, SIG_IGN); 202 signal(SIGTERM, SIG_IGN); 203 signal(SIGQUIT, SIG_IGN); 204 } else { 205 signal(SIGINT, restore_proc); 206 signal(SIGTERM, restore_proc); 207 signal(SIGQUIT, restore_proc); 208 } 209 210 211 /* 212 * At this point, if we started the process, it is stopped waiting to 213 * be woken up, either in exit() or in execve(). 214 */ 215 216 Procfd = start_tracing(pid, S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT | 217 (nosigs ? 0 : S_SIG)); 218 if (Procfd == -1) 219 return 0; 220 221 pfs.why = 0; 222 223 funcs = set_etype(); 224 /* 225 * At this point, it's a simple loop, waiting for the process to 226 * stop, finding out why, printing out why, and then continuing it. 227 * All of the grunt work is done in the support routines. 228 */ 229 230 do { 231 int val = 0; 232 233 if (ioctl(Procfd, PIOCWAIT, &pfs) == -1) 234 warn("PIOCWAIT top of loop"); 235 else { 236 switch(i = pfs.why) { 237 case S_SCE: 238 funcs->enter_syscall(pid, pfs.val); 239 break; 240 case S_SCX: 241 /* 242 * This is so we don't get two messages for an exec -- one 243 * for the S_EXEC, and one for the syscall exit. It also, 244 * conveniently, ensures that the first message printed out 245 * isn't the return-from-syscall used to create the process. 246 */ 247 248 if (in_exec) { 249 in_exec = 0; 250 break; 251 } 252 funcs->exit_syscall(pid, pfs.val); 253 break; 254 case S_SIG: 255 fprintf(outfile, "SIGNAL %lu\n", pfs.val); 256 sigexit = pfs.val; 257 break; 258 case S_EXIT: 259 fprintf (outfile, "process exit, rval = %lu\n", pfs.val); 260 break; 261 case S_EXEC: 262 funcs = set_etype(); 263 in_exec = 1; 264 break; 265 default: 266 fprintf (outfile, "Process stopped because of: %d\n", i); 267 break; 268 } 269 } 270 if (ioctl(Procfd, PIOCCONT, val) == -1) { 271 if (kill(pid, 0) == -1 && errno == ESRCH) 272 break; 273 else 274 warn("PIOCCONT"); 275 } 276 } while (pfs.why != S_EXIT); 277 fflush(outfile); 278 if (sigexit) { 279 if (sigexit == SIGQUIT) 280 exit(sigexit); 281 (void) signal(sigexit, SIG_DFL); 282 (void) kill(getpid(), sigexit); 283 } 284 return 0; 285 } 286