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 1.3 2003/08/28 02:42:00 hmp 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 45 #include <err.h> 46 #include <errno.h> 47 #include <fcntl.h> 48 #include <signal.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 #include "extern.h" 55 56 /* 57 * These should really be parameterized -- I don't like having globals, 58 * but this is the easiest way, right now, to deal with them. 59 */ 60 61 int pid = 0; 62 int nosigs = 0; 63 FILE *outfile; 64 int Procfd; 65 66 static inline void 67 usage(void) 68 { 69 fprintf(stderr, "%s\n%s\n", 70 "usage: truss [-S] [-o file] -p pid", 71 " truss [-S] [-o file] command [args]"); 72 exit(1); 73 } 74 75 /* 76 * WARNING! "FreeBSD a.out" must be first, or set_etype will not 77 * work correctly. 78 */ 79 struct ex_types { 80 const char *type; 81 void (*enter_syscall)(int, int); 82 void (*exit_syscall)(int, int); 83 } ex_types[] = { 84 #ifdef __alpha__ 85 { "FreeBSD ELF", alpha_syscall_entry, alpha_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 { "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit }, 91 #endif 92 { 0, 0, 0 }, 93 }; 94 95 /* 96 * Set the execution type. This is called after every exec, and when 97 * a process is first monitored. The procfs pseudo-file "etype" has 98 * the execution module type -- see /proc/curproc/etype for an example. 99 */ 100 101 static struct ex_types * 102 set_etype(void) { 103 struct ex_types *funcs; 104 char etype[24]; 105 char progt[32]; 106 int fd; 107 108 sprintf(etype, "/proc/%d/etype", pid); 109 if ((fd = open(etype, O_RDONLY)) == -1) { 110 strcpy(progt, "FreeBSD a.out"); 111 } else { 112 int len = read(fd, progt, sizeof(progt)); 113 progt[len-1] = '\0'; 114 close(fd); 115 } 116 117 for (funcs = ex_types; funcs->type; funcs++) 118 if (!strcmp(funcs->type, progt)) 119 break; 120 121 if (funcs->type == NULL) { 122 funcs = &ex_types[0]; 123 warn("Execution type %s is not supported -- using %s\n", 124 progt, funcs->type); 125 } 126 return funcs; 127 } 128 129 int 130 main(int ac, char **av) { 131 int c; 132 int i; 133 char **command; 134 struct procfs_status pfs; 135 struct ex_types *funcs; 136 int in_exec = 0; 137 char *fname = NULL; 138 int sigexit = 0; 139 140 outfile = stderr; 141 while ((c = getopt(ac, av, "p:o:S")) != -1) { 142 switch (c) { 143 case 'p': /* specified pid */ 144 pid = atoi(optarg); 145 if (pid == getpid()) { 146 /* make sure truss doesn't trace itself */ 147 fprintf(stderr, "truss: attempt to self trace: %d\n", pid); 148 exit(2); 149 } 150 break; 151 case 'o': /* Specified output file */ 152 fname = optarg; 153 break; 154 case 'S': /* Don't trace signals */ 155 nosigs = 1; 156 break; 157 default: 158 usage(); 159 } 160 } 161 162 ac -= optind; av += optind; 163 if ((pid == 0 && ac == 0) || (pid != 0 && ac != 0)) 164 usage(); 165 166 if (fname != NULL) { /* Use output file */ 167 if ((outfile = fopen(fname, "w")) == NULL) 168 errx(1, "cannot open %s", fname); 169 } 170 171 /* 172 * If truss starts the process itself, it will ignore some signals -- 173 * they should be passed off to the process, which may or may not 174 * exit. If, however, we are examining an already-running process, 175 * then we restore the event mask on these same signals. 176 */ 177 178 if (pid == 0) { /* Start a command ourselves */ 179 command = av; 180 pid = setup_and_wait(command); 181 signal(SIGINT, SIG_IGN); 182 signal(SIGTERM, SIG_IGN); 183 signal(SIGQUIT, SIG_IGN); 184 } else { 185 signal(SIGINT, restore_proc); 186 signal(SIGTERM, restore_proc); 187 signal(SIGQUIT, restore_proc); 188 } 189 190 191 /* 192 * At this point, if we started the process, it is stopped waiting to 193 * be woken up, either in exit() or in execve(). 194 */ 195 196 Procfd = start_tracing(pid, S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT | 197 (nosigs ? 0 : S_SIG)); 198 if (Procfd == -1) 199 return 0; 200 201 pfs.why = 0; 202 203 funcs = set_etype(); 204 /* 205 * At this point, it's a simple loop, waiting for the process to 206 * stop, finding out why, printing out why, and then continuing it. 207 * All of the grunt work is done in the support routines. 208 */ 209 210 do { 211 int val = 0; 212 213 if (ioctl(Procfd, PIOCWAIT, &pfs) == -1) 214 warn("PIOCWAIT top of loop"); 215 else { 216 switch(i = pfs.why) { 217 case S_SCE: 218 funcs->enter_syscall(pid, pfs.val); 219 break; 220 case S_SCX: 221 /* 222 * This is so we don't get two messages for an exec -- one 223 * for the S_EXEC, and one for the syscall exit. It also, 224 * conveniently, ensures that the first message printed out 225 * isn't the return-from-syscall used to create the process. 226 */ 227 228 if (in_exec) { 229 in_exec = 0; 230 break; 231 } 232 funcs->exit_syscall(pid, pfs.val); 233 break; 234 case S_SIG: 235 fprintf(outfile, "SIGNAL %lu\n", pfs.val); 236 sigexit = pfs.val; 237 break; 238 case S_EXIT: 239 fprintf (outfile, "process exit, rval = %lu\n", pfs.val); 240 break; 241 case S_EXEC: 242 funcs = set_etype(); 243 in_exec = 1; 244 break; 245 default: 246 fprintf (outfile, "Process stopped because of: %d\n", i); 247 break; 248 } 249 } 250 if (ioctl(Procfd, PIOCCONT, val) == -1) { 251 if (kill(pid, 0) == -1 && errno == ESRCH) 252 break; 253 else 254 warn("PIOCCONT"); 255 } 256 } while (pfs.why != S_EXIT); 257 fflush(outfile); 258 if (sigexit) { 259 if (sigexit == SIGQUIT) 260 exit(sigexit); 261 (void) signal(sigexit, SIG_DFL); 262 (void) kill(getpid(), sigexit); 263 } 264 return 0; 265 } 266