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 #ifndef lint 33 static const char rcsid[] = 34 "$FreeBSD$"; 35 #endif /* not lint */ 36 37 /* 38 * The main module for truss. Suprisingly simple, but, then, the other 39 * files handle the bulk of the work. And, of course, the kernel has to 40 * do a lot of the work :). 41 */ 42 43 #include <sys/param.h> 44 #include <sys/ioctl.h> 45 #include <sys/pioctl.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 extern int setup_and_wait(char **); 57 extern int start_tracing(int, int); 58 #ifdef __alpha__ 59 extern void alpha_syscall_entry(int, int); 60 extern void alpha_syscall_exit(int, int); 61 #endif 62 #ifdef __i386__ 63 extern void i386_syscall_entry(int, int); 64 extern void i386_syscall_exit(int, int); 65 extern void i386_linux_syscall_entry(int, int); 66 extern void i386_linux_syscall_exit(int, int); 67 #endif 68 69 /* 70 * These should really be parameterized -- I don't like having globals, 71 * but this is the easiest way, right now, to deal with them. 72 */ 73 74 int pid = 0; 75 int nosigs = 0; 76 FILE *outfile; 77 int Procfd; 78 char progtype[50]; /* OS and type of executable */ 79 80 static inline void 81 usage(void) 82 { 83 fprintf(stderr, "%s\n%s\n", 84 "usage: truss [-S] [-o file] -p pid", 85 " truss [-S] [-o file] command [args]"); 86 exit(1); 87 } 88 89 /* 90 * WARNING! "FreeBSD a.out" must be first, or set_etype will not 91 * work correctly. 92 */ 93 struct ex_types { 94 char *type; 95 void (*enter_syscall)(int, int); 96 void (*exit_syscall)(int, int); 97 } ex_types[] = { 98 #ifdef __alpha__ 99 { "FreeBSD ELF", alpha_syscall_entry, alpha_syscall_exit }, 100 #endif 101 #ifdef __i386__ 102 { "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit }, 103 { "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit }, 104 { "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit }, 105 #endif 106 { 0, 0, 0 }, 107 }; 108 109 /* 110 * Set the execution type. This is called after every exec, and when 111 * a process is first monitored. The procfs pseudo-file "etype" has 112 * the execution module type -- see /proc/curproc/etype for an example. 113 */ 114 115 static struct ex_types * 116 set_etype() { 117 struct ex_types *funcs; 118 char etype[24]; 119 char progtype[32]; 120 int fd; 121 122 sprintf(etype, "/proc/%d/etype", pid); 123 if ((fd = open(etype, O_RDONLY)) == -1) { 124 strcpy(progtype, "FreeBSD a.out"); 125 } else { 126 int len = read(fd, progtype, sizeof(progtype)); 127 progtype[len-1] = '\0'; 128 close(fd); 129 } 130 131 for (funcs = ex_types; funcs->type; funcs++) 132 if (!strcmp(funcs->type, progtype)) 133 break; 134 135 if (funcs == NULL) { 136 warn("Execution type %s is not supported -- using FreeBSD a.out\n", 137 progtype); 138 funcs = &ex_types[0]; 139 } 140 return funcs; 141 } 142 143 int 144 main(int ac, char **av) { 145 int c; 146 int i; 147 char **command; 148 struct procfs_status pfs; 149 struct ex_types *funcs; 150 int in_exec = 0; 151 char *fname = NULL; 152 int sigexit = 0; 153 154 outfile = stdout; 155 while ((c = getopt(ac, av, "p:o:S")) != -1) { 156 switch (c) { 157 case 'p': /* specified pid */ 158 pid = atoi(optarg); 159 break; 160 case 'o': /* Specified output file */ 161 fname = optarg; 162 break; 163 case 'S': /* Don't trace signals */ 164 nosigs = 1; 165 break; 166 default: 167 usage(); 168 } 169 } 170 171 ac -= optind; av += optind; 172 if ((pid == 0 && ac == 0) || (pid != 0 && ac != 0)) 173 usage(); 174 175 if (fname != NULL) { /* Use output file */ 176 if ((outfile = fopen(fname, "w")) == NULL) 177 errx(1, "cannot open %s", fname); 178 } 179 180 /* 181 * If truss starts the process itself, it will ignore some signals -- 182 * they should be passed off to the process, which may or may not 183 * exit. If, however, we are examining an already-running process, 184 * then we restore the event mask on these same signals. 185 */ 186 187 if (pid == 0) { /* Start a command ourselves */ 188 command = av; 189 pid = setup_and_wait(command); 190 signal(SIGINT, SIG_IGN); 191 signal(SIGTERM, SIG_IGN); 192 signal(SIGQUIT, SIG_IGN); 193 } else { 194 extern void restore_proc(int); 195 signal(SIGINT, restore_proc); 196 signal(SIGTERM, restore_proc); 197 signal(SIGQUIT, restore_proc); 198 } 199 200 201 /* 202 * At this point, if we started the process, it is stopped waiting to 203 * be woken up, either in exit() or in execve(). 204 */ 205 206 Procfd = start_tracing(pid, S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT | 207 (nosigs ? 0 : S_SIG)); 208 if (Procfd == -1) 209 return 0; 210 211 pfs.why = 0; 212 213 funcs = set_etype(); 214 /* 215 * At this point, it's a simple loop, waiting for the process to 216 * stop, finding out why, printing out why, and then continuing it. 217 * All of the grunt work is done in the support routines. 218 */ 219 220 do { 221 int val = 0; 222 223 if (ioctl(Procfd, PIOCWAIT, &pfs) == -1) 224 warn("PIOCWAIT top of loop"); 225 else { 226 switch(i = pfs.why) { 227 case S_SCE: 228 funcs->enter_syscall(pid, pfs.val); 229 break; 230 case S_SCX: 231 /* 232 * This is so we don't get two messages for an exec -- one 233 * for the S_EXEC, and one for the syscall exit. It also, 234 * conveniently, ensures that the first message printed out 235 * isn't the return-from-syscall used to create the process. 236 */ 237 238 if (in_exec) { 239 in_exec = 0; 240 break; 241 } 242 funcs->exit_syscall(pid, pfs.val); 243 break; 244 case S_SIG: 245 fprintf(outfile, "SIGNAL %lu\n", pfs.val); 246 sigexit = pfs.val; 247 break; 248 case S_EXIT: 249 fprintf (outfile, "process exit, rval = %lu\n", pfs.val); 250 break; 251 case S_EXEC: 252 funcs = set_etype(); 253 in_exec = 1; 254 break; 255 default: 256 fprintf (outfile, "Process stopped because of: %d\n", i); 257 break; 258 } 259 } 260 if (ioctl(Procfd, PIOCCONT, val) == -1) { 261 if (kill(pid, 0) == -1 && errno == ESRCH) 262 break; 263 else 264 warn("PIOCCONT"); 265 } 266 } while (pfs.why != S_EXIT); 267 fflush(outfile); 268 if (sigexit) { 269 if (sigexit == SIGQUIT) 270 exit(sigexit); 271 (void) signal(sigexit, SIG_DFL); 272 (void) kill(getpid(), sigexit); 273 } 274 return 0; 275 } 276