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 "$Id: main.c,v 1.10 1998/08/24 10:17:20 cracauer Exp $"; 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 <err.h> 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <signal.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 #include <sys/ioctl.h> 52 #include <sys/pioctl.h> 53 54 extern int setup_and_wait(char **); 55 extern int start_tracing(int, int); 56 extern void i386_syscall_entry(int, int); 57 extern void i386_syscall_exit(int, int); 58 extern void i386_linux_syscall_entry(int, int); 59 extern void i386_linux_syscall_exit(int, int); 60 61 /* 62 * These should really be parameterized -- I don't like having globals, 63 * but this is the easiest way, right now, to deal with them. 64 */ 65 66 int pid = 0; 67 int nosigs = 0; 68 FILE *outfile = stderr; 69 int Procfd; 70 char progtype[50]; /* OS and type of executable */ 71 72 static inline void 73 usage(void) 74 { 75 fprintf(stderr, "%s\n%s\n", 76 "usage: truss [-S] [-o file] -p pid", 77 " truss [-S] [-o file] command [args]"); 78 exit(1); 79 } 80 81 /* 82 * WARNING! "FreeBSD a.out" must be first, or set_etype will not 83 * work correctly. 84 */ 85 struct ex_types { 86 char *type; 87 void (*enter_syscall)(int, int); 88 void (*exit_syscall)(int, int); 89 } ex_types[] = { 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 { 0, 0, 0 }, 94 }; 95 96 /* 97 * Set the execution type. This is called after every exec, and when 98 * a process is first monitored. The procfs pseudo-file "etype" has 99 * the execution module type -- see /proc/curproc/etype for an example. 100 */ 101 102 static struct ex_types * 103 set_etype() { 104 struct ex_types *funcs; 105 char etype[24]; 106 char progtype[32]; 107 int fd; 108 109 sprintf(etype, "/proc/%d/etype", pid); 110 if ((fd = open(etype, O_RDONLY)) == -1) { 111 strcpy(progtype, "FreeBSD a.out"); 112 } else { 113 int len = read(fd, progtype, sizeof(progtype)); 114 progtype[len-1] = '\0'; 115 close(fd); 116 } 117 118 for (funcs = ex_types; funcs->type; funcs++) 119 if (!strcmp(funcs->type, progtype)) 120 break; 121 122 if (funcs == NULL) { 123 warn("Execution type %s is not supported -- using FreeBSD a.out\n", 124 progtype); 125 funcs = &ex_types[0]; 126 } 127 return funcs; 128 } 129 130 int 131 main(int ac, char **av) { 132 int c; 133 int i; 134 char **command; 135 struct procfs_status pfs; 136 struct ex_types *funcs; 137 int in_exec = 0; 138 char *fname = NULL; 139 int sigexit = 0; 140 141 while ((c = getopt(ac, av, "p:o:S")) != -1) { 142 switch (c) { 143 case 'p': /* specified pid */ 144 pid = atoi(optarg); 145 break; 146 case 'o': /* Specified output file */ 147 fname = optarg; 148 break; 149 case 'S': /* Don't trace signals */ 150 nosigs = 1; 151 break; 152 default: 153 usage(); 154 } 155 } 156 157 ac -= optind; av += optind; 158 if ((pid == 0 && ac == 0) || (pid != 0 && ac != 0)) 159 usage(); 160 161 if (fname != NULL) { /* Use output file */ 162 if ((outfile = fopen(fname, "w")) == NULL) 163 errx(1, "cannot open %s", fname); 164 } 165 166 /* 167 * If truss starts the process itself, it will ignore some signals -- 168 * they should be passed off to the process, which may or may not 169 * exit. If, however, we are examining an already-running process, 170 * then we restore the event mask on these same signals. 171 */ 172 173 if (pid == 0) { /* Start a command ourselves */ 174 command = av; 175 pid = setup_and_wait(command); 176 signal(SIGINT, SIG_IGN); 177 signal(SIGTERM, SIG_IGN); 178 signal(SIGQUIT, SIG_IGN); 179 } else { 180 extern void restore_proc(int); 181 signal(SIGINT, restore_proc); 182 signal(SIGTERM, restore_proc); 183 signal(SIGQUIT, restore_proc); 184 } 185 186 187 /* 188 * At this point, if we started the process, it is stopped waiting to 189 * be woken up, either in exit() or in execve(). 190 */ 191 192 Procfd = start_tracing(pid, S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT | 193 (nosigs ? 0 : S_SIG)); 194 pfs.why = 0; 195 196 funcs = set_etype(); 197 /* 198 * At this point, it's a simple loop, waiting for the process to 199 * stop, finding out why, printing out why, and then continuing it. 200 * All of the grunt work is done in the support routines. 201 */ 202 203 do { 204 int val = 0; 205 206 if (ioctl(Procfd, PIOCWAIT, &pfs) == -1) 207 warn("PIOCWAIT top of loop"); 208 else { 209 switch(i = pfs.why) { 210 case S_SCE: 211 funcs->enter_syscall(pid, pfs.val); 212 break; 213 case S_SCX: 214 /* 215 * This is so we don't get two messages for an exec -- one 216 * for the S_EXEC, and one for the syscall exit. It also, 217 * conveniently, ensures that the first message printed out 218 * isn't the return-from-syscall used to create the process. 219 */ 220 221 if (in_exec) { 222 in_exec = 0; 223 break; 224 } 225 funcs->exit_syscall(pid, pfs.val); 226 break; 227 case S_SIG: 228 fprintf(outfile, "SIGNAL %lu\n", pfs.val); 229 sigexit = pfs.val; 230 break; 231 case S_EXIT: 232 fprintf (outfile, "process exit, rval = %lu\n", pfs.val); 233 break; 234 case S_EXEC: 235 funcs = set_etype(); 236 in_exec = 1; 237 break; 238 default: 239 fprintf (outfile, "Process stopped because of: %d\n", i); 240 break; 241 } 242 } 243 if (ioctl(Procfd, PIOCCONT, val) == -1) 244 warn("PIOCCONT"); 245 } while (pfs.why != S_EXIT); 246 if (sigexit) { 247 if (sigexit == SIGQUIT) 248 exit(sigexit); 249 (void) signal(sigexit, SIG_DFL); 250 (void) kill(getpid(), sigexit); 251 } 252 return 0; 253 } 254