i386-fbsd.c revision 101282
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 33static const char rcsid[] = 34 "$FreeBSD: head/usr.bin/truss/i386-fbsd.c 101282 2002-08-04 00:46:48Z mdodd $"; 35#endif /* not lint */ 36 37/* 38 * FreeBSD/386-specific system call handling. This is probably the most 39 * complex part of the entire truss program, although I've got lots of 40 * it handled relatively cleanly now. The system call names are generated 41 * automatically, thanks to /usr/src/sys/kern/syscalls.master. The 42 * names used for the various structures are confusing, I sadly admit. 43 */ 44 45#include <sys/types.h> 46#include <sys/ioctl.h> 47#include <sys/pioctl.h> 48#include <sys/syscall.h> 49 50#include <machine/reg.h> 51#include <machine/psl.h> 52 53#include <errno.h> 54#include <fcntl.h> 55#include <signal.h> 56#include <stdio.h> 57#include <stdlib.h> 58#include <string.h> 59#include <unistd.h> 60 61#include "truss.h" 62#include "syscall.h" 63 64static int fd = -1; 65static int cpid = -1; 66extern int Procfd; 67 68#include "syscalls.h" 69 70static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); 71 72/* 73 * This is what this particular file uses to keep track of a system call. 74 * It is probably not quite sufficient -- I can probably use the same 75 * structure for the various syscall personalities, and I also probably 76 * need to nest system calls (for signal handlers). 77 * 78 * 'struct syscall' describes the system call; it may be NULL, however, 79 * if we don't know about this particular system call yet. 80 */ 81static struct freebsd_syscall { 82 struct syscall *sc; 83 char *name; 84 int number; 85 unsigned long *args; 86 int nargs; /* number of arguments -- *not* number of words! */ 87 char **s_args; /* the printable arguments */ 88} fsc; 89 90/* Clear up and free parts of the fsc structure. */ 91static __inline void 92clear_fsc() { 93 if (fsc.args) { 94 free(fsc.args); 95 } 96 if (fsc.s_args) { 97 int i; 98 for (i = 0; i < fsc.nargs; i++) 99 if (fsc.s_args[i]) 100 free(fsc.s_args[i]); 101 free(fsc.s_args); 102 } 103 memset(&fsc, 0, sizeof(fsc)); 104} 105 106/* 107 * Called when a process has entered a system call. nargs is the 108 * number of words, not number of arguments (a necessary distinction 109 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 110 * is ever changed these functions need to keep up. 111 */ 112 113void 114i386_syscall_entry(struct trussinfo *trussinfo, int nargs) { 115 char buf[32]; 116 struct reg regs = { 0 }; 117 int syscall; 118 int i; 119 unsigned int parm_offset; 120 struct syscall *sc; 121 122 if (fd == -1 || trussinfo->pid != cpid) { 123 sprintf(buf, "/proc/%d/regs", trussinfo->pid); 124 fd = open(buf, O_RDWR); 125 if (fd == -1) { 126 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 127 return; 128 } 129 cpid = trussinfo->pid; 130 } 131 132 clear_fsc(); 133 lseek(fd, 0L, 0); 134 i = read(fd, ®s, sizeof(regs)); 135 parm_offset = regs.r_esp + sizeof(int); 136 137 /* 138 * FreeBSD has two special kinds of system call redirctions -- 139 * SYS_syscall, and SYS___syscall. The former is the old syscall() 140 * routine, basicly; the latter is for quad-aligned arguments. 141 */ 142 syscall = regs.r_eax; 143 switch (syscall) { 144 case SYS_syscall: 145 lseek(Procfd, parm_offset, SEEK_SET); 146 read(Procfd, &syscall, sizeof(int)); 147 parm_offset += sizeof(int); 148 break; 149 case SYS___syscall: 150 lseek(Procfd, parm_offset, SEEK_SET); 151 read(Procfd, &syscall, sizeof(int)); 152 parm_offset += sizeof(quad_t); 153 break; 154 } 155 156 fsc.number = syscall; 157 fsc.name = 158 (syscall < 0 || syscall > nsyscalls) ? NULL : syscallnames[syscall]; 159 if (!fsc.name) { 160 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall); 161 } 162 163 if (nargs == 0) 164 return; 165 166 fsc.args = malloc((1+nargs) * sizeof(unsigned long)); 167 lseek(Procfd, parm_offset, SEEK_SET); 168 if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1) 169 return; 170 171 sc = get_syscall(fsc.name); 172 if (sc) { 173 fsc.nargs = sc->nargs; 174 } else { 175#if DEBUG 176 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", 177 fsc.name, nargs); 178#endif 179 fsc.nargs = nargs; 180 } 181 182 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); 183 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); 184 fsc.sc = sc; 185 186 /* 187 * At this point, we set up the system call arguments. 188 * We ignore any OUT ones, however -- those are arguments that 189 * are set by the system call, and so are probably meaningless 190 * now. This doesn't currently support arguments that are 191 * passed in *and* out, however. 192 */ 193 194 if (fsc.name) { 195 196#if DEBUG 197 fprintf(stderr, "syscall %s(", fsc.name); 198#endif 199 for (i = 0; i < fsc.nargs; i++) { 200#if DEBUG 201 fprintf(stderr, "0x%x%s", 202 sc 203 ? fsc.args[sc->args[i].offset] 204 : fsc.args[i], 205 i < (fsc.nargs -1) ? "," : ""); 206#endif 207 if (sc && !(sc->args[i].type & OUT)) { 208 fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args); 209 } 210 } 211#if DEBUG 212 fprintf(stderr, ")\n"); 213#endif 214 } 215 216#if DEBUG 217 fprintf(trussinfo->outfile, "\n"); 218#endif 219 220 /* 221 * Some system calls should be printed out before they are done -- 222 * execve() and exit(), for example, never return. Possibly change 223 * this to work for any system call that doesn't have an OUT 224 * parameter? 225 */ 226 227 if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) { 228 print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args); 229 } 230 231 return; 232} 233 234/* 235 * And when the system call is done, we handle it here. 236 * Currently, no attempt is made to ensure that the system calls 237 * match -- this needs to be fixed (and is, in fact, why S_SCX includes 238 * the sytem call number instead of, say, an error status). 239 */ 240 241int 242i386_syscall_exit(struct trussinfo *trussinfo, int syscall) { 243 char buf[32]; 244 struct reg regs; 245 int retval; 246 int i; 247 int errorp; 248 struct syscall *sc; 249 250 if (fd == -1 || trussinfo->pid != cpid) { 251 sprintf(buf, "/proc/%d/regs", trussinfo->pid); 252 fd = open(buf, O_RDONLY); 253 if (fd == -1) { 254 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 255 return; 256 } 257 cpid = trussinfo->pid; 258 } 259 260 lseek(fd, 0L, 0); 261 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) { 262 fprintf(trussinfo->outfile, "\n"); 263 return; 264 } 265 retval = regs.r_eax; 266 errorp = !!(regs.r_eflags & PSL_C); 267 268 /* 269 * This code, while simpler than the initial versions I used, could 270 * stand some significant cleaning. 271 */ 272 273 sc = fsc.sc; 274 if (!sc) { 275 for (i = 0; i < fsc.nargs; i++) { 276 fsc.s_args[i] = malloc(12); 277 sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]); 278 } 279 } else { 280 /* 281 * Here, we only look for arguments that have OUT masked in -- 282 * otherwise, they were handled in the syscall_entry function. 283 */ 284 for (i = 0; i < sc->nargs; i++) { 285 char *temp; 286 if (sc->args[i].type & OUT) { 287 /* 288 * If an error occurred, than don't bothe getting the data; 289 * it may not be valid. 290 */ 291 if (errorp) { 292 temp = malloc(12); 293 sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]); 294 } else { 295 temp = print_arg(Procfd, &sc->args[i], fsc.args); 296 } 297 fsc.s_args[i] = temp; 298 } 299 } 300 } 301 302 /* 303 * It would probably be a good idea to merge the error handling, 304 * but that complicates things considerably. 305 */ 306 307 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval); 308 clear_fsc(); 309 310 return (retval); 311} 312