i386-linux.c revision 204977
1/* 2 * Copyright 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-linux.c 204977 2010-03-10 20:31:30Z imp $"; 35#endif /* not lint */ 36 37/* 38 * Linux/i386-specific system call handling. Given how much of this code 39 * is taken from the freebsd equivalent, I can probably put even more of 40 * it in support routines that can be used by any personality support. 41 */ 42 43#include <sys/types.h> 44#include <sys/ptrace.h> 45 46#include <machine/reg.h> 47#include <machine/psl.h> 48 49#include <errno.h> 50#include <fcntl.h> 51#include <signal.h> 52#include <stdio.h> 53#include <stdlib.h> 54#include <string.h> 55#include <time.h> 56#include <unistd.h> 57 58#include "truss.h" 59#include "syscall.h" 60#include "extern.h" 61 62static int cpid = -1; 63 64#include "linux_syscalls.h" 65 66static int nsyscalls = 67 sizeof(linux_syscallnames) / sizeof(linux_syscallnames[0]); 68 69/* 70 * This is what this particular file uses to keep track of a system call. 71 * It is probably not quite sufficient -- I can probably use the same 72 * structure for the various syscall personalities, and I also probably 73 * need to nest system calls (for signal handlers). 74 * 75 * 'struct syscall' describes the system call; it may be NULL, however, 76 * if we don't know about this particular system call yet. 77 */ 78static struct linux_syscall { 79 struct syscall *sc; 80 const char *name; 81 int number; 82 unsigned long args[5]; 83 int nargs; /* number of arguments -- *not* number of words! */ 84 char **s_args; /* the printable arguments */ 85} fsc; 86 87/* Clear up and free parts of the fsc structure. */ 88static __inline void 89clear_fsc(void) { 90 if (fsc.s_args) { 91 int i; 92 for (i = 0; i < fsc.nargs; i++) 93 if (fsc.s_args[i]) 94 free(fsc.s_args[i]); 95 free(fsc.s_args); 96 } 97 memset(&fsc, 0, sizeof(fsc)); 98} 99 100/* 101 * Called when a process has entered a system call. nargs is the 102 * number of words, not number of arguments (a necessary distinction 103 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 104 * is ever changed these functions need to keep up. 105 */ 106 107void 108i386_linux_syscall_entry(struct trussinfo *trussinfo, int nargs) { 109 struct reg regs; 110 int syscall_num; 111 int i; 112 struct syscall *sc; 113 114 cpid = trussinfo->curthread->tid; 115 116 clear_fsc(); 117 118 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) 119 { 120 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 121 return; 122 } 123 syscall_num = regs.r_eax; 124 125 fsc.number = syscall_num; 126 fsc.name = 127 (syscall_num < 0 || syscall_num >= nsyscalls) ? NULL : linux_syscallnames[syscall_num]; 128 if (!fsc.name) { 129 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num); 130 } 131 132 if (fsc.name && (trussinfo->flags & FOLLOWFORKS) 133 && ((!strcmp(fsc.name, "linux_fork") 134 || !strcmp(fsc.name, "linux_vfork")))) 135 { 136 trussinfo->curthread->in_fork = 1; 137 } 138 139 if (nargs == 0) 140 return; 141 142 /* 143 * Linux passes syscall arguments in registers, not 144 * on the stack. Fortunately, we've got access to the 145 * register set. Note that we don't bother checking the 146 * number of arguments. And what does linux do for syscalls 147 * that have more than five arguments? 148 */ 149 150 fsc.args[0] = regs.r_ebx; 151 fsc.args[1] = regs.r_ecx; 152 fsc.args[2] = regs.r_edx; 153 fsc.args[3] = regs.r_esi; 154 fsc.args[4] = regs.r_edi; 155 156 sc = get_syscall(fsc.name); 157 if (sc) { 158 fsc.nargs = sc->nargs; 159 } else { 160#if DEBUG 161 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", 162 fsc.name, nargs); 163#endif 164 fsc.nargs = nargs; 165 } 166 167 fsc.s_args = calloc(1, (1+fsc.nargs) * sizeof(char*)); 168 fsc.sc = sc; 169 170 /* 171 * At this point, we set up the system call arguments. 172 * We ignore any OUT ones, however -- those are arguments that 173 * are set by the system call, and so are probably meaningless 174 * now. This doesn't currently support arguments that are 175 * passed in *and* out, however. 176 */ 177 178 if (fsc.name) { 179 180#if DEBUG 181 fprintf(stderr, "syscall %s(", fsc.name); 182#endif 183 for (i = 0; i < fsc.nargs; i++) { 184#if DEBUG 185 fprintf(stderr, "0x%x%s", 186 sc 187 ? fsc.args[sc->args[i].offset] 188 : fsc.args[i], 189 i < (fsc.nargs - 1) ? "," : ""); 190#endif 191 if (sc && !(sc->args[i].type & OUT)) { 192 fsc.s_args[i] = print_arg(&sc->args[i], fsc.args, 0, trussinfo); 193 } 194 } 195#if DEBUG 196 fprintf(stderr, ")\n"); 197#endif 198 } 199 200#if DEBUG 201 fprintf(trussinfo->outfile, "\n"); 202#endif 203 204 if (fsc.name != NULL && 205 (!strcmp(fsc.name, "linux_execve") || !strcmp(fsc.name, "exit"))) { 206 207 /* XXX 208 * This could be done in a more general 209 * manner but it still wouldn't be very pretty. 210 */ 211 if (!strcmp(fsc.name, "linux_execve")) { 212 if ((trussinfo->flags & EXECVEARGS) == 0) 213 if (fsc.s_args[1]) { 214 free(fsc.s_args[1]); 215 fsc.s_args[1] = NULL; 216 } 217 if ((trussinfo->flags & EXECVEENVS) == 0) 218 if (fsc.s_args[2]) { 219 free(fsc.s_args[2]); 220 fsc.s_args[2] = NULL; 221 } 222 } 223 } 224 225 return; 226} 227 228/* 229 * Linux syscalls return negative errno's, we do positive and map them 230 */ 231const int bsd_to_linux_errno[] = { 232 -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, 233 -10, -35, -12, -13, -14, -15, -16, -17, -18, -19, 234 -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, 235 -30, -31, -32, -33, -34, -11,-115,-114, -88, -89, 236 -90, -91, -92, -93, -94, -95, -96, -97, -98, -99, 237 -100,-101,-102,-103,-104,-105,-106,-107,-108,-109, 238 -110,-111, -40, -36,-112,-113, -39, -11, -87,-122, 239 -116, -66, -6, -6, -6, -6, -6, -37, -38, -9, 240 -6, 241}; 242 243long 244i386_linux_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 245{ 246 struct reg regs; 247 long retval; 248 int i; 249 int errorp; 250 struct syscall *sc; 251 252 if (fsc.name == NULL) 253 return (-1); 254 255 cpid = trussinfo->curthread->tid; 256 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) 257 { 258 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 259 return (-1); 260 } 261 262 retval = regs.r_eax; 263 errorp = !!(regs.r_eflags & PSL_C); 264 265 /* 266 * This code, while simpler than the initial versions I used, could 267 * stand some significant cleaning. 268 */ 269 270 sc = fsc.sc; 271 if (!sc) { 272 for (i = 0; i < fsc.nargs; i++) 273 asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]); 274 } else { 275 /* 276 * Here, we only look for arguments that have OUT masked in -- 277 * otherwise, they were handled in the syscall_entry function. 278 */ 279 for (i = 0; i < sc->nargs; i++) { 280 char *temp; 281 if (sc->args[i].type & OUT) { 282 /* 283 * If an error occurred, than don't bothe getting the data; 284 * it may not be valid. 285 */ 286 if (errorp) 287 asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]); 288 else 289 temp = print_arg(&sc->args[i], fsc.args, retval, trussinfo); 290 fsc.s_args[i] = temp; 291 } 292 } 293 } 294 295 /* 296 * It would probably be a good idea to merge the error handling, 297 * but that complicates things considerably. 298 */ 299 if (errorp) { 300 for (i = 0; (size_t)i < sizeof(bsd_to_linux_errno) / sizeof(int); i++) 301 if (retval == bsd_to_linux_errno[i]) 302 break; 303 } 304 305 if (fsc.name != NULL && 306 (!strcmp(fsc.name, "linux_execve") || !strcmp(fsc.name, "exit"))) { 307 trussinfo->curthread->in_syscall = 1; 308 } 309 310 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, 311 errorp ? i : retval, fsc.sc); 312 clear_fsc(); 313 314 return (retval); 315} 316