i386-linux.c revision 240005
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 240005 2012-09-02 11:03:18Z zont $"; 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{ 91 int i; 92 93 if (fsc.s_args) { 94 for (i = 0; i < fsc.nargs; i++) 95 if (fsc.s_args[i]) 96 free(fsc.s_args[i]); 97 free(fsc.s_args); 98 } 99 memset(&fsc, 0, sizeof(fsc)); 100} 101 102/* 103 * Called when a process has entered a system call. nargs is the 104 * number of words, not number of arguments (a necessary distinction 105 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c 106 * is ever changed these functions need to keep up. 107 */ 108 109void 110i386_linux_syscall_entry(struct trussinfo *trussinfo, int nargs) 111{ 112 struct reg regs; 113 struct syscall *sc; 114 int i, syscall_num; 115 116 clear_fsc(); 117 118 cpid = trussinfo->curthread->tid; 119 120 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) { 121 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); 122 return; 123 } 124 125 syscall_num = regs.r_eax; 126 127 fsc.number = syscall_num; 128 fsc.name = (syscall_num < 0 || syscall_num >= nsyscalls) ? 129 NULL : linux_syscallnames[syscall_num]; 130 if (!fsc.name) { 131 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", 132 syscall_num); 133 } 134 135 if (fsc.name && (trussinfo->flags & FOLLOWFORKS) && 136 (strcmp(fsc.name, "linux_fork") == 0 || 137 strcmp(fsc.name, "linux_vfork") == 0)) 138 trussinfo->curthread->in_fork = 1; 139 140 if (nargs == 0) 141 return; 142 143 /* 144 * Linux passes syscall arguments in registers, not 145 * on the stack. Fortunately, we've got access to the 146 * register set. Note that we don't bother checking the 147 * number of arguments. And what does linux do for syscalls 148 * that have more than five arguments? 149 */ 150 151 fsc.args[0] = regs.r_ebx; 152 fsc.args[1] = regs.r_ecx; 153 fsc.args[2] = regs.r_edx; 154 fsc.args[3] = regs.r_esi; 155 fsc.args[4] = regs.r_edi; 156 157 sc = get_syscall(fsc.name); 158 if (sc) 159 fsc.nargs = sc->nargs; 160 else { 161#if DEBUG 162 fprintf(trussinfo->outfile, "unknown syscall %s -- setting " 163 "args to %d\n", fsc.name, nargs); 164#endif 165 fsc.nargs = nargs; 166 } 167 168 fsc.s_args = calloc(1, (1 + fsc.nargs) * sizeof(char *)); 169 fsc.sc = sc; 170 171 /* 172 * At this point, we set up the system call arguments. 173 * We ignore any OUT ones, however -- those are arguments that 174 * are set by the system call, and so are probably meaningless 175 * now. This doesn't currently support arguments that are 176 * passed in *and* out, however. 177 */ 178 179 if (fsc.name) { 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", sc ? 186 fsc.args[sc->args[i].offset] : fsc.args[i], 187 i < (fsc.nargs - 1) ? "," : ""); 188#endif 189 if (sc && !(sc->args[i].type & OUT)) { 190 fsc.s_args[i] = print_arg(&sc->args[i], 191 fsc.args, 0, trussinfo); 192 } 193 } 194#if DEBUG 195 fprintf(stderr, ")\n"); 196#endif 197 } 198 199#if DEBUG 200 fprintf(trussinfo->outfile, "\n"); 201#endif 202 203 if (fsc.name != NULL && (strcmp(fsc.name, "linux_execve") == 0 || 204 strcmp(fsc.name, "exit") == 0)) { 205 /* 206 * XXX 207 * This could be done in a more general 208 * manner but it still wouldn't be very pretty. 209 */ 210 if (strcmp(fsc.name, "linux_execve") == 0) { 211 if ((trussinfo->flags & EXECVEARGS) == 0) { 212 if (fsc.s_args[1]) { 213 free(fsc.s_args[1]); 214 fsc.s_args[1] = NULL; 215 } 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 } 225 226 return; 227} 228 229/* 230 * Linux syscalls return negative errno's, we do positive and map them 231 */ 232static const int bsd_to_linux_errno[] = { 233 -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, 234 -10, -35, -12, -13, -14, -15, -16, -17, -18, -19, 235 -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, 236 -30, -31, -32, -33, -34, -11,-115,-114, -88, -89, 237 -90, -91, -92, -93, -94, -95, -96, -97, -98, -99, 238 -100,-101,-102,-103,-104,-105,-106,-107,-108,-109, 239 -110,-111, -40, -36,-112,-113, -39, -11, -87,-122, 240 -116, -66, -6, -6, -6, -6, -6, -37, -38, -9, 241 -6, 242}; 243 244long 245i386_linux_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) 246{ 247 struct reg regs; 248 struct syscall *sc; 249 long retval; 250 int errorp, i; 251 252 if (fsc.name == NULL) 253 return (-1); 254 255 cpid = trussinfo->curthread->tid; 256 257 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) { 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, then don't bother 284 * getting the data; it may not be valid. 285 */ 286 if (errorp) { 287 asprintf(&temp, "0x%lx", 288 fsc.args[sc->args[i].offset]); 289 } else { 290 temp = print_arg(&sc->args[i], 291 fsc.args, retval, trussinfo); 292 } 293 fsc.s_args[i] = temp; 294 } 295 } 296 } 297 298 /* 299 * It would probably be a good idea to merge the error handling, 300 * but that complicates things considerably. 301 */ 302 if (errorp) { 303 for (i = 0; 304 (size_t)i < sizeof(bsd_to_linux_errno) / sizeof(int); i++) { 305 if (retval == bsd_to_linux_errno[i]) 306 break; 307 } 308 } 309 310 if (fsc.name != NULL && (strcmp(fsc.name, "linux_execve") == 0 || 311 strcmp(fsc.name, "exit") == 0)) 312 trussinfo->curthread->in_syscall = 1; 313 314 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, 315 errorp ? i : retval, fsc.sc); 316 clear_fsc(); 317 318 return (retval); 319} 320