granicus.if.org Git - strace/blob - desc.c

   1 /*
   2  * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
   3  * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
   4  * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
   5  * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
   6  * Copyright (c) 1999-2017 The strace developers.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. The name of the author may not be used to endorse or promote products
  18  *    derived from this software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include "defs.h"
  33
  34 SYS_FUNC(close)
  35 {
  36         printfd(tcp, tcp->u_arg[0]);
  37
  38         return RVAL_DECODED;
  39 }
  40
  41 SYS_FUNC(dup)
  42 {
  43         printfd(tcp, tcp->u_arg[0]);
  44
  45         return RVAL_DECODED | RVAL_FD;
  46 }
  47
  48 static int
  49 do_dup2(struct tcb *tcp, int flags_arg)
  50 {
  51         printfd(tcp, tcp->u_arg[0]);
  52         tprints(", ");
  53         printfd(tcp, tcp->u_arg[1]);
  54         if (flags_arg >= 0) {
  55                 tprints(", ");
  56                 printflags(open_mode_flags, tcp->u_arg[flags_arg], "O_???");
  57         }
  58
  59         return RVAL_DECODED | RVAL_FD;
  60 }
  61
  62 SYS_FUNC(dup2)
  63 {
  64         return do_dup2(tcp, -1);
  65 }
  66
  67 SYS_FUNC(dup3)
  68 {
  69         return do_dup2(tcp, 2);
  70 }
  71
  72 static int
  73 decode_select(struct tcb *const tcp, const kernel_ulong_t *const args,
  74               void (*const print_tv_ts) (struct tcb *, kernel_ulong_t),
  75               const char * (*const sprint_tv_ts) (struct tcb *, kernel_ulong_t))
  76 {
  77         int i, j;
  78         int nfds, fdsize;
  79         fd_set *fds = NULL;
  80         const char *sep;
  81         kernel_ulong_t addr;
  82
  83         /* Kernel truncates args[0] to int, we do the same. */
  84         nfds = (int) args[0];
  85
  86         /* Kernel rejects negative nfds, so we don't parse it either. */
  87         if (nfds < 0)
  88                 nfds = 0;
  89
  90         /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
  91         if (nfds > 1024*1024)
  92                 nfds = 1024*1024;
  93
  94         /*
  95          * We had bugs a-la "while (j < args[0])" and "umoven(args[0])" below.
  96          * Instead of args[0], use nfds for fd count, fdsize for array lengths.
  97          */
  98         fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize;
  99
 100         if (entering(tcp)) {
 101                 tprintf("%d", (int) args[0]);
 102
 103                 if (verbose(tcp) && fdsize > 0)
 104                         fds = malloc(fdsize);
 105                 for (i = 0; i < 3; i++) {
 106                         addr = args[i+1];
 107                         tprints(", ");
 108                         if (!fds) {
 109                                 printaddr(addr);
 110                                 continue;
 111                         }
 112                         if (umoven_or_printaddr(tcp, addr, fdsize, fds))
 113                                 continue;
 114                         tprints("[");
 115                         for (j = 0, sep = "";; j++) {
 116                                 j = next_set_bit(fds, j, nfds);
 117                                 if (j < 0)
 118                                         break;
 119                                 tprints(sep);
 120                                 printfd(tcp, j);
 121                                 sep = " ";
 122                         }
 123                         tprints("]");
 124                 }
 125                 free(fds);
 126                 tprints(", ");
 127                 print_tv_ts(tcp, args[4]);
 128         } else {
 129                 static char outstr[1024];
 130                 char *outptr;
 131 #define end_outstr (outstr + sizeof(outstr))
 132                 int ready_fds;
 133
 134                 if (syserror(tcp))
 135                         return 0;
 136
 137                 ready_fds = tcp->u_rval;
 138                 if (ready_fds == 0) {
 139                         tcp->auxstr = "Timeout";
 140                         return RVAL_STR;
 141                 }
 142
 143                 fds = malloc(fdsize);
 144
 145                 outptr = outstr;
 146                 sep = "";
 147                 for (i = 0; i < 3 && ready_fds > 0; i++) {
 148                         int first = 1;
 149
 150                         addr = args[i+1];
 151                         if (!addr || !fds || umoven(tcp, addr, fdsize, fds) < 0)
 152                                 continue;
 153                         for (j = 0;; j++) {
 154                                 j = next_set_bit(fds, j, nfds);
 155                                 if (j < 0)
 156                                         break;
 157                                 /* +2 chars needed at the end: ']',NUL */
 158                                 if (outptr < end_outstr - (sizeof(", except [") + sizeof(int)*3 + 2)) {
 159                                         if (first) {
 160                                                 outptr += sprintf(outptr, "%s%s [%u",
 161                                                         sep,
 162                                                         i == 0 ? "in" : i == 1 ? "out" : "except",
 163                                                         j
 164                                                 );
 165                                                 first = 0;
 166                                                 sep = ", ";
 167                                         } else {
 168                                                 outptr += sprintf(outptr, " %u", j);
 169                                         }
 170                                 }
 171                                 if (--ready_fds == 0)
 172                                         break;
 173                         }
 174                         if (outptr != outstr)
 175                                 *outptr++ = ']';
 176                 }
 177                 free(fds);
 178                 /* This contains no useful information on SunOS.  */
 179                 if (args[4]) {
 180                         const char *str = sprint_tv_ts(tcp, args[4]);
 181                         if (outptr + sizeof("left ") + strlen(sep) + strlen(str) < end_outstr) {
 182                                 outptr += sprintf(outptr, "%sleft %s", sep, str);
 183                         }
 184                 }
 185                 *outptr = '\0';
 186                 tcp->auxstr = outstr;
 187                 return RVAL_STR;
 188 #undef end_outstr
 189         }
 190         return 0;
 191 }
 192
 193 SYS_FUNC(oldselect)
 194 {
 195         kernel_ulong_t select_args[5];
 196         unsigned int oldselect_args[5];
 197
 198         if (sizeof(*select_args) == sizeof(*oldselect_args)) {
 199                 if (umove_or_printaddr(tcp, tcp->u_arg[0], &select_args)) {
 200                         return 0;
 201                 }
 202         } else {
 203                 unsigned int i;
 204
 205                 if (umove_or_printaddr(tcp, tcp->u_arg[0], &oldselect_args)) {
 206                         return 0;
 207                 }
 208
 209                 for (i = 0; i < 5; ++i) {
 210                         select_args[i] = oldselect_args[i];
 211                 }
 212         }
 213
 214         return decode_select(tcp, select_args, print_timeval, sprint_timeval);
 215 }
 216
 217 #ifdef ALPHA
 218 SYS_FUNC(osf_select)
 219 {
 220         return decode_select(tcp, tcp->u_arg, print_timeval32, sprint_timeval32);
 221 }
 222 #endif
 223
 224 SYS_FUNC(select)
 225 {
 226         return decode_select(tcp, tcp->u_arg, print_timeval, sprint_timeval);
 227 }
 228
 229 static int
 230 umove_kulong_array_or_printaddr(struct tcb *const tcp, const kernel_ulong_t addr,
 231                                 kernel_ulong_t *const ptr, const size_t n)
 232 {
 233 #ifndef current_klongsize
 234         if (current_klongsize < sizeof(*ptr)) {
 235                 uint32_t ptr32[n];
 236                 int r = umove_or_printaddr(tcp, addr, &ptr32);
 237                 if (!r) {
 238                         size_t i;
 239
 240                         for (i = 0; i < n; ++i)
 241                                 ptr[i] = ptr32[i];
 242                 }
 243                 return r;
 244         }
 245 #endif /* !current_klongsize */
 246         return umoven_or_printaddr(tcp, addr, n * sizeof(*ptr), ptr);
 247 }
 248
 249 SYS_FUNC(pselect6)
 250 {
 251         int rc = decode_select(tcp, tcp->u_arg, print_timespec, sprint_timespec);
 252         if (entering(tcp)) {
 253                 kernel_ulong_t data[2];
 254
 255                 tprints(", ");
 256                 if (!umove_kulong_array_or_printaddr(tcp, tcp->u_arg[5],
 257                                                      data, ARRAY_SIZE(data))) {
 258                         tprints("{");
 259                         /* NB: kernel requires data[1] == NSIG_BYTES */
 260                         print_sigset_addr_len(tcp, data[0], data[1]);
 261                         tprintf(", %" PRI_klu "}", data[1]);
 262                 }
 263         }
 264
 265         return rc;
 266 }