granicus.if.org Git - strace/blob - dirent.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) 2005-2015 Dmitry V. Levin <ldv@altlinux.org>
   7  * Copyright (c) 2014-2018 The strace developers.
   8  * All rights reserved.
   9  *
  10  * SPDX-License-Identifier: LGPL-2.1-or-later
  11  */
  12
  13 #include "defs.h"
  14
  15 #include DEF_MPERS_TYPE(kernel_dirent)
  16
  17 #include MPERS_DEFS
  18
  19 #define D_NAME_LEN_MAX 256
  20
  21 static void
  22 print_old_dirent(struct tcb *const tcp, const kernel_ulong_t addr)
  23 {
  24         kernel_dirent d;
  25
  26         if (umove_or_printaddr(tcp, addr, &d))
  27                 return;
  28
  29         tprintf("{d_ino=%llu, d_off=%llu, d_reclen=%u, d_name=",
  30                 zero_extend_signed_to_ull(d.d_ino),
  31                 zero_extend_signed_to_ull(d.d_off), d.d_reclen);
  32         if (d.d_reclen > D_NAME_LEN_MAX)
  33                 d.d_reclen = D_NAME_LEN_MAX;
  34         printpathn(tcp, addr + offsetof(kernel_dirent, d_name), d.d_reclen);
  35         tprints("}");
  36 }
  37
  38 SYS_FUNC(readdir)
  39 {
  40         if (entering(tcp)) {
  41                 printfd(tcp, tcp->u_arg[0]);
  42                 tprints(", ");
  43         } else {
  44                 if (tcp->u_rval == 0)
  45                         printaddr(tcp->u_arg[1]);
  46                 else
  47                         print_old_dirent(tcp, tcp->u_arg[1]);
  48                 /* Not much point in printing this out, it is always 1. */
  49                 if (tcp->u_arg[2] != 1)
  50                         tprintf(", %" PRI_klu, tcp->u_arg[2]);
  51         }
  52         return 0;
  53 }
  54
  55 SYS_FUNC(getdents)
  56 {
  57         unsigned int i, len, dents = 0;
  58         unsigned char *buf;
  59
  60         if (entering(tcp)) {
  61                 printfd(tcp, tcp->u_arg[0]);
  62                 return 0;
  63         }
  64
  65         const unsigned int count = tcp->u_arg[2];
  66
  67         if (syserror(tcp) || !verbose(tcp)) {
  68                 tprints(", ");
  69                 printaddr(tcp->u_arg[1]);
  70                 tprintf(", %u", count);
  71                 return 0;
  72         }
  73
  74         /* Beware of insanely large or too small values in tcp->u_rval */
  75         if (tcp->u_rval > 1024*1024)
  76                 len = 1024*1024;
  77         else if (tcp->u_rval < (int) sizeof(kernel_dirent))
  78                 len = 0;
  79         else
  80                 len = tcp->u_rval;
  81
  82         if (len) {
  83                 buf = malloc(len);
  84                 if (!buf || umoven(tcp, tcp->u_arg[1], len, buf) < 0) {
  85                         tprints(", ");
  86                         printaddr(tcp->u_arg[1]);
  87                         tprintf(", %u", count);
  88                         free(buf);
  89                         return 0;
  90                 }
  91         } else {
  92                 buf = NULL;
  93         }
  94
  95         tprints(",");
  96         if (!abbrev(tcp))
  97                 tprints(" [");
  98         for (i = 0; len && i <= len - sizeof(kernel_dirent); ) {
  99                 kernel_dirent *d = (kernel_dirent *) &buf[i];
 100
 101                 if (!abbrev(tcp)) {
 102                         int oob = d->d_reclen < sizeof(kernel_dirent) ||
 103                                   i + d->d_reclen - 1 >= len;
 104                         int d_name_len = oob ? len - i : d->d_reclen;
 105                         d_name_len -= offsetof(kernel_dirent, d_name) + 1;
 106                         if (d_name_len > D_NAME_LEN_MAX)
 107                                 d_name_len = D_NAME_LEN_MAX;
 108
 109                         tprintf("%s{d_ino=%llu, d_off=%llu, d_reclen=%u"
 110                                 ", d_name=", i ? ", " : "",
 111                                 zero_extend_signed_to_ull(d->d_ino),
 112                                 zero_extend_signed_to_ull(d->d_off),
 113                                 d->d_reclen);
 114
 115                         print_quoted_cstring(d->d_name, d_name_len);
 116
 117                         tprints(", d_type=");
 118                         if (oob)
 119                                 tprints("?");
 120                         else
 121                                 printxval(dirent_types, buf[i + d->d_reclen - 1], "DT_???");
 122                         tprints("}");
 123                 }
 124                 dents++;
 125                 if (d->d_reclen < sizeof(kernel_dirent)) {
 126                         tprints_comment("d_reclen < sizeof(struct dirent)");
 127                         break;
 128                 }
 129                 i += d->d_reclen;
 130         }
 131         if (!abbrev(tcp))
 132                 tprints("]");
 133         else
 134                 tprintf_comment("%u entries", dents);
 135         tprintf(", %u", count);
 136         free(buf);
 137         return 0;
 138 }