lib/krb5/store_fd.c

   1 /*
   2  * Copyright (c) 1997 - 2017 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35 #include "store-int.h"
  36
  37 typedef struct fd_storage {
  38     int fd;
  39 } fd_storage;
  40
  41 #define FD(S) (((fd_storage*)(S)->data)->fd)
  42
  43 static ssize_t
  44 fd_fetch(krb5_storage * sp, void *data, size_t size)
  45 {
  46     char *cbuf = (char *)data;
  47     ssize_t count;
  48     size_t rem = size;
  49
  50     /* similar pattern to net_read() to support pipes */
  51     while (rem > 0) {
  52         count = read (FD(sp), cbuf, rem);
  53         if (count < 0) {
  54             if (errno == EINTR)
  55                 continue;
  56             else if (rem == size)
  57                 return count;
  58             else
  59                 return size - rem;
  60         } else if (count == 0) {
  61             return count;
  62         }
  63         cbuf += count;
  64         rem -= count;
  65     }
  66     return size;
  67 }
  68
  69 static ssize_t
  70 fd_store(krb5_storage * sp, const void *data, size_t size)
  71 {
  72     const char *cbuf = (const char *)data;
  73     ssize_t count;
  74     size_t rem = size;
  75
  76     /* similar pattern to net_write() to support pipes */
  77     while (rem > 0) {
  78         count = write(FD(sp), cbuf, rem);
  79         if (count < 0) {
  80             if (errno == EINTR)
  81                 continue;
  82             else
  83                 return size - rem;
  84         }
  85         cbuf += count;
  86         rem -= count;
  87     }
  88     return size;
  89 }
  90
  91 static off_t
  92 fd_seek(krb5_storage * sp, off_t offset, int whence)
  93 {
  94     return lseek(FD(sp), offset, whence);
  95 }
  96
  97 static int
  98 fd_trunc(krb5_storage * sp, off_t offset)
  99 {
 100     off_t tmpoff;
 101
 102     if (ftruncate(FD(sp), offset) == -1)
 103         return errno;
 104
 105     tmpoff = lseek(FD(sp), 0, SEEK_CUR);
 106     if (tmpoff == -1)
 107         return errno;
 108
 109     if (tmpoff > offset) {
 110         tmpoff = lseek(FD(sp), offset, SEEK_SET);
 111         if (tmpoff == -1)
 112             return errno;
 113     }
 114
 115     return 0;
 116 }
 117
 118 static int
 119 fd_sync(krb5_storage * sp)
 120 {
 121     if (fsync(FD(sp)) == -1)
 122         return errno;
 123     return 0;
 124 }
 125
 126 static void
 127 fd_free(krb5_storage * sp)
 128 {
 129     int save_errno = errno;
 130     if (close(FD(sp)) == 0)
 131         errno = save_errno;
 132 }
 133
 134 /**
 135  *
 136  *
 137  * @return A krb5_storage on success, or NULL on out of memory error.
 138  *
 139  * @ingroup krb5_storage
 140  *
 141  * @sa krb5_storage_emem()
 142  * @sa krb5_storage_from_mem()
 143  * @sa krb5_storage_from_readonly_mem()
 144  * @sa krb5_storage_from_data()
 145  * @sa krb5_storage_from_socket()
 146  */
 147
 148 KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL
 149 krb5_storage_from_fd(int fd_in)
 150 {
 151     krb5_storage *sp;
 152     int saved_errno;
 153     int fd;
 154
 155 #ifdef _MSC_VER
 156     /*
 157      * This function used to try to pass the input to
 158      * _get_osfhandle() to test if the value is a HANDLE
 159      * but this doesn't work because doing so throws an
 160      * exception that will result in Watson being triggered
 161      * to file a Windows Error Report.
 162      */
 163     fd = _dup(fd_in);
 164 #else
 165     fd = dup(fd_in);
 166 #endif
 167
 168     if (fd < 0)
 169         return NULL;
 170
 171     errno = ENOMEM;
 172     sp = malloc(sizeof(krb5_storage));
 173     if (sp == NULL) {
 174         saved_errno = errno;
 175         close(fd);
 176         errno = saved_errno;
 177         return NULL;
 178     }
 179
 180     errno = ENOMEM;
 181     sp->data = malloc(sizeof(fd_storage));
 182     if (sp->data == NULL) {
 183         saved_errno = errno;
 184         close(fd);
 185         free(sp);
 186         errno = saved_errno;
 187         return NULL;
 188     }
 189     sp->flags = 0;
 190     sp->eof_code = HEIM_ERR_EOF;
 191     FD(sp) = fd;
 192     sp->fetch = fd_fetch;
 193     sp->store = fd_store;
 194     sp->seek = fd_seek;
 195     sp->trunc = fd_trunc;
 196     sp->fsync = fd_sync;
 197     sp->free = fd_free;
 198     sp->max_alloc = UINT32_MAX/64;
 199     return sp;
 200 }