contrib/sendmail-8.13.6/libsm/fvwrite.c

   1 /*
   2  * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
   3  *      All rights reserved.
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * By using this file, you agree to the terms and conditions set
  11  * forth in the LICENSE file which can be found at the top level of
  12  * the sendmail distribution.
  13  */
  14
  15 #include <sm/gen.h>
  16 SM_RCSID("@(#)$Id: fvwrite.c,v 1.49 2001/09/11 04:04:48 gshapiro Exp $")
  17 #include <stdlib.h>
  18 #include <unistd.h>
  19 #include <string.h>
  20 #include <errno.h>
  21 #include <signal.h>
  22 #include <fcntl.h>
  23 #include <sm/io.h>
  24 #include <sm/setjmp.h>
  25 #include <sm/conf.h>
  26 #include "local.h"
  27 #include "fvwrite.h"
  28
  29 /*
  30 **  SM_FVWRITE -- write memory regions and buffer for file pointer
  31 **
  32 **      Parameters:
  33 **              fp -- the file pointer to write to
  34 **              timeout -- time length for function to return by
  35 **              uio -- the memory regions to write
  36 **
  37 **      Returns:
  38 **              Failure: returns SM_IO_EOF and sets errno
  39 **              Success: returns 0 (zero)
  40 **
  41 **      This routine is large and unsightly, but most of the ugliness due
  42 **      to the different kinds of output buffering handled here.
  43 */
  44
  45 #define COPY(n)   (void)memcpy((void *)fp->f_p, (void *)p, (size_t)(n))
  46 #define GETIOV(extra_work)              \
  47         while (len == 0)                \
  48         {                               \
  49                 extra_work;             \
  50                 p = iov->iov_base;      \
  51                 len = iov->iov_len;     \
  52                 iov++;                  \
  53         }
  54
  55 int
  56 sm_fvwrite(fp, timeout, uio)
  57         register SM_FILE_T *fp;
  58         int timeout;
  59         register struct sm_uio *uio;
  60 {
  61         register size_t len;
  62         register char *p;
  63         register struct sm_iov *iov;
  64         register int w, s;
  65         char *nl;
  66         int nlknown, nldist;
  67         int fd;
  68         struct timeval to;
  69
  70         if (uio->uio_resid == 0)
  71                 return 0;
  72
  73         /* make sure we can write */
  74         if (cantwrite(fp))
  75         {
  76                 errno = EBADF;
  77                 return SM_IO_EOF;
  78         }
  79
  80         SM_CONVERT_TIME(fp, fd, timeout, &to);
  81
  82         iov = uio->uio_iov;
  83         p = iov->iov_base;
  84         len = iov->iov_len;
  85         iov++;
  86         if (fp->f_flags & SMNBF)
  87         {
  88                 /* Unbuffered: write up to BUFSIZ bytes at a time. */
  89                 do
  90                 {
  91                         GETIOV(;);
  92                         errno = 0; /* needed to ensure EOF correctly found */
  93                         w = (*fp->f_write)(fp, p, SM_MIN(len, SM_IO_BUFSIZ));
  94                         if (w <= 0)
  95                         {
  96                                 if (w == 0 && errno == 0)
  97                                         break; /* EOF found */
  98                                 if (IS_IO_ERROR(fd, w, timeout))
  99                                         goto err; /* errno set */
 100
 101                                 /* write would block */
 102                                 SM_IO_WR_TIMEOUT(fp, fd, timeout);
 103                                 w = 0;
 104                         }
 105                         else
 106                         {
 107                                 p += w;
 108                                 len -= w;
 109                         }
 110                 } while ((uio->uio_resid -= w) != 0);
 111         }
 112         else if ((fp->f_flags & SMLBF) == 0)
 113         {
 114                 /*
 115                 **  Not SMLBF (line-buffered). Either SMFBF or SMNOW
 116                 **  buffered: fill partially full buffer, if any,
 117                 **  and then flush.  If there is no partial buffer, write
 118                 **  one bf._size byte chunk directly (without copying).
 119                 **
 120                 **  String output is a special case: write as many bytes
 121                 **  as fit, but pretend we wrote everything.  This makes
 122                 **  snprintf() return the number of bytes needed, rather
 123                 **  than the number used, and avoids its write function
 124                 **  (so that the write function can be invalid).
 125                 */
 126
 127                 do
 128                 {
 129                         GETIOV(;);
 130                         if ((((fp->f_flags & (SMALC | SMSTR)) == (SMALC | SMSTR))
 131                             || ((fp->f_flags & SMNOW) != 0))
 132                             && (size_t) fp->f_w < len)
 133                         {
 134                                 size_t blen = fp->f_p - fp->f_bf.smb_base;
 135                                 unsigned char *tbase;
 136                                 int tsize;
 137
 138                                 /* Allocate space exponentially. */
 139                                 tsize = fp->f_bf.smb_size;
 140                                 do
 141                                 {
 142                                         tsize = (tsize << 1) + 1;
 143                                 } while ((size_t) tsize < blen + len);
 144                                 tbase = (unsigned char *) sm_realloc(fp->f_bf.smb_base,
 145                                                                      tsize + 1);
 146                                 if (tbase == NULL)
 147                                 {
 148                                         errno = ENOMEM;
 149                                         goto err; /* errno set */
 150                                 }
 151                                 fp->f_w += tsize - fp->f_bf.smb_size;
 152                                 fp->f_bf.smb_base = tbase;
 153                                 fp->f_bf.smb_size = tsize;
 154                                 fp->f_p = tbase + blen;
 155                         }
 156                         w = fp->f_w;
 157                         errno = 0; /* needed to ensure EOF correctly found */
 158                         if (fp->f_flags & SMSTR)
 159                         {
 160                                 if (len < (size_t) w)
 161                                         w = len;
 162                                 COPY(w);        /* copy SM_MIN(fp->f_w,len), */
 163                                 fp->f_w -= w;
 164                                 fp->f_p += w;
 165                                 w = len;        /* but pretend copied all */
 166                         }
 167                         else if (fp->f_p > fp->f_bf.smb_base
 168                                  && len > (size_t) w)
 169                         {
 170                                 /* fill and flush */
 171                                 COPY(w);
 172                                 fp->f_p += w;
 173                                 if (sm_flush(fp, &timeout))
 174                                         goto err; /* errno set */
 175                         }
 176                         else if (len >= (size_t) (w = fp->f_bf.smb_size))
 177                         {
 178                                 /* write directly */
 179                                 w = (*fp->f_write)(fp, p, w);
 180                                 if (w <= 0)
 181                                 {
 182                                         if (w == 0 && errno == 0)
 183                                                 break; /* EOF found */
 184                                         if (IS_IO_ERROR(fd, w, timeout))
 185                                                 goto err; /* errno set */
 186
 187                                         /* write would block */
 188                                         SM_IO_WR_TIMEOUT(fp, fd, timeout);
 189                                         w = 0;
 190                                 }
 191                         }
 192                         else
 193                         {
 194                                 /* fill and done */
 195                                 w = len;
 196                                 COPY(w);
 197                                 fp->f_w -= w;
 198                                 fp->f_p += w;
 199                         }
 200                         p += w;
 201                         len -= w;
 202                 } while ((uio->uio_resid -= w) != 0);
 203
 204                 if ((fp->f_flags & SMNOW) != 0 && sm_flush(fp, &timeout))
 205                         goto err; /* errno set */
 206         }
 207         else
 208         {
 209                 /*
 210                 **  Line buffered: like fully buffered, but we
 211                 **  must check for newlines.  Compute the distance
 212                 **  to the first newline (including the newline),
 213                 **  or `infinity' if there is none, then pretend
 214                 **  that the amount to write is SM_MIN(len,nldist).
 215                 */
 216
 217                 nlknown = 0;
 218                 nldist = 0;     /* XXX just to keep gcc happy */
 219                 do
 220                 {
 221                         GETIOV(nlknown = 0);
 222                         if (!nlknown)
 223                         {
 224                                 nl = memchr((void *)p, '\n', len);
 225                                 nldist = nl != NULL ? nl + 1 - p : len + 1;
 226                                 nlknown = 1;
 227                         }
 228                         s = SM_MIN(len, ((size_t) nldist));
 229                         w = fp->f_w + fp->f_bf.smb_size;
 230                         errno = 0; /* needed to ensure EOF correctly found */
 231                         if (fp->f_p > fp->f_bf.smb_base && s > w)
 232                         {
 233                                 COPY(w);
 234                                 /* fp->f_w -= w; */
 235                                 fp->f_p += w;
 236                                 if (sm_flush(fp, &timeout))
 237                                         goto err; /* errno set */
 238                         }
 239                         else if (s >= (w = fp->f_bf.smb_size))
 240                         {
 241                                 w = (*fp->f_write)(fp, p, w);
 242                                 if (w <= 0)
 243                                 {
 244                                         if (w == 0 && errno == 0)
 245                                                 break; /* EOF found */
 246                                         if (IS_IO_ERROR(fd, w, timeout))
 247                                                 goto err; /* errno set */
 248
 249                                         /* write would block */
 250                                         SM_IO_WR_TIMEOUT(fp, fd, timeout);
 251                                         w = 0;
 252                                 }
 253                         }
 254                         else
 255                         {
 256                                 w = s;
 257                                 COPY(w);
 258                                 fp->f_w -= w;
 259                                 fp->f_p += w;
 260                         }
 261                         if ((nldist -= w) == 0)
 262                         {
 263                                 /* copied the newline: flush and forget */
 264                                 if (sm_flush(fp, &timeout))
 265                                         goto err; /* errno set */
 266                                 nlknown = 0;
 267                         }
 268                         p += w;
 269                         len -= w;
 270                 } while ((uio->uio_resid -= w) != 0);
 271         }
 272
 273         return 0;
 274
 275 err:
 276         /* errno set before goto places us here */
 277         fp->f_flags |= SMERR;
 278         return SM_IO_EOF;
 279 }