usr/src/cmd/sendmail/libmilter/comm.c

   1 /*
   2  *  Copyright (c) 1999-2004, 2009 Sendmail, Inc. and its suppliers.
   3  *      All rights reserved.
   4  *
   5  * By using this file, you agree to the terms and conditions set
   6  * forth in the LICENSE file which can be found at the top level of
   7  * the sendmail distribution.
   8  *
   9  */
  10
  11 #include <sm/gen.h>
  12 SM_RCSID("@(#)$Id: comm.c,v 8.70 2009/12/16 16:33:48 ca Exp $")
  13
  14 #include "libmilter.h"
  15 #include <sm/errstring.h>
  16 #include <sys/uio.h>
  17
  18 static ssize_t  retry_writev __P((socket_t, struct iovec *, int, struct timeval *));
  19 static size_t Maxdatasize = MILTER_MAX_DATA_SIZE;
  20
  21 /*
  22 **  SMFI_SETMAXDATASIZE -- set limit for milter data read/write.
  23 **
  24 **      Parameters:
  25 **              sz -- new limit.
  26 **
  27 **      Returns:
  28 **              old limit
  29 */
  30
  31 size_t
  32 smfi_setmaxdatasize(sz)
  33         size_t sz;
  34 {
  35         size_t old;
  36
  37         old = Maxdatasize;
  38         Maxdatasize = sz;
  39         return old;
  40 }
  41
  42 /*
  43 **  MI_RD_CMD -- read a command
  44 **
  45 **      Parameters:
  46 **              sd -- socket descriptor
  47 **              timeout -- maximum time to wait
  48 **              cmd -- single character command read from sd
  49 **              rlen -- pointer to length of result
  50 **              name -- name of milter
  51 **
  52 **      Returns:
  53 **              buffer with rest of command
  54 **              (malloc()ed here, should be free()d)
  55 **              hack: encode error in cmd
  56 */
  57
  58 char *
  59 mi_rd_cmd(sd, timeout, cmd, rlen, name)
  60         socket_t sd;
  61         struct timeval *timeout;
  62         char *cmd;
  63         size_t *rlen;
  64         char *name;
  65 {
  66         ssize_t len;
  67         mi_int32 expl;
  68         ssize_t i;
  69         FD_RD_VAR(rds, excs);
  70         int ret;
  71         int save_errno;
  72         char *buf;
  73         char data[MILTER_LEN_BYTES + 1];
  74
  75         *cmd = '\0';
  76         *rlen = 0;
  77
  78         i = 0;
  79         for (;;)
  80         {
  81                 FD_RD_INIT(sd, rds, excs);
  82                 ret = FD_RD_READY(sd, rds, excs, timeout);
  83                 if (ret == 0)
  84                         break;
  85                 else if (ret < 0)
  86                 {
  87                         if (errno == EINTR)
  88                                 continue;
  89                         break;
  90                 }
  91                 if (FD_IS_RD_EXC(sd, rds, excs))
  92                 {
  93                         *cmd = SMFIC_SELECT;
  94                         return NULL;
  95                 }
  96
  97                 len = MI_SOCK_READ(sd, data + i, sizeof data - i);
  98                 if (MI_SOCK_READ_FAIL(len))
  99                 {
 100                         smi_log(SMI_LOG_ERR,
 101                                 "%s, mi_rd_cmd: read returned %d: %s",
 102                                 name, (int) len, sm_errstring(errno));
 103                         *cmd = SMFIC_RECVERR;
 104                         return NULL;
 105                 }
 106                 if (len == 0)
 107                 {
 108                         *cmd = SMFIC_EOF;
 109                         return NULL;
 110                 }
 111                 if (len >= (ssize_t) sizeof data - i)
 112                         break;
 113                 i += len;
 114         }
 115         if (ret == 0)
 116         {
 117                 *cmd = SMFIC_TIMEOUT;
 118                 return NULL;
 119         }
 120         else if (ret < 0)
 121         {
 122                 smi_log(SMI_LOG_ERR,
 123                         "%s: mi_rd_cmd: %s() returned %d: %s",
 124                         name, MI_POLLSELECT, ret, sm_errstring(errno));
 125                 *cmd = SMFIC_RECVERR;
 126                 return NULL;
 127         }
 128
 129         *cmd = data[MILTER_LEN_BYTES];
 130         data[MILTER_LEN_BYTES] = '\0';
 131         (void) memcpy((void *) &expl, (void *) &(data[0]), MILTER_LEN_BYTES);
 132         expl = ntohl(expl) - 1;
 133         if (expl <= 0)
 134                 return NULL;
 135         if (expl > Maxdatasize)
 136         {
 137                 *cmd = SMFIC_TOOBIG;
 138                 return NULL;
 139         }
 140 #if _FFR_ADD_NULL
 141         buf = malloc(expl + 1);
 142 #else /* _FFR_ADD_NULL */
 143         buf = malloc(expl);
 144 #endif /* _FFR_ADD_NULL */
 145         if (buf == NULL)
 146         {
 147                 *cmd = SMFIC_MALLOC;
 148                 return NULL;
 149         }
 150
 151         i = 0;
 152         for (;;)
 153         {
 154                 FD_RD_INIT(sd, rds, excs);
 155                 ret = FD_RD_READY(sd, rds, excs, timeout);
 156                 if (ret == 0)
 157                         break;
 158                 else if (ret < 0)
 159                 {
 160                         if (errno == EINTR)
 161                                 continue;
 162                         break;
 163                 }
 164                 if (FD_IS_RD_EXC(sd, rds, excs))
 165                 {
 166                         *cmd = SMFIC_SELECT;
 167                         free(buf);
 168                         return NULL;
 169                 }
 170                 len = MI_SOCK_READ(sd, buf + i, expl - i);
 171                 if (MI_SOCK_READ_FAIL(len))
 172                 {
 173                         smi_log(SMI_LOG_ERR,
 174                                 "%s: mi_rd_cmd: read returned %d: %s",
 175                                 name, (int) len, sm_errstring(errno));
 176                         ret = -1;
 177                         break;
 178                 }
 179                 if (len == 0)
 180                 {
 181                         *cmd = SMFIC_EOF;
 182                         free(buf);
 183                         return NULL;
 184                 }
 185                 if (len > expl - i)
 186                 {
 187                         *cmd = SMFIC_RECVERR;
 188                         free(buf);
 189                         return NULL;
 190                 }
 191                 if (len >= expl - i)
 192                 {
 193                         *rlen = expl;
 194 #if _FFR_ADD_NULL
 195                         /* makes life simpler for common string routines */
 196                         buf[expl] = '\0';
 197 #endif /* _FFR_ADD_NULL */
 198                         return buf;
 199                 }
 200                 i += len;
 201         }
 202
 203         save_errno = errno;
 204         free(buf);
 205
 206         /* select returned 0 (timeout) or < 0 (error) */
 207         if (ret == 0)
 208         {
 209                 *cmd = SMFIC_TIMEOUT;
 210                 return NULL;
 211         }
 212         if (ret < 0)
 213         {
 214                 smi_log(SMI_LOG_ERR,
 215                         "%s: mi_rd_cmd: %s() returned %d: %s",
 216                         name, MI_POLLSELECT, ret, sm_errstring(save_errno));
 217                 *cmd = SMFIC_RECVERR;
 218                 return NULL;
 219         }
 220         *cmd = SMFIC_UNKNERR;
 221         return NULL;
 222 }
 223
 224 /*
 225 **  RETRY_WRITEV -- Keep calling the writev() system call
 226 **      until all the data is written out or an error occurs.
 227 **
 228 **      Parameters:
 229 **              fd -- socket descriptor
 230 **              iov -- io vector
 231 **              iovcnt -- number of elements in io vector
 232 **                      must NOT exceed UIO_MAXIOV.
 233 **              timeout -- maximum time to wait
 234 **
 235 **      Returns:
 236 **              success: number of bytes written
 237 **              otherwise: MI_FAILURE
 238 */
 239
 240 static ssize_t
 241 retry_writev(fd, iov, iovcnt, timeout)
 242         socket_t fd;
 243         struct iovec *iov;
 244         int iovcnt;
 245         struct timeval *timeout;
 246 {
 247         int i;
 248         ssize_t n, written;
 249         FD_WR_VAR(wrs);
 250
 251         written = 0;
 252         for (;;)
 253         {
 254                 while (iovcnt > 0 && iov[0].iov_len == 0)
 255                 {
 256                         iov++;
 257                         iovcnt--;
 258                 }
 259                 if (iovcnt <= 0)
 260                         return written;
 261
 262                 /*
 263                 **  We don't care much about the timeout here,
 264                 **  it's very long anyway; correct solution would be
 265                 **  to take the time before the loop and reduce the
 266                 **  timeout after each invocation.
 267                 **  FD_SETSIZE is checked when socket is created.
 268                 */
 269
 270                 FD_WR_INIT(fd, wrs);
 271                 i = FD_WR_READY(fd, wrs, timeout);
 272                 if (i == 0)
 273                         return MI_FAILURE;
 274                 if (i < 0)
 275                 {
 276                         if (errno == EINTR || errno == EAGAIN)
 277                                 continue;
 278                         return MI_FAILURE;
 279                 }
 280                 n = writev(fd, iov, iovcnt);
 281                 if (n == -1)
 282                 {
 283                         if (errno == EINTR || errno == EAGAIN)
 284                                 continue;
 285                         return MI_FAILURE;
 286                 }
 287
 288                 written += n;
 289                 for (i = 0; i < iovcnt; i++)
 290                 {
 291                         if (iov[i].iov_len > (unsigned int) n)
 292                         {
 293                                 iov[i].iov_base = (char *)iov[i].iov_base + n;
 294                                 iov[i].iov_len -= (unsigned int) n;
 295                                 break;
 296                         }
 297                         n -= (int) iov[i].iov_len;
 298                         iov[i].iov_len = 0;
 299                 }
 300                 if (i == iovcnt)
 301                         return written;
 302         }
 303 }
 304
 305 /*
 306 **  MI_WR_CMD -- write a cmd to sd
 307 **
 308 **      Parameters:
 309 **              sd -- socket descriptor
 310 **              timeout -- maximum time to wait
 311 **              cmd -- single character command to write
 312 **              buf -- buffer with further data
 313 **              len -- length of buffer (without cmd!)
 314 **
 315 **      Returns:
 316 **              MI_SUCCESS/MI_FAILURE
 317 */
 318
 319 int
 320 mi_wr_cmd(sd, timeout, cmd, buf, len)
 321         socket_t sd;
 322         struct timeval *timeout;
 323         int cmd;
 324         char *buf;
 325         size_t len;
 326 {
 327         size_t sl;
 328         ssize_t l;
 329         mi_int32 nl;
 330         int iovcnt;
 331         struct iovec iov[2];
 332         char data[MILTER_LEN_BYTES + 1];
 333
 334         if (len > Maxdatasize || (len > 0 && buf == NULL))
 335                 return MI_FAILURE;
 336
 337         nl = htonl(len + 1);    /* add 1 for the cmd char */
 338         (void) memcpy(data, (void *) &nl, MILTER_LEN_BYTES);
 339         data[MILTER_LEN_BYTES] = (char) cmd;
 340         sl = MILTER_LEN_BYTES + 1;
 341
 342         /* set up the vector for the size / command */
 343         iov[0].iov_base = (void *) data;
 344         iov[0].iov_len  = sl;
 345         iovcnt = 1;
 346         if (len >= 0 && buf != NULL)
 347         {
 348                 iov[1].iov_base = (void *) buf;
 349                 iov[1].iov_len  = len;
 350                 iovcnt = 2;
 351         }
 352
 353         l = retry_writev(sd, iov, iovcnt, timeout);
 354         if (l == MI_FAILURE)
 355                 return MI_FAILURE;
 356         return MI_SUCCESS;
 357 }