rosapps/net/ncftp/sio/PRead.c

   1 #include "syshdrs.h"
   2
   3 #if !defined(NO_SIGNALS) && defined(SIGPIPE)
   4 extern volatile Sjmp_buf gPipeJmp;
   5 #endif
   6
   7 /* Read up to "size" bytes on sfd.
   8  *
   9  * If "retry" is on, after a successful read of less than "size"
  10  * bytes, it will attempt to read more, upto "size."
  11  *
  12  * Although "retry" would seem to indicate you may want to always
  13  * read "size" bytes or else it is an error, even with that on you
  14  * may get back a value < size.  Set "retry" to 0 when you want to
  15  * return as soon as there is a chunk of data whose size is <= "size".
  16  */
  17
  18 int
  19 PRead(int sfd, char *const buf0, size_t size, int retry)
  20 {
  21         int nread;
  22         volatile int nleft;
  23         char *volatile buf = buf0;
  24 #if !defined(NO_SIGNALS) && defined(SIGPIPE)
  25         vsio_sigproc_t sigpipe;
  26
  27         if (SSetjmp(gPipeJmp) != 0) {
  28                 (void) SSignal(SIGPIPE, (sio_sigproc_t) sigpipe);
  29                 nread = size - nleft;
  30                 if (nread > 0)
  31                         return (nread);
  32                 errno = EPIPE;
  33                 return (kBrokenPipeErr);
  34         }
  35
  36         sigpipe = (vsio_sigproc_t) SSignal(SIGPIPE, SIOHandler);
  37 #endif
  38         errno = 0;
  39
  40         nleft = (int) size;
  41         forever {
  42                 nread = read(sfd, buf, nleft);
  43                 if (nread <= 0) {
  44                         if (nread == 0) {
  45                                 /* EOF */
  46                                 nread = size - nleft;
  47                                 goto done;
  48                         } else if (errno != EINTR) {
  49                                 nread = size - nleft;
  50                                 if (nread == 0)
  51                                         nread = -1;
  52                                 goto done;
  53                         } else {
  54                                 errno = 0;
  55                                 nread = 0;
  56                                 /* Try again. */
  57                         }
  58                 }
  59                 nleft -= nread;
  60                 if ((nleft <= 0) || (retry == 0))
  61                         break;
  62                 buf += nread;
  63         }
  64         nread = size - nleft;
  65
  66 done:
  67 #if !defined(NO_SIGNALS) && defined(SIGPIPE)
  68         (void) SSignal(SIGPIPE, (sio_sigproc_t) sigpipe);
  69 #endif
  70         return (nread);
  71 }       /* PRead */