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71 lines
1.6 KiB
C
71 lines
1.6 KiB
C
#include "syshdrs.h"
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#if !defined(NO_SIGNALS) && defined(SIGPIPE)
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extern volatile Sjmp_buf gPipeJmp;
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#endif
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/* Read up to "size" bytes on sfd.
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*
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* If "retry" is on, after a successful read of less than "size"
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* bytes, it will attempt to read more, upto "size."
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*
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* Although "retry" would seem to indicate you may want to always
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* read "size" bytes or else it is an error, even with that on you
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* may get back a value < size. Set "retry" to 0 when you want to
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* return as soon as there is a chunk of data whose size is <= "size".
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*/
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int
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PRead(int sfd, char *const buf0, size_t size, int retry)
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{
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int nread;
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volatile int nleft;
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char *volatile buf = buf0;
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#if !defined(NO_SIGNALS) && defined(SIGPIPE)
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vsio_sigproc_t sigpipe;
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if (SSetjmp(gPipeJmp) != 0) {
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(void) SSignal(SIGPIPE, (sio_sigproc_t) sigpipe);
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nread = size - nleft;
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if (nread > 0)
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return (nread);
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errno = EPIPE;
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return (kBrokenPipeErr);
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}
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sigpipe = (vsio_sigproc_t) SSignal(SIGPIPE, SIOHandler);
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#endif
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errno = 0;
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nleft = (int) size;
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forever {
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nread = read(sfd, buf, nleft);
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if (nread <= 0) {
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if (nread == 0) {
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/* EOF */
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nread = size - nleft;
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goto done;
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} else if (errno != EINTR) {
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nread = size - nleft;
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if (nread == 0)
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nread = -1;
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goto done;
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} else {
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errno = 0;
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nread = 0;
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/* Try again. */
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}
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}
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nleft -= nread;
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if ((nleft <= 0) || (retry == 0))
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break;
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buf += nread;
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}
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nread = size - nleft;
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done:
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#if !defined(NO_SIGNALS) && defined(SIGPIPE)
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(void) SSignal(SIGPIPE, (sio_sigproc_t) sigpipe);
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#endif
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return (nread);
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} /* PRead */
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