225 lines
6.1 KiB
C
225 lines
6.1 KiB
C
# include <stdio.h>
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# include "gen.h"
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# include "../h/dbs.h"
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# include "../h/pipes.h"
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/*
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** Buffered Read From Pipe
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**
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** Reads from the pipe with the file descriptor `des' into
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** the buffer `buf'. `Mode' tells what is to be done. `Msg' is
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** the address of the input buffer, and `n' is the length of the
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** info. If `n' is zero, the data is assumed to be a null-
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** terminated string.
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**
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** `Buf' is defined in "../pipes.h" together with the modes.
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** The pipe should be written by wrpipe() to insure that the
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** pipe formats match.
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**
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** Modes:
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**
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** P_PRIME -- Primes the buffer. This involves cleaning out all
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** the header stuff so that a physical read is forced
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** on the next normal call to rdpipe(). It also resets
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** the error flag, etc.
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**
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** P_NORM -- This is the normal mode. If the buffer is empty,
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** it is filled from the pipe. `N' bytes are moved into
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** `msg'. If `n' is zero, bytes are moved into `msg' up
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** to and including the first null byte. The pipe is
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** read whenever necessary, so the size of the data
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** buffer (controlled by PBUFSIZ) has absolutely no
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** effect on operation.
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**
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** P_SYNC -- This mode reads the buffer, filling the pipe as
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** necessary, until an End Of Pipe (EOP) is encountered.
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** An EOP is defined as an empty buffer with a mode
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** ("hdrstat") of "END_STAT". Any data left in the pipe
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** is thrown away, but error messages are not. Anything
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** not already read by the user is read by P_SYNC, so if
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** you are not certain that you have already read the
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** previous EOP.
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**
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** P_EXECID -- The first (exec_id) field of the pipe buffer header
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** is read and returned. This is used (for instance) by
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** the DBU routines, which must get the exec_id, but must
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** not read the rest of the pipe in case they must overlay
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** themselves. It must ALWAYS be followed by a RDPIPE of
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** mode P_FUNCID!!
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**
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** P_FUNCID -- The second through last bytes of the pipe are read
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** into the buffer, and the function code ("func_id") is
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** returned. This is the second half of a P_EXECID call.
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**
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** P_INT -- In the event of an interrupt, a wrpipe() call should
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** be made to all writable pipes of mode P_INT, and then
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** rdpipe() calls should be made on all readable pipes
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** of this mode. This clears out the pipe up until a
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** special type of pipe header ("SYNC_STAT") is read. It
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** is absolutely critical that this is called in conjunc-
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** tion with all other processes. This mode is used in
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** resyncpipes(), which performs all the correct calls
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** in the correct order.
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**
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** In all cases except P_INT mode, if an error is read from the
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** pipe it is automatically passed to proc_error(). This routine
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** is responsible for passing the error message to the next higher
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** process.
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**
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** If an end of file is read from the pipe, the end_job() routine
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** is called. This routine should do any necessary end of job
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** processing needed (closing relations, etc.) and return with
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** a zero value.
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**
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** Default proc_error() and end_job() routines exist in the
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** library, so if you don't want any extra processing, you can
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** just not bother to define them.
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**
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** In general, the number of bytes actually read is returned. If
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** you read an EOP, zero is returned.
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*/
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extern int (*AAexitfn)(); /* defined in AAsyserr */
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extern int read(); /* standard read routine */
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int (*Pi_rd_fn)() = read; /* fn to read from pipe */
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rdpipe(mode, buf, des, msg, n)
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int mode;
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char *msg;
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int n;
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int des; /* file descriptor for pipe */
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register struct pipfrmt *buf;
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{
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register int knt;
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register int syncflg;
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int i;
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extern char *AAproc_name;
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# ifdef xATR1
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AAtTfp(99, 0, "%s ent RDPIPE md %d buf 0%o des %d\n",
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AAproc_name, mode, buf, des);
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# endif
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syncflg = 0;
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switch (mode)
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{
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case P_PRIME:
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buf->pbuf_pt = buf->buf_len = buf->err_id = 0;
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buf->hdrstat = NORM_STAT;
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return (0);
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case P_NORM:
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break;
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case P_SYNC:
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syncflg++;
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break;
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case P_EXECID:
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# ifdef xATR3
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AAtTfp(99, 1, "%s RDPIPE ret %c\n", AAproc_name, buf->exec_id);
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# endif
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syncflg++;
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break;
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case P_FUNCID:
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return (buf->func_id);
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case P_INT:
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syncflg--;
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buf->hdrstat = NORM_STAT;
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break;
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case P_PARAM:
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/* If there is currently some data, return param_id.
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** else read next block are return its param_id
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*/
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if (buf->pbuf_pt < buf->buf_len || buf->hdrstat == LAST_STAT)
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return (buf->param_id);
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break;
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default:
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AAsyserr(15028, mode);
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}
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knt = 0;
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do
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{
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/* check for buffer empty */
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while (buf->pbuf_pt >= buf->buf_len || syncflg)
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{
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/* read a new buffer full */
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if (buf->hdrstat == LAST_STAT && syncflg >= 0)
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goto out;
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# ifdef xATR3
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AAtTfp(99, 2, "%s RDPIPE %d w len %d pt 0%o err %d sf %d\n",
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AAproc_name, des, buf->buf_len, buf->pbuf_pt, buf->err_id, syncflg);
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# endif
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if (!(i = (*Pi_rd_fn)(des, buf, HDRSIZ + PBUFSIZ)))
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{
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# ifdef xATR3
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AAtTfp(99, 1, "%s RDPIPE exit\n", AAproc_name);
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# endif
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if (syncflg < 0)
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AAsyserr(15029, des);
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close(W_down);
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if (des != R_up)
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{
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# ifdef xATR1
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if (AAtTf(99, -1))
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AAsyserr(15030, buf, des);
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# endif
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(*AAexitfn)(-1);
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}
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fflush(stdout);
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exit(end_job());
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}
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buf->pbuf_pt = 0;
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# ifdef xATR2
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if (AAtTf(99, 2))
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prpipe(buf);
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# endif
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if (i < HDRSIZ + PBUFSIZ)
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AAsyserr(15033, buf, des);
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if (buf->hdrstat == SYNC_STAT)
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{
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if (syncflg < 0)
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return (1);
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else
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AAsyserr(15036);
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}
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if (buf->err_id && syncflg >= 0)
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{
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# ifdef xATR2
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AAtTfp(99, 3, "%s RDPIPE err %d\n", AAproc_name, buf->err_id);
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# endif
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proc_error(buf, des);
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# ifdef xATR3
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AAtTfp(99, 3, "%s RDPIPE ret\n", AAproc_name);
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# endif
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buf->pbuf_pt = buf->buf_len;
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buf->hdrstat = NORM_STAT;
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continue;
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}
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if (mode == P_PARAM)
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return (buf->param_id);
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if (mode == P_EXECID)
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return (buf->exec_id);
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}
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/* get a byte of information */
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msg[knt++] = buf->pbuf[buf->pbuf_pt++];
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} while (!n? (msg[knt - 1]): (knt < n));
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out:
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# ifdef xATR1
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if (AAtTfp(99, 1, "%s RDPIPE ret %d", AAproc_name, knt))
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{
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if (!n && !syncflg)
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printf(", str `%s'", msg);
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putchar('\n');
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}
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# endif
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return (knt);
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}
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