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devcomm.c
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Tue, May 14, 01:01

devcomm.c
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#ifndef lint
static const char RCSid[] = "$Id: devcomm.c,v 2.19 2016/08/18 00:52:48 greg Exp $";
#endif
/*
* devcomm.c - communication routines for separate drivers.
*
* External symbols declared in driver.h
*/
#include "copyright.h"
#include <sys/types.h>
#if !defined(_WIN32) && !defined(_WIN64)
#include <sys/wait.h>
#endif
#include "paths.h"
#include "platform.h"
#include "standard.h"
#include "driver.h"
#ifndef DEVPATH
#define DEVPATH getenv("PATH") /* device search path */
#endif
FILE *devin, *devout;
int devchild;
static struct driver * final_connect(void);
static void mygets(char *s, FILE *fp);
static void myputs(char *s, FILE *fp);
static void reply_error(char *routine);
static void getstate(void);
static dr_closef_t comm_close;
static dr_clearf_t comm_clear;
static dr_paintrf_t comm_paintr;
static dr_getcurf_t comm_getcur;
static dr_comoutf_t comm_comout;
static dr_cominf_t comm_comin;
static dr_flushf_t comm_flush;
struct driver comm_driver = {
comm_close, comm_clear, comm_paintr, comm_getcur,
comm_comout, comm_comin, comm_flush
};
static struct driver *
final_connect(void) /* verify and initialize connection */
{
putw(COM_SENDM, devout);
fflush(devout);
if (getw(devin) != COM_RECVM)
return(NULL);
/* get driver parameters */
getstate();
/* set error vectors */
erract[COMMAND].pf = comm_comout;
/* doesn't work with raypcalls.c
if (erract[WARNING].pf != NULL)
erract[WARNING].pf = comm_comout;
*/
return(&comm_driver);
}
struct driver *
slave_init( /* run rview in slave mode */
char *dname,
char *id
)
{
devchild = -1; /* we're the slave here */
devout = stdout; /* use standard input */
devin = stdin; /* and standard output */
return(final_connect()); /* verify initialization */
}
struct driver *
comm_init( /* set up and execute driver */
char *dname,
char *id
)
{
char *dvcname;
int p1[2], p2[2];
char pin[16], pout[16];
/* find driver program */
if ((dvcname = getpath(dname, DEVPATH, X_OK)) == NULL) {
eputs(dname);
eputs(": not found\n");
return(NULL);
}
#ifdef RHAS_FORK_EXEC
/* open communication pipes */
if (pipe(p1) == -1 || pipe(p2) == -1)
goto syserr;
if ((devchild = fork()) == 0) { /* fork driver process */
close(p1[1]);
close(p2[0]);
sprintf(pin, "%d", p1[0]);
sprintf(pout, "%d", p2[1]);
execl(dvcname, dname, pin, pout, id, NULL);
perror(dvcname);
_exit(127);
}
if (devchild == -1)
goto syserr;
close(p1[0]);
close(p2[1]);
/*
* Close write stream on exec to avoid multiprocessing deadlock.
* No use in read stream without it, so set flag there as well.
*/
fcntl(p1[1], F_SETFD, FD_CLOEXEC);
fcntl(p2[0], F_SETFD, FD_CLOEXEC);
if ((devout = fdopen(p1[1], "w")) == NULL)
goto syserr;
if ((devin = fdopen(p2[0], "r")) == NULL)
goto syserr;
return(final_connect()); /* verify initialization */
syserr:
perror(dname);
return(NULL);
#else /* ! RHAS_FORK_EXEC */
eputs(dname);
eputs(": no fork/exec\n");
return(NULL);
#endif /* ! RHAS_FORK_EXEC */
}
static void
comm_close(void) /* done with driver */
{
int pid;
erract[COMMAND].pf = NULL; /* reset error vectors */
if (erract[WARNING].pf != NULL)
erract[WARNING].pf = wputs;
fclose(devout);
fclose(devin);
if (devchild < 0)
return;
#if !defined(_WIN32) && !defined(_WIN64)
while ((pid = wait(0)) != -1 && pid != devchild)
;
#endif
}
static void
comm_clear( /* clear screen */
int xres,
int yres
)
{
putc(COM_CLEAR, devout);
putw(xres, devout);
putw(yres, devout);
fflush(devout);
}
static void
comm_paintr( /* paint a rectangle */
COLOR col,
int xmin,
int ymin,
int xmax,
int ymax
)
{
putc(COM_PAINTR, devout);
putbinary(col, sizeof(COLOR), 1, devout);
putw(xmin, devout);
putw(ymin, devout);
putw(xmax, devout);
putw(ymax, devout);
}
static void
comm_flush(void) /* flush output to driver */
{
putc(COM_FLUSH, devout);
fflush(devout);
if (getc(devin) != COM_FLUSH)
reply_error("flush");
getstate();
}
static int
comm_getcur( /* get and return cursor position */
int *xp,
int *yp
)
{
int c;
putc(COM_GETCUR, devout);
fflush(devout);
if (getc(devin) != COM_GETCUR)
reply_error("getcur");
c = getc(devin);
*xp = getw(devin);
*yp = getw(devin);
return(c);
}
static void
comm_comout( /* print string to command line */
char *str
)
{
putc(COM_COMOUT, devout);
myputs(str, devout);
if (str[strlen(str)-1] == '\n')
fflush(devout);
}
static void
comm_comin( /* read string from command line */
char *buf,
char *prompt
)
{
putc(COM_COMIN, devout);
if (prompt == NULL)
putc(0, devout);
else {
putc(1, devout);
myputs(prompt, devout);
}
fflush(devout);
if (getc(devin) != COM_COMIN)
reply_error("comin");
mygets(buf, devin);
getstate();
}
static void
mygets( /* get string from file (with nul) */
char *s,
FILE *fp
)
{
int c;
while ((c = getc(fp)) != EOF)
if ((*s++ = c) == '\0')
return;
*s = '\0';
}
static void
myputs( /* put string to file (with nul) */
char *s,
FILE *fp
)
{
do
putc(*s, fp);
while (*s++);
}
static void
reply_error( /* what should we do here? */
char *routine
)
{
eputs(routine);
eputs(": driver reply error\n");
quit(1);
}
static void
getstate(void) /* get driver state variables */
{
getbinary((char *)&comm_driver.pixaspect,
sizeof(comm_driver.pixaspect), 1, devin);
comm_driver.xsiz = getw(devin);
comm_driver.ysiz = getw(devin);
comm_driver.inpready = getw(devin);
}

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