devfile.c

APUE(第二版)的随书源代码,与第一版的代码相比增加了一些章节的代码(详见第二版的说明)

#include	"calld.h"

static FILE	*fpdev = NULL;
static int	devlineno;			/* for error messages */
static char	devline[MAXLINE];
		/* can't be automatic; dev_next() returns pointers into here */

/* Read and break apart a line in the Devices file. */

int
dev_next(Devices *devptr)		/* pointers in structure are filled in */
{
	if (fpdev == NULL) {
		if ( (fpdev = fopen(DEVICES, "r")) == NULL)
			log_sys("can't open %s", DEVICES);
		devlineno = 0;
	}

again:
	if (fgets(devline, MAXLINE, fpdev) == NULL)
		return(-1);		/* EOF */
	devlineno++;

	if ( (devptr->type = strtok(devline, WHITE)) == NULL) {
		if (devline[0] == '\n')
			goto again;		/* ignore empty line */
		log_quit("missing `type' in Devices file, line %d", devlineno);
	}
	if (devptr->type[0] == '#')
		goto again;			/* ignore comment line */

	if ( (devptr->line = strtok(NULL, WHITE)) == NULL)
		log_quit("missing `line' in Devices file, line %d", devlineno);

	if ( (devptr->line2 = strtok(NULL, WHITE)) == NULL)
		log_quit("missing `line2' in Devices file, line %d", devlineno);

	if ( (devptr->class = strtok(NULL, WHITE)) == NULL)
		log_quit("missing `class' in Devices file, line %d", devlineno);

	if ( (devptr->dialer = strtok(NULL, WHITE)) == NULL)
		log_quit("missing `dialer' in Devices file, line %d", devlineno);

	return(0);
}

void
dev_rew(void)
{
	if (fpdev != NULL)
		rewind(fpdev);
	devlineno = 0;
}

/* Find a match of type and class */

int
dev_find(Devices *devptr, const Systems *sysptr)
{
	dev_rew();
	while (dev_next(devptr) >= 0) {
		if (strcmp(sysptr->type, devptr->type) == 0 &&
			strcmp(sysptr->class, devptr->class) == 0)
				return(0);		/* found a device match */
	}
	sprintf(errmsg, "device `%s'/`%s' not found\n",
							sysptr->type, sysptr->class);
	return(-1);
}