#include <err.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/select.h>

#define MAXFILES 100	/* Maximum number of files. */
#define MAXFILE 255	/* Maximum file name length. */
#define MAXLINE MAXFILE+1

void waitstdin(void);

int
main(int argc, char *argv[])
{
	char file[30];
	char from[MAXLINE], *froms[MAXFILES], to[MAXLINE], *tos[MAXFILES];
	FILE *fp;
	int i, j;

	/* Allocate memory. */
	for (i = 0; i < MAXFILES; i++)
		if (!(froms[i]=malloc(MAXFILE)) || !(tos[i]=malloc(MAXFILE)))
			err(1, "malloc");

	sprintf(file, "/var/tmp/re.%d", getppid());

	if (waitstdin(), access(file, F_OK)) {
		fprintf(stderr, "%s: %s does not exist\n", argv[0], file);
		return 1;
	}

	if (!(fp = fopen(file, "r")))
		err(1, "fopen");

	for (i = 0; fgets(from, MAXLINE, fp); i++) {
		from[strcspn(from, "\n")] = 0;
		strcpy(froms[i], from);
		printf("from %s\n", from);
	}

	for (j = 0; fgets(to, MAXLINE, stdin); j++) {
		to[strcspn(to, "\n")] = 0;
		strcpy(tos[j], to);
		printf("to %s\n", to);
	}

	if (i != j) {
		fprintf(stderr, "%s: too %s lines\n",
			argv[0], j > i ? "many" : "few");
		return 1;
	}

	fclose(fp);
}

void
waitstdin()
{
	fd_set readfds;

	FD_ZERO(&readfds);
	FD_SET(0, &readfds);
	if (select(1, &readfds, NULL, NULL, NULL) == -1)
		err(1, "select");
}