minix/test/t40c.c

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2009-07-14 11:43:33 +02:00
/* t40c.c
*
* Test (pseudo) terminal devices
*
* Select works on regular files, (pseudo) terminal devices, streams-based
* files, FIFOs, pipes, and sockets. This test verifies selecting for (pseudo)
* terminal devices.
*
* This test is part of a bigger select test. It expects as argument which sub-
* test it is.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <errno.h>
#include <sys/wait.h>
#include <string.h>
#define TERMINALW "/dev/ttyp0"
#define TERMINALR "/dev/ptyp0"
#define SENDSTRING "minixrocks"
#define MAX_ERROR 5
int errct = 0, subtest = -1;
void e(int n, char *s) {
printf("Subtest %d, error %d, %s\n", subtest, n, s);
if (errct++ > MAX_ERROR) {
printf("Too many errors; test aborted\n");
exit(errct);
}
}
int do_child(void) {
int fd, retval;
struct timeval tv;
/* Opening master terminal for writing */
if((fd = open(TERMINALW, O_WRONLY)) == -1) {
printf("Error opening %s for writing, signalling parent to quit\n",
TERMINALW);
perror(NULL);
printf("Please make sure that %s is not in use while running this test\n",
TERMINALW);
exit(-1);
}
/* Going to sleep for two seconds to allow the parent proc to get ready */
tv.tv_sec = 2;
tv.tv_usec = 0;
select(0, NULL, NULL, NULL, &tv);
/* Try to write. Doesn't matter how many bytes we actually send. */
retval = write(fd, SENDSTRING, strlen(SENDSTRING));
close(fd);
/* Wait for another second to allow the parent to process incoming data */
tv.tv_usec = 1000000;
retval = select(0,NULL, NULL, NULL, &tv);
exit(0);
}
int do_parent(int child) {
int fd;
fd_set fds_read, fds_write, fds_error;
int retval;
/* Open slave terminal for reading */
if((fd = open(TERMINALR, O_RDONLY)) == -1) {
printf("Error opening %s for reading\n", TERMINALR);
perror(NULL);
printf("Please make sure that %s is not in use while running this test.\n",
TERMINALR);
waitpid(child, &retval, 0);
exit(-1);
}
/* Clear bit masks */
FD_ZERO(&fds_read); FD_ZERO(&fds_write); FD_ZERO(&fds_error);
/* Set read bits */
FD_SET(fd, &fds_read);
FD_SET(fd, &fds_write);
/* Test if we can read or write from/to fd. As fd is opened read only we
* cannot actually write, so the select should return immediately with fd
* set in fds_write, but not in fds_read. Note that the child waits two
* seconds before sending data. This gives us the opportunity run this
* sub-test as reading from fd is blocking at this point. */
retval = select(fd+1, &fds_read, &fds_write, &fds_error, NULL);
if(retval != 1) e(1, "incorrect amount of ready file descriptors");
if(FD_ISSET(fd, &fds_read)) e(2, "read should NOT be set");
if(!FD_ISSET(fd, &fds_write)) e(3, "write should be set");
if(FD_ISSET(fd, &fds_error)) e(4, "error should NOT be set");
/* Block until ready; until child wrote stuff */
FD_ZERO(&fds_read); FD_ZERO(&fds_write); FD_ZERO(&fds_error);
FD_SET(fd, &fds_read);
retval = select(fd+1, &fds_read, NULL, &fds_error, NULL);
if(retval != 1) e(5, "incorrect amount of ready file descriptors");
if(!FD_ISSET(fd, &fds_read)) e(6, "read should be set");
if(FD_ISSET(fd, &fds_error)) e(7, "error should not be set");
FD_ZERO(&fds_read); FD_ZERO(&fds_error);
FD_SET(fd,&fds_write);
retval = select(fd+1, NULL, &fds_write, NULL, NULL);
/* As it is impossible to write to a read only fd, this select should return
* immediately with fd set in fds_write. */
if(retval != 1) e(8, "incorrect amount or ready file descriptors");
close(fd);
waitpid(child, &retval, 0);
exit(errct);
}
int main(int argc, char **argv) {
int forkres;
/* Get subtest number */
if(argc != 2) {
printf("Usage: %s subtest_no\n", argv[0]);
exit(-1);
} else if(sscanf(argv[1], "%d", &subtest) != 1) {
printf("Usage: %s subtest_no\n", argv[0]);
exit(-1);
}
forkres = fork();
if(forkres == 0) do_child();
else if(forkres > 0) do_parent(forkres);
else { /* Fork failed */
perror("Unable to fork");
exit(-1);
}
exit(-2); /* We're not supposed to get here. Both do_* routines should exit*/
}