Rewrite nc to be simpler, smaller, and to check syscalls for errors.
diff --git a/nc.c b/nc.c
index 84c1a81..a2be8ec 100644
--- a/nc.c
+++ b/nc.c
@@ -38,14 +38,10 @@
#include <sys/time.h>
#include <sys/ioctl.h>
-#define BUFSIZE 100
-
int nc_main(int argc, char **argv)
{
int sfd;
- int result;
- int len;
- char ch[BUFSIZE];
+ char buf[BUFSIZ];
struct sockaddr_in address;
struct hostent *hostinfo;
@@ -54,34 +50,26 @@
argc--;
argv++;
- if (argc < 2 || **(argv + 1) == '-') {
+ if (argc < 2 || **argv == '-') {
usage(nc_usage);
}
- sfd = socket(AF_INET, SOCK_STREAM, 0);
+ if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+ perror_msg_and_die("socket");
- hostinfo = (struct hostent *) gethostbyname(*argv);
-
- if (!hostinfo) {
+ if ((hostinfo = gethostbyname(*argv)) == NULL)
error_msg_and_die("cannot resolve %s\n", *argv);
- }
address.sin_family = AF_INET;
address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
address.sin_port = htons(atoi(*(++argv)));
- len = sizeof(address);
-
- result = connect(sfd, (struct sockaddr *) &address, len);
-
- if (result < 0) {
- perror("nc: connect");
- exit(2);
- }
+ if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
+ perror_msg_and_die("connect");
FD_ZERO(&readfds);
FD_SET(sfd, &readfds);
- FD_SET(fileno(stdin), &readfds);
+ FD_SET(STDIN_FILENO, &readfds);
while (1) {
int fd;
@@ -90,41 +78,26 @@
testfds = readfds;
- result =
- select(FD_SETSIZE, &testfds, (fd_set *) NULL, (fd_set *) NULL,
- (struct timeval *) 0);
-
- if (result < 1) {
- perror("nc: select");
- exit(3);
- }
+ if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
+ perror_msg_and_die("select");
for (fd = 0; fd < FD_SETSIZE; fd++) {
if (FD_ISSET(fd, &testfds)) {
- int trn = 0;
- int rn;
-
- ioctl(fd, FIONREAD, &nread);
+ if ((nread = safe_read(fd, buf, sizeof(buf))) < 0)
+ perror_msg_and_die("read");
if (fd == sfd) {
if (nread == 0)
exit(0);
- ofd = fileno(stdout);
+ ofd = STDOUT_FILENO;
} else {
if (nread == 0)
shutdown(sfd, 1);
ofd = sfd;
}
-
-
- do {
- rn = (BUFSIZE < nread - trn) ? BUFSIZE : nread - trn;
- trn += rn;
- read(fd, ch, rn);
- write(ofd, ch, rn);
- }
- while (trn < nread);
+ if (full_write(ofd, buf, nread) < 0)
+ perror_msg_and_die("write");
}
}
}