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Rewrite nc to be simpler, smaller, and to check syscalls for errors.

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This commit is contained in:
Matt Kraai
2000-12-15 22:34:34 +00:00
parent 8677d7b6ec
commit bfa7967c4a
5 changed files with 46 additions and 85 deletions
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57
nc.c
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@ -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 @@ int nc_main(int argc, char **argv)
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 @@ int nc_main(int argc, char **argv)
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");
}
}
}