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

1 files changed, 15 insertions, 42 deletions

diff --git a/networking/nc.c b/networking/nc.c
index 84c1a815e..a2be8ec46 100644
--- a/networking/nc.c
+++ b/networking/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 @@ 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);
-
-        hostinfo = (struct hostent *) gethostbyname(*argv);
+        if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+                perror_msg_and_die("socket");
 
-        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");
                         }
                 }
         }