Clean up dtch (again, probably)

Mostly changes to exit codes and renaming len to size. Also no more
writeAll.

1 files changed, 69 insertions, 72 deletions

diff --git a/bin/dtch.c b/bin/dtch.c
index a5982a5e..41659243 100644
--- a/bin/dtch.c
+++ b/bin/dtch.c
@@ -52,30 +52,21 @@ static struct sockaddr_un sockAddr(const char *home, const char *name) {
     return addr;
 }
 
-static ssize_t writeAll(int fd, const char *buf, size_t len) {
-    ssize_t writeLen;
-    while (0 < (writeLen = write(fd, buf, len))) {
-        buf += writeLen;
-        len -= writeLen;
-    }
-    return writeLen;
-}
-
 static char z;
 static struct iovec iov = { .iov_base = &z, .iov_len = 1 };
 
 static ssize_t sendFd(int sock, int fd) {
-    size_t len = CMSG_LEN(sizeof(int));
-    char buf[len];
+    size_t size = CMSG_LEN(sizeof(int));
+    char buf[size];
     struct msghdr msg = {
         .msg_iov = &iov,
         .msg_iovlen = 1,
         .msg_control = buf,
-        .msg_controllen = len,
+        .msg_controllen = size,
     };
 
     struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
-    cmsg->cmsg_len = len;
+    cmsg->cmsg_len = size;
     cmsg->cmsg_level = SOL_SOCKET;
     cmsg->cmsg_type = SCM_RIGHTS;
     *(int *)CMSG_DATA(cmsg) = fd;
@@ -84,13 +75,13 @@ static ssize_t sendFd(int sock, int fd) {
 }
 
 static int recvFd(int sock) {
-    size_t len = CMSG_LEN(sizeof(int));
-    char buf[len];
+    size_t size = CMSG_LEN(sizeof(int));
+    char buf[size];
     struct msghdr msg = {
         .msg_iov = &iov,
         .msg_iovlen = 1,
         .msg_control = buf,
-        .msg_controllen = len,
+        .msg_controllen = size,
     };
 
     ssize_t n = recvmsg(sock, &msg, 0);
@@ -106,7 +97,6 @@ static int recvFd(int sock) {
 }
 
 static struct sockaddr_un addr;
-
 static void unlinkAddr(void) {
     unlink(addr.sun_path);
 }
@@ -114,23 +104,26 @@ static void unlinkAddr(void) {
 static int dtch(int argc, char *argv[]) {
     int error;
 
-    struct passwd *user = getUser();
+    const struct passwd *user = getUser();
 
-    char *name = user->pw_name;
-    char *cmd = user->pw_shell;
-    if (argc > 2) {
-        name = argv[1];
-        cmd = argv[2];
-        argv += 2;
-    } else if (argc > 1) {
+    const char *name = user->pw_name;
+    if (argc > 1) {
         name = argv[1];
         argv++;
+        argc--;
+    }
+    if (argc > 1) {
+        argv++;
+    } else {
+        argv[0] = user->pw_shell;
     }
 
     int home = open(user->pw_dir, 0);
-    if (home < 0) err(EX_IOERR, "%s", user->pw_dir);
-    error = mkdirat(home, ".dtch", S_IRWXU);
-    if (error && errno != EEXIST) err(EX_IOERR, "%s/.dtch", user->pw_dir);
+    if (home < 0) err(EX_CANTCREAT, "%s", user->pw_dir);
+
+    error = mkdirat(home, ".dtch", 0700);
+    if (error && errno != EEXIST) err(EX_CANTCREAT, "%s/.dtch", user->pw_dir);
+
     error = close(home);
     if (error) err(EX_IOERR, "%s", user->pw_dir);
 
@@ -139,21 +132,22 @@ static int dtch(int argc, char *argv[]) {
 
     addr = sockAddr(user->pw_dir, name);
     error = bind(server, (struct sockaddr *)&addr, sizeof(addr));
-    if (error) err(EX_IOERR, "%s", addr.sun_path);
+    if (error) err(EX_CANTCREAT, "%s", addr.sun_path);
     atexit(unlinkAddr);
 
     error = chmod(addr.sun_path, 0600);
     if (error) err(EX_IOERR, "%s", addr.sun_path);
 
-    int master;
-    pid_t pid = forkpty(&master, NULL, NULL, NULL);
+    error = fcntl(server, F_SETFD, FD_CLOEXEC);
+    if (error) err(EX_IOERR, "fcntl(%d)", server);
+
+    int pty;
+    pid_t pid = forkpty(&pty, NULL, NULL, NULL);
     if (pid < 0) err(EX_OSERR, "forkpty");
 
     if (!pid) {
-        error = close(server);
-        if (error) warn("close(%d)", server);
-        execvp(cmd, argv);
-        err(EX_OSERR, "%s", cmd);
+        execvp(*argv, argv);
+        err(EX_NOINPUT, "%s", *argv);
     }
 
     error = listen(server, 0);
@@ -163,26 +157,27 @@ static int dtch(int argc, char *argv[]) {
         int client = accept(server, NULL, NULL);
         if (client < 0) err(EX_IOERR, "accept(%d)", server);
 
-        ssize_t len = sendFd(client, master);
-        if (len < 0) warn("sendmsg(%d)", client);
+        ssize_t size = sendFd(client, pty);
+        if (size < 0) warn("sendmsg(%d)", client);
 
-        len = recv(client, &z, sizeof(z), 0);
-        if (len < 0) warn("recv(%d)", client);
+        size = recv(client, &z, sizeof(z), 0);
+        if (size < 0) warn("recv(%d)", client);
 
         error = close(client);
         if (error) warn("close(%d)", client);
 
-        pid_t dead = waitpid(pid, NULL, WNOHANG);
-        if (dead < 0) warn("waitpid(%d)", pid);
-        if (dead) exit(EX_OK);
+        int status;
+        pid_t dead = waitpid(pid, &status, WNOHANG);
+        if (dead < 0) err(EX_OSERR, "waitpid(%d)", pid);
+        if (dead) return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
     }
 }
 
 static struct termios saveTerm;
-
 static void restoreTerm(void) {
     tcsetattr(STDERR_FILENO, TCSADRAIN, &saveTerm);
-    printf(
+    fprintf(
+        stderr,
         "\x1b[?1049l" // rmcup
         "\x1b\x63\x1b[!p\x1b[?3;4l\x1b[4l\x1b>" // reset
     );
@@ -191,25 +186,25 @@ static void restoreTerm(void) {
 static int atch(int argc, char *argv[]) {
     int error;
 
-    struct passwd *user = getUser();
-    char *name = (argc > 1) ? argv[1] : user->pw_name;
+    const struct passwd *user = getUser();
+    const char *name = (argc > 1) ? argv[1] : user->pw_name;
 
     int client = socket(PF_LOCAL, SOCK_STREAM, 0);
     if (client < 0) err(EX_OSERR, "socket");
 
     struct sockaddr_un addr = sockAddr(user->pw_dir, name);
     error = connect(client, (struct sockaddr *)&addr, sizeof(addr));
-    if (error) err(EX_IOERR, "%s", addr.sun_path);
+    if (error) err(EX_NOINPUT, "%s", addr.sun_path);
 
-    int master = recvFd(client);
-    if (master < 0) err(EX_IOERR, "recvmsg(%d)", client);
+    int pty = recvFd(client);
+    if (pty < 0) err(EX_IOERR, "recvmsg(%d)", client);
 
     struct winsize window;
     error = ioctl(STDERR_FILENO, TIOCGWINSZ, &window);
     if (error) err(EX_IOERR, "ioctl(%d, TIOCGWINSZ)", STDERR_FILENO);
 
-    error = ioctl(master, TIOCSWINSZ, &window);
-    if (error) err(EX_IOERR, "ioctl(%d, TIOCSWINSZ)", master);
+    error = ioctl(pty, TIOCSWINSZ, &window);
+    if (error) err(EX_IOERR, "ioctl(%d, TIOCSWINSZ)", pty);
 
     error = tcgetattr(STDERR_FILENO, &saveTerm);
     if (error) err(EX_IOERR, "tcgetattr(%d)", STDERR_FILENO);
@@ -220,43 +215,45 @@ static int atch(int argc, char *argv[]) {
     error = tcsetattr(STDERR_FILENO, TCSADRAIN, &raw);
     if (error) err(EX_IOERR, "tcsetattr(%d)", STDERR_FILENO);
 
-    char ctrlL = CTRL('L');
-    ssize_t len = write(master, &ctrlL, 1);
-    if (len < 0) err(EX_IOERR, "write(%d)", master);
+    char c = CTRL('L');
+    ssize_t size = write(pty, &c, 1);
+    if (size < 0) err(EX_IOERR, "write(%d)", pty);
 
+    char buf[4096];
     struct pollfd fds[2] = {
         { .fd = STDIN_FILENO, .events = POLLIN },
-        { .fd = master, .events = POLLIN },
+        { .fd = pty, .events = POLLIN },
     };
-
     while (0 < poll(fds, 2, -1)) {
-        char buf[4096];
-        ssize_t len;
+        if (fds[0].revents == POLLIN) {
+            ssize_t readSize = read(STDIN_FILENO, buf, sizeof(buf));
+            if (readSize < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO);
 
-        if (fds[0].revents) {
-            len = read(STDIN_FILENO, buf, sizeof(buf));
-            if (len < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO);
+            if (readSize == 1 && buf[0] == CTRL('Q')) return EX_OK;
 
-            if (len && buf[0] == CTRL('Q')) exit(EX_OK);
-
-            len = writeAll(master, buf, len);
-            if (len < 0) err(EX_IOERR, "write(%d)", master);
+            ssize_t writeSize = write(pty, buf, readSize);
+            if (writeSize < 0) err(EX_IOERR, "write(%d)", pty);
+            if (writeSize < readSize) errx(EX_IOERR, "short write(%d)", pty);
         }
 
-        if (fds[1].revents) {
-            len = read(master, buf, sizeof(buf));
-            if (len < 0) err(EX_IOERR, "read(%d)", master);
-            len = writeAll(STDOUT_FILENO, buf, len);
-            if (len < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO);
+        if (fds[1].revents == POLLIN) {
+            ssize_t readSize = read(pty, buf, sizeof(buf));
+            if (readSize < 0) err(EX_IOERR, "read(%d)", pty);
+
+            ssize_t writeSize = write(STDOUT_FILENO, buf, readSize);
+            if (writeSize < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO);
+            if (writeSize < readSize) {
+                errx(EX_IOERR, "short write(%d)", STDOUT_FILENO);
+            }
         }
     }
-    err(EX_IOERR, "poll([%d,%d])", STDIN_FILENO, master);
+    err(EX_IOERR, "poll");
 }
 
 int main(int argc, char *argv[]) {
     switch (argv[0][0]) {
         case 'd': return dtch(argc, argv);
         case 'a': return atch(argc, argv);
+        default:  return EX_USAGE;
     }
-    return EX_USAGE;
 }