added website data, because it had heaps of good tutorials and info

1 files changed, 278 insertions, 0 deletions

diff --git a/riemann.fmi.uni-sofia.bg/ngetty/ngetty-1.1/ngetty.c b/riemann.fmi.uni-sofia.bg/ngetty/ngetty-1.1/ngetty.c
new file mode 100644
index 0000000..926e904
--- /dev/null
+++ b/riemann.fmi.uni-sofia.bg/ngetty/ngetty-1.1/ngetty.c
@@ -0,0 +1,278 @@
+/*
+ * ngetty.c - daemon for virtual console terminals
+ *
+ * Copyright 2007 Andre Oliveira
+ * Copyright 2007,2008 Nikola Vladov
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * Synopsis: ngetty tty...
+ *
+ * ngetty open()s the virtual console terminals specified as arguments and
+ * poll()s them for user input.  Once input is available on one of the
+ * terminals, it fork()s and exec()s the ngetty-helper programs with that 
+ * terminal set up as the controlling terminal.  ngetty-helper make 
+ * utmp/wtmp records, print /etc/issue, ask for user name and then 
+ * exec()s login(1) program.  When a ngetty session terminates,
+ * the sig_handler() restarts the corresponding terminal.
+ */
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <alloca.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include "lib.h"
+#include "sig_action.h"
+
+#ifdef NEED_HELPER_OPTION
+static char *helper;
+#else
+#define helper NGETTY_HELPER
+#endif
+
+struct tty_name {
+  char *tty;	/* original ttyname */
+  char tmp[23]; /* expanded ttyname; /dev/ttyX or /dev/vc/X */
+  char st;
+};
+typedef struct tty_name tty_name_;
+typedef struct pollfd pollfd_;
+
+static tty_name_ *tty;
+
+/* Number of managed terminals (argc - 1). */
+static int npfd;
+
+/*
+ * Poll data for the terminals.
+ * When polling for input on a terminal, the fd field stores its
+ * file descriptor, as customary.  After fork()ing, though, the parent 
+ * process closes the terminal and stores the child's _negative_ pid 
+ * in the fd field, so that poll() ignores that entry and 
+ * main() knows every child's pid.
+ */
+static pollfd_ *pfd;
+
+static void nano_sleep(int n) {		/* sleep n.5 secs */
+  struct timespec ts = { n, 500111222 };
+  nanosleep(&ts, 0);
+}
+
+static void max_copy(char *out,const char *in) {
+  int len;
+  for (len=0; len<10; len++) { if (!(out[len]=in[len])) break; }
+  out[len] = 0;
+}
+
+/*
+ * Exec NGETTY_HELPER.
+ */
+static void exechelper(int i, char *login) {
+  pollfd_ *xx = pfd + i;
+  int pid;
+  while ((pid=fork()) < 0)
+    nano_sleep(0);
+
+  if (pid==0) {
+    tty_name_ *tt = tty + i;
+    char *a1 = (tt->tmp[0]) ? tt->tmp : tt->tty;
+    char *arg[4] = { helper, a1, login, 0 };
+
+#ifndef NGETTY_SELFPIPE
+    if (xx->fd)
+#endif
+      dup2(xx->fd, 0);
+    i = npfd + 8;
+    while (--i) close(i);
+
+    execve(*arg, arg, environ);
+    nano_sleep(5);
+    _exit(127);
+  }
+  close(xx->fd);
+  xx->fd = -pid;
+}
+
+/*
+ * Open virtual console terminal i.
+ *
+ * In case of failure, most likely because the device node does not exist,
+ * poll() will simply ignore this entry and users get a blank screen and
+ * locked keyboard on this console.  That's enough error reporting. ;-)
+ * No need to add code to check all syscalls' return values.
+ *
+ * Linux does not implement revoke(); the *BSD do.
+ */
+void opentty(int k) {
+  tty_name_ *tt = tty + k;
+  char *path = tt->tty, *m = tt->tmp, st;
+  int fd;
+
+  if (*path != '/') {
+    max_copy(m, "/dev/vc/");
+    if ('0'<=*path && *path<='9') {
+      max_copy(m+8, path);
+      if (chown(m,0,0))
+	{ m[5]='t'; m[6]='t'; m[7]='y'; }
+    } else {
+      if (path[0]==0) { fd = -1; goto do_it; }
+      max_copy(m+5, path);
+    }
+    path = m;
+  } else
+    m[0] = 0;
+
+  chown(path, 0, 0);
+  chmod(path, 0600);
+#ifdef HAVE_REVOKE
+  revoke(path);
+#endif
+
+  fd = open(path, O_RDWR | O_NOCTTY);
+  if (fd > npfd + 4) _exit(100);
+ do_it:
+  pfd[k].fd = fd;
+  if (fd < 0) st = 0;
+  else {
+    st = tt->st ^ 1;
+    if (st) exechelper(k,0);
+  }
+  tt->st = st;
+}
+
+#ifndef NGETTY_SELFPIPE
+static int volatile poll_timeout;
+#endif
+/*
+ * SIG handler.
+ */
+static void sig_handler(int sig) {
+  if (sig == SIGTERM) {
+    int k;
+  again:
+    for (k = 0; k < npfd; k++) {
+      int pid = -pfd[k].fd;
+      if (pid > 1) kill(pid, sig);
+    }
+    nano_sleep(0);
+    if (sig == SIGKILL) _exit(0);
+    sig = SIGKILL;
+    goto again;
+  }
+#ifdef NGETTY_SELFPIPE
+  write(1,"",1);
+#else
+  poll_timeout = 1;
+#endif
+}
+
+static void set_handler() {
+  struct sigaction sa;
+  sigset_t *mask = &sa.sa_mask;
+  sigemptyset(mask);
+  sa.sa_flags =  SA_RESTART | SA_NOCLDSTOP;
+  sa.sa_handler = sig_handler;
+  sigaction(SIGTERM, &sa, 0);
+  sigaction(SIGCHLD, &sa, 0);
+}
+
+#ifdef NGETTY_SORT
+#include "sortpfd.h"
+#define SORT_x_PFD k = sortpfd()
+#define KK_selfpipe k+1
+#define KK k
+#else 
+#define SORT_x_PFD
+#define KK_selfpipe argc
+#define KK npfd
+#endif
+
+#ifdef NGETTY_SELFPIPE
+#define DO_x_POLL poll(pfd-1, KK_selfpipe, -1)
+#else
+#define DO_x_POLL poll(pfd, KK, poll_timeout); poll_timeout = 512*1024
+#endif
+
+/*
+ * Synopsis: ngetty tty...
+ *
+ * Since each terminal's struct pollfd only takes up 8 bytes, just 
+ * alloca()te the array on the stack, instead of using the bloated malloc().
+ */
+int main(int argc, char **argv) {
+  int i,k;
+#ifdef NGETTY_SELFPIPE
+  int pi[6];
+#endif
+
+#ifdef NEED_HELPER_OPTION
+  if ((helper=argv[1]) && helper[0] == '-' && helper[1] == 'H') {
+    argv++; argc--; helper += 2;
+  } else helper = NGETTY_HELPER;
+#endif
+
+  npfd = argc - 1;
+  tty = alloca(npfd * sizeof(tty_name_)); if (tty==0) _exit(111);
+  pfd = alloca(argc * sizeof(pollfd_));   if (pfd==0) _exit(111);
+
+#ifdef NGETTY_SELFPIPE
+  pfd->fd = 0;
+  pfd->events = POLLIN;
+  pfd++;
+#endif
+
+  for (k = 0; k < npfd; k++) {
+    tty[k].tty = *++argv;
+    tty[k].st = 0;
+    pfd[k].fd = -1;
+    pfd[k].events = POLLIN;
+  }
+  for (k = 0; k < 127; k++) close(k);
+
+#ifdef NGETTY_SELFPIPE
+  if (pipe(pi) || pi[0] != 0 || pi[1] != 1) _exit(111);
+  for (k=0; k<2; k++)
+    fcntl(k, F_SETFL, fcntl(k,F_GETFL,0) | O_NONBLOCK);
+#endif 
+
+  set_handler();
+
+ again:
+  while ((i = waitpid(-1, NULL, WNOHANG)) > 1)
+    for (k = 0; k < npfd; k++)
+      if (pfd[k].fd == -i)
+	{ pfd[k].fd = -1; break; }
+
+  for (k = 0; k < npfd; k++)
+    if (pfd[k].fd == -1) opentty(k);
+
+  SORT_x_PFD;
+  i = DO_x_POLL;
+
+  if (i==-1) {
+    if (errno != EINTR)
+      sig_handler(SIGTERM);	/* poll failed, what to do? */
+  } else {
+    for (i = 0; i < KK; i++)
+      if (pfd[i].revents)
+	exechelper(i,"login");
+  }
+
+#ifdef NGETTY_SELFPIPE
+  read(0, pi, sizeof pi);
+#endif
+  goto again;
+  return 1;
+}