Squashed 'tclcheckdns/' content from commit 3cf3e91

git-subtree-dir: tclcheckdns
git-subtree-split: 3cf3e919ea92aca6598df3beec77bab053868da7

1 files changed, 174 insertions, 0 deletions

diff --git a/checkdns.C b/checkdns.C
new file mode 100644
index 0000000..f3c0590
--- /dev/null
+++ b/checkdns.C
@@ -0,0 +1,174 @@
+// Copyright (C) 1999-2015
+// Smithsonian Astrophysical Observatory, Cambridge, MA, USA
+// For conditions of distribution and use, see copyright notice in "copyright"
+
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <netdb.h>
+
+#include <iostream>
+#include <sstream>
+#include <iomanip>
+using namespace std;
+
+#include <tcl.h>
+
+#define SZ_LINE 2048
+static int debug =0;
+
+// alarm signal handler
+static sigjmp_buf alarmbuf;
+static void alarmHandler(int dummy)
+{
+  siglongjmp(alarmbuf, 1);
+}
+
+extern "C" {
+  int Tclcheckdns_Init(void *vinterp);
+};
+
+static int checkdns(char *name, int delay, int cflag)
+{
+  int result =0;
+ 
+  // get temp name, look for port
+  char tbuf[SZ_LINE];
+  unsigned int port=80;
+  if (name && *name) {
+    char* ss=NULL;
+    strncpy(tbuf, name, SZ_LINE-1);
+    if ((ss=strchr(tbuf, ':'))) {
+      *ss = '\0';
+      port = atoi(ss+1);
+    }
+  }
+  else
+    *tbuf = '\0';
+
+  // start the alarm, if necessary
+  struct sigaction sigact, osigact;
+  if (delay>0) {
+    if (sigsetjmp(alarmbuf, 1)) {
+      if (debug)
+	cerr << "alarm activated" << endl;
+
+      result= 1;
+      goto done;
+    }
+    else {
+      sigact.sa_handler = alarmHandler;
+      sigemptyset(&sigact.sa_mask);
+      sigact.sa_flags = 0;
+      sigaction(SIGALRM, &sigact, &osigact);
+
+      alarm(delay);
+    }
+  }
+
+  // get name of host we are interested in
+  char host[SZ_LINE];
+  if (*tbuf)
+    strncpy(host, tbuf, SZ_LINE-1);
+  else {
+    // use current host
+    if (gethostname(host, SZ_LINE) < 0) {
+      result =2;
+      goto done;
+    }
+    else if (debug)
+      cerr << "gethostname: " << host << endl;
+  }
+
+  // try to get info on this host
+  struct hostent* h;
+  if (!(h=gethostbyname(host))) {
+    result =3;
+    goto done;
+  }
+  else if (debug)
+    cerr << "gethostbyname: " << h->h_name << '(' << port << ')' << endl;
+
+  // connect, if necessary
+  if (cflag) {
+    unsigned int ip;
+    memcpy(&ip, h->h_addr_list[0], (size_t)h->h_length);
+    ip = ntohl(ip);
+    int fd;
+    if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+      result =4;
+      goto done;
+    }
+    struct sockaddr_in sock_in;
+    memset((char *)&sock_in, 0, sizeof(sock_in));
+    sock_in.sin_family = AF_INET;
+    sock_in.sin_addr.s_addr = htonl(ip);
+    sock_in.sin_port = htons(port);
+    int got = connect(fd, (struct sockaddr *)&sock_in, sizeof(sock_in));
+    close(fd);
+    if (got < 0) {
+      result =5;
+      goto done;
+    }
+    else if (debug)
+      cerr << "connect succeeded" << endl;
+  }
+
+ done:
+  if (delay) {
+    alarm(0);
+    sigaction(SIGALRM, &osigact, NULL);
+  }
+
+  return result;
+}
+
+static int TclcheckdnsCmd(ClientData clientData, Tcl_Interp *interp,
+			  int objc, Tcl_Obj *CONST objv[])
+{
+  if (objc < 3) {
+    Tcl_WrongNumArgs(interp, 1, objv, "host delay [connect]");
+    return TCL_ERROR;
+  }
+
+  char* host =NULL;
+  char* ss = Tcl_GetStringFromObj(objv[1], NULL);
+  if (ss && *ss)
+    host = ss;
+
+  int delay=5;
+  char* tt = Tcl_GetStringFromObj(objv[2], NULL);
+  if (tt && *tt)
+    delay = atoi(tt);
+
+  int cflag=0;
+  if (objc >= 4) {
+    char* uu = Tcl_GetStringFromObj(objv[3], NULL);
+    if (uu && *uu)
+      cflag = atoi(uu);
+  }
+
+  ostringstream str;
+  str << checkdns(host, delay, cflag) << ends;
+  Tcl_AppendResult(interp, str.str().c_str(), NULL);
+
+  return TCL_OK;
+}
+
+int Tclcheckdns_Init(void *vinterp)
+{
+  Tcl_Interp *interp = (Tcl_Interp *)vinterp;
+
+  if (Tcl_InitStubs(interp, TCL_PATCH_LEVEL, 0) == NULL)
+    return TCL_ERROR;
+
+  Tcl_CreateObjCommand(interp, "checkdns", TclcheckdnsCmd,
+		       (ClientData)NULL, (Tcl_CmdDeleteProc *)NULL);
+
+  if (Tcl_PkgProvide(interp, PACKAGE_NAME, PACKAGE_VERSION) != TCL_OK)
+    return TCL_ERROR;
+
+  return TCL_OK;
+}