git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@12769 f3b2605a-c512-4ea7-a41b-209d697bcdaa

tools/i-pi/drivers/sockets.c

@@ -0,0 +1,147 @@
+/* A minimal wrapper for socket communication.
+
+Copyright (C) 2013, Joshua More and Michele Ceriotti
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+Contains both the functions that transmit data to the socket and read the data
+back out again once finished, and the function which opens the socket initially.
+Can be linked to a FORTRAN code that does not support sockets natively.
+
+Functions:
+   error: Prints an error message and then exits.
+   open_socket_: Opens a socket with the required host server, socket type and
+      port number.
+   write_buffer_: Writes a string to the socket.
+   read_buffer_: Reads data from the socket.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <sys/un.h>
+#include <netdb.h>
+
+void error(const char *msg)
+// Prints an error message and then exits.
+{   perror(msg);  exit(-1);   }
+
+void open_socket_(int *psockfd, int* inet, int* port, char* host)
+/* Opens a socket.
+
+Note that fortran passes an extra argument for the string length, but this is
+ignored here for C compatibility.
+
+Args:
+   psockfd: The id of the socket that will be created.
+   inet: An integer that determines whether the socket will be an inet or unix
+      domain socket. Gives unix if 0, inet otherwise.
+   port: The port number for the socket to be created. Low numbers are often
+      reserved for important channels, so use of numbers of 4 or more digits is
+      recommended.
+   host: The name of the host server.
+*/
+
+{
+   int sockfd, portno, n;
+   struct hostent *server;
+
+   struct sockaddr * psock; int ssock;
+
+   if (*inet>0)
+   {  // creates an internet socket
+      struct sockaddr_in serv_addr;      psock=(struct sockaddr *)&serv_addr;     ssock=sizeof(serv_addr);
+      sockfd = socket(AF_INET, SOCK_STREAM, 0);
+      if (sockfd < 0)  error("Error opening socket");
+
+      server = gethostbyname(host);
+      if (server == NULL)
+      {
+         fprintf(stderr, "Error opening socket: no such host %s \n", host);
+         exit(-1);
+      }
+
+      bzero((char *) &serv_addr, sizeof(serv_addr));
+      serv_addr.sin_family = AF_INET;
+      bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length);
+      serv_addr.sin_port = htons(*port);
+      if (connect(sockfd, psock, ssock) < 0) error("Error opening socket: wrong host address, or broken connection");
+   }
+   else
+   {  // creates a unix socket
+      struct sockaddr_un serv_addr;      psock=(struct sockaddr *)&serv_addr;     ssock=sizeof(serv_addr);
+      sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+      bzero((char *) &serv_addr, sizeof(serv_addr));
+      serv_addr.sun_family = AF_UNIX;
+      strcpy(serv_addr.sun_path, "/tmp/ipi_");
+      strcpy(serv_addr.sun_path+9, host);
+      if (connect(sockfd, psock, ssock) < 0) error("Error opening socket: wrong host address, or broken connection");
+   }
+
+   *psockfd=sockfd;
+}
+
+void writebuffer_(int *psockfd, char *data, int* plen)
+/* Writes to a socket.
+
+Args:
+   psockfd: The id of the socket that will be written to.
+   data: The data to be written to the socket.
+   plen: The length of the data in bytes.
+*/
+
+{
+   int n;
+   int sockfd=*psockfd;
+   int len=*plen;
+
+   n = write(sockfd,data,len);
+   if (n < 0) error("Error writing to socket: server has quit or connection broke");
+}
+
+
+void readbuffer_(int *psockfd, char *data, int* plen)
+/* Reads from a socket.
+
+Args:
+   psockfd: The id of the socket that will be read from.
+   data: The storage array for data read from the socket.
+   plen: The length of the data in bytes.
+*/
+
+{
+   int n, nr;
+   int sockfd=*psockfd;
+   int len=*plen;
+
+   n = nr = read(sockfd,data,len);
+
+   while (nr>0 && n<len )
+   {  nr=read(sockfd,&data[n],len-n); n+=nr; }
+
+   if (n == 0) error("Error reading from socket: server has quit or connection broke");
+}
+
+