152 lines
4.5 KiB
C
152 lines
4.5 KiB
C
/*---------------------------------------------------------------------
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Gopher Support
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I'm a big fan of Gopher, so RRE provides support for fetching files
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via the Gopher protocol.
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---------------------------------------------------------------------*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <math.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#include <errno.h>
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#include <sys/wait.h>
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#include <signal.h>
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typedef void (*Handler)(void);
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/*---------------------------------------------------------------------
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First, a few things that relate to the Nga virtual machine that RETRO
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runs on.
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---------------------------------------------------------------------*/
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#define CELL int32_t /* Cell size (32 bit, signed integer */
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#define IMAGE_SIZE 524288 * 48 /* Amount of RAM. 12MiB by default. */
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#define ADDRESSES 2048 /* Depth of address stack */
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#define STACK_DEPTH 512 /* Depth of data stack */
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extern CELL sp, rp, ip; /* Stack & instruction pointers */
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extern CELL data[STACK_DEPTH]; /* The data stack */
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extern CELL address[ADDRESSES]; /* The address stack */
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extern CELL memory[IMAGE_SIZE + 1]; /* The memory for the image */
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#define TOS data[sp] /* Shortcut for top item on stack */
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#define NOS data[sp-1] /* Shortcut for second item on stack */
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#define TORS address[rp] /* Shortcut for top item on address stack */
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/*---------------------------------------------------------------------
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Function prototypes.
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---------------------------------------------------------------------*/
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CELL stack_pop();
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void stack_push(CELL value);
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char *string_extract(CELL at);
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CELL string_inject(char *str, CELL buffer);
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/*---------------------------------------------------------------------
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The first Gopher related function is `error()`, which prints an
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error message and exits if there is a problem.
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---------------------------------------------------------------------*/
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void error(const char *msg) {
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perror(msg);
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exit(0);
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}
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/*---------------------------------------------------------------------
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`gopher_fetch()` is the part that does all the real work.
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---------------------------------------------------------------------*/
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void gopher_fetch(char *host, CELL port, char *selector, CELL dest) {
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int sockfd, portno, n;
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struct sockaddr_in serv_addr;
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struct hostent *server;
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char data[128 * 1024 + 1];
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char buffer[1025];
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portno = (int)port;
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sockfd = socket(AF_INET, SOCK_STREAM, 0);
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if (sockfd < 0)
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error("ERROR opening socket");
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server = gethostbyname(host);
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if (server == NULL) {
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fprintf(stderr,"ERROR, no such host\n");
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exit(0);
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}
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bzero(data, 128 * 1024 + 1);
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bzero((char *) &serv_addr, sizeof(serv_addr));
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serv_addr.sin_family = AF_INET;
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bcopy((char *)server->h_addr,
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(char *)&serv_addr.sin_addr.s_addr,
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server->h_length);
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serv_addr.sin_port = htons(portno);
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if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)
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error("ERROR connecting");
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n = write(sockfd,selector,strlen(selector));
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if (n < 0)
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error("ERROR writing to socket");
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n = write(sockfd,"\n",strlen("\n"));
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if (n < 0)
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error("ERROR writing to socket");
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n = 1;
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while (n > 0) {
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bzero(buffer,1025);
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n = read(sockfd,buffer,1024);
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strcat(data, buffer);
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}
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close(sockfd);
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string_inject(data, dest);
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stack_push(strlen(data));
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}
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/*---------------------------------------------------------------------
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The last Gopher function, `ngaGopherUnit()` pulls the values needed
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from the stack and passes them to the `gopher_fetch()` function.
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This will take the following from the stack (TOS to bottom):
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Selector (NULL terminated string)
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Port (Number)
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Server (NULL terminated string)
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Buffer (Pointer to memory that will hold the received file)
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---------------------------------------------------------------------*/
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void ngaGopherUnit() {
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CELL port, dest;
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char server[1025], selector[4097];
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strcpy(selector, string_extract(stack_pop()));
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port = stack_pop();
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strcpy(server, string_extract(stack_pop()));
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dest = stack_pop();
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gopher_fetch(server, port, selector, dest);
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}
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Handler GopherActions[1] = {
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ngaGopherUnit
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};
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void io_gopher_query() {
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stack_push(0);
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stack_push(5);
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}
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void io_gopher_handler() {
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GopherActions[stack_pop()]();
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}
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