Echo server: Difference between revisions
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syscall
</lang>
=={{header|Wren}}==
{{trans|C}}
An embedded program so we can ask the C host to call the relevant library functions for us and also handle simultaneous connections from multiple clients using a multi-process approach.
<lang ecmascript>/* echo_server.wren */
var MAX_ENQUEUED = 20
var BUF_LEN = 256
var PORT_STR = "12321"
var AF_UNSPEC = 0
var SOCK_STREAM = 1
var AI_PASSIVE = 1
foreign class AddrInfo {
foreign static getAddrInfo(name, service, req, pai)
construct new() {}
foreign family
foreign family=(f)
foreign sockType
foreign sockType=(st)
foreign flags
foreign flags=(f)
foreign protocol
foreign addr
foreign addrLen
}
foreign class AddrInfoPtr {
construct new() {}
foreign deref
foreign free()
}
class Socket {
foreign static create(domain, type, protocol)
foreign static bind(fd, addr, len)
foreign static listen(fd, n)
foreign static accept(fd, addr, addrLen)
}
foreign class SockAddrPtr {
construct new() {}
foreign size
}
class SigAction {
foreign static cleanUpProcesses()
}
foreign class Buffer {
construct new(size) {}
}
class Posix {
foreign static read(fd, buf, nbytes)
foreign static write(fd, buf, n)
foreign static fork()
foreign static close(fd)
}
// Child process.
var echoLines = Fn.new { |csock|
var buf = Buffer.new(BUF_LEN)
var r
while ((r = Posix.read(csock, buf, BUF_LEN)) > 0) {
Posix.write(csock, buf, r)
}
}
// Parent process.
var takeConnectionsForever = Fn.new { |ssock|
while (true) {
var addr = SockAddrPtr.new()
var addrSize = addr.size
/* Block until we take one connection to the server socket */
var csock = Socket.accept(ssock, addr, addrSize)
/* If it was a successful connection, spawn a worker process to service it. */
if (csock == -1) {
System.print("Error accepting socket.")
} else if (Posix.fork() == 0) {
Posix.close(ssock)
echoLines.call(csock)
return
} else {
Posix.close(csock)
}
}
}
/* Look up the address to bind to. */
var hints = AddrInfo.new()
hints.family = AF_UNSPEC
hints.sockType = SOCK_STREAM
hints.flags = AI_PASSIVE
var addrInfoPtr = AddrInfoPtr.new()
if (AddrInfo.getAddrInfo("", PORT_STR, hints, addrInfoPtr) != 0) {
Fiber.abort("Failed to get pointer to addressinfo.")
}
/* Make a socket. */
var res = addrInfoPtr.deref
var sock = Socket.create(res.family, res.sockType, res.protocol)
if (sock == -1) Fiber.abort("Failed to make a socket.")
/* Arrange to clean up child processes (the workers). */
SigAction.cleanUpProcesses()
/* Associate the socket with its address. */
if (Socket.bind(sock, res.addr, res.addrLen) != 0) {
Fiber.abort("Failed to bind socket.")
}
addrInfoPtr.free()
/* State that we've opened a server socket and are listening for connections. */
if (Socket.listen(sock, MAX_ENQUEUED) != 0) {
Fiber.abort("Failed to listen for connections.")
}
/* Serve the listening socket until killed */
takeConnectionsForever.call(sock)</lang>
<br>
which we now embed in the following C program, build and run:
<lang c>/* gcc echo_server.c -o echo_server -lwren -lm */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <sys/wait.h>
#include <signal.h>
#include "wren.h"
/* Clean up dead processes. */
void wait_for_zombie(int s) {
while (waitpid(-1, NULL, WNOHANG) > 0) ;
}
/* C <=> Wren interface functions */
void C_addrInfoAllocate(WrenVM* vm) {
wrenSetSlotNewForeign(vm, 0, 0, sizeof(struct addrinfo));
}
void C_addrInfoPtrAllocate(WrenVM* vm) {
wrenSetSlotNewForeign(vm, 0, 0, sizeof(struct addrinfo*));
}
void C_sockAddrPtrAllocate(WrenVM* vm) {
wrenSetSlotNewForeign(vm, 0, 0, sizeof(struct sockaddr*));
}
void C_bufferAllocate(WrenVM* vm) {
size_t bufsize = (size_t)wrenGetSlotDouble(vm, 1);
wrenSetSlotNewForeign(vm, 0, 0, bufsize);
}
void C_getAddrInfo(WrenVM* vm) {
const char *name = wrenGetSlotString(vm, 1);
if (strcmp(name, "") == 0) name = NULL;
const char *service = wrenGetSlotString(vm, 2);
const struct addrinfo *req = (const struct addrinfo *)wrenGetSlotForeign(vm, 3);
struct addrinfo** ppai = (struct addrinfo**)wrenGetSlotForeign(vm, 4);
int status = getaddrinfo(name, service, req, ppai);
wrenSetSlotDouble(vm, 0, (double)status);
}
void C_family(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
wrenSetSlotDouble(vm, 0, (double)(pai->ai_family));
}
void C_setFamily(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
int f = (int)wrenGetSlotDouble(vm, 1);
pai->ai_family = f;
}
void C_sockType(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
wrenSetSlotDouble(vm, 0, (double)(pai->ai_socktype));
}
void C_setSockType(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
int type = (int)wrenGetSlotDouble(vm, 1);
pai->ai_socktype = type;
}
void C_flags(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
wrenSetSlotDouble(vm, 0, (double)(pai->ai_flags));
}
void C_setFlags(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
int flags = (int)wrenGetSlotDouble(vm, 1);
pai->ai_flags = flags;
}
void C_protocol(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
wrenSetSlotDouble(vm, 0, (double)(pai->ai_protocol));
}
void C_addr(WrenVM* vm) {
wrenEnsureSlots(vm, 2);
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
wrenGetVariable(vm, "main", "SockAddrPtr", 1);
struct sockaddr **ppsa = (struct sockaddr**)wrenSetSlotNewForeign(vm, 0, 1, sizeof(struct sockaddr*));
*ppsa = pai->ai_addr;
}
void C_addrLen(WrenVM* vm) {
struct addrinfo* pai = (struct addrinfo*)wrenGetSlotForeign(vm, 0);
wrenSetSlotDouble(vm, 0, (double)(pai->ai_addrlen));
}
void C_deref(WrenVM* vm) {
wrenEnsureSlots(vm, 2);
struct addrinfo** ppai = (struct addrinfo**)wrenGetSlotForeign(vm, 0);
wrenGetVariable(vm, "main", "AddrInfo", 1);
struct addrinfo *pai = (struct addrinfo*)wrenSetSlotNewForeign(vm, 0, 1, sizeof(struct addrinfo));
*pai = **ppai;
}
void C_free(WrenVM* vm) {
struct addrinfo* pai = *(struct addrinfo**)wrenGetSlotForeign(vm, 0);
freeaddrinfo(pai);
}
void C_create(WrenVM* vm) {
int domain = (int)wrenGetSlotDouble(vm, 1);
int type = (int)wrenGetSlotDouble(vm, 2);
int protocol = (int)wrenGetSlotDouble(vm, 3);
int fd = socket(domain, type, protocol);
wrenSetSlotDouble(vm, 0, (double)fd);
}
void C_bind(WrenVM* vm) {
int fd = (int)wrenGetSlotDouble(vm, 1);
__CONST_SOCKADDR_ARG *psa = (__CONST_SOCKADDR_ARG *)wrenGetSlotForeign(vm, 2);
socklen_t len = (socklen_t)wrenGetSlotDouble(vm, 3);
int status = bind(fd, *psa, len);
wrenSetSlotDouble(vm, 0, (double)status);
}
void C_listen(WrenVM* vm) {
int fd = (int)wrenGetSlotDouble(vm, 1);
int n = (int)wrenGetSlotDouble(vm, 2);
int status = listen(fd, n);
wrenSetSlotDouble(vm, 0, (double)status);
}
void C_accept(WrenVM* vm) {
int fd = (int)wrenGetSlotDouble(vm, 1);
__SOCKADDR_ARG *psa = (__SOCKADDR_ARG *)wrenGetSlotForeign(vm, 2);
socklen_t len = (socklen_t)wrenGetSlotDouble(vm, 3);
int status = accept(fd, *psa, &len);
wrenSetSlotDouble(vm, 0, (double)status);
}
void C_size(WrenVM* vm) {
struct sockaddr** ppaddr = (struct sockaddr**)wrenGetSlotForeign(vm, 0);
wrenSetSlotDouble(vm, 0, (double)sizeof(**ppaddr));
}
void C_cleanUpProcesses(WrenVM* vm) {
struct sigaction sa;
sa.sa_handler = wait_for_zombie;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCHLD, &sa, NULL) == -1 ) {
perror("sigaction");
exit(EXIT_FAILURE);
}
}
void C_read(WrenVM* vm) {
int fd = (int)wrenGetSlotDouble(vm, 1);
void *buf = (void *)wrenGetSlotForeign(vm, 2);
size_t nbytes = (size_t)wrenGetSlotDouble(vm, 3);
ssize_t res = read(fd, buf, nbytes);
wrenSetSlotDouble(vm, 0, (double)res);
}
void C_write(WrenVM* vm) {
int fd = (int)wrenGetSlotDouble(vm, 1);
void *buf = (void *)wrenGetSlotForeign(vm, 2);
size_t n = (size_t)wrenGetSlotDouble(vm, 3);
ssize_t res = write(fd, buf, n);
wrenSetSlotDouble(vm, 0, (double)res);
}
void C_fork(WrenVM* vm) {
__pid_t pid = fork();
wrenSetSlotDouble(vm, 0, (double)pid);
}
void C_close(WrenVM* vm) {
int fd = (int)wrenGetSlotDouble(vm, 1);
int status = close(fd);
wrenSetSlotDouble(vm, 0, (double)status);
}
WrenForeignClassMethods bindForeignClass(WrenVM* vm, const char* module, const char* className) {
WrenForeignClassMethods methods;
methods.allocate = NULL;
methods.finalize = NULL;
if (strcmp(module, "main") == 0) {
if (strcmp(className, "AddrInfo") == 0) {
methods.allocate = C_addrInfoAllocate;
} else if (strcmp(className, "AddrInfoPtr") == 0) {
methods.allocate = C_addrInfoPtrAllocate;
} else if (strcmp(className, "SockAddrPtr") == 0) {
methods.allocate = C_sockAddrPtrAllocate;
} else if (strcmp(className, "Buffer") == 0) {
methods.allocate = C_bufferAllocate;
}
}
return methods;
}
WrenForeignMethodFn bindForeignMethod(
WrenVM* vm,
const char* module,
const char* className,
bool isStatic,
const char* signature) {
if (strcmp(module, "main") == 0) {
if (strcmp(className, "AddrInfo") == 0) {
if ( isStatic && strcmp(signature, "getAddrInfo(_,_,_,_)") == 0) return C_getAddrInfo;
if (!isStatic && strcmp(signature, "family") == 0) return C_family;
if (!isStatic && strcmp(signature, "family=(_)") == 0) return C_setFamily;
if (!isStatic && strcmp(signature, "sockType") == 0) return C_sockType;
if (!isStatic && strcmp(signature, "sockType=(_)") == 0) return C_setSockType;
if (!isStatic && strcmp(signature, "flags") == 0) return C_flags;
if (!isStatic && strcmp(signature, "flags=(_)") == 0) return C_setFlags;
if (!isStatic && strcmp(signature, "protocol") == 0) return C_protocol;
if (!isStatic && strcmp(signature, "addr") == 0) return C_addr;
if (!isStatic && strcmp(signature, "addrLen") == 0) return C_addrLen;
} else if (strcmp(className, "AddrInfoPtr") == 0) {
if (!isStatic && strcmp(signature, "deref") == 0) return C_deref;
if (!isStatic && strcmp(signature, "free()") == 0) return C_free;
} else if (strcmp(className, "Socket") == 0) {
if ( isStatic && strcmp(signature, "create(_,_,_)") == 0) return C_create;
if ( isStatic && strcmp(signature, "bind(_,_,_)") == 0) return C_bind;
if ( isStatic && strcmp(signature, "listen(_,_)") == 0) return C_listen;
if ( isStatic && strcmp(signature, "accept(_,_,_)") == 0) return C_accept;
} else if (strcmp(className, "SockAddrPtr") == 0) {
if (!isStatic && strcmp(signature, "size") == 0) return C_size;
} else if (strcmp(className, "SigAction") == 0) {
if ( isStatic && strcmp(signature, "cleanUpProcesses()") == 0) return C_cleanUpProcesses;
} else if (strcmp(className, "Posix") == 0) {
if ( isStatic && strcmp(signature, "read(_,_,_)") == 0) return C_read;
if ( isStatic && strcmp(signature, "write(_,_,_)") == 0) return C_write;
if ( isStatic && strcmp(signature, "fork()") == 0) return C_fork;
if ( isStatic && strcmp(signature, "close(_)") == 0) return C_close;
}
}
return NULL;
}
static void writeFn(WrenVM* vm, const char* text) {
printf("%s", text);
}
void errorFn(WrenVM* vm, WrenErrorType errorType, const char* module, const int line, const char* msg) {
switch (errorType) {
case WREN_ERROR_COMPILE:
printf("[%s line %d] [Error] %s\n", module, line, msg);
break;
case WREN_ERROR_STACK_TRACE:
printf("[%s line %d] in %s\n", module, line, msg);
break;
case WREN_ERROR_RUNTIME:
printf("[Runtime Error] %s\n", msg);
break;
}
}
char *readFile(const char *fileName) {
FILE *f = fopen(fileName, "r");
fseek(f, 0, SEEK_END);
long fsize = ftell(f);
rewind(f);
char *script = malloc(fsize + 1);
fread(script, 1, fsize, f);
fclose(f);
script[fsize] = 0;
return script;
}
int main(int argc, char **argv) {
WrenConfiguration config;
wrenInitConfiguration(&config);
config.writeFn = &writeFn;
config.errorFn = &errorFn;
config.bindForeignClassFn = &bindForeignClass;
config.bindForeignMethodFn = &bindForeignMethod;
WrenVM* vm = wrenNewVM(&config);
const char* module = "main";
const char* fileName = "echo_server.wren";
char *script = readFile(fileName);
WrenInterpretResult result = wrenInterpret(vm, module, script);
switch (result) {
case WREN_RESULT_COMPILE_ERROR:
printf("Compile Error!\n");
break;
case WREN_RESULT_RUNTIME_ERROR:
printf("Runtime Error!\n");
break;
case WREN_RESULT_SUCCESS:
break;
}
wrenFreeVM(vm);
free(script);
return 0;
}</lang>
{{out}}
Quick test using 2 terminals and telnet as the client (also tested on 3 terminals - not shown here):
<pre>
/* start server on terminal 1 */
$ ./echo_server
/* start telnet on terminal 2 and type 'hello' */
$ telnet localhost 12321
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
hello
hello
^]
telnet> quit
Connection closed.
/* press ctrl-c on terminal 1 to kill the server */
^C
</pre>
=={{header|zkl}}==
| |||