implement basic network server

.gitignore

@@ -5,4 +5,6 @@ compile_commands.json
 site
 libflint.so
 test
+tcptest
+testrunner
 .idea

CMakeLists.txt

@@ -1,41 +0,0 @@
-cmake_minimum_required(VERSION 3.17)
-project(flint C)
-set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
-
-set(CMAKE_C_STANDARD 99)
-include_directories(include)
-
-set(SOURCES
-        src/linkedlist.c
-        src/set.c
-        src/stack.c
-        src/binarytree.c
-        src/input.c
-        src/math.c
-        src/string.c
-        src/vector.c
-        src/utility.c
-        src/crypto.c
-        src/parsing.c
-)
-
-if ((${CMAKE_SYSTEM_NAME} STREQUAL "Darwin"))
-    add_library(flint ${SOURCES} src/macos/macos.c)
-else()
-    add_library(flint ${SOURCES})
-endif()
-
-if ((${CMAKE_SYSTEM_NAME} STREQUAL "Linux"))
-    target_link_libraries(flint bsd)
-endif()
-
-if(${CMAKE_PROJECT_NAME} STREQUAL flint)
-    add_executable(tests tests/tests.c)
-    target_include_directories(tests PRIVATE include)
-
-    if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
-        target_link_libraries(tests flint bsd)
-    else()
-        target_link_libraries(tests flint)
-    endif()
-endif()

Makefile

@@ -1,6 +1,7 @@
-.PHONY : clean
+.PHONY : clean tests all
 
-CFLAGS =		-std=c99 -Iinclude -pedantic -Wall -Wextra
+CFLAGS =		-std=c99 -Iinclude -pedantic
+WARNINGS= 	-Wall -Wextra
 LDFLAGS =		-fPIC -shared
 
 TARGET = 	libflint.so
@@ -11,9 +12,10 @@ PREFIX =	$(DESTDIR)/usr/local
 LIBDIR =	$(PREFIX)/lib
 
 all: $(TARGET)
+	./clanggen.sh
 
 $(TARGET): $(OBJ)
-	cc $(CFLAGS) $(LDFLAGS) -o $(TARGET) $(OBJ)
+	cc $(CFLAGS) $(WARNINGS) $(LDFLAGS) -o $(TARGET) $(OBJ)
 
 ./obj/%.o: ./src/%.c
 	cc $(CFLAGS) -c $< -o $@
@@ -26,7 +28,12 @@ uninstall:
 
 clean:
 	rm -f $(TARGET)
-	rm -f test
+	rm -f testrunner
+	rm -f tcptest
+	rm -f compile_commands.json
+
+tests:
+	cc $(CFLAGS) -o testrunner tests/tests.c src/*.c
+	cc $(CFLAGS) -o tcptest tests/tcptest.c src/*.c 
+	./run_tests.sh
 
-test:
-	cc $(CFLAGS) -o test tests/tests.c src/*.c

build.sh

@@ -1,10 +0,0 @@
-#!/bin/sh -e
-
-# For building outside of CLion
-
-mkdir -p build
-cd build
-cmake ..
-make
-cp compile_commands.json ..
-cd

clanggen.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env sh
+
+set -e
+
+CFLAGS="-I./include -I/usr/local/include"
+
+rm -f compile_commands.json
+
+for f in $(find ./src -type f | grep -v macos); do
+  n=$(echo $f | grep -o '[^/]*$' | sed 's/c$/json/')
+  cc -MJ $n $CFLAGS -c $f
+done
+
+rm *.o
+sed -e '1s/^/[/' -e '$s/,$/]/' *.json > compile_commands.out
+rm *.json
+mv compile_commands.out compile_commands.json

include/lfnetwork.h

@@ -0,0 +1,28 @@
+#ifndef LIBFLINT_NET_H
+#define LIBFLINT_NET_H
+
+#include <netdb.h>
+
+typedef enum ServerType {
+    SERVERTYPE_TCP,
+    SERVERTYPE_UDP
+} ServerType;
+
+typedef struct Server {
+    ServerType server_type;
+    int fd;
+    int port;
+    void (*handler)(struct Server *s);
+} Server;
+
+#define DEFAULT_BACKLOG 10
+
+Server *new_server(ServerType type, const char *port, void(handler)(Server *s));
+void delete_server(Server *s);
+int serve(Server *s, int backlog_size);
+void *get_in_addr(struct sockaddr *sa);
+
+// Example handlers
+void handler_tcp_echo(Server *s);
+
+#endif //LIBFLINT_NET_H

run_tests.sh

@@ -0,0 +1,12 @@
+set -e
+
+#./testrunner
+./tcptest &
+tcpout=$(echo "hello" | nc localhost 18632)
+echo "tcpout: $tcpout" 
+if [ "$tcpout" != "TEST SEND" ]; then
+ echo "Error: \"$tcpout\" != \"TEST SEND\""
+ exit 1
+fi
+
+exit 0

src/network.c

@@ -0,0 +1,130 @@
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <sys/wait.h>
+#include <netdb.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <signal.h>
+
+#include "lfnetwork.h"
+
+static void sighandler(int s) {
+    int saved_errno = errno;
+    while (waitpid(-1, NULL, WNOHANG) > 0);
+    errno = saved_errno;
+}
+
+void *get_in_addr(struct sockaddr *sa)
+{
+    if (sa->sa_family == AF_INET) {
+        return &(((struct sockaddr_in*)sa)->sin_addr);
+    }
+
+    return &(((struct sockaddr_in6*)sa)->sin6_addr);
+}
+
+Server *new_server(ServerType type, const char *port, void(handler)(Server *s)) {
+    Server *s = (Server *)malloc(sizeof(Server));
+    if (s == NULL) {
+        return NULL;
+    }
+    s->server_type = type;
+    s->handler = handler;
+
+    struct addrinfo *addr = NULL;
+    if (getaddrinfo(NULL, port, NULL, &addr) != 0) {
+        free(s);
+        return NULL;
+    }
+    s->port = (int)strtol(port, NULL, 10);
+
+    int socktype = 0;
+    switch (type) {
+    case SERVERTYPE_TCP:
+        socktype = SOCK_STREAM;
+        break;
+    case SERVERTYPE_UDP:
+        socktype = SOCK_DGRAM;
+        break;
+    }
+
+    struct addrinfo *p;
+    for (p = addr; p != NULL; p = p->ai_next) {
+        s->fd = socket(AF_INET, socktype, 0);
+        if (s->fd == -1) {
+            continue;
+        }
+
+        if (bind(s->fd, p->ai_addr, p->ai_addrlen) != 0) {
+            close(s->fd);
+            continue;
+        }
+
+        break;
+    }
+
+    if (p == NULL) {
+        fprintf(stderr, "Failed to bind\n");
+        free(s);
+        return NULL;
+    }
+
+    freeaddrinfo(addr);
+    return s;
+}
+
+void delete_server(Server *s) {
+    free(s);
+    s = NULL;
+}
+
+int serve(Server *s, int backlog_size) {
+    if (listen(s->fd, backlog_size) != 0) {
+        return 1;
+    }
+
+    struct sigaction sa;
+    sa.sa_handler = sighandler; 
+    sa.sa_flags = SA_RESTART;
+    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
+        fprintf(stderr, "Failed to set sigaction\n");
+        return 1;
+    }
+
+    printf("Server is waiting for connections on port %d...\n", s->port);
+    s->handler(s);
+
+    return 0;
+}
+
+void handler_tcp_echo(Server *s) {
+    struct sockaddr_storage client_addr;
+    while (1) {
+       socklen_t client_addr_sz = sizeof(client_addr); 
+       int new_fd = accept(s->fd, (struct sockaddr *)&client_addr, &client_addr_sz);
+       if (new_fd == -1) {
+           printf("failed to accept. Errno: %d\n", errno);
+           continue;
+       }
+
+       char buf[33];
+       inet_ntop(client_addr.ss_family, get_in_addr((struct sockaddr *)&client_addr), buf, 32);
+       printf("Received connection from %s\n", buf);
+
+       // Start child process
+       if (!fork()) { 
+           close(s->fd); // Child doesn't need the initial socket
+           if (send(new_fd, "Hello, world!", 13, 0) == -1) {
+               fprintf(stderr, "Failed to send hello world\n");
+           }
+           close(new_fd);
+           _exit(0);
+       }
+       // End child process
+
+       close(new_fd); // new_fd is not used by the parent
+    }
+}

tests/tcptest.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <errno.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "lfnetwork.h"
+
+void test_handler(Server *s) {
+    struct sockaddr_storage client_addr;
+        socklen_t client_addr_sz = sizeof(client_addr); 
+        int new_fd = accept(s->fd, (struct sockaddr *)&client_addr, &client_addr_sz);
+        if (new_fd == -1) {
+            printf("failed to accept. Errno: %d\n", errno);
+            return;
+        }
+
+        char buf[33];
+        inet_ntop(client_addr.ss_family, get_in_addr((struct sockaddr *)&client_addr), buf, 32);
+        printf("Received connection from %s\n", buf);
+
+        if (send(new_fd, "TEST SEND", 10, 0) == -1) {
+            printf("Failed to send hello world. Errno: %d\n", errno);
+        }
+        close(new_fd);
+}
+
+int main(int argc, char **argv) {
+    Server *server = new_server(SERVERTYPE_TCP, "18632", test_handler);
+    serve(server, DEFAULT_BACKLOG);
+    delete_server(server);
+}

tests/tests.c

@@ -4,6 +4,7 @@
 #include <unistd.h>
 
 #include "lflinkedlist.h"
+#include "lfnetwork.h"
 #include "lfset.h"
 #include "lfstack.h"
 #include "lfbinarytree.h"
@@ -426,4 +427,4 @@ int main() {
 #endif
 
     return 0;
-}
+}