cristian-programmer · July 22, 2019 19:06 · Nov 8, 2016 · Nov 7, 2016
diff --git a/httpd.c b/httpd.c
@@ -1,15 +1,16 @@
 #include "httpd.h"
 
-#include<stdio.h>
-#include<string.h>
-#include<stdlib.h>
-#include<unistd.h>
-#include<sys/types.h>
-#include<sys/stat.h>
-#include<sys/socket.h>
-#include<arpa/inet.h>
-#include<netdb.h>
-#include<fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <fcntl.h>
+#include <signal.h>
 
 #define CONNMAX 1000
 
@@ -42,6 +43,9 @@ void serve_forever(const char *PORT)
     for (i=0; i<CONNMAX; i++)
         clients[i]=-1;
     startServer(PORT);
+
+    // Ignore SIGCHLD to avoid zombie threads
+    signal(SIGCHLD,SIG_IGN);
 
     // ACCEPT connections
     while (1)
@@ -140,6 +144,13 @@ void respond(int n)
         prot   = strtok(NULL, " \t\r\n"); 
 
         fprintf(stderr, "\x1b[32m + [%s] %s\x1b[0m\n", method, uri);
+
+        if (qs = strchr(uri, '?'))
+        {
+            *qs++ = '\0'; //split URI
+        } else {
+            qs = uri - 1; //use an empty string
+        }
 
         header_t *h = reqhdr;
         char *t, *t2;

diff --git a/httpd.h b/httpd.h
@@ -11,7 +11,8 @@ void serve_forever(const char *PORT);
 // Client request
 
 char    *method,    // "GET" or "POST"
-        *uri,       // "/index.html"
+        *uri,       // "/index.html" things before '?'
+        *qs,        // "a=1&b=2"     things after  '?'
         *prot;      // "HTTP/1.1"
 
 char    *payload;     // for POST

diff --git a/ABOUT.md b/ABOUT.md
@@ -0,0 +1,17 @@
+# Pico HTTP Server in C 
+
+This is a very simple HTTP server for Unix, using fork(). It's very easy to use
+
+## How to use
+
+1. include header `httpd.h`
+2. write your route method, handling requests.
+3. call `serve_forever("12913")` to start serving on port 12913
+
+See `main.c`, an interesting example.
+
+To log stuff, use `fprintf(stderr, "message");`
+
+View `httpd.h` for more information
+
+based on <http://blog.abhijeetr.com/2010/04/very-simple-http-server-writen-in-c.html>
diff --git a/Makefile b/Makefile
@@ -0,0 +1,15 @@
+all: server
+
+clean:
+	@rm -rf *.o
+	@rm -rf server
+
+server: main.o httpd.o
+	gcc -o server $^
+
+main.o: main.c httpd.h
+	gcc -c -o main.o main.c
+
+httpd.o: httpd.c httpd.h
+	gcc -c -o httpd.o httpd.c
+
diff --git a/httpd.c b/httpd.c
@@ -0,0 +1,180 @@
+#include "httpd.h"
+
+#include<stdio.h>
+#include<string.h>
+#include<stdlib.h>
+#include<unistd.h>
+#include<sys/types.h>
+#include<sys/stat.h>
+#include<sys/socket.h>
+#include<arpa/inet.h>
+#include<netdb.h>
+#include<fcntl.h>
+
+#define CONNMAX 1000
+
+static int listenfd, clients[CONNMAX];
+static void error(char *);
+static void startServer(const char *);
+static void respond(int);
+
+typedef struct { char *name, *value; } header_t;
+static header_t reqhdr[17] = { {"\0", "\0"} };
+static int clientfd;
+
+static char *buf;
+
+void serve_forever(const char *PORT)
+{
+    struct sockaddr_in clientaddr;
+    socklen_t addrlen;
+    char c;    
+
+    int slot=0;
+
+    printf(
+            "Server started %shttp://127.0.0.1:%s%s\n",
+            "\033[92m",PORT,"\033[0m"
+            );
+
+    // Setting all elements to -1: signifies there is no client connected
+    int i;
+    for (i=0; i<CONNMAX; i++)
+        clients[i]=-1;
+    startServer(PORT);
+
+    // ACCEPT connections
+    while (1)
+    {
+        addrlen = sizeof(clientaddr);
+        clients[slot] = accept (listenfd, (struct sockaddr *) &clientaddr, &addrlen);
+
+        if (clients[slot]<0)
+        {
+            perror("accept() error");
+        }
+        else
+        {
+            if ( fork()==0 )
+            {
+                respond(slot);
+                exit(0);
+            }
+        }
+
+        while (clients[slot]!=-1) slot = (slot+1)%CONNMAX;
+    }
+}
+
+//start server
+void startServer(const char *port)
+{
+    struct addrinfo hints, *res, *p;
+
+    // getaddrinfo for host
+    memset (&hints, 0, sizeof(hints));
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = AI_PASSIVE;
+    if (getaddrinfo( NULL, port, &hints, &res) != 0)
+    {
+        perror ("getaddrinfo() error");
+        exit(1);
+    }
+    // socket and bind
+    for (p = res; p!=NULL; p=p->ai_next)
+    {
+        int option = 1;
+        listenfd = socket (p->ai_family, p->ai_socktype, 0);
+        setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
+        if (listenfd == -1) continue;
+        if (bind(listenfd, p->ai_addr, p->ai_addrlen) == 0) break;
+    }
+    if (p==NULL)
+    {
+        perror ("socket() or bind()");
+        exit(1);
+    }
+
+    freeaddrinfo(res);
+
+    // listen for incoming connections
+    if ( listen (listenfd, 1000000) != 0 )
+    {
+        perror("listen() error");
+        exit(1);
+    }
+}
+
+
+// get request header
+char *request_header(const char* name)
+{
+    header_t *h = reqhdr;
+    while(h->name) {
+        if (strcmp(h->name, name) == 0) return h->value;
+        h++;
+    }
+    return NULL;
+}
+
+//client connection
+void respond(int n)
+{
+    int rcvd, fd, bytes_read;
+    char *ptr;
+
+    buf = malloc(65535);
+    rcvd=recv(clients[n], buf, 65535, 0);
+
+    if (rcvd<0)    // receive error
+        fprintf(stderr,("recv() error\n"));
+    else if (rcvd==0)    // receive socket closed
+        fprintf(stderr,"Client disconnected upexpectedly.\n");
+    else    // message received
+    {
+        buf[rcvd] = '\0';
+
+        method = strtok(buf,  " \t\r\n");
+        uri    = strtok(NULL, " \t");
+        prot   = strtok(NULL, " \t\r\n"); 
+
+        fprintf(stderr, "\x1b[32m + [%s] %s\x1b[0m\n", method, uri);
+
+        header_t *h = reqhdr;
+        char *t, *t2;
+        while(h < reqhdr+16) {
+            char *k,*v,*t;
+            k = strtok(NULL, "\r\n: \t"); if (!k) break;
+            v = strtok(NULL, "\r\n");     while(*v && *v==' ') v++;
+            h->name  = k;
+            h->value = v;
+            h++;
+            fprintf(stderr, "[H] %s: %s\n", k, v);
+            t = v + 1 + strlen(v);
+            if (t[1] == '\r' && t[2] == '\n') break;
+        }
+        t++; // now the *t shall be the beginning of user payload
+        t2 = request_header("Content-Length"); // and the related header if there is  
+        payload = t;
+        payload_size = t2 ? atol(t2) : (rcvd-(t-buf));
+
+        // bind clientfd to stdout, making it easier to write
+        clientfd = clients[n];
+        dup2(clientfd, STDOUT_FILENO);
+        close(clientfd);
+
+        // call router
+        route();
+
+        // tidy up
+        fflush(stdout);
+        shutdown(STDOUT_FILENO, SHUT_WR);
+        close(STDOUT_FILENO);
+    }
+
+    //Closing SOCKET
+    shutdown(clientfd, SHUT_RDWR);         //All further send and recieve operations are DISABLED...
+    close(clientfd);
+    clients[n]=-1;
+}
diff --git a/httpd.h b/httpd.h
@@ -0,0 +1,36 @@
+#ifndef _HTTPD_H___
+#define _HTTPD_H___
+
+#include <string.h>
+#include <stdio.h>
+
+//Server control functions
+
+void serve_forever(const char *PORT);
+
+// Client request
+
+char    *method,    // "GET" or "POST"
+        *uri,       // "/index.html"
+        *prot;      // "HTTP/1.1"
+
+char    *payload;     // for POST
+int      payload_size;
+
+char *request_header(const char* name);
+
+// user shall implement this function
+
+void route();
+
+// some interesting macro for `route()`
+#define ROUTE_START()       if (0) {
+#define ROUTE(METHOD,URI)   } else if (strcmp(URI,uri)==0&&strcmp(METHOD,method)==0) {
+#define ROUTE_GET(URI)      ROUTE("GET", URI) 
+#define ROUTE_POST(URI)     ROUTE("POST", URI) 
+#define ROUTE_END()         } else printf(\
+                                "HTTP/1.1 500 Not Handled\r\n\r\n" \
+                                "The server has no handler to the request.\r\n" \
+                            );
+
+#endif
diff --git a/main.c b/main.c
@@ -0,0 +1,27 @@
+#include "httpd.h"
+
+int main(int c, char** v)
+{
+    serve_forever("12913");
+    return 0;
+}
+
+void route()
+{
+    ROUTE_START()
+
+    ROUTE_GET("/")
+    {
+        printf("HTTP/1.1 200 OK\r\n\r\n");
+        printf("Hello! You are using %s", request_header("User-Agent"));
+    }
+
+    ROUTE_POST("/")
+    {
+        printf("HTTP/1.1 200 OK\r\n\r\n");
+        printf("Wow, seems that you POSTed %d bytes. \r\n", payload_size);
+        printf("Fetch the data using `payload` variable.");
+    }
+
+    ROUTE_END()
+}