add docs and some hashmap code

include/colors.h

@@ -1,6 +1,7 @@
 #ifndef __COLORS_H__
 #define __COLORS_H__
 
+/* ANSI color escape sequences */
 #define RED "\033[31m"
 #define GREEN "\033[32m"
 #define YELLOW "\033[33m"

include/hashmap.h

@@ -1,19 +1,32 @@
 #ifndef __HASHMAP_C__
 #define __HASHMAP_C__
 
+#include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 
-#define HASHMAP_MAX_CLIENTS 10000
+/* Each process on Linux can have a maximum of 1024 open file descriptors */
+#define HASHMAP_MAX_CLIENTS 1024
 
 struct hashmap {
 	int sockfd;
 	struct sockaddr_storage sas;
+	struct hashmap *next;
 };
 
+/* Calculate the hash code of a file descriptor */
 int hash(int sockfd);
+
+/* Initialize the hash map */
 void hm_init(struct hashmap *map);
+
+/* Insert a new key in the hash map */
 void hm_insert(struct hashmap *map, int sockfd, struct sockaddr_storage *sas);
+
+/* Search for a key in the hash map */
 struct hashmap *hm_lookup(struct hashmap *map, int sockfd);
 
+/* Clean up the hash map */
+void hm_free(struct hashmap *map);
+
 #endif

include/server.h

@@ -14,17 +14,76 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+/* On which port the server will run */
 #define PORT 3030
+
+/* Clients max queue */
 #define BACKLOG 10
+
+/* Size of the epoll_event array */
 #define EPOLL_MAXEVENTS 10
+
+/* Wait forever (epoll_wait()) */
 #define EPOLL_TIMEOUT -1
 
+/**
+ * @brief Runs the server
+ *
+ * @param hostname[in] The hostname of the server (default localhost, it could be NULL)
+ * @param service[in] The service (found in /etc/services) or the port where to run
+ * @return int 0 on success, -1 on error
+ */
 int start_server(const char *hostname, const char *service);
+
+/**
+ * @brief Sets the up hints object
+ *
+ * @param hints[out] The hints addrinfo
+ * @param len[in] The length of hints
+ * @param hostname[in] The hostname (could be NULL)
+ */
 void setup_hints(struct addrinfo *hints, size_t len, const char *hostname);
+
+/**
+ * @brief Main server loop
+ *
+ * @param sockfd[in,out] Socket of the commincation endpoint
+ */
 void handle_clients(int sockfd);
+
+/**
+ * @brief Adds a file descriptor to the interest list
+ *
+ * @param epfd[in] epoll file descriptor
+ * @param sockfd[in] The file descriptor to watch
+ * @param events[in] The events to follow
+ */
 void epoll_ctl_add(int epfd, int sockfd, uint32_t events);
+
+/* Remove a file descriptor from the interest list */
+/**
+ * @brief Removes a file descriptor from the interest list
+ *
+ * @param epfd[in] epoll file descriptor
+ * @param sockfd[in] The file descriptor to remove
+ */
 void epoll_ctl_del(int epfd, int sockfd);
+
+/**
+ * @brief Makes a file descriptor non blocking
+ *
+ * @param sockfd[in] The file descriptor to make non blocking
+ */
 void setnonblocking(int sockfd);
+
+/**
+ * @brief Handles the new client
+ *
+ * @param sockfd[in] Server's file descriptor
+ * @param their_sa[out] Populates the struct with client's information
+ * @param theirsa_size[in] Size of the struct
+ * @return int Returns -1 on error or the file descriptor on success
+ */
 int handle_new_client(int sockfd, struct sockaddr_storage *their_sa, socklen_t *theirsa_size);
 
 #endif

include/utils.h

@@ -10,8 +10,20 @@
 #include <sys/socket.h>
 #include <sys/types.h>
 
-// print every IPs of a hostname
+/**
+ * @brief Prints each IP address associated with a host
+ *
+ * @param hostname[in] Hostname
+ * @param port[in] Port
+ */
 void print_ips(const char *hostname, const char *port);
+
+/**
+ * @brief Retrieves the client ip from the sockaddr_storage and put it in the ip str
+ *
+ * @param sa[in] The sockaddr_storage of the client
+ * @param ip[out] The IP of the client
+ */
 void get_client_ip(struct sockaddr_storage *sa, char *ip);
 
 #endif

notes/advanced-techniques.md

@@ -85,5 +85,3 @@ union epoll_data {
     uint64_t  u64;
 };
 ```
-
-**TODO: improve the notes for epoll()**

notes/hash-table.md

@@ -17,5 +17,3 @@ $$ hash(\text{key}) = \text{key} \mod \text{table\_dim} $$
 
 - String keys:
 $$ hash(key) = \sum_{i=0}^{len(key) - 1} ascii\_value(key[i]) * prime\_number$$
-
-**TODO**

src/hashmap.c

@@ -7,18 +7,41 @@ void hm_init(struct hashmap *map) {
 
 	for (size_t i = 0; i < HASHMAP_MAX_CLIENTS; ++i) {
 		map[i].sockfd = -1;
+		map[i].next = NULL;
 	}
 }
 
 void hm_insert(struct hashmap *map, int sockfd, struct sockaddr_storage *sas) {
 	int index = hash(sockfd);
-	map[index].sockfd = sockfd;
-	map[index].sas = *sas;
 
-    // I should check the collisions
+	if (map[index].sockfd == -1) {
+		map[index].sockfd = sockfd;
+		map[index].sas = *sas;
+	} else {
+		/* Go through the linked list and append the new item */
+		struct hashmap *p;
+		for (p = &map[index]; p->next != NULL; p = p->next);
+		struct hashmap *new = malloc(sizeof(struct hashmap));
+		new->sockfd = sockfd;
+		new->sas = *sas;
+		new->next = NULL;
+
+		p->next = new;
+	}
 }
 
 struct hashmap *hm_lookup(struct hashmap *map, int sockfd) {
 	int index = hash(sockfd);
-	return &map[index];
+
+	if (map[index].sockfd != sockfd) {
+		struct hashmap *p;
+		for (p = map[index].next; p->sockfd != sockfd; p = p->next);
+		return p;
+	} else {
+		return &map[index];
+	}
+
+	return NULL;
 }
+
+void hm_free(struct hashmap *map) {}