new feature list, merge of README and FEATURES

[paraslash.git] / command.c

diff --git a/command.c b/command.c
index acd539693748deebb035ba08e07b9bb49394bd1f..21131248c29cd894c8bb74cb13801cd54205e066 100644 (file)
--- a/command.c
+++ b/command.c
@@ -43,7 +43,6 @@ extern struct misc_meta_data *mmd;
 extern struct audio_file_selector selectors[];
 extern struct sender senders[];
 extern char *user_list;
-struct sockaddr_in *in_addr;
 
 static void dummy(__a_unused int s)
 {}
@@ -72,14 +71,14 @@ static char *vss_status_tohuman(unsigned int flags)
 /*
  * return human readable permission string. Never returns NULL.
  */
-char *cmd_perms_itohuman(unsigned int perms)
+static char *cmd_perms_itohuman(unsigned int perms)
 {
-       char *msg = para_malloc(7 * sizeof(char));
+       char *msg = para_malloc(5 * sizeof(char));
 
-       msg[0] = perms & DB_READ? 'd' : '-';
-       msg[1] = perms & DB_WRITE? 'D' : '-';
-       msg[2] = perms & VSS_READ? 'a' : '-';
-       msg[3] = perms & VSS_WRITE? 'A' : '-';
+       msg[0] = perms & DB_READ? 'a' : '-';
+       msg[1] = perms & DB_WRITE? 'A' : '-';
+       msg[2] = perms & VSS_READ? 'v' : '-';
+       msg[3] = perms & VSS_WRITE? 'V' : '-';
        msg[4] = '\0';
        return msg;
 }
@@ -102,7 +101,7 @@ static char *vss_get_status_flags(unsigned int flags)
 /*
  * compute status bar string. Never returns NULL
  */
-char *get_sb_string(struct misc_meta_data *nmmd)
+static char *get_sb_string(struct misc_meta_data *nmmd)
 {
        char *base, *ret;
        long long unsigned secs = 0, rsecs = 0, percent = 0;
@@ -462,9 +461,9 @@ static int send_list_of_commands(int fd, struct server_command *cmd,
 /* always returns string that must be freed by the caller in handler */
 static struct server_command *get_cmd_ptr(char *name, char **handler)
 {
-       struct server_command *cmd = cmd_struct;
+       struct server_command *cmd;
 
-       for (cmd = cmd_struct; cmd->name; cmd++)
+       for (cmd = server_cmds; cmd->name; cmd++)
                if (!strcmp(cmd->name, name)) {
                        if (handler)
                                *handler = para_strdup("para_server"); /* server commands */
@@ -492,7 +491,7 @@ int com_help(int fd, int argc, char **argv)
 
        if (argc < 2) {
                /* no argument given, print list of commands */
-               if ((ret = send_list_of_commands(fd, cmd_struct, "server")) < 0)
+               if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
                        return ret;
                mmd_lock();
                handler = para_strdup(selectors[mmd->selector_num].name);
@@ -510,20 +509,17 @@ int com_help(int fd, int argc, char **argv)
        }
        perms = cmd_perms_itohuman(cmd->perms);
        ret = send_va_buffer(fd,
-               "NAME\n\t%s - %s\n"
-               "SYNOPSIS\n\t para_client %s\n"
-               "DESCRIPTION\n%s\n"
-               "HANDLER\n"
-               "This command is handled by %s.\n\n"
-               "PERMISSIONS\n"
-               "Needed privileges for %s: %s\n",
+               "%s - %s\n\n"
+               "handler: %s\n"
+               "permissions: %s\n"
+               "usage: %s\n\n"
+               "%s\n",
                argv[1],
                cmd->description,
-               cmd->synopsis,
-               cmd->help,
                handler,
-               argv[1],
-               perms
+               perms,
+               cmd->usage,
+               cmd->help
        );
        free(perms);
        free(handler);
@@ -730,7 +726,7 @@ static struct server_command *parse_cmd(const char *cmdstr)
        return get_cmd_ptr(buf, NULL);
 }
 
-long int para_rand(long unsigned max)
+static long int para_rand(long unsigned max)
 {
        return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
 }
@@ -760,6 +756,37 @@ static void rc4_send(unsigned long len, const unsigned char *indata,
        RC4(&rc4_send_key, len, indata, outdata);
 }
 
+/**
+ * perform user authentication and execute a command
+ *
+ * \param fd the file descriptor to send output to
+ * \param addr socket address info of peer
+ *
+ * \return EXIT_SUCCESS or EXIT_FAILURE
+ *
+ * Whenever para_server accepts an incoming tcp connection on
+ * the port it listens on, it forks and the resulting child
+ * calls this function.
+ *
+ * An RSA-based challenge/response is used to authenticate
+ * the peer. It that authentication succeeds, a random RC4
+ * session key is generated and sent back to the peer,
+ * encrypted with its RSA public key.  From this point on,
+ * all transfers are crypted with this session key.
+ *
+ * Next it is checked if the peer supplied  a valid server
+ * command or a command for the audio file selector currently
+ * in use.  If yes, and if the user has sufficient
+ * permissions to execute that command, the function calls
+ * the corresponding command handler which does argument
+ * checking and further processing.
+ *
+ * In order to cope with a DOS attacks, a timeout is set up
+ * which terminates the function if the connection was not
+ * authenticated when the timeout expires.
+ *
+ * \sa alarm(2), rc4(3), crypt.c, crypt.h
+ */
 int handle_connect(int fd, struct sockaddr_in *addr)
 {
        int numbytes, ret, argc, use_rc4 = 0;
@@ -777,7 +804,6 @@ int handle_connect(int fd, struct sockaddr_in *addr)
        signal(SIGHUP, SIG_DFL);
        signal(SIGUSR1, SIG_IGN);
 
-       in_addr = addr;
        challenge_nr = random();
        /* send Welcome message */
        ret = send_va_buffer(fd, "This is para_server, version "