Using right type for data bytes:

* char:
It is the type that makes up C strings like "abcde"
It also works out as a number value, but it is unspecified whether that value is treated as signed or unsigned. Beware character comparisons through inequalities - although if you limit yourself to ASCII (0-127) you're just about safe.

* signed char:
Gives you at least the -128 to 127 range.

* unsigned char:
Gives you at least the 0 to 255 range.

There is this warning: pointer targets in passing argument 1 of ‘system’ differ in signedness
I guess, it does not hurt me.

diff --git a/Daemon/javafork.c b/Daemon/javafork.c
index 214ea53..ff6abc3 100644 (file)
--- a/Daemon/javafork.c
+++ b/Daemon/javafork.c
@@ -262,12 +262,12 @@ int daemonize(const char *pname, int facility, int option)
 
 void *serverThread (void * arg)
 {
-       int socket = -1;                /*Open socket by the Java client*/
-       long timeout, utimeout;         /*Timeout for reading data from client: secs and usecs*/
-                                    /*respectively*/
-    uint32_t commandLength = 0;     /*Store the command length*/
-    char *command = NULL;           /*The command sent by the client, to be executed by this process*/
-       char buffer[sizeof(uint32_t)];  /*This buffer is intended to store the data received from the client*/
+    int socket = -1;                        /*Open socket by the Java client*/
+    long timeout, utimeout;                 /*Timeout for reading data from client: secs and usecs*/
+                                            /*respectively*/
+    uint32_t commandLength = 0;             /*Store the command length*/
+    unsigned char *command = NULL;          /*The command sent by the client as bytes, to be executed by this process*/
+    unsigned char buffer[sizeof(uint32_t)]; /*This buffer is intended to store the data received from the client*/
        
        socket = (int) arg;
        
@@ -311,7 +311,7 @@ void *serverThread (void * arg)
 
     /*2. COMMAND*/
     /*Reserving commandLength + 1 because of the string end character*/
-    if ((command = (char *) malloc(commandLength + 1)) == NULL) {
+    if ((command = (unsigned char *) malloc(commandLength + 1)) == NULL) {
         syslog (LOG_ERR, "command malloc failed: %m");
         goto err;
     }
@@ -407,7 +407,7 @@ int readable_timeout (int fd, long timeout, long utimeout)
 
 
 
-int readable (int socket, char *data, int len, int flags) 
+int readable (int socket, unsigned char *data, int len, int flags)
 {
     int received;   /*Stores received data from socket*/
 
@@ -434,7 +434,7 @@ int readable (int socket, char *data, int len, int flags)
 
 
 
-int receive_from_socket (int socket, char *data, int len, long timeout, long utimeout)
+int receive_from_socket (int socket, unsigned char *data, int len, long timeout, long utimeout)
 {
     int nData, iPos;   /*Control variables.*/
 
@@ -455,7 +455,7 @@ int receive_from_socket (int socket, char *data, int len, long timeout, long uti
 
 
 
-int pre_fork_system(int socket, char *command)
+int pre_fork_system(int socket, unsigned char *command)
 {
     /*Required variables in order to share memory between processes*/
     key_t keyvalue;
@@ -523,7 +523,7 @@ end:
 
 
 
-int fork_system(int socket, char *command, int *returnstatus) 
+int fork_system(int socket, unsigned char *command, int *returnstatus)
 {
     int pid;                /*Child or parent PID.*/
     int out[2], err[2];     /*Store pipes file descriptors. Write ends attached to the stdout*/
@@ -568,6 +568,7 @@ int fork_system(int socket, char *command, int *returnstatus)
         /*TODO: I should use execve with setlocale and the environment instead of system.*/
         /*During execution of the command, SIGCHLD will be blocked, and SIGINT and SIGQUIT*/
         /* will be ignored. From man system(3)*/
+        /*Attention: warning about signedness. I guess it does not hurt me.*/
         *returnstatus=system(command);
         if (WIFEXITED(returnstatus) == 1)
             (*returnstatus) = WEXITSTATUS(*returnstatus);

diff --git a/Daemon/javafork.h b/Daemon/javafork.h
index a006d5a..7bb3a57 100644 (file)
--- a/Daemon/javafork.h
+++ b/Daemon/javafork.h
@@ -58,7 +58,7 @@ int main_daemon (char *address, int port, int queue);
 /* INPUT PARAMETER: socket file descriptor                                              */
 /* RETURNS: void                                                                        */
 /****************************************************************************************/
-int fork_system(int socket, char *command, int *returnst);
+int fork_system(int socket, unsigned char *command, int *returnst);
 
 
 
@@ -68,7 +68,7 @@ int fork_system(int socket, char *command, int *returnst);
 /* INPUT PARAMETER: socket file descriptor                                              */
 /* RETURNS: void                                                                        */
 /****************************************************************************************/
-int pre_fork_system(int socket, char *command);
+int pre_fork_system(int socket, unsigned char *command);
 
 
 
@@ -86,7 +86,7 @@ int required_sock_options (int socket);
 
 
 
-int receive_from_socket (int socket, char *data, int len, long timeout, long utimeout);
+int receive_from_socket (int socket, unsigned char *data, int len, long timeout, long utimeout);
 
 
 
@@ -94,4 +94,4 @@ int readable_timeout (int fd, long timeout, long utimeout);
 
 
 
-int readable (int socket, char *data, int len, int flags);
+int readable (int socket, unsigned char *data, int len, int flags);