/* * All command functions have the same set of arguments. An * integer (the socket FD) followed by a string. The "real" * arguments are contained in the string. Command functions * are free to treat this string any way they want to. Many * commands simply ignore it. If however you need to pass * floating point, string or integer data to your command * here is an example of how to do it. Notice in the example * below the nere paranoiia about error checking and logging. * You cannot do to much of this. Clients can and will send * abusive data and without such nere paranoiia the server * can crash. Also when it is 3:00am and you are trying to * debug a program, having a log message that points to the * souce code file and line number and prints the suspect bad * data can be a real help. * * Command functions do not need to send any data back to thier * client. If they choose to they must use the sl_Send2Client() * function to send newline terminated lines of test. Binary * data is not allowed. * * Succues or failure of the command function is normally * communicated back to the client by the command function's * return code. The Mk4d server will look at the value returned * and send the required protocol. You may also send informative * text to the client but remember that ssome clients are programs * that do not pass this test on to the user. A failure is * caused b a programming error and should be uncommon after * the software is operational. But still "bugs happen" and * crashing a server process is unacceptable. */ #include #include #include #include "MLog.h" #include "server_lib.h" #include "commands.h" #include "tasks.h" #include "time_funct.h" /* Common string used in lots of places */ static const char LocMsg[] = " %s:%d <%s>\n"; /********************************************************************/ /* */ /* cmd_example_arguments */ /* */ /* */ /* PURPOSE: To show by example how to parse arguments. One of */ /* each type is passed in an ASCII string. Commands */ /* must parse tier argument strings themselves. */ /* Here is a test example. */ /* */ /* ARGUMENTS: A string with the following fields */ /* 1) float */ /* 2) doublet */ /* 3) int */ /* 4) string */ /* */ /********************************************************************/ int cmd_example_arguments(int sd, char args[]) { /* These are the argument expected in the args[] string */ /* they must appear in the order shown. */ float fee; double fie; int foe; char fum[80]; /* Used internally */ char FaiureMsg1[] = "WARNING invalid argument passed to cmd_example_arguments\n"; int nargs; char line[80]; int res; /* convert the args[] string to values. First check for sanity */ if ( !args ) { /* null pointer */ ml_print (ML_MANDATORY, ML_ERROR, FaiureMsg1); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, "(null pointer)"); return CMD_FAIL; } if ( strlen(args) < 7 ) { /* to short to be valid */ ml_print (ML_MANDATORY, ML_ERROR, FaiureMsg1); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, args); return CMD_FAIL; } /* convert string and return count of arguments */ nargs = sscanf(args, "%f %lf %d %s", &fee, &fie, &foe, fum); if (nargs != 4) { /* Some error in args string detected */ ml_print (ML_MANDATORY, ML_ERROR, FaiureMsg1); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, args); return CMD_FAIL; } /* If we get to this point we know the arguments are */ /* converted with no errors. We still need to do a */ /* range check */ if ( (fee > 10000.0) || (fee < -10000.0) ) { /* fee is out of it's valid range */ ml_print (ML_MANDATORY, ML_ERROR, FaiureMsg1); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, args); return CMD_FAIL; } /* Finally, we know we have good input and can proceed */ /* As this is just an example all we do here is send a */ /* back to the client saying what the parameter values are */ snprintf(line, sizeof(line), "fee: %f, fie: %f, foe: %d, fum: %s\n", fee, fie, foe, fum); /* send line to client and check for error */ res = sl_Send2Client(sd, line); if (res < 0) { /* error sending command. Client died? */ ml_printf(ML_MANDATORY, ML_ERROR, "ERROR: Send to client failed on socket %d\n", sd); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, line); return CMD_FAIL; } /* We are done. Send positive return code. */ return CMD_OK; } /********************************************************************/ int cmd_example_task(int sd, char args[]) { int res; char line[80]; /* send line to client and check for error */ res = sl_Send2Client(sd, "example task is started\n"); if (res < 0) { /* error sending command. Client died? */ ml_printf(ML_MANDATORY, ML_ERROR, "ERROR: Send to client failed on socket %d\n", sd); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, line); return CMD_FAIL; } /* We will ask that _this_ command be run again in 15 second */ res = AddTask(cmd_example_task, "example_task", " ", sd, get_epoc()+15.0); if (res < 0) { /* error sending command. Client died? */ ml_printf(ML_MANDATORY, ML_ERROR, "ERROR: Could not add task to task table\n"); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, line); return CMD_FAIL; } /* send line to client and check for error */ res = sl_Send2Client(sd, "example task is ending\n"); if (res < 0) { /* error sending command. Client died? */ ml_printf(ML_MANDATORY, ML_ERROR, "ERROR: Send to client failed on socket %d\n", sd); ml_printf(ML_MANDATORY, ML_ERROR, LocMsg, __FILE__, __LINE__, line); return CMD_FAIL; } /* No errors detected so must be OK */ return CMD_OK; }