diff --git a/src/helpers.h b/src/helpers.h new file mode 100644 index 0000000..9922d01 --- /dev/null +++ b/src/helpers.h @@ -0,0 +1,8 @@ + +// Convert a defined token to a string +#define _STR(x) #x + +// Usable wrapper for above +// Note: #x does not work in context, 2nd layer is required ?? +// http://www.decompile.com/cpp/faq/file_and_line_error_string.htm +#define STR(x) _STR(x) diff --git a/src/main.c b/src/main.c index 144b1d0..b09e7e0 100644 --- a/src/main.c +++ b/src/main.c @@ -10,6 +10,8 @@ #include #include +#include "helpers.h" + // UDP server-related mostly lifted from https://cs.nyu.edu/~mwalfish/classes/16sp/classnotes/handout01.pdf void panic(const char* s) { @@ -17,15 +19,18 @@ void panic(const char* s) { exit(1); } +// TODO check max app name length +#define MSG_APP_LEN 64 struct Message { int priority; - char application[64]; + char application[MSG_APP_LEN]; }; +#define DF_MONTH_LEN 9 struct Datefields { - char month[9]; + char month[DF_MONTH_LEN]; // TODO numeric indicator? int day; int hour; int minute; @@ -76,7 +81,7 @@ int parse_datefield(char* message, struct Datefields* date, int* position) { // char month[8]; // memset(&month, '\0', sizeof(month)); // makes valgrind happy as the above char contains uninitialized memory int date_length; - if(sscanf(message + *position, "%s %d %d:%d:%d%n", + if(sscanf(message + *position, "%"STR(DF_MONTH_LEN)"s %d %d:%d:%d%n", date->month, &(date->day), &(date->hour), &(date->minute), &(date->second), &date_length) != 5) { return 1; // Failed to parse all desired fields } @@ -84,6 +89,19 @@ int parse_datefield(char* message, struct Datefields* date, int* position) { return 0; } + +int parse_application(char* message, char* application, int* position) { + int app_length; + if(sscanf(message + *position, "%"STR(MSG_APP_LEN)"s%n", application, &app_length) != 1) { // %n not counted in returned field count + return 1; // Failed to parse all desired fields + } + if(strlen(application) < 2) return 1; // Expect at least chars + application[app_length-1] = '\0'; // Remove the trailing : + *position += app_length; + return 0; +} + + int parse_message(struct Message* result, char* message) { /* parse a message like: @@ -92,21 +110,30 @@ int parse_message(struct Message* result, char* message) { VERSION ISOTIMESTAMP HOSTNAME APPLICATION PID MESSAGEID STRUCTURED-DATA MSG Assumes null termed string */ - printf("Got message: %s\n", message); int priority = 0; int position = 0; if(parse_priority(message, &priority, &position) != 0) return 1; result->priority = priority; position++; // Now sits on the first character of the ISOTIMESTAMP - - // Parse date + // Parse ISOTIMESTAMP + // Note: does not parse a full iso timestamp, only the format above struct Datefields date; if(parse_datefield(message, &date, &position) != 0) { return 1; } position++; // position now at beginning of HOSTNAME field + // Parse APPLICATION + // filterlog: 5,,,1000000103,cpsw0,match.... + char application[MSG_APP_LEN]; + if(parse_application(message, application, &position) != 0) return 1; + memcpy(result->application, application, sizeof(application)); + position += 1; // pass over the space + + printf("remaining: '%s'\n", message + position); + return 0; + // char msg_remaining[4096]; // memset(&msg_remaining, '\0', sizeof(msg_remaining)); // memcpy(msg_remaining, &message[position], strlen(message) - position); @@ -115,30 +142,16 @@ int parse_message(struct Message* result, char* message) { // memmove(message, &message[position], strlen(message) - position); // printf("'%s'\n", message); - // Parse APPLICATION - // filterlog: 5,,,1000000103,cpsw0,match.... - char application[64]; // TODO check max length - int app_length; - if(sscanf(message + position, "%s%n", application, &app_length) != 1) { // %n not counted in returned field count - return 1; // Failed to parse all desired fields - } - application[app_length-1] = '\0'; // Remove the trailing : - memcpy(result->application, application, sizeof(application)); - - position += app_length + 1; - - printf("remaining: '%s'\n", message + position); - return 0; } + int main(int argc, char** argv) { int sock_fd; struct sockaddr_in my_addr, my_peer_addr; char* endptr; unsigned int portl; unsigned short port; - int size_recvd; char msg[4096]; socklen_t addrlen; @@ -161,7 +174,7 @@ int main(int argc, char** argv) { if ((sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) panic("socket"); int one = 1; - setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(1)); + setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); memset(&my_addr, 0, sizeof(my_addr)); my_addr.sin_family = AF_INET; @@ -173,7 +186,7 @@ int main(int argc, char** argv) { while (1) { addrlen = sizeof(struct sockaddr_in); - + int size_recvd; if ((size_recvd = recvfrom(sock_fd, /* socket */ msg, /* buffer */ sizeof(msg), /* size of buffer */ @@ -185,6 +198,7 @@ int main(int argc, char** argv) { assert(size_recvd < sizeof(msg)); // messages can't be longer than our buffer assert(addrlen == sizeof(struct sockaddr_in)); + printf("Got message: %s\n", msg); // TODO should we check that msg[size_recvd] == \0 ? // printf("From host %s src port %d got message %.*s\n",