add check for sufficient free memory, update exes, update ReadMe

ReadMe.md

@@ -4,14 +4,14 @@
 ### 64-bit multi-threading random data generator
 
 
-##### RND64 v.0.32
+##### RND64 v.0.33
 
 ##### Linux and Windows
 
 
 ## Purpose
 
-Generate large files (non-sparse) and large streams of random data (4GB+) at fast generation rates (~1.25GB/sec on modest CPUs such as Intel i3 desktop / Intel Xeon AWS microinstance (running Linux)).
+Generate large files (non-sparse) and large streams of random data (4GB+) at fast generation rates (~1.25GB/sec (under Linux using -f option) on modest CPUs such as Intel i3 desktop / Intel Xeon AWS microinstance).
 
 
 ## OS Support
@@ -50,7 +50,7 @@ Windows x64
     rnd64 -a 1k | nc 192.168.1.20 80      pipe 1kB of random bytes to 'netcat' to send to 192.168.1.20 on port 80
 
 
-###### WARNING: Be careful of the amount of data generated in regards to the available memory of the PC for creating data, and the age and performance of the PC's hard-drive for writing data.  A file dump of more than 1GB can be brutal.
+###### WARNING: Be careful of the amount of data generated in regards to the available memory of the PC for creating data, and the age and performance of the PC's hard-drive for writing data.  A file dump of more than 1GB can be brutal.  On Linux, a large <size> gigabyte value that works on a freshly booted system, may not work on the same busy long-running system, because of caching and application requirements.
 
 
 ## Build
@@ -92,6 +92,14 @@ Move the rnd64 executable to a location such as */usr/local/bin*  (location must
 (Windows/Super key + Break) > Advanced tab > Environmental Variables button > click Path line > Edit button > Variable value - append at the end of existing line information: *C:\directory paths\to rnd64.exe\;*
 
 
+## Credits
+
++ Aleksandr Sergeev: testing, recommendations.
++ Travis Gockel: Linux free memory report.
++ MSDN: Windows crypto and free system memory.
++ Ben Alpert: microsecond timer.
+
+
 ## License
 
 RND64 is released under the [GPL v.3](https://www.gnu.org/licenses/gpl-3.0.html).

rnd64.c

@@ -7,7 +7,7 @@
 	*
 	* @author        Martin Latter <copysense.co.uk>
 	* @copyright     Martin Latter, April 2014
-	* @version       0.32 mt
+	* @version       0.33 mt
 	* @license       GNU GPL version 3.0 (GPL v3); https://www.gnu.org/licenses/gpl-3.0.html
 	* @link          https://github.com/Tinram/RND64.git
 	*
@@ -76,6 +76,8 @@ int main(int iArgCount, char* aArgV[]) {
 	unsigned int i;
 	unsigned int j;
 	unsigned int iFIndex = 0;
+	unsigned int iUnavailMB;
+	unsigned long long iFreeMemory;
 	char cUnit;
 	char sFileSize[iSizeLen];
 	char* aBuffer[iNumThreads];
@@ -133,6 +135,16 @@ int main(int iArgCount, char* aArgV[]) {
 		return EXIT_FAILURE;
 	}
 
+	iFreeMemory = getFreeSystemMemory();
+
+	/* bail out if required memory exceeds, or is likely to dangerously exhaust, free memory */
+	if (iTotalBytes > iFreeMemory) {
+
+		iUnavailMB = iTotalBytes / 1024 / 1024;
+		fprintf(stderr,"\n%s: insufficient memory to allocate %u MB.\nPlease use a smaller <size>\n\n", pFilename, iUnavailMB);
+		return EXIT_FAILURE;
+	}
+
 	/* set global variable for thread functions */
 	iBytes = iTotalBytes / iNumThreads;
 
@@ -163,7 +175,8 @@ int main(int iArgCount, char* aArgV[]) {
 
 		if (aBuffer[i] == NULL) {
 
-			fprintf(stderr, "\n%s: insufficient memory to allocate %"PRId64" bytes.\n\n", pFilename, iBytesLocal);
+			iUnavailMB = iBytesLocal / 1024 / 1024;
+			fprintf(stderr, "\n%s: insufficient memory to allocate %u MB in thread buffer.\n\n", pFilename, iUnavailMB);
 
 			for (j = 0; j <= i; j++) { /* deallocate up to this i */
 				free(aBuffer[j]);
@@ -189,7 +202,7 @@ int main(int iArgCount, char* aArgV[]) {
 		#endif
 	}
 
-	/* create stream if no specified <file> argument, then exit */
+	/* create stream if no specified [file] argument, then exit */
 	if (aArgV[3] == NULL) {
 
 		for (i = 0; i < iNumThreads; i++) {
@@ -453,6 +466,50 @@ int main(int iArgCount, char* aArgV[]) {
 #endif
 
 
+/**
+	* Attempt to find free memory available for allocation.
+	* Windows reporting through MEMORYSTATUSEX seems accurate.
+	* Linux is trickier: what is reported as free in conjunction with considerable buffering and caching.
+	*
+	* @return  integer
+*/
+
+#ifdef __linux
+
+unsigned long long getFreeSystemMemory() {
+
+	/**
+		* Derived from an example by Travis Gockel.
+		* Linux apparently provides only total and free (unbuffered) memory values reliably.
+		* Found that 0.5GB margin on kernel 4.4 with 6GB RAM is not quite enough (e.g 5g okay, 5300m locks system).
+	*/
+
+	long iPages;
+	long iPageSize;
+
+	iPages = sysconf(_SC_PHYS_PAGES);
+	iPageSize = sysconf(_SC_PAGE_SIZE);
+
+	return (iPages * iPageSize) - cSafetyChunk; /* assumes system has at least 1GB total memory */
+}
+
+#elif _WIN64
+
+unsigned long long getFreeSystemMemory() {
+
+	/* from MSDN */
+
+	MEMORYSTATUSEX stMemState;
+
+	stMemState.dwLength = sizeof(stMemState);
+	GlobalMemoryStatusEx(&stMemState);
+
+	return stMemState.ullAvailPhys;
+}
+
+#endif
+
+
 /**
 	* Display menu.
 	*

rnd64.h

@@ -7,7 +7,7 @@
 	*
 	* @author        Martin Latter <copysense.co.uk>
 	* @copyright     Martin Latter, April 2014
-	* @version       0.32 mt
+	* @version       0.33 mt
 	* @license       GNU GPL version 3.0 (GPL v3); http://www.gnu.org/licenses/gpl.html
 	* @link          https://github.com/Tinram/RND64.git
 	*
@@ -25,21 +25,23 @@
 #ifdef __linux
 	#include <pthread.h>
 	#include <sys/sysinfo.h>
+	#include <unistd.h>
 	#define RANDOM_PATH "/dev/urandom"
 #elif _WIN64
 	#include <windows.h>
 	#include <wincrypt.h> /* CryptAcquireContext, CryptGenRandom */
 #endif
 
 
-#define RND64_VERSION "0.32 mt"
+#define RND64_VERSION "0.33 mt"
 
 
 #ifdef __linux
 	void* generateAll(void* buff);
 	void* generateRestricted(void* buff);
 	void* generateSingleChar(void* buff);
 	void* generateCrypto(void* buff);
+	const unsigned long cSafetyChunk = 786432000; /* 0.75 MB non-allocation margin */
 #elif _WIN64
 	DWORD WINAPI generateAll(LPVOID buff);
 	DWORD WINAPI generateRestricted(LPVOID buff);
@@ -48,6 +50,7 @@
 #endif
 
 
+unsigned long long getFreeSystemMemory();
 void menu(char* pFilename);