Small test for mprotect().

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26872 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/tests/system/libroot/posix/Jamfile

@@ -18,6 +18,10 @@ SimpleTest flock_test
 	: flock_test.cpp
 ;
 
+SimpleTest mprotect_test
+	: mprotect_test.cpp
+;
+
 SimpleTest realtime_sem_test1
 	: realtime_sem_test1.cpp
 ;

src/tests/system/libroot/posix/mprotect_test.cpp

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2008, Ingo Weinhold, [email protected].
+ * Distributed under the terms of the MIT License.
+ */
+
+#include <errno.h>
+#include <limits.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/mman.h>
+
+
+#ifndef PAGE_SIZE
+#	define PAGE_SIZE 4096
+#endif
+
+
+static const size_t kMapChunkSize = 4 * PAGE_SIZE;
+static const size_t kTestSize = 256 * PAGE_SIZE;
+
+static int64_t sHandledSignals = 0;
+
+static uint8_t* sMappedBase;
+static size_t sMappedSize;
+static uint8_t* sTouchedAddress;
+
+
+static void
+signal_handler(int signal)
+{
+	sHandledSignals++;
+
+	//printf("SIGSEGV at %p\n", sTouchedAddress);
+
+	// protect the last page of the current allocation writable
+	if (mprotect(sMappedBase + sMappedSize - PAGE_SIZE, PAGE_SIZE,
+			PROT_READ | PROT_WRITE) < 0) {
+		fprintf(stderr, "SIGSEGV: mprotect() failed: %s\n", strerror(errno));
+		exit(1);
+	}
+
+	// allocate the next chunk
+	void* mappedAddress = mmap(sMappedBase + sMappedSize, kMapChunkSize,
+		PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+	if (mappedAddress == MAP_FAILED) {
+		fprintf(stderr, "SIGSEGV: mmap() failed: %s\n", strerror(errno));
+		exit(1);
+	}
+
+	printf("mapped %d bytes at %p\n", (int)kMapChunkSize, mappedAddress);
+
+	sMappedSize += kMapChunkSize;
+
+	// map the last page read-only
+	if (mprotect(sMappedBase + sMappedSize - PAGE_SIZE, PAGE_SIZE, PROT_READ)
+			< 0) {
+		fprintf(stderr, "SIGSEGV: mprotect() failed: %s\n", strerror(errno));
+		exit(1);
+	}
+}
+
+
+int
+main()
+{
+	// install signal handler
+	if (signal(SIGSEGV, signal_handler) == SIG_ERR) {
+		fprintf(stderr, "Error: Failed to install signal handler: %s\n",
+			strerror(errno));
+		exit(1);
+	}
+
+	// Map the complete test size plus one chunk and unmap all but the first
+	// chunk again, so no other memory gets into the way, when we mmap() the
+	// other chunks with MAP_FIXED.
+	sMappedBase = (uint8_t*)mmap(NULL, kTestSize + kMapChunkSize,
+		PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if (sMappedBase == MAP_FAILED) {
+		fprintf(stderr, "mmap() failed: %s\n", strerror(errno));
+		return 1;
+	}
+	munmap(sMappedBase + kMapChunkSize, kTestSize);
+
+	sMappedSize = kMapChunkSize;
+
+	printf("mapped %d bytes at %p\n", (int)sMappedSize, sMappedBase);
+
+	if (mprotect(sMappedBase + sMappedSize - PAGE_SIZE, PAGE_SIZE, PROT_READ)
+			< 0) {
+		fprintf(stderr, "mprotect() failed: %s\n", strerror(errno));
+		return 1;
+	}
+
+	for (int i = 0; i < 256 * PAGE_SIZE; i++) {
+		sTouchedAddress = sMappedBase + i;
+		*sTouchedAddress = 1;
+	}
+
+	printf("test finished successfully!\n");
+
+	return 0;
+}