Misc

Signed-off-by: Mattias Andrée <m@maandree.se>

6 files changed, 73 insertions, 5 deletions

diff --git a/libtest/common.h b/libtest/common.h
index ab59bab..d6557b1 100644
--- a/libtest/common.h
+++ b/libtest/common.h
@@ -160,6 +160,8 @@ extern struct meminfo libtest_allocs_head;
 extern struct meminfo libtest_allocs_tail;
 extern int libtest_allocs_list_inited;
 extern atomic_flag libtest_allocs_list_spinlock;
+extern void *libtest_pretend_list[128];
+extern size_t libtest_npretends;
 
 extern _Thread_local int libtest_zero_on_alloc;
 extern _Thread_local int libtest_expect_zeroed;
diff --git a/libtest/globals.c b/libtest/globals.c
index e5229a1..6e79402 100644
--- a/libtest/globals.c
+++ b/libtest/globals.c
@@ -25,10 +25,14 @@ volatile int libtest_mmap_is_custom = -1;
 volatile int libtest_munmap_is_custom = -1;
 volatile int libtest_mremap_is_custom = -1;
 
+volatile int libtest_pretend_allocation_successful = 0;
+
 struct meminfo libtest_allocs_head;
 struct meminfo libtest_allocs_tail;
 int libtest_allocs_list_inited = 0;
 atomic_flag libtest_allocs_list_spinlock = ATOMIC_FLAG_INIT;
+void *libtest_pretend_list[128];
+size_t libtest_npretends = 0u;
 
 _Thread_local int libtest_zero_on_alloc = 0;
 _Thread_local int libtest_expect_zeroed = 0;
diff --git a/libtest/libtest.h b/libtest/libtest.h
index e4b4098..6eadd6f 100644
--- a/libtest/libtest.h
+++ b/libtest/libtest.h
@@ -437,6 +437,8 @@ size_t libtest_get_alloc_failure_in(void);
 void libtest_set_alloc_failure_in(size_t n);
 
 
+extern volatile int libtest_pretend_allocation_successful;
+
 extern const unsigned char *volatile libtest_random_pattern;
 extern volatile size_t libtest_random_pattern_length;
 extern volatile size_t libtest_random_pattern_offset;
diff --git a/libtest/libtest_alloc.c b/libtest/libtest_alloc.c
index 96aa132..022881a 100644
--- a/libtest/libtest_alloc.c
+++ b/libtest/libtest_alloc.c
@@ -53,8 +53,8 @@ mmap_anon(size_t size)
 }
 
 
-void *
-libtest_alloc(struct meminfo *meminfo)
+static void *
+try_alloc(struct meminfo *meminfo)
 {
 	static _Thread_local int recursion_guard = 0;
 	void *base_ptr, *ret_ptr;
@@ -206,6 +206,60 @@ libtest_alloc(struct meminfo *meminfo)
 }
 
 
+void *
+libtest_alloc(struct meminfo *meminfo)
+{
+	void *ptr;
+	size_t reqsize;
+	ptr = try_alloc(meminfo);
+	if (!ptr && libtest_pretend_allocation_successful) {
+		reqsize = meminfo->requested_alloc_size;
+		meminfo->requested_alloc_size = 0u;
+		ptr = try_alloc(meminfo);
+		assert(ptr != NULL);
+		meminfo->requested_alloc_size = reqsize;
+		GET_MEMINFO(ptr)->requested_alloc_size = reqsize;
+		SPINLOCK(libtest_allocs_list_spinlock);
+		if (libtest_npretends >= ELEMSOF(libtest_pretend_list))
+			SPINUNLOCK(libtest_allocs_list_spinlock);
+		assert(libtest_npretends < ELEMSOF(libtest_pretend_list));
+		libtest_pretend_list[libtest_npretends++] = ptr;
+		SPINUNLOCK(libtest_allocs_list_spinlock);
+	}
+	return ptr;
+}
+
+
+void *
+(memset)(void *s, int c, size_t n)
+{
+	unsigned char *us = s, uc = (unsigned char)c;
+	size_t i;
+
+	SPINLOCK(libtest_allocs_list_spinlock);
+	for (i = 0u; i < libtest_npretends; i++) {
+		if (libtest_pretend_list[i] == s) {
+			/* We only do this for pointers in the pretend list
+			 * because we must know that it is actually a
+			 * pointer created with libtest_alloc, and not
+			 * mmap(2) or stack-allocated or statically
+			 * allocated buffer; and that's why libtest_pretend_list
+			 * exist instead of being inferred or a flag. */
+			if (n > GET_MEMINFO(s)->usable_alloc_size)
+				n = GET_MEMINFO(s)->usable_alloc_size;
+			break;
+		}
+	}
+	SPINUNLOCK(libtest_allocs_list_spinlock);
+
+	for (i = 0u; i < n; i++)
+		us[i] = uc;
+
+	return us;
+}
+
+
+
 #else
 
 
diff --git a/libtest/libtest_free.c b/libtest/libtest_free.c
index 5592e0a..d46218e 100644
--- a/libtest/libtest_free.c
+++ b/libtest/libtest_free.c
@@ -39,12 +39,18 @@ libtest_free(void *ptr, enum libtest_zero_check zero_checking)
 	assert(mem->origin != FROM_MMAP_ANON);
 
 	/* Delist allocation */
+	SPINLOCK(libtest_allocs_list_spinlock);
 	if (!libtest_kill_malloc_tracking) {
-		SPINLOCK(libtest_allocs_list_spinlock);
 		mem->prev->next = mem->next;
 		mem->next->prev = mem->prev;
-		SPINUNLOCK(libtest_allocs_list_spinlock);
 	}
+	for (i = 0u; i < libtest_npretends; i++) {
+		if (libtest_pretend_list[i] == ptr) {
+			libtest_pretend_list[i] = libtest_pretend_list[--libtest_npretends];
+			break;
+		}
+	}
+	SPINUNLOCK(libtest_allocs_list_spinlock);
 
 	/* Check memory is zeroed */
 	if (zero_checking && libtest_expect_zeroed && !mem->accept_leakage) {
diff --git a/libtest/mmap.c b/libtest/mmap.c
index c3b3067..3bd3cb3 100644
--- a/libtest/mmap.c
+++ b/libtest/mmap.c
@@ -8,7 +8,7 @@
 
 
 #ifdef SYS_mmap2
-# define IF_MMAP2(A) (A)
+# define IF_MMAP2(A) do { A; } while (0)
 #else
 # define IF_MMAP2(A) ((void)0)
 #endif