X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=liblttng-ust-libc-wrapper%2Flttng-ust-malloc.c;h=33ed18be09d5ea48eb5f0cabd73ce27ca151da46;hb=86a4e97112c40b1ec823c60de8138d6bb55262fe;hp=3212ff0bacca50f7e8511977ce66b708113f3c81;hpb=476037d9a24fdd5e339e3565743aadb9cb8a0a96;p=lttng-ust.git

diff --git a/liblttng-ust-libc-wrapper/lttng-ust-malloc.c b/liblttng-ust-libc-wrapper/lttng-ust-malloc.c
index 3212ff0b..33ed18be 100644
--- a/liblttng-ust-libc-wrapper/lttng-ust-malloc.c
+++ b/liblttng-ust-libc-wrapper/lttng-ust-malloc.c
@@ -21,14 +21,42 @@
 #include <dlfcn.h>
 #include <sys/types.h>
 #include <stdio.h>
+#include <urcu/system.h>
+#include <urcu/uatomic.h>
 
 #define TRACEPOINT_DEFINE
 #define TRACEPOINT_CREATE_PROBES
 #include "ust_libc.h"
 
+#define STATIC_CALLOC_LEN 4096
+static char static_calloc_buf[STATIC_CALLOC_LEN];
+static unsigned long static_calloc_buf_offset;
+
+static void *static_calloc(size_t nmemb, size_t size)
+{
+	unsigned long prev_offset, new_offset, res_offset;
+
+	/*
+	 * Protect static_calloc_buf_offset from concurrent updates
+	 * using a cmpxchg loop rather than a mutex to remove a
+	 * dependency on pthread. This will minimize the risk of bad
+	 * interaction between mutex and malloc instrumentation.
+	 */
+	res_offset = CMM_LOAD_SHARED(static_calloc_buf_offset);
+	do {
+		prev_offset = res_offset;
+		if (nmemb * size > sizeof(static_calloc_buf) - prev_offset) {
+			return NULL;
+		}
+		new_offset = prev_offset + nmemb * size;
+	} while ((res_offset = uatomic_cmpxchg(&static_calloc_buf_offset,
+			prev_offset, new_offset)) != prev_offset);
+	return &static_calloc_buf[prev_offset];
+}
+
 void *malloc(size_t size)
 {
-	static void *(*plibc_malloc)(size_t size) = NULL;
+	static void *(*plibc_malloc)(size_t size);
 	void *retval;
 
 	if (plibc_malloc == NULL) {
@@ -45,7 +73,16 @@ void *malloc(size_t size)
 
 void free(void *ptr)
 {
-	static void *(*plibc_free)(void *ptr) = NULL;
+	static void (*plibc_free)(void *ptr);
+
+	/* Check whether the memory was allocated with
+	 * static_calloc, in which case there is nothing
+	 * to free.
+	 */
+	if ((char *)ptr >= static_calloc_buf &&
+	    (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN) {
+		return;
+	}
 
 	if (plibc_free == NULL) {
 		plibc_free = dlsym(RTLD_NEXT, "free");
@@ -57,3 +94,76 @@ void free(void *ptr)
 	tracepoint(ust_libc, free, ptr);
 	plibc_free(ptr);
 }
+
+void *calloc(size_t nmemb, size_t size)
+{
+	static void *(*volatile plibc_calloc)(size_t nmemb, size_t size);
+	void *retval;
+
+	if (plibc_calloc == NULL) {
+		/*
+		 * Temporarily redirect to static_calloc,
+		 * until the dlsym lookup has completed.
+		 */
+		plibc_calloc = static_calloc;
+		plibc_calloc = dlsym(RTLD_NEXT, "calloc");
+		if (plibc_calloc == NULL) {
+			fprintf(stderr, "callocwrap: unable to find calloc\n");
+			return NULL;
+		}
+	}
+	retval = plibc_calloc(nmemb, size);
+	tracepoint(ust_libc, calloc, nmemb, size, retval);
+	return retval;
+}
+
+void *realloc(void *ptr, size_t size)
+{
+	static void *(*plibc_realloc)(void *ptr, size_t size);
+	void *retval;
+
+	if (plibc_realloc == NULL) {
+		plibc_realloc = dlsym(RTLD_NEXT, "realloc");
+		if (plibc_realloc == NULL) {
+			fprintf(stderr, "reallocwrap: unable to find realloc\n");
+			return NULL;
+		}
+	}
+	retval = plibc_realloc(ptr, size);
+	tracepoint(ust_libc, realloc, ptr, size, retval);
+	return retval;
+}
+
+void *memalign(size_t alignment, size_t size)
+{
+	static void *(*plibc_memalign)(size_t alignment, size_t size);
+	void *retval;
+
+	if (plibc_memalign == NULL) {
+		plibc_memalign = dlsym(RTLD_NEXT, "memalign");
+		if (plibc_memalign == NULL) {
+			fprintf(stderr, "memalignwrap: unable to find memalign\n");
+			return NULL;
+		}
+	}
+	retval = plibc_memalign(alignment, size);
+	tracepoint(ust_libc, memalign, alignment, size, retval);
+	return retval;
+}
+
+int posix_memalign(void **memptr, size_t alignment, size_t size)
+{
+	static int(*plibc_posix_memalign)(void **memptr, size_t alignment, size_t size);
+	int retval;
+
+	if (plibc_posix_memalign == NULL) {
+		plibc_posix_memalign = dlsym(RTLD_NEXT, "posix_memalign");
+		if (plibc_posix_memalign == NULL) {
+			fprintf(stderr, "posix_memalignwrap: unable to find posix_memalign\n");
+			return ENOMEM;
+		}
+	}
+	retval = plibc_posix_memalign(memptr, alignment, size);
+	tracepoint(ust_libc, posix_memalign, *memptr, alignment, size, retval);
+	return retval;
+}