Allow je_malloc_message to be overridden when linking statically

[Mike Hommey]

From: Mike Hommey <mh at glandium.org>

If an application wants to override je_malloc_message, it is better to define
the symbol locally than to change its value in main(), which might be too late
for various reasons.

Due to je_malloc_message being initialized in util.c, statically linking
jemalloc with an application defining je_malloc_message fails due to
"multiple definition of" the symbol.

Defining it without a value (like je_malloc_conf) makes it more easily
overridable.
---
 src/stats.c |   22 +++++++---------------
 src/util.c  |   10 ++++++----
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/src/stats.c b/src/stats.c
index 2854b30..1234e56 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -295,16 +295,6 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 		abort();
 	}
 
-	if (write_cb == NULL) {
-		/*
-		 * The caller did not provide an alternate write_cb callback
-		 * function, so use the default one.  malloc_write() is an
-		 * inline function, so use malloc_message() directly here.
-		 */
-		write_cb = je_malloc_message;
-		cbopaque = NULL;
-	}
-
 	if (opts != NULL) {
 		unsigned i;
 
@@ -330,7 +320,8 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 		}
 	}
 
-	write_cb(cbopaque, "___ Begin jemalloc statistics ___\n");
+	malloc_cprintf(write_cb, cbopaque,
+	    "___ Begin jemalloc statistics ___\n");
 	if (general) {
 		int err;
 		const char *cpv;
@@ -375,7 +366,8 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 			    "  opt."#n": \"%s\"\n", cpv);		\
 		}
 
-		write_cb(cbopaque, "Run-time option settings:\n");
+		malloc_cprintf(write_cb, cbopaque,
+		    "Run-time option settings:\n");
 		OPT_WRITE_BOOL(abort)
 		OPT_WRITE_SIZE_T(lg_chunk)
 		OPT_WRITE_SIZE_T(narenas)
@@ -425,7 +417,7 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 			    "Min active:dirty page ratio per arena: %u:1\n",
 			    (1U << ssv));
 		} else {
-			write_cb(cbopaque,
+			malloc_cprintf(write_cb, cbopaque,
 			    "Min active:dirty page ratio per arena: N/A\n");
 		}
 		if ((err = je_mallctl("arenas.tcache_max", &sv, &ssz, NULL, 0))
@@ -447,7 +439,7 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 				    " (2^%zd)\n",
 				    (((uint64_t)1U) << ssv), ssv);
 			} else {
-				write_cb(cbopaque,
+				malloc_cprintf(write_cb, cbopaque,
 				    "Average profile dump interval: N/A\n");
 			}
 		}
@@ -547,5 +539,5 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 			}
 		}
 	}
-	write_cb(cbopaque, "--- End jemalloc statistics ---\n");
+	malloc_cprintf(write_cb, cbopaque, "--- End jemalloc statistics ---\n");
 }
diff --git a/src/util.c b/src/util.c
index 4f71695..aa65621 100644
--- a/src/util.c
+++ b/src/util.c
@@ -56,8 +56,7 @@ wrtmessage(void *cbopaque, const char *s)
 #endif
 }
 
-JEMALLOC_EXPORT void	(*je_malloc_message)(void *, const char *s) =
-    wrtmessage;
+JEMALLOC_EXPORT void	(*je_malloc_message)(void *, const char *s);
 
 /*
  * Wrapper around malloc_message() that avoids the need for
@@ -67,7 +66,10 @@ void
 malloc_write(const char *s)
 {
 
-	je_malloc_message(NULL, s);
+	if (je_malloc_message)
+		je_malloc_message(NULL, s);
+	else
+		wrtmessage(NULL, s);
 }
 
 /*
@@ -606,7 +608,7 @@ malloc_vcprintf(void (*write_cb)(void *, const char *), void *cbopaque,
 		 * function, so use the default one.  malloc_write() is an
 		 * inline function, so use malloc_message() directly here.
 		 */
-		write_cb = je_malloc_message;
+		write_cb = je_malloc_message ? je_malloc_message : wrtmessage;
 		cbopaque = NULL;
 	}
 
-- 
1.7.10