add recaloc(3)

3 files changed, 62 insertions, 20 deletions

diff --git a/src/lib/libc/stdlib/Makefile.inc b/src/lib/libc/stdlib/Makefile.inc
index c7ee0a80ec..04e84fe941 100644
--- a/src/lib/libc/stdlib/Makefile.inc
+++ b/src/lib/libc/stdlib/Makefile.inc
@@ -1,4 +1,4 @@
-#       $OpenBSD: Makefile.inc,v 1.35 2006/01/13 17:58:09 millert Exp $
+#       $OpenBSD: Makefile.inc,v 1.36 2007/09/03 14:37:02 millert Exp $
 
 # stdlib sources
 .PATH: ${LIBCSRCDIR}/arch/${MACHINE_ARCH}/stdlib ${LIBCSRCDIR}/stdlib
@@ -55,7 +55,7 @@ MLINKS+=insque.3 remque.3
 MLINKS+=labs.3 llabs.3
 MLINKS+=lsearch.3 lfind.3
 MLINKS+=malloc.3 free.3 malloc.3 realloc.3 malloc.3 calloc.3
-MLINKS+=malloc.3 cfree.3 malloc.3 malloc.conf.5
+MLINKS+=malloc.3 recalloc.3 malloc.3 cfree.3 malloc.3 malloc.conf.5
 MLINKS+=qsort.3 heapsort.3 qsort.3 mergesort.3
 MLINKS+=radixsort.3 sradixsort.3
 MLINKS+=rand.3 srand.3 rand.3 rand_r.3
diff --git a/src/lib/libc/stdlib/malloc.3 b/src/lib/libc/stdlib/malloc.3
index 35f83a0c24..4c5ea84c08 100644
--- a/src/lib/libc/stdlib/malloc.3
+++ b/src/lib/libc/stdlib/malloc.3
@@ -30,15 +30,16 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"     $OpenBSD: malloc.3,v 1.47 2007/08/08 21:24:29 millert Exp $
+.\"     $OpenBSD: malloc.3,v 1.48 2007/09/03 14:37:02 millert Exp $
 .\"
-.Dd $Mdocdate: August 8 2007 $
+.Dd $Mdocdate: September 3 2007 $
 .Dt MALLOC 3
 .Os
 .Sh NAME
 .Nm malloc ,
 .Nm calloc ,
 .Nm realloc ,
+.Nm recalloc ,
 .Nm free ,
 .Nm cfree
 .Nd memory allocation and deallocation
@@ -50,6 +51,8 @@
 .Fn calloc "size_t nmemb" "size_t size"
 .Ft void *
 .Fn realloc "void *ptr" "size_t size"
+.Ft void *
+.Fn recalloc "void *ptr" "size_t nmemb" "size_t size"
 .Ft void
 .Fn free "void *ptr"
 .Ft void
@@ -203,7 +206,18 @@ if ((newp = realloc(p, num * size)) == NULL) {
         ...
 .Ed
 .Pp
-Malloc will first look for a symbolic link called
+The
+.Fn recalloc
+function is similar to
+.Fn realloc
+except that it shares semantics with
+.Fn calloc
+rather than
+.Fn malloc .
+Newly allocated space is initialized to zero and the resulting size is
+checked for integer overflow.
+.Pp
+These functions will first look for a symbolic link called
 .Pa /etc/malloc.conf
 and next check the environment for a variable called
 .Ev MALLOC_OPTIONS
@@ -258,6 +272,8 @@ sizeof(ptr) errors where sizeof(*ptr) is meant.
 .Dq realloc .
 Always reallocate when
 .Fn realloc
+or
+.Fn recalloc
 is called, even if the initial allocation was big enough.
 This can substantially aid in compacting memory.
 .\".Pp
@@ -440,6 +456,12 @@ The
 .Fn malloc
 function conforms to
 .St -ansiC .
+.Pp
+The
+.Fn recalloc
+function is an
+.Ox
+extension.
 .Sh HISTORY
 The present implementation of
 .Fn malloc
diff --git a/src/lib/libc/stdlib/malloc.c b/src/lib/libc/stdlib/malloc.c
index 67f5de512e..08b8a088d0 100644
--- a/src/lib/libc/stdlib/malloc.c
+++ b/src/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: malloc.c,v 1.86 2007/02/12 20:00:14 otto Exp $        */
+/*      $OpenBSD: malloc.c,v 1.87 2007/09/03 14:37:02 millert Exp $     */
 
 /*
  * ----------------------------------------------------------------------------
@@ -250,9 +250,9 @@ static char	*malloc_func;
 /*
  * Necessary function declarations.
  */
-static void     *imalloc(size_t size);
+static void     *imalloc(size_t size, int zero_fill);
 static void     ifree(void *ptr);
-static void     *irealloc(void *ptr, size_t size);
+static void     *irealloc(void *ptr, size_t size, int zero_fill);
 static void     *malloc_bytes(size_t size);
 
 static struct pginfo *pginfo_list;
@@ -1188,7 +1188,7 @@ malloc_bytes(size_t size)
  * Allocate a piece of memory
  */
 static void *
-imalloc(size_t size)
+imalloc(size_t size, int zero_fill)
 {
         void            *result;
         int             ptralloc = 0;
@@ -1218,7 +1218,7 @@ imalloc(size_t size)
         if (malloc_abort == 1 && result == NULL)
                 wrterror("allocation failed");
 
-        if (malloc_zero && result != NULL)
+        if ((malloc_zero || zero_fill) && result != NULL)
                 memset(result, 0, size);
 
         if (result && ptralloc)
@@ -1230,7 +1230,7 @@ imalloc(size_t size)
  * Change the size of an allocation.
  */
 static void *
-irealloc(void *ptr, size_t size)
+irealloc(void *ptr, size_t size, int zero_fill)
 {
         void            *p;
         size_t          osize;
@@ -1253,7 +1253,7 @@ irealloc(void *ptr, size_t size)
                 if (size <= PTR_SIZE)
                         return (ptr);
 
-                p = imalloc(size);
+                p = imalloc(size, zero_fill);
                 if (p)
                         memcpy(p, ptr, PTR_SIZE);
                 ifree(ptr);
@@ -1315,7 +1315,9 @@ irealloc(void *ptr, size_t size)
 
                 if (!malloc_realloc && size <= osize &&
                     size > osize - malloc_pagesize) {
-                        if (malloc_junk)
+                        if (zero_fill)
+                                memset((char *)ptr + size, 0, osize - size);
+                        else if (malloc_junk)
                                 memset((char *)ptr + size, SOME_JUNK, osize - size);
                         return (ptr);   /* ..don't do anything else. */
                 }
@@ -1338,7 +1340,9 @@ irealloc(void *ptr, size_t size)
 
                 if (!malloc_realloc && size <= osize &&
                     (size > osize / 2 || osize == malloc_minsize)) {
-                        if (malloc_junk)
+                        if (zero_fill)
+                                memset((char *) ptr + size, 0, osize - size);
+                        else if (malloc_junk)
                                 memset((char *) ptr + size, SOME_JUNK, osize - size);
                         return (ptr);   /* ..don't do anything else. */
                 }
@@ -1347,7 +1351,7 @@ irealloc(void *ptr, size_t size)
                 return (NULL);
         }
 
-        p = imalloc(size);
+        p = imalloc(size, zero_fill);
 
         if (p != NULL) {
                 /* copy the lesser of the two sizes, and free the old one */
@@ -1876,7 +1880,7 @@ malloc(size_t size)
                 malloc_recurse();
                 return (NULL);
         }
-        r = imalloc(size);
+        r = imalloc(size, 0);
         UTRACE(0, size, r);
         malloc_active--;
         _MALLOC_UNLOCK();
@@ -1907,8 +1911,8 @@ free(void *ptr)
         return;
 }
 
-void *
-realloc(void *ptr, size_t size)
+static void *
+_realloc(void *ptr, size_t size, int zero_fill)
 {
         void            *r;
 
@@ -1920,9 +1924,9 @@ realloc(void *ptr, size_t size)
         }
 
         if (ptr == NULL)
-                r = imalloc(size);
+                r = imalloc(size, zero_fill);
         else
-                r = irealloc(ptr, size);
+                r = irealloc(ptr, size, zero_fill);
 
         UTRACE(ptr, size, r);
         malloc_active--;
@@ -1933,3 +1937,19 @@ realloc(void *ptr, size_t size)
         }
         return (r);
 }
+
+void *
+realloc(void *ptr, size_t size)
+{
+        return (_realloc(ptr, size, 0));
+}
+
+void *
+recalloc(void *ptr, size_t nmemb, size_t size)
+{
+        if (nmemb && SIZE_MAX / nmemb < size) {
+                errno = ENOMEM;
+                return (NULL);
+        }
+        return (_realloc(ptr, nmemb * size, 1));
+}