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authorFred Fish <fnf@specifix.com>1992-04-17 03:01:54 +0000
committerFred Fish <fnf@specifix.com>1992-04-17 03:01:54 +0000
commit13b33d2b0a53a588bbec6e9ab9946d40947a84b1 (patch)
treea9bba09ddaf1f4132b14bbe46fb42865aad1cdc5
parent2d6d969c616d286076df1778db0d06a64f11251a (diff)
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* TODO: New file.
* attach.c, mcalloc.c, mfree.c, mmalloc.c, mmalloc.h, mmap-sup.c, mmcheck.c, mtrace.c, mrealloc.c, mvalloc.c, sbrk-sup.c: Lint.
-rw-r--r--mmalloc/TODO15
-rw-r--r--mmalloc/sbrk-sup.c69
2 files changed, 84 insertions, 0 deletions
diff --git a/mmalloc/TODO b/mmalloc/TODO
new file mode 100644
index 0000000..46bccc2
--- /dev/null
+++ b/mmalloc/TODO
@@ -0,0 +1,15 @@
+(1) Make implementation changes necessary to allow multiple processes
+ to use the mmalloc managed region simultaneously. This requires,
+ at the minimum, some sort of cooperative locking that ensures that
+ only one process at a time is changing any of the mmalloc managed
+ data structures (its ok for the mmalloc managed data regions to be
+ changed at any time since we don't care about their contents).
+
+(2) In order to support multiple processes using the mmalloc managed
+ region, the malloc descriptor needs to be broken into two parts,
+ one part which is specific to the given process and is maintained
+ separately on a per process basis, and another part which is common
+ to all processes. As an example, the file descriptor is specific
+ to a given process, as are the morecore and abortfunc pointers.
+ However magic[], the version number, the flags field, etc are
+ common to all processes.
diff --git a/mmalloc/sbrk-sup.c b/mmalloc/sbrk-sup.c
new file mode 100644
index 0000000..f6efa17
--- /dev/null
+++ b/mmalloc/sbrk-sup.c
@@ -0,0 +1,69 @@
+/* Support for sbrk() regions.
+ Copyright 1992 Free Software Foundation, Inc.
+ Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+
+#include <string.h> /* Prototypes for memcpy, memmove, memset, etc */
+
+#include "mmalloc.h"
+
+extern PTR sbrk ();
+
+/* The mmalloc() package can use a single implicit malloc descriptor
+ for mmalloc/mrealloc/mfree operations which do not supply an explicit
+ descriptor. For these operations, sbrk() is used to obtain more core
+ from the system, or return core. This allows mmalloc() to provide
+ backwards compatibility with the non-mmap'd version. */
+
+struct mdesc *__mmalloc_default_mdp;
+
+/* Use sbrk() to get more core. */
+
+static PTR
+sbrk_morecore (mdp, size)
+ struct mdesc *mdp;
+ int size;
+{
+ PTR result;
+
+ if ((result = sbrk (size)) != NULL)
+ {
+ mdp -> breakval += size;
+ mdp -> top += size;
+ }
+ return (result);
+}
+
+/* Initialize the default malloc descriptor if this is the first time
+ a request has been made to use the default sbrk'd region. */
+
+struct mdesc *
+__mmalloc_sbrk_init ()
+{
+ PTR base;
+
+ base = sbrk (0);
+ __mmalloc_default_mdp = (struct mdesc *) sbrk (sizeof (struct mdesc));
+ (void) memset ((char *) __mmalloc_default_mdp, 0, sizeof (struct mdesc));
+ __mmalloc_default_mdp -> morecore = sbrk_morecore;
+ __mmalloc_default_mdp -> base = base;
+ __mmalloc_default_mdp -> breakval = __mmalloc_default_mdp -> top = sbrk (0);
+ __mmalloc_default_mdp -> fd = -1;
+ return (__mmalloc_default_mdp);
+}
+
+