initial import of NetBSD tree

1 files changed, 421 insertions, 0 deletions

diff --git a/src/lib/libc/stdlib/malloc.c b/src/lib/libc/stdlib/malloc.c
new file mode 100644
index 0000000000..3c57fad024
--- /dev/null
+++ b/src/lib/libc/stdlib/malloc.c
@@ -0,0 +1,421 @@
+/*
+ * Copyright (c) 1983 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by the University of
+ *      California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+/*static char *sccsid = "from: @(#)malloc.c     5.11 (Berkeley) 2/23/91";*/
+static char *rcsid = "$Id: malloc.c,v 1.1.1.1 1995/10/18 08:42:18 deraadt Exp $";
+#endif /* LIBC_SCCS and not lint */
+
+/*
+ * malloc.c (Caltech) 2/21/82
+ * Chris Kingsley, kingsley@cit-20.
+ *
+ * This is a very fast storage allocator.  It allocates blocks of a small 
+ * number of different sizes, and keeps free lists of each size.  Blocks that
+ * don't exactly fit are passed up to the next larger size.  In this 
+ * implementation, the available sizes are 2^n-4 (or 2^n-10) bytes long.
+ * This is designed for use in a virtual memory environment.
+ */
+
+#include <sys/types.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define NULL 0
+
+static void morecore();
+static int findbucket();
+
+/*
+ * The overhead on a block is at least 4 bytes.  When free, this space
+ * contains a pointer to the next free block, and the bottom two bits must
+ * be zero.  When in use, the first byte is set to MAGIC, and the second
+ * byte is the size index.  The remaining bytes are for alignment.
+ * If range checking is enabled then a second word holds the size of the
+ * requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
+ * The order of elements is critical: ov_magic must overlay the low order
+ * bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
+ */
+union   overhead {
+        union   overhead *ov_next;      /* when free */
+        struct {
+                u_char  ovu_magic;      /* magic number */
+                u_char  ovu_index;      /* bucket # */
+#ifdef RCHECK
+                u_short ovu_rmagic;     /* range magic number */
+                u_long  ovu_size;       /* actual block size */
+#endif
+        } ovu;
+#define ov_magic        ovu.ovu_magic
+#define ov_index        ovu.ovu_index
+#define ov_rmagic       ovu.ovu_rmagic
+#define ov_size         ovu.ovu_size
+};
+
+#define MAGIC           0xef            /* magic # on accounting info */
+#define RMAGIC          0x5555          /* magic # on range info */
+
+#ifdef RCHECK
+#define RSLOP           sizeof (u_short)
+#else
+#define RSLOP           0
+#endif
+
+/*
+ * nextf[i] is the pointer to the next free block of size 2^(i+3).  The
+ * smallest allocatable block is 8 bytes.  The overhead information
+ * precedes the data area returned to the user.
+ */
+#define NBUCKETS 30
+static  union overhead *nextf[NBUCKETS];
+extern  char *sbrk();
+
+static  int pagesz;                     /* page size */
+static  int pagebucket;                 /* page size bucket */
+
+#ifdef MSTATS
+/*
+ * nmalloc[i] is the difference between the number of mallocs and frees
+ * for a given block size.
+ */
+static  u_int nmalloc[NBUCKETS];
+#include <stdio.h>
+#endif
+
+#if defined(DEBUG) || defined(RCHECK)
+#define ASSERT(p)   if (!(p)) botch("p")
+#include <stdio.h>
+static
+botch(s)
+        char *s;
+{
+        fprintf(stderr, "\r\nassertion botched: %s\r\n", s);
+        (void) fflush(stderr);          /* just in case user buffered it */
+        abort();
+}
+#else
+#define ASSERT(p)
+#endif
+
+void *
+malloc(nbytes)
+        size_t nbytes;
+{
+        register union overhead *op;
+        register long bucket, n;
+        register unsigned amt;
+
+        /*
+         * First time malloc is called, setup page size and
+         * align break pointer so all data will be page aligned.
+         */
+        if (pagesz == 0) {
+                pagesz = n = getpagesize();
+                op = (union overhead *)sbrk(0);
+                n = n - sizeof (*op) - ((long)op & (n - 1));
+                if (n < 0)
+                        n += pagesz;
+                if (n) {
+                        if (sbrk(n) == (char *)-1)
+                                return (NULL);
+                }
+                bucket = 0;
+                amt = 8;
+                while (pagesz > amt) {
+                        amt <<= 1;
+                        bucket++;
+                }
+                pagebucket = bucket;
+        }
+        /*
+         * Convert amount of memory requested into closest block size
+         * stored in hash buckets which satisfies request.
+         * Account for space used per block for accounting.
+         */
+        if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
+#ifndef RCHECK
+                amt = 8;        /* size of first bucket */
+                bucket = 0;
+#else
+                amt = 16;       /* size of first bucket */
+                bucket = 1;
+#endif
+                n = -((long)sizeof (*op) + RSLOP);
+        } else {
+                amt = pagesz;
+                bucket = pagebucket;
+        }
+        while (nbytes > amt + n) {
+                amt <<= 1;
+                if (amt == 0)
+                        return (NULL);
+                bucket++;
+        }
+        /*
+         * If nothing in hash bucket right now,
+         * request more memory from the system.
+         */
+        if ((op = nextf[bucket]) == NULL) {
+                morecore(bucket);
+                if ((op = nextf[bucket]) == NULL)
+                        return (NULL);
+        }
+        /* remove from linked list */
+        nextf[bucket] = op->ov_next;
+        op->ov_magic = MAGIC;
+        op->ov_index = bucket;
+#ifdef MSTATS
+        nmalloc[bucket]++;
+#endif
+#ifdef RCHECK
+        /*
+         * Record allocated size of block and
+         * bound space with magic numbers.
+         */
+        op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
+        op->ov_rmagic = RMAGIC;
+        *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
+#endif
+        return ((char *)(op + 1));
+}
+
+/*
+ * Allocate more memory to the indicated bucket.
+ */
+static void
+morecore(bucket)
+        int bucket;
+{
+        register union overhead *op;
+        register long sz;               /* size of desired block */
+        long amt;                       /* amount to allocate */
+        int nblks;                      /* how many blocks we get */
+
+        /*
+         * sbrk_size <= 0 only for big, FLUFFY, requests (about
+         * 2^30 bytes on a VAX, I think) or for a negative arg.
+         */
+        sz = 1 << (bucket + 3);
+#ifdef DEBUG
+        ASSERT(sz > 0);
+#else
+        if (sz <= 0)
+                return;
+#endif
+        if (sz < pagesz) {
+                amt = pagesz;
+                nblks = amt / sz;
+        } else {
+                amt = sz + pagesz;
+                nblks = 1;
+        }
+        op = (union overhead *)sbrk(amt);
+        /* no more room! */
+        if ((long)op == -1)
+                return;
+        /*
+         * Add new memory allocated to that on
+         * free list for this hash bucket.
+         */
+        nextf[bucket] = op;
+        while (--nblks > 0) {
+                op->ov_next = (union overhead *)((caddr_t)op + sz);
+                op = (union overhead *)((caddr_t)op + sz);
+        }
+}
+
+void
+free(cp)
+        void *cp;
+{   
+        register long size;
+        register union overhead *op;
+
+        if (cp == NULL)
+                return;
+        op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
+#ifdef DEBUG
+        ASSERT(op->ov_magic == MAGIC);          /* make sure it was in use */
+#else
+        if (op->ov_magic != MAGIC)
+                return;                         /* sanity */
+#endif
+#ifdef RCHECK
+        ASSERT(op->ov_rmagic == RMAGIC);
+        ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
+#endif
+        size = op->ov_index;
+        ASSERT(size < NBUCKETS);
+        op->ov_next = nextf[size];      /* also clobbers ov_magic */
+        nextf[size] = op;
+#ifdef MSTATS
+        nmalloc[size]--;
+#endif
+}
+
+/*
+ * When a program attempts "storage compaction" as mentioned in the
+ * old malloc man page, it realloc's an already freed block.  Usually
+ * this is the last block it freed; occasionally it might be farther
+ * back.  We have to search all the free lists for the block in order
+ * to determine its bucket: 1st we make one pass thru the lists
+ * checking only the first block in each; if that fails we search
+ * ``realloc_srchlen'' blocks in each list for a match (the variable
+ * is extern so the caller can modify it).  If that fails we just copy
+ * however many bytes was given to realloc() and hope it's not huge.
+ */
+int realloc_srchlen = 4;        /* 4 should be plenty, -1 =>'s whole list */
+
+void *
+realloc(cp, nbytes)
+        void *cp; 
+        size_t nbytes;
+{   
+        register u_long onb;
+        register long i;
+        union overhead *op;
+        char *res;
+        int was_alloced = 0;
+
+        if (cp == NULL)
+                return (malloc(nbytes));
+        op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
+        if (op->ov_magic == MAGIC) {
+                was_alloced++;
+                i = op->ov_index;
+        } else {
+                /*
+                 * Already free, doing "compaction".
+                 *
+                 * Search for the old block of memory on the
+                 * free list.  First, check the most common
+                 * case (last element free'd), then (this failing)
+                 * the last ``realloc_srchlen'' items free'd.
+                 * If all lookups fail, then assume the size of
+                 * the memory block being realloc'd is the
+                 * largest possible (so that all "nbytes" of new
+                 * memory are copied into).  Note that this could cause
+                 * a memory fault if the old area was tiny, and the moon
+                 * is gibbous.  However, that is very unlikely.
+                 */
+                if ((i = findbucket(op, 1)) < 0 &&
+                    (i = findbucket(op, realloc_srchlen)) < 0)
+                        i = NBUCKETS;
+        }
+        onb = 1 << (i + 3);
+        if (onb < pagesz)
+                onb -= sizeof (*op) + RSLOP;
+        else
+                onb += pagesz - sizeof (*op) - RSLOP;
+        /* avoid the copy if same size block */
+        if (was_alloced) {
+                if (i) {
+                        i = 1 << (i + 2);
+                        if (i < pagesz)
+                                i -= sizeof (*op) + RSLOP;
+                        else
+                                i += pagesz - sizeof (*op) - RSLOP;
+                }
+                if (nbytes <= onb && nbytes > i) {
+#ifdef RCHECK
+                        op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
+                        *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
+#endif
+                        return(cp);
+                } else
+                        free(cp);
+        }
+        if ((res = malloc(nbytes)) == NULL)
+                return (NULL);
+        if (cp != res)          /* common optimization if "compacting" */
+                bcopy(cp, res, (nbytes < onb) ? nbytes : onb);
+        return (res);
+}
+
+/*
+ * Search ``srchlen'' elements of each free list for a block whose
+ * header starts at ``freep''.  If srchlen is -1 search the whole list.
+ * Return bucket number, or -1 if not found.
+ */
+static
+findbucket(freep, srchlen)
+        union overhead *freep;
+        int srchlen;
+{
+        register union overhead *p;
+        register int i, j;
+
+        for (i = 0; i < NBUCKETS; i++) {
+                j = 0;
+                for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
+                        if (p == freep)
+                                return (i);
+                        j++;
+                }
+        }
+        return (-1);
+}
+
+#ifdef MSTATS
+/*
+ * mstats - print out statistics about malloc
+ * 
+ * Prints two lines of numbers, one showing the length of the free list
+ * for each size category, the second showing the number of mallocs -
+ * frees for each size category.
+ */
+mstats(s)
+        char *s;
+{
+        register int i, j;
+        register union overhead *p;
+        int totfree = 0,
+        totused = 0;
+
+        fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s);
+        for (i = 0; i < NBUCKETS; i++) {
+                for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
+                        ;
+                fprintf(stderr, " %d", j);
+                totfree += j * (1 << (i + 3));
+        }
+        fprintf(stderr, "\nused:\t");
+        for (i = 0; i < NBUCKETS; i++) {
+                fprintf(stderr, " %d", nmalloc[i]);
+                totused += nmalloc[i] * (1 << (i + 3));
+        }
+        fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n",
+            totused, totfree);
+}
+#endif