[newlib-cygwin] search: Fix Berkeley DB hash code for 16-bit targets.

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=bd993df0e6aee5080a791b54cb0074ad76bab681

commit bd993df0e6aee5080a791b54cb0074ad76bab681
Author: Jon Beniston <jon@beniston.com>
Date:   Thu Sep 6 13:53:15 2018 +0100

    search: Fix Berkeley DB hash code for 16-bit targets.
    
    hash.h: Use 32-bit type for data stored on disk, so code
    works for 16 and 64-bit targets. Reduce maximum bucket size on 16-bit
    targets, so it fits in available memory.
    hash.c: Check bucket size isn't too big for target.
    hash_buf.c: Fix overflow warning on 16-bit targets.

Diff:
---
 newlib/libc/search/hash.c     |  5 ++++-
 newlib/libc/search/hash.h     | 45 ++++++++++++++++++++++++++-----------------
 newlib/libc/search/hash_buf.c |  2 +-
 3 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/newlib/libc/search/hash.c b/newlib/libc/search/hash.c
index af2be9a..e409618 100644
--- a/newlib/libc/search/hash.c
+++ b/newlib/libc/search/hash.c
@@ -193,6 +193,9 @@ __hash_open (const char *file,
 			RETURN_ERROR(EFTYPE, error1);
 		if (hashp->hash(CHARKEY, sizeof(CHARKEY)) != hashp->H_CHARKEY)
 			RETURN_ERROR(EFTYPE, error1);
+                /* Check bucket size isn't too big for target int. */
+                if (hashp->BSIZE > INT_MAX)
+                        RETURN_ERROR(EFTYPE, error1);
 		/*
 		 * Figure out how many segments we need.  Max_Bucket is the
 		 * maximum bucket number, so the number of buckets is
@@ -343,7 +346,7 @@ init_hash(hashp, file, info)
 		if (stat(file, &statbuf))
 #endif
 			return (NULL);
-		hashp->BSIZE = statbuf.st_blksize;
+		hashp->BSIZE = MIN(statbuf.st_blksize, MAX_BSIZE);
 		hashp->BSHIFT = __log2(hashp->BSIZE);
 	}
 
diff --git a/newlib/libc/search/hash.h b/newlib/libc/search/hash.h
index 6491814..1b094d6 100644
--- a/newlib/libc/search/hash.h
+++ b/newlib/libc/search/hash.h
@@ -40,6 +40,7 @@
 #include <sys/param.h>
 #define __need_size_t
 #include <stddef.h>
+#include <stdint.h>
 
 /* Check that newlib understands the byte order of its target system.  */
 #ifndef BYTE_ORDER
@@ -82,28 +83,28 @@ typedef BUFHEAD **SEGMENT;
 
 /* Hash Table Information */
 typedef struct hashhdr {		/* Disk resident portion */
-	int		magic;		/* Magic NO for hash tables */
-	int		version;	/* Version ID */
+	int32_t		magic;		/* Magic NO for hash tables */
+	int32_t		version;	/* Version ID */
 	__uint32_t	lorder;		/* Byte Order */
-	int		bsize;		/* Bucket/Page Size */
-	int		bshift;		/* Bucket shift */
-	int		dsize;		/* Directory Size */
-	int		ssize;		/* Segment Size */
-	int		sshift;		/* Segment shift */
-	int		ovfl_point;	/* Where overflow pages are being 
+	int32_t		bsize;		/* Bucket/Page Size */
+	int32_t		bshift;		/* Bucket shift */
+	int32_t		dsize;		/* Directory Size */
+	int32_t		ssize;		/* Segment Size */
+	int32_t		sshift;		/* Segment shift */
+	int32_t		ovfl_point;	/* Where overflow pages are being
 					 * allocated */
-	int		last_freed;	/* Last overflow page freed */
-	int		max_bucket;	/* ID of Maximum bucket in use */
-	int		high_mask;	/* Mask to modulo into entire table */
-	int		low_mask;	/* Mask to modulo into lower half of 
+	int32_t		last_freed;	/* Last overflow page freed */
+	int32_t		max_bucket;	/* ID of Maximum bucket in use */
+	int32_t		high_mask;	/* Mask to modulo into entire table */
+	int32_t		low_mask;	/* Mask to modulo into lower half of
 					 * table */
-	int		ffactor;	/* Fill factor */
-	int		nkeys;		/* Number of keys in hash table */
-	int		hdrpages;	/* Size of table header */
-	int		h_charkey;	/* value of hash(CHARKEY) */
+	int32_t		ffactor;	/* Fill factor */
+	int32_t		nkeys;		/* Number of keys in hash table */
+	int32_t		hdrpages;	/* Size of table header */
+	int32_t		h_charkey;	/* value of hash(CHARKEY) */
 #define NCACHED	32			/* number of bit maps and spare 
 					 * points */
-	int		spares[NCACHED];/* spare pages for overflow */
+	int32_t		spares[NCACHED];/* spare pages for overflow */
 	__uint16_t	bitmaps[NCACHED];	/* address of overflow page 
 						 * bitmaps */
 } HASHHDR;
@@ -120,7 +121,7 @@ typedef struct htab	 {		/* Memory resident data structure */
 	char		*tmp_buf;	/* Temporary Buffer for BIG data */
 	char		*tmp_key;	/* Temporary Buffer for BIG keys */
 	BUFHEAD 	*cpage;		/* Current page */
-	int		cbucket;	/* Current bucket */
+	int32_t		cbucket;	/* Current bucket */
 	int		cndx;		/* Index of next item on cpage */
 	int		error;		/* Error Number -- for DBM 
 					 * compatibility */
@@ -140,10 +141,18 @@ typedef struct htab	 {		/* Memory resident data structure */
 /*
  * Constants
  */
+#if INT_MAX == 32767
+#define	MAX_BSIZE		4096
+#else
 #define	MAX_BSIZE		65536		/* 2^16 */
+#endif
 #define MIN_BUFFERS		6
 #define MINHDRSIZE		512
+#if INT_MAX == 32767
+#define DEF_BUFSIZE		4096
+#else
 #define DEF_BUFSIZE		65536		/* 64 K */
+#endif
 #define DEF_BUCKET_SIZE		4096
 #define DEF_BUCKET_SHIFT	12		/* log2(BUCKET) */
 #define DEF_SEGSIZE		256
diff --git a/newlib/libc/search/hash_buf.c b/newlib/libc/search/hash_buf.c
index d50fc57..81475e9 100644
--- a/newlib/libc/search/hash_buf.c
+++ b/newlib/libc/search/hash_buf.c
@@ -151,7 +151,7 @@ __get_buf(hashp, addr, prev_bp, newpage)
 			return (NULL);
 		if (!prev_bp)
 			segp[segment_ndx] =
-			    (BUFHEAD *)((ptrdiff_t)bp | is_disk_mask);
+			    (BUFHEAD *)((ptrdiff_t)bp | (intptr_t)is_disk_mask);
 	} else {
 		BUF_REMOVE(bp);
 		MRU_INSERT(bp);