Add krb5_storage_truncate

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@24226 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/krb5/store-int.h

@@ -39,6 +39,7 @@ struct krb5_storage_data {
     ssize_t (*fetch)(struct krb5_storage_data*, void*, size_t);
     ssize_t (*store)(struct krb5_storage_data*, const void*, size_t);
     off_t (*seek)(struct krb5_storage_data*, off_t, int);
+    int (*trunc)(struct krb5_storage_data*, off_t);
     void (*free)(struct krb5_storage_data*);
     krb5_flags flags;
     int eof_code;

lib/krb5/store_emem.c

@@ -104,6 +104,29 @@ emem_seek(krb5_storage *sp, off_t offset, int whence)
     return s->ptr - s->base;
 }
 
+static int
+emem_trunc(krb5_storage *sp, off_t offset)
+{
+    emem_storage *s = (emem_storage*)sp->data;
+    /*
+     * If offset is larget then current size, or current size is
+     * shrunk more then half of the current size, adjust buffer.
+     */
+    if (offset > s->size || s->size / 2 > offset ) {
+	void *base;
+	base = realloc(s->base, offset);
+	if(base == NULL)
+	    return ENOMEM;
+	if (offset > s->size)
+	    memset(s->len, 0, offset);
+	s->size = offset;
+	s->base = base;
+    }
+    s->len = offset;
+    return 0;
+}
+
+
 static void
 emem_free(krb5_storage *sp)
 {
@@ -142,6 +165,7 @@ krb5_storage_emem(void)
     sp->fetch = emem_fetch;
     sp->store = emem_store;
     sp->seek = emem_seek;
+    sp->trunc = emem_trunc;
     sp->free = emem_free;
     return sp;
 }

lib/krb5/store_fd.c

@@ -60,6 +60,12 @@ fd_seek(krb5_storage * sp, off_t offset, int whence)
     return lseek(FD(sp), offset, whence);
 }
 
+static off_t
+fd_trunc(krb5_storage * sp, off_t offset)
+{
+    return ftruncate(FD(sp), offset);
+}
+
 static void
 fd_free(krb5_storage * sp)
 {
@@ -93,6 +99,7 @@ krb5_storage_from_fd(int fd)
     sp->fetch = fd_fetch;
     sp->store = fd_store;
     sp->seek = fd_seek;
+    sp->trunc = fd_trunc;
     sp->free = fd_free;
     return sp;
 }

lib/krb5/store_mem.c

@@ -93,6 +93,24 @@ mem_seek(krb5_storage *sp, off_t offset, int whence)
     return s->ptr - s->base;
 }
 
+static ssize_t
+mem_trunc(krb5_storage *sp, size_t offset)
+{
+    mem_storage *s = (mem_storage*)sp->data;
+    if(offset > s->size)
+	return ERANGE;
+    s->size = offset;
+    if ((s->ptr - s->base) > offset)
+	s->ptr = s->base + offset;
+    return 0;
+}
+
+static krb5_error_code
+mem_no_trunc(krb5_storage *sp, off_t offset)
+{
+    return EINVAL;
+}
+
 krb5_storage * KRB5_LIB_FUNCTION
 krb5_storage_from_mem(void *buf, size_t len)
 {
@@ -114,6 +132,7 @@ krb5_storage_from_mem(void *buf, size_t len)
     sp->fetch = mem_fetch;
     sp->store = mem_store;
     sp->seek = mem_seek;
+    sp->trunc = mem_trunc;
     sp->free = NULL;
     return sp;
 }
@@ -145,6 +164,7 @@ krb5_storage_from_readonly_mem(const void *buf, size_t len)
     sp->fetch = mem_fetch;
     sp->store = mem_no_store;
     sp->seek = mem_seek;
+    sp->trunc = mem_no_trunc;
     sp->free = NULL;
     return sp;
 }