+/*
+ Copyright (C) Andrew Tridgell 1998
+
+ 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.
+*/
+
+/*
+ File IO utilities used in rsync
+ */
+#include "rsync.h"
+
+static char last_byte;
+static int last_sparse;
+extern int sparse_files;
+
+int sparse_end(int f)
+{
+ if (last_sparse) {
+ do_lseek(f,-1,SEEK_CUR);
+ return (write(f,&last_byte,1) == 1 ? 0 : -1);
+ }
+ last_sparse = 0;
+ return 0;
+}
+
+
+static int write_sparse(int f,char *buf,int len)
+{
+ int l1=0,l2=0;
+ int ret;
+
+ for (l1=0;l1<len && buf[l1]==0;l1++) ;
+ for (l2=0;l2<(len-l1) && buf[len-(l2+1)]==0;l2++) ;
+
+ last_byte = buf[len-1];
+
+ if (l1 == len || l2 > 0)
+ last_sparse=1;
+
+ if (l1 > 0)
+ do_lseek(f,l1,SEEK_CUR);
+
+ if (l1 == len)
+ return len;
+
+ if ((ret=write(f,buf+l1,len-(l1+l2))) != len-(l1+l2)) {
+ if (ret == -1 || ret == 0) return ret;
+ return (l1+ret);
+ }
+
+ if (l2 > 0)
+ do_lseek(f,l2,SEEK_CUR);
+
+ return len;
+}
+
+
+
+int write_file(int f,char *buf,int len)
+{
+ int ret = 0;
+
+ if (!sparse_files)
+ return write(f,buf,len);
+
+ while (len>0) {
+ int len1 = MIN(len, SPARSE_WRITE_SIZE);
+ int r1 = write_sparse(f, buf, len1);
+ if (r1 <= 0) {
+ if (ret > 0) return ret;
+ return r1;
+ }
+ len -= r1;
+ buf += r1;
+ ret += r1;
+ }
+ return ret;
+}
+
+
+
+struct map_struct *map_file(int fd,OFF_T len)
+{
+ struct map_struct *ret;
+ ret = (struct map_struct *)malloc(sizeof(*ret));
+ if (!ret) out_of_memory("map_file");
+
+ ret->map = NULL;
+ ret->fd = fd;
+ ret->size = len;
+ ret->p = NULL;
+ ret->p_size = 0;
+ ret->p_offset = 0;
+ ret->p_len = 0;
+
+#ifdef USE_MMAP
+ len = MIN(len, MAX_MAP_SIZE);
+ ret->map = (char *)do_mmap(NULL,len,PROT_READ,MAP_SHARED,fd,0);
+ if (ret->map == (char *)-1) {
+ ret->map = NULL;
+ } else {
+ ret->p_len = len;
+ }
+#endif
+ return ret;
+}
+
+
+char *map_ptr(struct map_struct *map,OFF_T offset,int len)
+{
+ int nread;
+
+ if (len == 0)
+ return NULL;
+
+ if (len > (map->size-offset))
+ len = map->size-offset;
+
+#ifdef USE_MMAP
+ if (map->map) {
+ if (offset >= map->p_offset &&
+ offset+len <= map->p_offset+map->p_len) {
+ return (map->map + (offset - map->p_offset));
+ }
+ if (munmap(map->map, map->p_len) != 0) {
+ rprintf(FERROR,"munmap failed : %s\n", strerror(errno));
+ exit_cleanup(1);
+ }
+
+ /* align the mmap region on a nice boundary back a bit from
+ where it is asked for to allow for some seeking */
+ if (offset > 2*CHUNK_SIZE) {
+ map->p_offset = offset - 2*CHUNK_SIZE;
+ map->p_offset &= ~((OFF_T)(CHUNK_SIZE-1));
+ } else {
+ map->p_offset = 0;
+ }
+
+ /* map up to MAX_MAP_SIZE */
+ map->p_len = MAX(len, MAX_MAP_SIZE);
+ map->p_len = MIN(map->p_len, map->size - map->p_offset);
+
+ map->map = (char *)do_mmap(NULL,map->p_len,PROT_READ,
+ MAP_SHARED,map->fd,map->p_offset);
+
+ if (map->map == (char *)-1) {
+ map->map = NULL;
+ map->p_len = 0;
+ map->p_offset = 0;
+ } else {
+ return (map->map + (offset - map->p_offset));
+ }
+ }
+#endif
+
+ if (offset >= map->p_offset &&
+ offset+len <= map->p_offset+map->p_len) {
+ return (map->p + (offset - map->p_offset));
+ }
+
+ len = MAX(len,CHUNK_SIZE);
+ if (len > (map->size-offset))
+ len = map->size-offset;
+
+ if (len > map->p_size) {
+ if (map->p) free(map->p);
+ map->p = (char *)malloc(len);
+ if (!map->p) out_of_memory("map_ptr");
+ map->p_size = len;
+ }
+
+ map->p_offset = offset;
+ map->p_len = len;
+
+ if (do_lseek(map->fd,offset,SEEK_SET) != offset) {
+ rprintf(FERROR,"lseek failed in map_ptr\n");
+ exit_cleanup(1);
+ }
+
+ if ((nread=read(map->fd,map->p,len)) != len) {
+ if (nread < 0) nread = 0;
+ /* the best we can do is zero the buffer - the file
+ has changed mid transfer! */
+ memset(map->p+nread, 0, len - nread);
+ }
+
+ return map->p;
+}
+
+
+void unmap_file(struct map_struct *map)
+{
+#ifdef USE_MMAP
+ if (map->map) {
+ munmap(map->map,map->p_len);
+ map->map = NULL;
+ }
+#endif
+ if (map->p) {
+ free(map->p);
+ map->p = NULL;
+ }
+ memset(map, 0, sizeof(*map));
+ free(map);
+}
+
Matt McCutchen's Web Site / rsync / rsync.git / commitdiff