-/*
- 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
- */
+ * File IO utilities used in rsync.
+ *
+ * Copyright (C) 1998 Andrew Tridgell
+ * Copyright (C) 2002 Martin Pool
+ * Copyright (C) 2004-2008 Wayne Davison
+ *
+ * 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 3 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, visit the http://fsf.org website.
+ */
+
#include "rsync.h"
-static char last_byte;
-static int last_sparse;
+#ifndef ENODATA
+#define ENODATA EAGAIN
+#endif
+
extern int sparse_files;
+static char last_byte;
+static size_t sparse_seek = 0;
+
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;
+ int ret;
+
+ if (!sparse_seek)
+ return 0;
+
+ do_lseek(f, sparse_seek-1, SEEK_CUR);
+ sparse_seek = 0;
+
+ do {
+ ret = write(f, "", 1);
+ } while (ret < 0 && errno == EINTR);
+
+ return ret <= 0 ? -1 : 0;
}
-static int write_sparse(int f,char *buf,int len)
+static int write_sparse(int f, char *buf, size_t len)
{
- int l1=0,l2=0;
+ size_t 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++) ;
+ for (l1 = 0; l1 < len && buf[l1] == 0; l1++) {}
+ for (l2 = 0; l2 < len-l1 && buf[len-(l2+1)] == 0; l2++) {}
+ /* XXX Riddle me this: why does this function SLOW DOWN when I
+ * remove the following (unneeded) line?? Core Duo weirdness? */
last_byte = buf[len-1];
- if (l1 == len || l2 > 0)
- last_sparse=1;
-
- if (l1 > 0)
- do_lseek(f,l1,SEEK_CUR);
+ sparse_seek += l1;
- if (l1 == len)
+ 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 (sparse_seek)
+ do_lseek(f, sparse_seek, SEEK_CUR);
+ sparse_seek = l2;
+
+ while ((ret = write(f, buf + l1, len - (l1+l2))) <= 0) {
+ if (ret < 0 && errno == EINTR)
+ continue;
+ return ret;
}
- if (l2 > 0)
- do_lseek(f,l2,SEEK_CUR);
-
+ if (ret != (int)(len - (l1+l2)))
+ return l1+ret;
+
return len;
}
+static char *wf_writeBuf;
+static size_t wf_writeBufSize;
+static size_t wf_writeBufCnt;
-int write_file(int f,char *buf,int len)
+int flush_write_file(int f)
{
int ret = 0;
+ char *bp = wf_writeBuf;
+
+ while (wf_writeBufCnt > 0) {
+ if ((ret = write(f, bp, wf_writeBufCnt)) < 0) {
+ if (errno == EINTR)
+ continue;
+ return ret;
+ }
+ wf_writeBufCnt -= ret;
+ bp += ret;
+ }
+ return ret;
+}
- 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);
+/*
+ * write_file does not allow incomplete writes. It loops internally
+ * until len bytes are written or errno is set.
+ */
+int write_file(int f,char *buf,size_t len)
+{
+ int ret = 0;
+
+ while (len > 0) {
+ int r1;
+ if (sparse_files > 0) {
+ int len1 = MIN(len, SPARSE_WRITE_SIZE);
+ r1 = write_sparse(f, buf, len1);
+ } else {
+ if (!wf_writeBuf) {
+ wf_writeBufSize = WRITE_SIZE * 8;
+ wf_writeBufCnt = 0;
+ wf_writeBuf = new_array(char, wf_writeBufSize);
+ if (!wf_writeBuf)
+ out_of_memory("write_file");
+ }
+ r1 = MIN(len, wf_writeBufSize - wf_writeBufCnt);
+ if (r1) {
+ memcpy(wf_writeBuf + wf_writeBufCnt, buf, r1);
+ wf_writeBufCnt += r1;
+ }
+ if (wf_writeBufCnt == wf_writeBufSize) {
+ if (flush_write_file(f) < 0)
+ return -1;
+ if (!r1 && len)
+ continue;
+ }
+ }
if (r1 <= 0) {
- if (ret > 0) return ret;
+ if (ret > 0)
+ return ret;
return r1;
}
len -= r1;
}
-
-struct map_struct *map_file(int fd,OFF_T len)
+/* This provides functionality somewhat similar to mmap() but using read().
+ * It gives sliding window access to a file. mmap() is not used because of
+ * the possibility of another program (such as a mailer) truncating the
+ * file thus giving us a SIGBUS. */
+struct map_struct *map_file(int fd, OFF_T len, int32 read_size,
+ int32 blk_size)
{
- 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;
-}
+ struct map_struct *map;
+ if (!(map = new0(struct map_struct)))
+ out_of_memory("map_file");
-char *map_ptr(struct map_struct *map,OFF_T offset,int len)
-{
- int nread;
+ if (blk_size && (read_size % blk_size))
+ read_size += blk_size - (read_size % blk_size);
- if (len == 0)
- return NULL;
+ map->fd = fd;
+ map->file_size = len;
+ map->def_window_size = read_size;
- if (len > (map->size-offset))
- len = map->size-offset;
+ return map;
+}
-#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
+/* slide the read window in the file */
+char *map_ptr(struct map_struct *map, OFF_T offset, int32 len)
+{
+ int32 nread;
+ OFF_T window_start, read_start;
+ int32 window_size, read_size, read_offset;
- if (offset >= map->p_offset &&
- offset+len <= map->p_offset+map->p_len) {
- return (map->p + (offset - map->p_offset));
+ if (len == 0)
+ return NULL;
+ if (len < 0) {
+ rprintf(FERROR, "invalid len passed to map_ptr: %ld\n",
+ (long)len);
+ exit_cleanup(RERR_FILEIO);
}
- 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;
+ /* in most cases the region will already be available */
+ if (offset >= map->p_offset && offset+len <= map->p_offset+map->p_len)
+ return map->p + (offset - map->p_offset);
+
+ /* nope, we are going to have to do a read. Work out our desired window */
+ window_start = offset;
+ window_size = map->def_window_size;
+ if (window_start + window_size > map->file_size)
+ window_size = (int32)(map->file_size - window_start);
+ if (len > window_size)
+ window_size = len;
+
+ /* make sure we have allocated enough memory for the window */
+ if (window_size > map->p_size) {
+ map->p = realloc_array(map->p, char, window_size);
+ if (!map->p)
+ out_of_memory("map_ptr");
+ map->p_size = window_size;
}
- map->p_offset = offset;
- map->p_len = len;
+ /* Now try to avoid re-reading any bytes by reusing any bytes
+ * from the previous buffer. */
+ if (window_start >= map->p_offset &&
+ window_start < map->p_offset + map->p_len &&
+ window_start + window_size >= map->p_offset + map->p_len) {
+ read_start = map->p_offset + map->p_len;
+ read_offset = (int32)(read_start - window_start);
+ read_size = window_size - read_offset;
+ memmove(map->p, map->p + (map->p_len - read_offset), read_offset);
+ } else {
+ read_start = window_start;
+ read_size = window_size;
+ read_offset = 0;
+ }
- if (do_lseek(map->fd,offset,SEEK_SET) != offset) {
- rprintf(FERROR,"lseek failed in map_ptr\n");
- exit_cleanup(1);
+ if (read_size <= 0) {
+ rprintf(FERROR, "invalid read_size of %ld in map_ptr\n",
+ (long)read_size);
+ exit_cleanup(RERR_FILEIO);
}
- 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);
+ if (map->p_fd_offset != read_start) {
+ OFF_T ret = do_lseek(map->fd, read_start, SEEK_SET);
+ if (ret != read_start) {
+ rsyserr(FERROR, errno, "lseek returned %s, not %s",
+ big_num(ret, 0), big_num(read_start, 0));
+ exit_cleanup(RERR_FILEIO);
+ }
+ map->p_fd_offset = read_start;
+ }
+ map->p_offset = window_start;
+ map->p_len = window_size;
+
+ while (read_size > 0) {
+ nread = read(map->fd, map->p + read_offset, read_size);
+ if (nread <= 0) {
+ if (!map->status)
+ map->status = nread ? errno : ENODATA;
+ /* The best we can do is zero the buffer -- the file
+ * has changed mid transfer! */
+ memset(map->p + read_offset, 0, read_size);
+ break;
+ }
+ map->p_fd_offset += nread;
+ read_offset += nread;
+ read_size -= nread;
}
-
- return map->p;
+
+ return map->p;
}
-void unmap_file(struct map_struct *map)
+int unmap_file(struct map_struct *map)
{
-#ifdef USE_MMAP
- if (map->map) {
- munmap(map->map,map->p_len);
- map->map = NULL;
- }
-#endif
+ int ret;
+
if (map->p) {
free(map->p);
map->p = NULL;
}
- memset(map, 0, sizeof(*map));
+ ret = map->status;
+ memset(map, 0, sizeof map[0]);
free(map);
-}
+ return ret;
+}
Matt McCutchen's Web Site / rsync / rsync.git / blobdiff