X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/4c36ddbeecdde407c870109d70527640ca127ace..d3d07a5e860f1cde0e234ec7a1aff7111a2c514f:/fileio.c diff --git a/fileio.c b/fileio.c index 1ae5eac3..f086494b 100644 --- a/fileio.c +++ b/fileio.c @@ -1,85 +1,145 @@ -/* - 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 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; @@ -90,129 +150,127 @@ int write_file(int f,char *buf,int len) } - -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 %.0f, not %.0f", + (double)ret, (double)read_start); + 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; +}