| 1 | /* |
| 2 | Copyright (C) Andrew Tridgell 1998 |
| 3 | |
| 4 | This program is free software; you can redistribute it and/or modify |
| 5 | it under the terms of the GNU General Public License as published by |
| 6 | the Free Software Foundation; either version 2 of the License, or |
| 7 | (at your option) any later version. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program; if not, write to the Free Software |
| 16 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 17 | */ |
| 18 | |
| 19 | /* |
| 20 | File IO utilities used in rsync |
| 21 | */ |
| 22 | #include "rsync.h" |
| 23 | |
| 24 | static char last_byte; |
| 25 | static int last_sparse; |
| 26 | extern int sparse_files; |
| 27 | |
| 28 | int sparse_end(int f) |
| 29 | { |
| 30 | if (last_sparse) { |
| 31 | do_lseek(f,-1,SEEK_CUR); |
| 32 | return (write(f,&last_byte,1) == 1 ? 0 : -1); |
| 33 | } |
| 34 | last_sparse = 0; |
| 35 | return 0; |
| 36 | } |
| 37 | |
| 38 | |
| 39 | static int write_sparse(int f,char *buf,int len) |
| 40 | { |
| 41 | int l1=0,l2=0; |
| 42 | int ret; |
| 43 | |
| 44 | for (l1=0;l1<len && buf[l1]==0;l1++) ; |
| 45 | for (l2=0;l2<(len-l1) && buf[len-(l2+1)]==0;l2++) ; |
| 46 | |
| 47 | last_byte = buf[len-1]; |
| 48 | |
| 49 | if (l1 == len || l2 > 0) |
| 50 | last_sparse=1; |
| 51 | |
| 52 | if (l1 > 0) |
| 53 | do_lseek(f,l1,SEEK_CUR); |
| 54 | |
| 55 | if (l1 == len) |
| 56 | return len; |
| 57 | |
| 58 | if ((ret=write(f,buf+l1,len-(l1+l2))) != len-(l1+l2)) { |
| 59 | if (ret == -1 || ret == 0) return ret; |
| 60 | return (l1+ret); |
| 61 | } |
| 62 | |
| 63 | if (l2 > 0) |
| 64 | do_lseek(f,l2,SEEK_CUR); |
| 65 | |
| 66 | return len; |
| 67 | } |
| 68 | |
| 69 | |
| 70 | |
| 71 | int write_file(int f,char *buf,int len) |
| 72 | { |
| 73 | int ret = 0; |
| 74 | |
| 75 | if (!sparse_files) |
| 76 | return write(f,buf,len); |
| 77 | |
| 78 | while (len>0) { |
| 79 | int len1 = MIN(len, SPARSE_WRITE_SIZE); |
| 80 | int r1 = write_sparse(f, buf, len1); |
| 81 | if (r1 <= 0) { |
| 82 | if (ret > 0) return ret; |
| 83 | return r1; |
| 84 | } |
| 85 | len -= r1; |
| 86 | buf += r1; |
| 87 | ret += r1; |
| 88 | } |
| 89 | return ret; |
| 90 | } |
| 91 | |
| 92 | |
| 93 | |
| 94 | struct map_struct *map_file(int fd,OFF_T len) |
| 95 | { |
| 96 | struct map_struct *ret; |
| 97 | ret = (struct map_struct *)malloc(sizeof(*ret)); |
| 98 | if (!ret) out_of_memory("map_file"); |
| 99 | |
| 100 | ret->map = NULL; |
| 101 | ret->fd = fd; |
| 102 | ret->size = len; |
| 103 | ret->p = NULL; |
| 104 | ret->p_size = 0; |
| 105 | ret->p_offset = 0; |
| 106 | ret->p_len = 0; |
| 107 | |
| 108 | #ifdef USE_MMAP |
| 109 | len = MIN(len, MAX_MAP_SIZE); |
| 110 | ret->map = (char *)do_mmap(NULL,len,PROT_READ,MAP_SHARED,fd,0); |
| 111 | if (ret->map == (char *)-1) { |
| 112 | ret->map = NULL; |
| 113 | } else { |
| 114 | ret->p_len = len; |
| 115 | } |
| 116 | #endif |
| 117 | return ret; |
| 118 | } |
| 119 | |
| 120 | |
| 121 | char *map_ptr(struct map_struct *map,OFF_T offset,int len) |
| 122 | { |
| 123 | int nread; |
| 124 | |
| 125 | if (len == 0) |
| 126 | return NULL; |
| 127 | |
| 128 | if (len > (map->size-offset)) |
| 129 | len = map->size-offset; |
| 130 | |
| 131 | #ifdef USE_MMAP |
| 132 | if (map->map) { |
| 133 | if (offset >= map->p_offset && |
| 134 | offset+len <= map->p_offset+map->p_len) { |
| 135 | return (map->map + (offset - map->p_offset)); |
| 136 | } |
| 137 | if (munmap(map->map, map->p_len) != 0) { |
| 138 | rprintf(FERROR,"munmap failed : %s\n", strerror(errno)); |
| 139 | exit_cleanup(1); |
| 140 | } |
| 141 | |
| 142 | /* align the mmap region on a nice boundary back a bit from |
| 143 | where it is asked for to allow for some seeking */ |
| 144 | if (offset > 2*CHUNK_SIZE) { |
| 145 | map->p_offset = offset - 2*CHUNK_SIZE; |
| 146 | map->p_offset &= ~((OFF_T)(CHUNK_SIZE-1)); |
| 147 | } else { |
| 148 | map->p_offset = 0; |
| 149 | } |
| 150 | |
| 151 | /* map up to MAX_MAP_SIZE */ |
| 152 | map->p_len = MAX(len, MAX_MAP_SIZE); |
| 153 | map->p_len = MIN(map->p_len, map->size - map->p_offset); |
| 154 | |
| 155 | map->map = (char *)do_mmap(NULL,map->p_len,PROT_READ, |
| 156 | MAP_SHARED,map->fd,map->p_offset); |
| 157 | |
| 158 | if (map->map == (char *)-1) { |
| 159 | map->map = NULL; |
| 160 | map->p_len = 0; |
| 161 | map->p_offset = 0; |
| 162 | } else { |
| 163 | return (map->map + (offset - map->p_offset)); |
| 164 | } |
| 165 | } |
| 166 | #endif |
| 167 | |
| 168 | if (offset >= map->p_offset && |
| 169 | offset+len <= map->p_offset+map->p_len) { |
| 170 | return (map->p + (offset - map->p_offset)); |
| 171 | } |
| 172 | |
| 173 | len = MAX(len,CHUNK_SIZE); |
| 174 | if (len > (map->size-offset)) |
| 175 | len = map->size-offset; |
| 176 | |
| 177 | if (len > map->p_size) { |
| 178 | if (map->p) free(map->p); |
| 179 | map->p = (char *)malloc(len); |
| 180 | if (!map->p) out_of_memory("map_ptr"); |
| 181 | map->p_size = len; |
| 182 | } |
| 183 | |
| 184 | map->p_offset = offset; |
| 185 | map->p_len = len; |
| 186 | |
| 187 | if (do_lseek(map->fd,offset,SEEK_SET) != offset) { |
| 188 | rprintf(FERROR,"lseek failed in map_ptr\n"); |
| 189 | exit_cleanup(1); |
| 190 | } |
| 191 | |
| 192 | if ((nread=read(map->fd,map->p,len)) != len) { |
| 193 | if (nread < 0) nread = 0; |
| 194 | /* the best we can do is zero the buffer - the file |
| 195 | has changed mid transfer! */ |
| 196 | memset(map->p+nread, 0, len - nread); |
| 197 | } |
| 198 | |
| 199 | return map->p; |
| 200 | } |
| 201 | |
| 202 | |
| 203 | void unmap_file(struct map_struct *map) |
| 204 | { |
| 205 | #ifdef USE_MMAP |
| 206 | if (map->map) { |
| 207 | munmap(map->map,map->p_len); |
| 208 | map->map = NULL; |
| 209 | } |
| 210 | #endif |
| 211 | if (map->p) { |
| 212 | free(map->p); |
| 213 | map->p = NULL; |
| 214 | } |
| 215 | memset(map, 0, sizeof(*map)); |
| 216 | free(map); |
| 217 | } |
| 218 | |