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4c36ddbe AT |
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 |