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1 | /* | |
2 | * csum-file.c | |
3 | * | |
4 | * Copyright (C) 2005 Linus Torvalds | |
5 | * | |
6 | * Simple file write infrastructure for writing SHA1-summed | |
7 | * files. Useful when you write a file that you want to be | |
8 | * able to verify hasn't been messed with afterwards. | |
9 | */ | |
10 | #include "cache.h" | |
11 | #include "progress.h" | |
12 | #include "csum-file.h" | |
13 | ||
14 | static void flush(struct hashfile *f, const void *buf, unsigned int count) | |
15 | { | |
16 | if (0 <= f->check_fd && count) { | |
17 | unsigned char check_buffer[8192]; | |
18 | ssize_t ret = read_in_full(f->check_fd, check_buffer, count); | |
19 | ||
20 | if (ret < 0) | |
21 | die_errno("%s: sha1 file read error", f->name); | |
22 | if (ret != count) | |
23 | die("%s: sha1 file truncated", f->name); | |
24 | if (memcmp(buf, check_buffer, count)) | |
25 | die("sha1 file '%s' validation error", f->name); | |
26 | } | |
27 | ||
28 | for (;;) { | |
29 | int ret = xwrite(f->fd, buf, count); | |
30 | if (ret > 0) { | |
31 | f->total += ret; | |
32 | display_throughput(f->tp, f->total); | |
33 | buf = (char *) buf + ret; | |
34 | count -= ret; | |
35 | if (count) | |
36 | continue; | |
37 | return; | |
38 | } | |
39 | if (!ret) | |
40 | die("sha1 file '%s' write error. Out of diskspace", f->name); | |
41 | die_errno("sha1 file '%s' write error", f->name); | |
42 | } | |
43 | } | |
44 | ||
45 | void hashflush(struct hashfile *f) | |
46 | { | |
47 | unsigned offset = f->offset; | |
48 | ||
49 | if (offset) { | |
50 | the_hash_algo->update_fn(&f->ctx, f->buffer, offset); | |
51 | flush(f, f->buffer, offset); | |
52 | f->offset = 0; | |
53 | } | |
54 | } | |
55 | ||
56 | int finalize_hashfile(struct hashfile *f, unsigned char *result, unsigned int flags) | |
57 | { | |
58 | int fd; | |
59 | ||
60 | hashflush(f); | |
61 | the_hash_algo->final_fn(f->buffer, &f->ctx); | |
62 | if (result) | |
63 | hashcpy(result, f->buffer); | |
64 | if (flags & CSUM_HASH_IN_STREAM) | |
65 | flush(f, f->buffer, the_hash_algo->rawsz); | |
66 | if (flags & CSUM_FSYNC) | |
67 | fsync_or_die(f->fd, f->name); | |
68 | if (flags & CSUM_CLOSE) { | |
69 | if (close(f->fd)) | |
70 | die_errno("%s: sha1 file error on close", f->name); | |
71 | fd = 0; | |
72 | } else | |
73 | fd = f->fd; | |
74 | if (0 <= f->check_fd) { | |
75 | char discard; | |
76 | int cnt = read_in_full(f->check_fd, &discard, 1); | |
77 | if (cnt < 0) | |
78 | die_errno("%s: error when reading the tail of sha1 file", | |
79 | f->name); | |
80 | if (cnt) | |
81 | die("%s: sha1 file has trailing garbage", f->name); | |
82 | if (close(f->check_fd)) | |
83 | die_errno("%s: sha1 file error on close", f->name); | |
84 | } | |
85 | free(f); | |
86 | return fd; | |
87 | } | |
88 | ||
89 | void hashwrite(struct hashfile *f, const void *buf, unsigned int count) | |
90 | { | |
91 | while (count) { | |
92 | unsigned offset = f->offset; | |
93 | unsigned left = sizeof(f->buffer) - offset; | |
94 | unsigned nr = count > left ? left : count; | |
95 | const void *data; | |
96 | ||
97 | if (f->do_crc) | |
98 | f->crc32 = crc32(f->crc32, buf, nr); | |
99 | ||
100 | if (nr == sizeof(f->buffer)) { | |
101 | /* process full buffer directly without copy */ | |
102 | data = buf; | |
103 | } else { | |
104 | memcpy(f->buffer + offset, buf, nr); | |
105 | data = f->buffer; | |
106 | } | |
107 | ||
108 | count -= nr; | |
109 | offset += nr; | |
110 | buf = (char *) buf + nr; | |
111 | left -= nr; | |
112 | if (!left) { | |
113 | the_hash_algo->update_fn(&f->ctx, data, offset); | |
114 | flush(f, data, offset); | |
115 | offset = 0; | |
116 | } | |
117 | f->offset = offset; | |
118 | } | |
119 | } | |
120 | ||
121 | struct hashfile *hashfd(int fd, const char *name) | |
122 | { | |
123 | return hashfd_throughput(fd, name, NULL); | |
124 | } | |
125 | ||
126 | struct hashfile *hashfd_check(const char *name) | |
127 | { | |
128 | int sink, check; | |
129 | struct hashfile *f; | |
130 | ||
131 | sink = open("/dev/null", O_WRONLY); | |
132 | if (sink < 0) | |
133 | die_errno("unable to open /dev/null"); | |
134 | check = open(name, O_RDONLY); | |
135 | if (check < 0) | |
136 | die_errno("unable to open '%s'", name); | |
137 | f = hashfd(sink, name); | |
138 | f->check_fd = check; | |
139 | return f; | |
140 | } | |
141 | ||
142 | struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp) | |
143 | { | |
144 | struct hashfile *f = xmalloc(sizeof(*f)); | |
145 | f->fd = fd; | |
146 | f->check_fd = -1; | |
147 | f->offset = 0; | |
148 | f->total = 0; | |
149 | f->tp = tp; | |
150 | f->name = name; | |
151 | f->do_crc = 0; | |
152 | the_hash_algo->init_fn(&f->ctx); | |
153 | return f; | |
154 | } | |
155 | ||
156 | void hashfile_checkpoint(struct hashfile *f, struct hashfile_checkpoint *checkpoint) | |
157 | { | |
158 | hashflush(f); | |
159 | checkpoint->offset = f->total; | |
160 | checkpoint->ctx = f->ctx; | |
161 | } | |
162 | ||
163 | int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint) | |
164 | { | |
165 | off_t offset = checkpoint->offset; | |
166 | ||
167 | if (ftruncate(f->fd, offset) || | |
168 | lseek(f->fd, offset, SEEK_SET) != offset) | |
169 | return -1; | |
170 | f->total = offset; | |
171 | f->ctx = checkpoint->ctx; | |
172 | f->offset = 0; /* hashflush() was called in checkpoint */ | |
173 | return 0; | |
174 | } | |
175 | ||
176 | void crc32_begin(struct hashfile *f) | |
177 | { | |
178 | f->crc32 = crc32(0, NULL, 0); | |
179 | f->do_crc = 1; | |
180 | } | |
181 | ||
182 | uint32_t crc32_end(struct hashfile *f) | |
183 | { | |
184 | f->do_crc = 0; | |
185 | return f->crc32; | |
186 | } |