Use "-Wall -O2" for the compiler to get more warnings.
[git/git.git] / read-cache.c
CommitLineData
8bc9a0c7
LT
1/*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 */
e83c5163
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6#include "cache.h"
7
8const char *sha1_file_directory = NULL;
9struct cache_entry **active_cache = NULL;
10unsigned int active_nr = 0, active_alloc = 0;
11
12void usage(const char *err)
13{
14 fprintf(stderr, "read-tree: %s\n", err);
15 exit(1);
16}
17
18static unsigned hexval(char c)
19{
20 if (c >= '0' && c <= '9')
21 return c - '0';
22 if (c >= 'a' && c <= 'f')
23 return c - 'a' + 10;
24 if (c >= 'A' && c <= 'F')
25 return c - 'A' + 10;
26 return ~0;
27}
28
29int get_sha1_hex(char *hex, unsigned char *sha1)
30{
31 int i;
32 for (i = 0; i < 20; i++) {
33 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
34 if (val & ~0xff)
35 return -1;
36 *sha1++ = val;
37 hex += 2;
38 }
39 return 0;
40}
41
42char * sha1_to_hex(unsigned char *sha1)
43{
44 static char buffer[50];
45 static const char hex[] = "0123456789abcdef";
46 char *buf = buffer;
47 int i;
48
49 for (i = 0; i < 20; i++) {
50 unsigned int val = *sha1++;
51 *buf++ = hex[val >> 4];
52 *buf++ = hex[val & 0xf];
53 }
54 return buffer;
55}
56
57/*
58 * NOTE! This returns a statically allocated buffer, so you have to be
59 * careful about using it. Do a "strdup()" if you need to save the
60 * filename.
61 */
62char *sha1_file_name(unsigned char *sha1)
63{
64 int i;
65 static char *name, *base;
66
67 if (!base) {
68 char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
69 int len = strlen(sha1_file_directory);
70 base = malloc(len + 60);
71 memcpy(base, sha1_file_directory, len);
72 memset(base+len, 0, 60);
73 base[len] = '/';
74 base[len+3] = '/';
75 name = base + len + 1;
76 }
77 for (i = 0; i < 20; i++) {
78 static char hex[] = "0123456789abcdef";
79 unsigned int val = sha1[i];
80 char *pos = name + i*2 + (i > 0);
81 *pos++ = hex[val >> 4];
82 *pos = hex[val & 0xf];
83 }
84 return base;
85}
86
87void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
88{
89 z_stream stream;
90 char buffer[8192];
91 struct stat st;
19b2860c 92 int fd, ret, bytes;
e83c5163
LT
93 void *map, *buf;
94 char *filename = sha1_file_name(sha1);
95
96 fd = open(filename, O_RDONLY);
97 if (fd < 0) {
98 perror(filename);
99 return NULL;
100 }
101 if (fstat(fd, &st) < 0) {
102 close(fd);
103 return NULL;
104 }
105 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
106 close(fd);
107 if (-1 == (int)(long)map)
108 return NULL;
109
110 /* Get the data stream */
111 memset(&stream, 0, sizeof(stream));
112 stream.next_in = map;
113 stream.avail_in = st.st_size;
114 stream.next_out = buffer;
115 stream.avail_out = sizeof(buffer);
116
117 inflateInit(&stream);
118 ret = inflate(&stream, 0);
119 if (sscanf(buffer, "%10s %lu", type, size) != 2)
120 return NULL;
121 bytes = strlen(buffer) + 1;
122 buf = malloc(*size);
123 if (!buf)
124 return NULL;
125
126 memcpy(buf, buffer + bytes, stream.total_out - bytes);
127 bytes = stream.total_out - bytes;
128 if (bytes < *size && ret == Z_OK) {
129 stream.next_out = buf + bytes;
130 stream.avail_out = *size - bytes;
131 while (inflate(&stream, Z_FINISH) == Z_OK)
132 /* nothing */;
133 }
134 inflateEnd(&stream);
135 return buf;
136}
137
138int write_sha1_file(char *buf, unsigned len)
139{
140 int size;
141 char *compressed;
142 z_stream stream;
143 unsigned char sha1[20];
144 SHA_CTX c;
145
146 /* Set it up */
147 memset(&stream, 0, sizeof(stream));
148 deflateInit(&stream, Z_BEST_COMPRESSION);
149 size = deflateBound(&stream, len);
150 compressed = malloc(size);
151
152 /* Compress it */
153 stream.next_in = buf;
154 stream.avail_in = len;
155 stream.next_out = compressed;
156 stream.avail_out = size;
157 while (deflate(&stream, Z_FINISH) == Z_OK)
158 /* nothing */;
159 deflateEnd(&stream);
160 size = stream.total_out;
161
162 /* Sha1.. */
163 SHA1_Init(&c);
164 SHA1_Update(&c, compressed, size);
165 SHA1_Final(sha1, &c);
166
167 if (write_sha1_buffer(sha1, compressed, size) < 0)
168 return -1;
169 printf("%s\n", sha1_to_hex(sha1));
170 return 0;
171}
172
173int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
174{
175 char *filename = sha1_file_name(sha1);
19b2860c 176 int fd;
e83c5163
LT
177
178 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
179 if (fd < 0)
180 return (errno == EEXIST) ? 0 : -1;
181 write(fd, buf, size);
182 close(fd);
183 return 0;
184}
185
186static int error(const char * string)
187{
188 fprintf(stderr, "error: %s\n", string);
189 return -1;
190}
191
192static int verify_hdr(struct cache_header *hdr, unsigned long size)
193{
194 SHA_CTX c;
195 unsigned char sha1[20];
196
197 if (hdr->signature != CACHE_SIGNATURE)
198 return error("bad signature");
199 if (hdr->version != 1)
200 return error("bad version");
201 SHA1_Init(&c);
202 SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
203 SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
204 SHA1_Final(sha1, &c);
205 if (memcmp(sha1, hdr->sha1, 20))
206 return error("bad header sha1");
207 return 0;
208}
209
210int read_cache(void)
211{
212 int fd, i;
213 struct stat st;
214 unsigned long size, offset;
215 void *map;
216 struct cache_header *hdr;
217
218 errno = EBUSY;
219 if (active_cache)
220 return error("more than one cachefile");
221 errno = ENOENT;
222 sha1_file_directory = getenv(DB_ENVIRONMENT);
223 if (!sha1_file_directory)
224 sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
225 if (access(sha1_file_directory, X_OK) < 0)
226 return error("no access to SHA1 file directory");
227 fd = open(".dircache/index", O_RDONLY);
228 if (fd < 0)
229 return (errno == ENOENT) ? 0 : error("open failed");
230
19b2860c 231 size = 0; // avoid gcc warning
e83c5163
LT
232 map = (void *)-1;
233 if (!fstat(fd, &st)) {
234 map = NULL;
235 size = st.st_size;
236 errno = EINVAL;
237 if (size > sizeof(struct cache_header))
238 map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
239 }
240 close(fd);
241 if (-1 == (int)(long)map)
242 return error("mmap failed");
243
244 hdr = map;
245 if (verify_hdr(hdr, size) < 0)
246 goto unmap;
247
248 active_nr = hdr->entries;
249 active_alloc = alloc_nr(active_nr);
250 active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
251
252 offset = sizeof(*hdr);
253 for (i = 0; i < hdr->entries; i++) {
254 struct cache_entry *ce = map + offset;
255 offset = offset + ce_size(ce);
256 active_cache[i] = ce;
257 }
258 return active_nr;
259
260unmap:
261 munmap(map, size);
262 errno = EINVAL;
263 return error("verify header failed");
264}
265