Fix missing return values and some error tests for empty index files
[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
LT
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
2ade9340
LT
87int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
88{
89 unsigned char real_sha1[20];
90 SHA_CTX c;
91
92 SHA1_Init(&c);
93 SHA1_Update(&c, map, size);
94 SHA1_Final(real_sha1, &c);
95 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
96}
97
24778e33 98void *map_sha1_file(unsigned char *sha1, unsigned long *size)
e83c5163 99{
e83c5163 100 char *filename = sha1_file_name(sha1);
24778e33
LT
101 int fd = open(filename, O_RDONLY);
102 struct stat st;
103 void *map;
e83c5163 104
e83c5163
LT
105 if (fd < 0) {
106 perror(filename);
107 return NULL;
108 }
109 if (fstat(fd, &st) < 0) {
24778e33 110 close(fd);
e83c5163
LT
111 return NULL;
112 }
113 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
114 close(fd);
115 if (-1 == (int)(long)map)
116 return NULL;
24778e33
LT
117 *size = st.st_size;
118 return map;
119}
120
121void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
122{
123 int ret, bytes;
124 z_stream stream;
125 char buffer[8192];
126 char *buf;
e83c5163
LT
127
128 /* Get the data stream */
129 memset(&stream, 0, sizeof(stream));
130 stream.next_in = map;
24778e33 131 stream.avail_in = mapsize;
e83c5163
LT
132 stream.next_out = buffer;
133 stream.avail_out = sizeof(buffer);
134
135 inflateInit(&stream);
136 ret = inflate(&stream, 0);
137 if (sscanf(buffer, "%10s %lu", type, size) != 2)
138 return NULL;
24778e33 139
e83c5163
LT
140 bytes = strlen(buffer) + 1;
141 buf = malloc(*size);
142 if (!buf)
143 return NULL;
144
145 memcpy(buf, buffer + bytes, stream.total_out - bytes);
146 bytes = stream.total_out - bytes;
147 if (bytes < *size && ret == Z_OK) {
148 stream.next_out = buf + bytes;
149 stream.avail_out = *size - bytes;
150 while (inflate(&stream, Z_FINISH) == Z_OK)
151 /* nothing */;
152 }
153 inflateEnd(&stream);
154 return buf;
155}
156
24778e33
LT
157void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
158{
159 unsigned long mapsize;
160 void *map, *buf;
161
162 map = map_sha1_file(sha1, &mapsize);
163 if (map) {
164 buf = unpack_sha1_file(map, mapsize, type, size);
165 munmap(map, mapsize);
166 return buf;
167 }
168 return NULL;
169}
170
e83c5163
LT
171int write_sha1_file(char *buf, unsigned len)
172{
173 int size;
174 char *compressed;
175 z_stream stream;
176 unsigned char sha1[20];
177 SHA_CTX c;
178
179 /* Set it up */
180 memset(&stream, 0, sizeof(stream));
181 deflateInit(&stream, Z_BEST_COMPRESSION);
182 size = deflateBound(&stream, len);
183 compressed = malloc(size);
184
185 /* Compress it */
186 stream.next_in = buf;
187 stream.avail_in = len;
188 stream.next_out = compressed;
189 stream.avail_out = size;
190 while (deflate(&stream, Z_FINISH) == Z_OK)
191 /* nothing */;
192 deflateEnd(&stream);
193 size = stream.total_out;
194
195 /* Sha1.. */
196 SHA1_Init(&c);
197 SHA1_Update(&c, compressed, size);
198 SHA1_Final(sha1, &c);
199
200 if (write_sha1_buffer(sha1, compressed, size) < 0)
201 return -1;
202 printf("%s\n", sha1_to_hex(sha1));
203 return 0;
204}
205
206int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
207{
208 char *filename = sha1_file_name(sha1);
19b2860c 209 int fd;
e83c5163
LT
210
211 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
212 if (fd < 0)
213 return (errno == EEXIST) ? 0 : -1;
214 write(fd, buf, size);
215 close(fd);
216 return 0;
217}
218
219static int error(const char * string)
220{
221 fprintf(stderr, "error: %s\n", string);
222 return -1;
223}
224
225static int verify_hdr(struct cache_header *hdr, unsigned long size)
226{
227 SHA_CTX c;
228 unsigned char sha1[20];
229
230 if (hdr->signature != CACHE_SIGNATURE)
231 return error("bad signature");
232 if (hdr->version != 1)
233 return error("bad version");
234 SHA1_Init(&c);
235 SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
236 SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
237 SHA1_Final(sha1, &c);
238 if (memcmp(sha1, hdr->sha1, 20))
239 return error("bad header sha1");
240 return 0;
241}
242
243int read_cache(void)
244{
245 int fd, i;
246 struct stat st;
247 unsigned long size, offset;
248 void *map;
249 struct cache_header *hdr;
250
251 errno = EBUSY;
252 if (active_cache)
253 return error("more than one cachefile");
254 errno = ENOENT;
255 sha1_file_directory = getenv(DB_ENVIRONMENT);
256 if (!sha1_file_directory)
257 sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
258 if (access(sha1_file_directory, X_OK) < 0)
259 return error("no access to SHA1 file directory");
260 fd = open(".dircache/index", O_RDONLY);
261 if (fd < 0)
262 return (errno == ENOENT) ? 0 : error("open failed");
263
19b2860c 264 size = 0; // avoid gcc warning
e83c5163
LT
265 map = (void *)-1;
266 if (!fstat(fd, &st)) {
e83c5163
LT
267 size = st.st_size;
268 errno = EINVAL;
59c1e249 269 if (size >= sizeof(struct cache_header))
e83c5163
LT
270 map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
271 }
272 close(fd);
273 if (-1 == (int)(long)map)
274 return error("mmap failed");
275
276 hdr = map;
277 if (verify_hdr(hdr, size) < 0)
278 goto unmap;
279
280 active_nr = hdr->entries;
281 active_alloc = alloc_nr(active_nr);
282 active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
283
284 offset = sizeof(*hdr);
285 for (i = 0; i < hdr->entries; i++) {
286 struct cache_entry *ce = map + offset;
287 offset = offset + ce_size(ce);
288 active_cache[i] = ce;
289 }
290 return active_nr;
291
292unmap:
293 munmap(map, size);
294 errno = EINVAL;
295 return error("verify header failed");
296}
297