1#include "refs.h"
2#include "cache.h"
3#include <errno.h>
5static int read_ref(const char *path, unsigned char *sha1)
7{
8 int ret = -1;
9 int fd = open(path, O_RDONLY);
10 if (fd >= 0) {
12 char buffer[60];
13 if (read(fd, buffer, sizeof(buffer)) >= 40)
14 ret = get_sha1_hex(buffer, sha1);
15 close(fd);
16 }
17 return ret;
18}
19static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1))
21{
22 int retval = 0;
23 DIR *dir = opendir(base);
24 if (dir) {
26 struct dirent *de;
27 int baselen = strlen(base);
28 char *path = xmalloc(baselen + 257);
29 if (!strncmp(base, "./", 2)) {
31 base += 2;
32 baselen -= 2;
33 }
34 memcpy(path, base, baselen);
35 if (baselen && base[baselen-1] != '/')
36 path[baselen++] = '/';
37 while ((de = readdir(dir)) != NULL) {
39 unsigned char sha1[20];
40 struct stat st;
41 int namelen;
42 if (de->d_name[0] == '.')
44 continue;
45 namelen = strlen(de->d_name);
46 if (namelen > 255)
47 continue;
48 memcpy(path + baselen, de->d_name, namelen+1);
49 if (lstat(path, &st) < 0)
50 continue;
51 if (S_ISDIR(st.st_mode)) {
52 retval = do_for_each_ref(path, fn);
53 if (retval)
54 break;
55 continue;
56 }
57 if (read_ref(path, sha1) < 0)
58 continue;
59 if (!has_sha1_file(sha1))
60 continue;
61 retval = fn(path, sha1);
62 if (retval)
63 break;
64 }
65 free(path);
66 closedir(dir);
67 }
68 return retval;
69}
70int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
72{
73 unsigned char sha1[20];
74 const char *headpath = git_path("HEAD");
75 if (!read_ref(headpath, sha1))
76 return fn(headpath, sha1);
77 return 0;
78}
79int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
81{
82 return do_for_each_ref(get_refs_directory(), fn);
83}
84static char *ref_file_name(const char *ref)
86{
87 char *base = get_refs_directory();
88 int baselen = strlen(base);
89 int reflen = strlen(ref);
90 char *ret = xmalloc(baselen + 2 + reflen);
91 sprintf(ret, "%s/%s", base, ref);
92 return ret;
93}
94static char *ref_lock_file_name(const char *ref)
96{
97 char *base = get_refs_directory();
98 int baselen = strlen(base);
99 int reflen = strlen(ref);
100 char *ret = xmalloc(baselen + 7 + reflen);
101 sprintf(ret, "%s/%s.lock", base, ref);
102 return ret;
103}
104static int read_ref_file(const char *filename, unsigned char *sha1) {
106 int fd = open(filename, O_RDONLY);
107 char hex[41];
108 if (fd < 0) {
109 return error("Couldn't open %s\n", filename);
110 }
111 if ((read(fd, hex, 41) < 41) ||
112 (hex[40] != '\n') ||
113 get_sha1_hex(hex, sha1)) {
114 error("Couldn't read a hash from %s\n", filename);
115 close(fd);
116 return -1;
117 }
118 close(fd);
119 return 0;
120}
121int get_ref_sha1(const char *ref, unsigned char *sha1)
123{
124 char *filename;
125 int retval;
126 if (check_ref_format(ref))
127 return -1;
128 filename = ref_file_name(ref);
129 retval = read_ref_file(filename, sha1);
130 free(filename);
131 return retval;
132}
133static int lock_ref_file(const char *filename, const char *lock_filename,
135 const unsigned char *old_sha1)
136{
137 int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
138 unsigned char current_sha1[20];
139 int retval;
140 if (fd < 0) {
141 return error("Couldn't open lock file for %s: %s",
142 filename, strerror(errno));
143 }
144 retval = read_ref_file(filename, current_sha1);
145 if (old_sha1) {
146 if (retval) {
147 close(fd);
148 unlink(lock_filename);
149 return error("Could not read the current value of %s",
150 filename);
151 }
152 if (memcmp(current_sha1, old_sha1, 20)) {
153 close(fd);
154 unlink(lock_filename);
155 error("The current value of %s is %s",
156 filename, sha1_to_hex(current_sha1));
157 return error("Expected %s",
158 sha1_to_hex(old_sha1));
159 }
160 } else {
161 if (!retval) {
162 close(fd);
163 unlink(lock_filename);
164 return error("Unexpectedly found a value of %s for %s",
165 sha1_to_hex(current_sha1), filename);
166 }
167 }
168 return fd;
169}
170int lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
172{
173 char *filename;
174 char *lock_filename;
175 int retval;
176 if (check_ref_format(ref))
177 return -1;
178 filename = ref_file_name(ref);
179 lock_filename = ref_lock_file_name(ref);
180 retval = lock_ref_file(filename, lock_filename, old_sha1);
181 free(filename);
182 free(lock_filename);
183 return retval;
184}
185static int write_ref_file(const char *filename,
187 const char *lock_filename, int fd,
188 const unsigned char *sha1)
189{
190 char *hex = sha1_to_hex(sha1);
191 char term = '\n';
192 if (write(fd, hex, 40) < 40 ||
193 write(fd, &term, 1) < 1) {
194 error("Couldn't write %s\n", filename);
195 close(fd);
196 return -1;
197 }
198 close(fd);
199 rename(lock_filename, filename);
200 return 0;
201}
202int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
204{
205 char *filename;
206 char *lock_filename;
207 int retval;
208 if (fd < 0)
209 return -1;
210 if (check_ref_format(ref))
211 return -1;
212 filename = ref_file_name(ref);
213 lock_filename = ref_lock_file_name(ref);
214 retval = write_ref_file(filename, lock_filename, fd, sha1);
215 free(filename);
216 free(lock_filename);
217 return retval;
218}
219int check_ref_format(const char *ref)
221{
222 char *middle;
223 if (ref[0] == '.' || ref[0] == '/')
224 return -1;
225 middle = strchr(ref, '/');
226 if (!middle || !middle[1])
227 return -1;
228 if (strchr(middle + 1, '/'))
229 return -1;
230 return 0;
231}
232int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
234{
235 char *filename;
236 char *lock_filename;
237 int fd;
238 int retval;
239 if (check_ref_format(ref))
240 return -1;
241 filename = ref_file_name(ref);
242 lock_filename = ref_lock_file_name(ref);
243 fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
244 if (fd < 0) {
245 error("Writing %s", lock_filename);
246 perror("Open");
247 }
248 retval = write_ref_file(filename, lock_filename, fd, sha1);
249 free(filename);
250 free(lock_filename);
251 return retval;
252}