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diff --git a/cache.c b/cache.c index b701e13..add647e 100644 --- a/ cache.c+++ b/ cache.c |
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@@ -1,247 +1,247 @@ |
1 | /* cache.c: cache management |
1 | /* cache.c: cache management |
2 | * |
2 | * |
3 | * Copyright (C) 2006 Lars Hjemli |
3 | * Copyright (C) 2006 Lars Hjemli |
4 | * |
4 | * |
5 | * Licensed under GNU General Public License v2 |
5 | * Licensed under GNU General Public License v2 |
6 | * (see COPYING for full license text) |
6 | * (see COPYING for full license text) |
7 | * |
7 | * |
8 | * |
8 | * |
9 | * The cache is just a directory structure where each file is a cache slot, |
9 | * The cache is just a directory structure where each file is a cache slot, |
10 | * and each filename is based on the hash of some key (e.g. the cgit url). |
10 | * and each filename is based on the hash of some key (e.g. the cgit url). |
11 | * Each file contains the full key followed by the cached content for that |
11 | * Each file contains the full key followed by the cached content for that |
12 | * key. |
12 | * key. |
13 | * |
13 | * |
14 | */ |
14 | */ |
15 | |
15 | |
16 | #include "cgit.h" |
16 | #include "cgit.h" |
17 | #include "cache.h" |
17 | #include "cache.h" |
18 | |
18 | |
19 | #define CACHE_BUFSIZE (1024 * 4) |
19 | #define CACHE_BUFSIZE (1024 * 4) |
20 | |
20 | |
21 | struct cache_slot { |
21 | struct cache_slot { |
22 | const char *key; |
22 | const char *key; |
23 | int keylen; |
23 | int keylen; |
24 | int ttl; |
24 | int ttl; |
25 | cache_fill_fn fn; |
25 | cache_fill_fn fn; |
26 | void *cbdata; |
26 | void *cbdata; |
27 | int cache_fd; |
27 | int cache_fd; |
28 | int lock_fd; |
28 | int lock_fd; |
29 | const char *cache_name; |
29 | const char *cache_name; |
30 | const char *lock_name; |
30 | const char *lock_name; |
31 | int match; |
31 | int match; |
32 | struct stat cache_st; |
32 | struct stat cache_st; |
33 | struct stat lock_st; |
33 | struct stat lock_st; |
34 | int bufsize; |
34 | int bufsize; |
35 | char buf[CACHE_BUFSIZE]; |
35 | char buf[CACHE_BUFSIZE]; |
36 | }; |
36 | }; |
37 | |
37 | |
38 | /* Open an existing cache slot and fill the cache buffer with |
38 | /* Open an existing cache slot and fill the cache buffer with |
39 | * (part of) the content of the cache file. Return 0 on success |
39 | * (part of) the content of the cache file. Return 0 on success |
40 | * and errno otherwise. |
40 | * and errno otherwise. |
41 | */ |
41 | */ |
42 | static int open_slot(struct cache_slot *slot) |
42 | static int open_slot(struct cache_slot *slot) |
43 | { |
43 | { |
44 | char *bufz; |
44 | char *bufz; |
45 | int bufkeylen = -1; |
45 | int bufkeylen = -1; |
46 | |
46 | |
47 | slot->cache_fd = open(slot->cache_name, O_RDONLY); |
47 | slot->cache_fd = open(slot->cache_name, O_RDONLY); |
48 | if (slot->cache_fd == -1) |
48 | if (slot->cache_fd == -1) |
49 | return errno; |
49 | return errno; |
50 | |
50 | |
51 | if (fstat(slot->cache_fd, &slot->cache_st)) |
51 | if (fstat(slot->cache_fd, &slot->cache_st)) |
52 | return errno; |
52 | return errno; |
53 | |
53 | |
54 | slot->bufsize = read(slot->cache_fd, slot->buf, sizeof(slot->buf)); |
54 | slot->bufsize = read(slot->cache_fd, slot->buf, sizeof(slot->buf)); |
55 | if (slot->bufsize == 0) |
55 | if (slot->bufsize < 0) |
56 | return errno; |
56 | return errno; |
57 | |
57 | |
58 | bufz = memchr(slot->buf, 0, slot->bufsize); |
58 | bufz = memchr(slot->buf, 0, slot->bufsize); |
59 | if (bufz) |
59 | if (bufz) |
60 | bufkeylen = bufz - slot->buf; |
60 | bufkeylen = bufz - slot->buf; |
61 | |
61 | |
62 | slot->match = bufkeylen == slot->keylen && |
62 | slot->match = bufkeylen == slot->keylen && |
63 | !memcmp(slot->key, slot->buf, bufkeylen + 1); |
63 | !memcmp(slot->key, slot->buf, bufkeylen + 1); |
64 | |
64 | |
65 | return 0; |
65 | return 0; |
66 | } |
66 | } |
67 | |
67 | |
68 | /* Close the active cache slot */ |
68 | /* Close the active cache slot */ |
69 | static void close_slot(struct cache_slot *slot) |
69 | static void close_slot(struct cache_slot *slot) |
70 | { |
70 | { |
71 | if (slot->cache_fd > 0) { |
71 | if (slot->cache_fd > 0) { |
72 | close(slot->cache_fd); |
72 | close(slot->cache_fd); |
73 | slot->cache_fd = -1; |
73 | slot->cache_fd = -1; |
74 | } |
74 | } |
75 | } |
75 | } |
76 | |
76 | |
77 | /* Print the content of the active cache slot (but skip the key). */ |
77 | /* Print the content of the active cache slot (but skip the key). */ |
78 | static int print_slot(struct cache_slot *slot) |
78 | static int print_slot(struct cache_slot *slot) |
79 | { |
79 | { |
80 | ssize_t i, j = 0; |
80 | ssize_t i, j = 0; |
81 | |
81 | |
82 | i = lseek(slot->cache_fd, slot->keylen + 1, SEEK_SET); |
82 | i = lseek(slot->cache_fd, slot->keylen + 1, SEEK_SET); |
83 | if (i != slot->keylen + 1) |
83 | if (i != slot->keylen + 1) |
84 | return errno; |
84 | return errno; |
85 | |
85 | |
86 | while((i=read(slot->cache_fd, slot->buf, sizeof(slot->buf))) > 0) |
86 | while((i=read(slot->cache_fd, slot->buf, sizeof(slot->buf))) > 0) |
87 | j = write(STDOUT_FILENO, slot->buf, i); |
87 | j = write(STDOUT_FILENO, slot->buf, i); |
88 | |
88 | |
89 | if (j < 0) |
89 | if (j < 0) |
90 | return errno; |
90 | return errno; |
91 | else |
91 | else |
92 | return 0; |
92 | return 0; |
93 | } |
93 | } |
94 | |
94 | |
95 | /* Check if the slot has expired */ |
95 | /* Check if the slot has expired */ |
96 | static int is_expired(struct cache_slot *slot) |
96 | static int is_expired(struct cache_slot *slot) |
97 | { |
97 | { |
98 | if (slot->ttl < 0) |
98 | if (slot->ttl < 0) |
99 | return 0; |
99 | return 0; |
100 | else |
100 | else |
101 | return slot->cache_st.st_mtime + slot->ttl*60 < time(NULL); |
101 | return slot->cache_st.st_mtime + slot->ttl*60 < time(NULL); |
102 | } |
102 | } |
103 | |
103 | |
104 | /* Check if the slot has been modified since we opened it. |
104 | /* Check if the slot has been modified since we opened it. |
105 | * NB: If stat() fails, we pretend the file is modified. |
105 | * NB: If stat() fails, we pretend the file is modified. |
106 | */ |
106 | */ |
107 | static int is_modified(struct cache_slot *slot) |
107 | static int is_modified(struct cache_slot *slot) |
108 | { |
108 | { |
109 | struct stat st; |
109 | struct stat st; |
110 | |
110 | |
111 | if (stat(slot->cache_name, &st)) |
111 | if (stat(slot->cache_name, &st)) |
112 | return 1; |
112 | return 1; |
113 | return (st.st_ino != slot->cache_st.st_ino || |
113 | return (st.st_ino != slot->cache_st.st_ino || |
114 | st.st_mtime != slot->cache_st.st_mtime || |
114 | st.st_mtime != slot->cache_st.st_mtime || |
115 | st.st_size != slot->cache_st.st_size); |
115 | st.st_size != slot->cache_st.st_size); |
116 | } |
116 | } |
117 | |
117 | |
118 | /* Close an open lockfile */ |
118 | /* Close an open lockfile */ |
119 | static void close_lock(struct cache_slot *slot) |
119 | static void close_lock(struct cache_slot *slot) |
120 | { |
120 | { |
121 | if (slot->lock_fd > 0) { |
121 | if (slot->lock_fd > 0) { |
122 | close(slot->lock_fd); |
122 | close(slot->lock_fd); |
123 | slot->lock_fd = -1; |
123 | slot->lock_fd = -1; |
124 | } |
124 | } |
125 | } |
125 | } |
126 | |
126 | |
127 | /* Create a lockfile used to store the generated content for a cache |
127 | /* Create a lockfile used to store the generated content for a cache |
128 | * slot, and write the slot key + \0 into it. |
128 | * slot, and write the slot key + \0 into it. |
129 | * Returns 0 on success and errno otherwise. |
129 | * Returns 0 on success and errno otherwise. |
130 | */ |
130 | */ |
131 | static int lock_slot(struct cache_slot *slot) |
131 | static int lock_slot(struct cache_slot *slot) |
132 | { |
132 | { |
133 | slot->lock_fd = open(slot->lock_name, O_RDWR|O_CREAT|O_EXCL, |
133 | slot->lock_fd = open(slot->lock_name, O_RDWR|O_CREAT|O_EXCL, |
134 | S_IRUSR|S_IWUSR); |
134 | S_IRUSR|S_IWUSR); |
135 | if (slot->lock_fd == -1) |
135 | if (slot->lock_fd == -1) |
136 | return errno; |
136 | return errno; |
137 | write(slot->lock_fd, slot->key, slot->keylen + 1); |
137 | write(slot->lock_fd, slot->key, slot->keylen + 1); |
138 | return 0; |
138 | return 0; |
139 | } |
139 | } |
140 | |
140 | |
141 | /* Release the current lockfile. If `replace_old_slot` is set the |
141 | /* Release the current lockfile. If `replace_old_slot` is set the |
142 | * lockfile replaces the old cache slot, otherwise the lockfile is |
142 | * lockfile replaces the old cache slot, otherwise the lockfile is |
143 | * just deleted. |
143 | * just deleted. |
144 | */ |
144 | */ |
145 | static int unlock_slot(struct cache_slot *slot, int replace_old_slot) |
145 | static int unlock_slot(struct cache_slot *slot, int replace_old_slot) |
146 | { |
146 | { |
147 | int err; |
147 | int err; |
148 | |
148 | |
149 | if (replace_old_slot) |
149 | if (replace_old_slot) |
150 | err = rename(slot->lock_name, slot->cache_name); |
150 | err = rename(slot->lock_name, slot->cache_name); |
151 | else |
151 | else |
152 | err = unlink(slot->lock_name); |
152 | err = unlink(slot->lock_name); |
153 | return err; |
153 | return err; |
154 | } |
154 | } |
155 | |
155 | |
156 | /* Generate the content for the current cache slot by redirecting |
156 | /* Generate the content for the current cache slot by redirecting |
157 | * stdout to the lock-fd and invoking the callback function |
157 | * stdout to the lock-fd and invoking the callback function |
158 | */ |
158 | */ |
159 | static int fill_slot(struct cache_slot *slot) |
159 | static int fill_slot(struct cache_slot *slot) |
160 | { |
160 | { |
161 | int tmp; |
161 | int tmp; |
162 | |
162 | |
163 | /* Preserve stdout */ |
163 | /* Preserve stdout */ |
164 | tmp = dup(STDOUT_FILENO); |
164 | tmp = dup(STDOUT_FILENO); |
165 | if (tmp == -1) |
165 | if (tmp == -1) |
166 | return errno; |
166 | return errno; |
167 | |
167 | |
168 | /* Redirect stdout to lockfile */ |
168 | /* Redirect stdout to lockfile */ |
169 | if (dup2(slot->lock_fd, STDOUT_FILENO) == -1) |
169 | if (dup2(slot->lock_fd, STDOUT_FILENO) == -1) |
170 | return errno; |
170 | return errno; |
171 | |
171 | |
172 | /* Generate cache content */ |
172 | /* Generate cache content */ |
173 | slot->fn(slot->cbdata); |
173 | slot->fn(slot->cbdata); |
174 | |
174 | |
175 | /* Restore stdout */ |
175 | /* Restore stdout */ |
176 | if (dup2(tmp, STDOUT_FILENO) == -1) |
176 | if (dup2(tmp, STDOUT_FILENO) == -1) |
177 | return errno; |
177 | return errno; |
178 | |
178 | |
179 | /* Close the temporary filedescriptor */ |
179 | /* Close the temporary filedescriptor */ |
180 | close(tmp); |
180 | close(tmp); |
181 | return 0; |
181 | return 0; |
182 | } |
182 | } |
183 | |
183 | |
184 | /* Crude implementation of 32-bit FNV-1 hash algorithm, |
184 | /* Crude implementation of 32-bit FNV-1 hash algorithm, |
185 | * see http://www.isthe.com/chongo/tech/comp/fnv/ for details |
185 | * see http://www.isthe.com/chongo/tech/comp/fnv/ for details |
186 | * about the magic numbers. |
186 | * about the magic numbers. |
187 | */ |
187 | */ |
188 | #define FNV_OFFSET 0x811c9dc5 |
188 | #define FNV_OFFSET 0x811c9dc5 |
189 | #define FNV_PRIME 0x01000193 |
189 | #define FNV_PRIME 0x01000193 |
190 | |
190 | |
191 | unsigned long hash_str(const char *str) |
191 | unsigned long hash_str(const char *str) |
192 | { |
192 | { |
193 | unsigned long h = FNV_OFFSET; |
193 | unsigned long h = FNV_OFFSET; |
194 | unsigned char *s = (unsigned char *)str; |
194 | unsigned char *s = (unsigned char *)str; |
195 | |
195 | |
196 | if (!s) |
196 | if (!s) |
197 | return h; |
197 | return h; |
198 | |
198 | |
199 | while(*s) { |
199 | while(*s) { |
200 | h *= FNV_PRIME; |
200 | h *= FNV_PRIME; |
201 | h ^= *s++; |
201 | h ^= *s++; |
202 | } |
202 | } |
203 | return h; |
203 | return h; |
204 | } |
204 | } |
205 | |
205 | |
206 | static int process_slot(struct cache_slot *slot) |
206 | static int process_slot(struct cache_slot *slot) |
207 | { |
207 | { |
208 | int err; |
208 | int err; |
209 | |
209 | |
210 | err = open_slot(slot); |
210 | err = open_slot(slot); |
211 | if (!err && slot->match) { |
211 | if (!err && slot->match) { |
212 | if (is_expired(slot)) { |
212 | if (is_expired(slot)) { |
213 | if (!lock_slot(slot)) { |
213 | if (!lock_slot(slot)) { |
214 | /* If the cachefile has been replaced between |
214 | /* If the cachefile has been replaced between |
215 | * `open_slot` and `lock_slot`, we'll just |
215 | * `open_slot` and `lock_slot`, we'll just |
216 | * serve the stale content from the original |
216 | * serve the stale content from the original |
217 | * cachefile. This way we avoid pruning the |
217 | * cachefile. This way we avoid pruning the |
218 | * newly generated slot. The same code-path |
218 | * newly generated slot. The same code-path |
219 | * is chosen if fill_slot() fails for some |
219 | * is chosen if fill_slot() fails for some |
220 | * reason. |
220 | * reason. |
221 | * |
221 | * |
222 | * TODO? check if the new slot contains the |
222 | * TODO? check if the new slot contains the |
223 | * same key as the old one, since we would |
223 | * same key as the old one, since we would |
224 | * prefer to serve the newest content. |
224 | * prefer to serve the newest content. |
225 | * This will require us to open yet another |
225 | * This will require us to open yet another |
226 | * file-descriptor and read and compare the |
226 | * file-descriptor and read and compare the |
227 | * key from the new file, so for now we're |
227 | * key from the new file, so for now we're |
228 | * lazy and just ignore the new file. |
228 | * lazy and just ignore the new file. |
229 | */ |
229 | */ |
230 | if (is_modified(slot) || fill_slot(slot)) { |
230 | if (is_modified(slot) || fill_slot(slot)) { |
231 | unlock_slot(slot, 0); |
231 | unlock_slot(slot, 0); |
232 | close_lock(slot); |
232 | close_lock(slot); |
233 | } else { |
233 | } else { |
234 | close_slot(slot); |
234 | close_slot(slot); |
235 | unlock_slot(slot, 1); |
235 | unlock_slot(slot, 1); |
236 | slot->cache_fd = slot->lock_fd; |
236 | slot->cache_fd = slot->lock_fd; |
237 | } |
237 | } |
238 | } |
238 | } |
239 | } |
239 | } |
240 | print_slot(slot); |
240 | print_slot(slot); |
241 | close_slot(slot); |
241 | close_slot(slot); |
242 | return 0; |
242 | return 0; |
243 | } |
243 | } |
244 | |
244 | |
245 | /* If the cache slot does not exist (or its key doesn't match the |
245 | /* If the cache slot does not exist (or its key doesn't match the |
246 | * current key), lets try to create a new cache slot for this |
246 | * current key), lets try to create a new cache slot for this |
247 | * request. If this fails (for whatever reason), lets just generate |
247 | * request. If this fails (for whatever reason), lets just generate |
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