hashmap: add usage documentation explaining hashmap_free[_entries]()
[git] / fsmonitor.c
1 #include "cache.h"
2 #include "config.h"
3 #include "dir.h"
4 #include "ewah/ewok.h"
5 #include "fsmonitor.h"
6 #include "run-command.h"
7 #include "strbuf.h"
8
9 #define INDEX_EXTENSION_VERSION1        (1)
10 #define INDEX_EXTENSION_VERSION2        (2)
11 #define HOOK_INTERFACE_VERSION1         (1)
12 #define HOOK_INTERFACE_VERSION2         (2)
13
14 struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);
15
16 static void fsmonitor_ewah_callback(size_t pos, void *is)
17 {
18         struct index_state *istate = (struct index_state *)is;
19         struct cache_entry *ce;
20
21         if (pos >= istate->cache_nr)
22                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" >= %u)",
23                     (uintmax_t)pos, istate->cache_nr);
24
25         ce = istate->cache[pos];
26         ce->ce_flags &= ~CE_FSMONITOR_VALID;
27 }
28
29 static int fsmonitor_hook_version(void)
30 {
31         int hook_version;
32
33         if (git_config_get_int("core.fsmonitorhookversion", &hook_version))
34                 return -1;
35
36         if (hook_version == HOOK_INTERFACE_VERSION1 ||
37             hook_version == HOOK_INTERFACE_VERSION2)
38                 return hook_version;
39
40         warning("Invalid hook version '%i' in core.fsmonitorhookversion. "
41                 "Must be 1 or 2.", hook_version);
42         return -1;
43 }
44
45 int read_fsmonitor_extension(struct index_state *istate, const void *data,
46         unsigned long sz)
47 {
48         const char *index = data;
49         uint32_t hdr_version;
50         uint32_t ewah_size;
51         struct ewah_bitmap *fsmonitor_dirty;
52         int ret;
53         uint64_t timestamp;
54         struct strbuf last_update = STRBUF_INIT;
55
56         if (sz < sizeof(uint32_t) + 1 + sizeof(uint32_t))
57                 return error("corrupt fsmonitor extension (too short)");
58
59         hdr_version = get_be32(index);
60         index += sizeof(uint32_t);
61         if (hdr_version == INDEX_EXTENSION_VERSION1) {
62                 timestamp = get_be64(index);
63                 strbuf_addf(&last_update, "%"PRIu64"", timestamp);
64                 index += sizeof(uint64_t);
65         } else if (hdr_version == INDEX_EXTENSION_VERSION2) {
66                 strbuf_addstr(&last_update, index);
67                 index += last_update.len + 1;
68         } else {
69                 return error("bad fsmonitor version %d", hdr_version);
70         }
71
72         istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
73
74         ewah_size = get_be32(index);
75         index += sizeof(uint32_t);
76
77         fsmonitor_dirty = ewah_new();
78         ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size);
79         if (ret != ewah_size) {
80                 ewah_free(fsmonitor_dirty);
81                 return error("failed to parse ewah bitmap reading fsmonitor index extension");
82         }
83         istate->fsmonitor_dirty = fsmonitor_dirty;
84
85         if (!istate->split_index &&
86             istate->fsmonitor_dirty->bit_size > istate->cache_nr)
87                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
88                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
89
90         trace_printf_key(&trace_fsmonitor, "read fsmonitor extension successful");
91         return 0;
92 }
93
94 void fill_fsmonitor_bitmap(struct index_state *istate)
95 {
96         unsigned int i, skipped = 0;
97         istate->fsmonitor_dirty = ewah_new();
98         for (i = 0; i < istate->cache_nr; i++) {
99                 if (istate->cache[i]->ce_flags & CE_REMOVE)
100                         skipped++;
101                 else if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
102                         ewah_set(istate->fsmonitor_dirty, i - skipped);
103         }
104 }
105
106 void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
107 {
108         uint32_t hdr_version;
109         uint32_t ewah_start;
110         uint32_t ewah_size = 0;
111         int fixup = 0;
112
113         if (!istate->split_index &&
114             istate->fsmonitor_dirty->bit_size > istate->cache_nr)
115                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
116                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
117
118         put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
119         strbuf_add(sb, &hdr_version, sizeof(uint32_t));
120
121         strbuf_addstr(sb, istate->fsmonitor_last_update);
122         strbuf_addch(sb, 0); /* Want to keep a NUL */
123
124         fixup = sb->len;
125         strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
126
127         ewah_start = sb->len;
128         ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
129         ewah_free(istate->fsmonitor_dirty);
130         istate->fsmonitor_dirty = NULL;
131
132         /* fix up size field */
133         put_be32(&ewah_size, sb->len - ewah_start);
134         memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));
135
136         trace_printf_key(&trace_fsmonitor, "write fsmonitor extension successful");
137 }
138
139 /*
140  * Call the query-fsmonitor hook passing the last update token of the saved results.
141  */
142 static int query_fsmonitor(int version, const char *last_update, struct strbuf *query_result)
143 {
144         struct child_process cp = CHILD_PROCESS_INIT;
145
146         if (!core_fsmonitor)
147                 return -1;
148
149         strvec_push(&cp.args, core_fsmonitor);
150         strvec_pushf(&cp.args, "%d", version);
151         strvec_pushf(&cp.args, "%s", last_update);
152         cp.use_shell = 1;
153         cp.dir = get_git_work_tree();
154
155         return capture_command(&cp, query_result, 1024);
156 }
157
158 static void fsmonitor_refresh_callback(struct index_state *istate, const char *name)
159 {
160         int pos = index_name_pos(istate, name, strlen(name));
161
162         if (pos >= 0) {
163                 struct cache_entry *ce = istate->cache[pos];
164                 ce->ce_flags &= ~CE_FSMONITOR_VALID;
165         }
166
167         /*
168          * Mark the untracked cache dirty even if it wasn't found in the index
169          * as it could be a new untracked file.
170          */
171         trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
172         untracked_cache_invalidate_path(istate, name, 0);
173 }
174
175 void refresh_fsmonitor(struct index_state *istate)
176 {
177         struct strbuf query_result = STRBUF_INIT;
178         int query_success = 0, hook_version = -1;
179         size_t bol = 0; /* beginning of line */
180         uint64_t last_update;
181         struct strbuf last_update_token = STRBUF_INIT;
182         char *buf;
183         unsigned int i;
184
185         if (!core_fsmonitor || istate->fsmonitor_has_run_once)
186                 return;
187
188         hook_version = fsmonitor_hook_version();
189
190         istate->fsmonitor_has_run_once = 1;
191
192         trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
193         /*
194          * This could be racy so save the date/time now and query_fsmonitor
195          * should be inclusive to ensure we don't miss potential changes.
196          */
197         last_update = getnanotime();
198         if (hook_version == HOOK_INTERFACE_VERSION1)
199                 strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
200
201         /*
202          * If we have a last update token, call query_fsmonitor for the set of
203          * changes since that token, else assume everything is possibly dirty
204          * and check it all.
205          */
206         if (istate->fsmonitor_last_update) {
207                 if (hook_version == -1 || hook_version == HOOK_INTERFACE_VERSION2) {
208                         query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION2,
209                                 istate->fsmonitor_last_update, &query_result);
210
211                         if (query_success) {
212                                 if (hook_version < 0)
213                                         hook_version = HOOK_INTERFACE_VERSION2;
214
215                                 /*
216                                  * First entry will be the last update token
217                                  * Need to use a char * variable because static
218                                  * analysis was suggesting to use strbuf_addbuf
219                                  * but we don't want to copy the entire strbuf
220                                  * only the chars up to the first NUL
221                                  */
222                                 buf = query_result.buf;
223                                 strbuf_addstr(&last_update_token, buf);
224                                 if (!last_update_token.len) {
225                                         warning("Empty last update token.");
226                                         query_success = 0;
227                                 } else {
228                                         bol = last_update_token.len + 1;
229                                 }
230                         } else if (hook_version < 0) {
231                                 hook_version = HOOK_INTERFACE_VERSION1;
232                                 if (!last_update_token.len)
233                                         strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
234                         }
235                 }
236
237                 if (hook_version == HOOK_INTERFACE_VERSION1) {
238                         query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
239                                 istate->fsmonitor_last_update, &query_result);
240                 }
241
242                 trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
243                 trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
244                         core_fsmonitor, query_success ? "success" : "failure");
245         }
246
247         /* a fsmonitor process can return '/' to indicate all entries are invalid */
248         if (query_success && query_result.buf[bol] != '/') {
249                 /* Mark all entries returned by the monitor as dirty */
250                 buf = query_result.buf;
251                 for (i = bol; i < query_result.len; i++) {
252                         if (buf[i] != '\0')
253                                 continue;
254                         fsmonitor_refresh_callback(istate, buf + bol);
255                         bol = i + 1;
256                 }
257                 if (bol < query_result.len)
258                         fsmonitor_refresh_callback(istate, buf + bol);
259
260                 /* Now mark the untracked cache for fsmonitor usage */
261                 if (istate->untracked)
262                         istate->untracked->use_fsmonitor = 1;
263         } else {
264
265                 /* We only want to run the post index changed hook if we've actually changed entries, so keep track
266                  * if we actually changed entries or not */
267                 int is_cache_changed = 0;
268                 /* Mark all entries invalid */
269                 for (i = 0; i < istate->cache_nr; i++) {
270                         if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
271                                 is_cache_changed = 1;
272                                 istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
273                         }
274                 }
275
276                 /* If we're going to check every file, ensure we save the results */
277                 if (is_cache_changed)
278                         istate->cache_changed |= FSMONITOR_CHANGED;
279
280                 if (istate->untracked)
281                         istate->untracked->use_fsmonitor = 0;
282         }
283         strbuf_release(&query_result);
284
285         /* Now that we've updated istate, save the last_update_token */
286         FREE_AND_NULL(istate->fsmonitor_last_update);
287         istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
288 }
289
290 void add_fsmonitor(struct index_state *istate)
291 {
292         unsigned int i;
293         struct strbuf last_update = STRBUF_INIT;
294
295         if (!istate->fsmonitor_last_update) {
296                 trace_printf_key(&trace_fsmonitor, "add fsmonitor");
297                 istate->cache_changed |= FSMONITOR_CHANGED;
298                 strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
299                 istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
300
301                 /* reset the fsmonitor state */
302                 for (i = 0; i < istate->cache_nr; i++)
303                         istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
304
305                 /* reset the untracked cache */
306                 if (istate->untracked) {
307                         add_untracked_cache(istate);
308                         istate->untracked->use_fsmonitor = 1;
309                 }
310
311                 /* Update the fsmonitor state */
312                 refresh_fsmonitor(istate);
313         }
314 }
315
316 void remove_fsmonitor(struct index_state *istate)
317 {
318         if (istate->fsmonitor_last_update) {
319                 trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
320                 istate->cache_changed |= FSMONITOR_CHANGED;
321                 FREE_AND_NULL(istate->fsmonitor_last_update);
322         }
323 }
324
325 void tweak_fsmonitor(struct index_state *istate)
326 {
327         unsigned int i;
328         int fsmonitor_enabled = git_config_get_fsmonitor();
329
330         if (istate->fsmonitor_dirty) {
331                 if (fsmonitor_enabled) {
332                         /* Mark all entries valid */
333                         for (i = 0; i < istate->cache_nr; i++) {
334                                 istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
335                         }
336
337                         /* Mark all previously saved entries as dirty */
338                         if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
339                                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
340                                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
341                         ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
342
343                         refresh_fsmonitor(istate);
344                 }
345
346                 ewah_free(istate->fsmonitor_dirty);
347                 istate->fsmonitor_dirty = NULL;
348         }
349
350         switch (fsmonitor_enabled) {
351         case -1: /* keep: do nothing */
352                 break;
353         case 0: /* false */
354                 remove_fsmonitor(istate);
355                 break;
356         case 1: /* true */
357                 add_fsmonitor(istate);
358                 break;
359         default: /* unknown value: do nothing */
360                 break;
361         }
362 }