git.oblomov.eu Git - git/blob - 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         trace2_data_string("index", NULL, "extension/fsmn/read/token",
  91                            istate->fsmonitor_last_update);
  92         trace_printf_key(&trace_fsmonitor,
  93                          "read fsmonitor extension successful '%s'",
  94                          istate->fsmonitor_last_update);
  95         return 0;
  96 }
  97
  98 void fill_fsmonitor_bitmap(struct index_state *istate)
  99 {
 100         unsigned int i, skipped = 0;
 101         istate->fsmonitor_dirty = ewah_new();
 102         for (i = 0; i < istate->cache_nr; i++) {
 103                 if (istate->cache[i]->ce_flags & CE_REMOVE)
 104                         skipped++;
 105                 else if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
 106                         ewah_set(istate->fsmonitor_dirty, i - skipped);
 107         }
 108 }
 109
 110 void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
 111 {
 112         uint32_t hdr_version;
 113         uint32_t ewah_start;
 114         uint32_t ewah_size = 0;
 115         int fixup = 0;
 116
 117         if (!istate->split_index &&
 118             istate->fsmonitor_dirty->bit_size > istate->cache_nr)
 119                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
 120                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
 121
 122         put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
 123         strbuf_add(sb, &hdr_version, sizeof(uint32_t));
 124
 125         strbuf_addstr(sb, istate->fsmonitor_last_update);
 126         strbuf_addch(sb, 0); /* Want to keep a NUL */
 127
 128         fixup = sb->len;
 129         strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
 130
 131         ewah_start = sb->len;
 132         ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
 133         ewah_free(istate->fsmonitor_dirty);
 134         istate->fsmonitor_dirty = NULL;
 135
 136         /* fix up size field */
 137         put_be32(&ewah_size, sb->len - ewah_start);
 138         memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));
 139
 140         trace2_data_string("index", NULL, "extension/fsmn/write/token",
 141                            istate->fsmonitor_last_update);
 142         trace_printf_key(&trace_fsmonitor,
 143                          "write fsmonitor extension successful '%s'",
 144                          istate->fsmonitor_last_update);
 145 }
 146
 147 /*
 148  * Call the query-fsmonitor hook passing the last update token of the saved results.
 149  */
 150 static int query_fsmonitor(int version, const char *last_update, struct strbuf *query_result)
 151 {
 152         struct child_process cp = CHILD_PROCESS_INIT;
 153         int result;
 154
 155         if (!core_fsmonitor)
 156                 return -1;
 157
 158         strvec_push(&cp.args, core_fsmonitor);
 159         strvec_pushf(&cp.args, "%d", version);
 160         strvec_pushf(&cp.args, "%s", last_update);
 161         cp.use_shell = 1;
 162         cp.dir = get_git_work_tree();
 163
 164         trace2_region_enter("fsm_hook", "query", NULL);
 165
 166         result = capture_command(&cp, query_result, 1024);
 167
 168         if (result)
 169                 trace2_data_intmax("fsm_hook", NULL, "query/failed", result);
 170         else {
 171                 trace2_data_intmax("fsm_hook", NULL, "query/response-length",
 172                                    query_result->len);
 173
 174                 if (fsmonitor_is_trivial_response(query_result))
 175                         trace2_data_intmax("fsm_hook", NULL,
 176                                            "query/trivial-response", 1);
 177         }
 178
 179         trace2_region_leave("fsm_hook", "query", NULL);
 180
 181         return result;
 182 }
 183
 184 int fsmonitor_is_trivial_response(const struct strbuf *query_result)
 185 {
 186         static char trivial_response[3] = { '\0', '/', '\0' };
 187         int is_trivial = !memcmp(trivial_response,
 188                                  &query_result->buf[query_result->len - 3], 3);
 189
 190         return is_trivial;
 191 }
 192
 193 static void fsmonitor_refresh_callback(struct index_state *istate, char *name)
 194 {
 195         int i, len = strlen(name);
 196         if (name[len - 1] == '/') {
 197
 198                 /*
 199                  * TODO We should binary search to find the first path with
 200                  * TODO this directory prefix.  Then linearly update entries
 201                  * TODO while the prefix matches.  Taking care to search without
 202                  * TODO the trailing slash -- because '/' sorts after a few
 203                  * TODO interesting special chars, like '.' and ' '.
 204                  */
 205
 206                 /* Mark all entries for the folder invalid */
 207                 for (i = 0; i < istate->cache_nr; i++) {
 208                         if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID &&
 209                             starts_with(istate->cache[i]->name, name))
 210                                 istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
 211                 }
 212                 /* Need to remove the / from the path for the untracked cache */
 213                 name[len - 1] = '\0';
 214         } else {
 215                 int pos = index_name_pos(istate, name, strlen(name));
 216
 217                 if (pos >= 0) {
 218                         struct cache_entry *ce = istate->cache[pos];
 219                         ce->ce_flags &= ~CE_FSMONITOR_VALID;
 220                 }
 221         }
 222
 223         /*
 224          * Mark the untracked cache dirty even if it wasn't found in the index
 225          * as it could be a new untracked file.
 226          */
 227         trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
 228         untracked_cache_invalidate_path(istate, name, 0);
 229 }
 230
 231 void refresh_fsmonitor(struct index_state *istate)
 232 {
 233         struct strbuf query_result = STRBUF_INIT;
 234         int query_success = 0, hook_version = -1;
 235         size_t bol = 0; /* beginning of line */
 236         uint64_t last_update;
 237         struct strbuf last_update_token = STRBUF_INIT;
 238         char *buf;
 239         unsigned int i;
 240
 241         if (!core_fsmonitor || istate->fsmonitor_has_run_once)
 242                 return;
 243
 244         hook_version = fsmonitor_hook_version();
 245
 246         istate->fsmonitor_has_run_once = 1;
 247
 248         trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
 249         /*
 250          * This could be racy so save the date/time now and query_fsmonitor
 251          * should be inclusive to ensure we don't miss potential changes.
 252          */
 253         last_update = getnanotime();
 254         if (hook_version == HOOK_INTERFACE_VERSION1)
 255                 strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
 256
 257         /*
 258          * If we have a last update token, call query_fsmonitor for the set of
 259          * changes since that token, else assume everything is possibly dirty
 260          * and check it all.
 261          */
 262         if (istate->fsmonitor_last_update) {
 263                 if (hook_version == -1 || hook_version == HOOK_INTERFACE_VERSION2) {
 264                         query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION2,
 265                                 istate->fsmonitor_last_update, &query_result);
 266
 267                         if (query_success) {
 268                                 if (hook_version < 0)
 269                                         hook_version = HOOK_INTERFACE_VERSION2;
 270
 271                                 /*
 272                                  * First entry will be the last update token
 273                                  * Need to use a char * variable because static
 274                                  * analysis was suggesting to use strbuf_addbuf
 275                                  * but we don't want to copy the entire strbuf
 276                                  * only the chars up to the first NUL
 277                                  */
 278                                 buf = query_result.buf;
 279                                 strbuf_addstr(&last_update_token, buf);
 280                                 if (!last_update_token.len) {
 281                                         warning("Empty last update token.");
 282                                         query_success = 0;
 283                                 } else {
 284                                         bol = last_update_token.len + 1;
 285                                 }
 286                         } else if (hook_version < 0) {
 287                                 hook_version = HOOK_INTERFACE_VERSION1;
 288                                 if (!last_update_token.len)
 289                                         strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
 290                         }
 291                 }
 292
 293                 if (hook_version == HOOK_INTERFACE_VERSION1) {
 294                         query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
 295                                 istate->fsmonitor_last_update, &query_result);
 296                 }
 297
 298                 trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
 299                 trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
 300                         core_fsmonitor, query_success ? "success" : "failure");
 301         }
 302
 303         /* a fsmonitor process can return '/' to indicate all entries are invalid */
 304         if (query_success && query_result.buf[bol] != '/') {
 305                 /* Mark all entries returned by the monitor as dirty */
 306                 buf = query_result.buf;
 307                 for (i = bol; i < query_result.len; i++) {
 308                         if (buf[i] != '\0')
 309                                 continue;
 310                         fsmonitor_refresh_callback(istate, buf + bol);
 311                         bol = i + 1;
 312                 }
 313                 if (bol < query_result.len)
 314                         fsmonitor_refresh_callback(istate, buf + bol);
 315
 316                 /* Now mark the untracked cache for fsmonitor usage */
 317                 if (istate->untracked)
 318                         istate->untracked->use_fsmonitor = 1;
 319         } else {
 320
 321                 /* We only want to run the post index changed hook if we've actually changed entries, so keep track
 322                  * if we actually changed entries or not */
 323                 int is_cache_changed = 0;
 324                 /* Mark all entries invalid */
 325                 for (i = 0; i < istate->cache_nr; i++) {
 326                         if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
 327                                 is_cache_changed = 1;
 328                                 istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
 329                         }
 330                 }
 331
 332                 /* If we're going to check every file, ensure we save the results */
 333                 if (is_cache_changed)
 334                         istate->cache_changed |= FSMONITOR_CHANGED;
 335
 336                 if (istate->untracked)
 337                         istate->untracked->use_fsmonitor = 0;
 338         }
 339         strbuf_release(&query_result);
 340
 341         /* Now that we've updated istate, save the last_update_token */
 342         FREE_AND_NULL(istate->fsmonitor_last_update);
 343         istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
 344 }
 345
 346 void add_fsmonitor(struct index_state *istate)
 347 {
 348         unsigned int i;
 349         struct strbuf last_update = STRBUF_INIT;
 350
 351         if (!istate->fsmonitor_last_update) {
 352                 trace_printf_key(&trace_fsmonitor, "add fsmonitor");
 353                 istate->cache_changed |= FSMONITOR_CHANGED;
 354                 strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
 355                 istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
 356
 357                 /* reset the fsmonitor state */
 358                 for (i = 0; i < istate->cache_nr; i++)
 359                         istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
 360
 361                 /* reset the untracked cache */
 362                 if (istate->untracked) {
 363                         add_untracked_cache(istate);
 364                         istate->untracked->use_fsmonitor = 1;
 365                 }
 366
 367                 /* Update the fsmonitor state */
 368                 refresh_fsmonitor(istate);
 369         }
 370 }
 371
 372 void remove_fsmonitor(struct index_state *istate)
 373 {
 374         if (istate->fsmonitor_last_update) {
 375                 trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
 376                 istate->cache_changed |= FSMONITOR_CHANGED;
 377                 FREE_AND_NULL(istate->fsmonitor_last_update);
 378         }
 379 }
 380
 381 void tweak_fsmonitor(struct index_state *istate)
 382 {
 383         unsigned int i;
 384         int fsmonitor_enabled = git_config_get_fsmonitor();
 385
 386         if (istate->fsmonitor_dirty) {
 387                 if (fsmonitor_enabled) {
 388                         /* Mark all entries valid */
 389                         for (i = 0; i < istate->cache_nr; i++) {
 390                                 istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
 391                         }
 392
 393                         /* Mark all previously saved entries as dirty */
 394                         if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
 395                                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
 396                                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
 397                         ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
 398
 399                         refresh_fsmonitor(istate);
 400                 }
 401
 402                 ewah_free(istate->fsmonitor_dirty);
 403                 istate->fsmonitor_dirty = NULL;
 404         }
 405
 406         switch (fsmonitor_enabled) {
 407         case -1: /* keep: do nothing */
 408                 break;
 409         case 0: /* false */
 410                 remove_fsmonitor(istate);
 411                 break;
 412         case 1: /* true */
 413                 add_fsmonitor(istate);
 414                 break;
 415         default: /* unknown value: do nothing */
 416                 break;
 417         }
 418 }