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         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         int result;
 146
 147         if (!core_fsmonitor)
 148                 return -1;
 149
 150         strvec_push(&cp.args, core_fsmonitor);
 151         strvec_pushf(&cp.args, "%d", version);
 152         strvec_pushf(&cp.args, "%s", last_update);
 153         cp.use_shell = 1;
 154         cp.dir = get_git_work_tree();
 155
 156         trace2_region_enter("fsm_hook", "query", NULL);
 157
 158         result = capture_command(&cp, query_result, 1024);
 159
 160         if (result)
 161                 trace2_data_intmax("fsm_hook", NULL, "query/failed", result);
 162         else {
 163                 trace2_data_intmax("fsm_hook", NULL, "query/response-length",
 164                                    query_result->len);
 165
 166                 if (fsmonitor_is_trivial_response(query_result))
 167                         trace2_data_intmax("fsm_hook", NULL,
 168                                            "query/trivial-response", 1);
 169         }
 170
 171         trace2_region_leave("fsm_hook", "query", NULL);
 172
 173         return result;
 174 }
 175
 176 int fsmonitor_is_trivial_response(const struct strbuf *query_result)
 177 {
 178         static char trivial_response[3] = { '\0', '/', '\0' };
 179         int is_trivial = !memcmp(trivial_response,
 180                                  &query_result->buf[query_result->len - 3], 3);
 181
 182         return is_trivial;
 183 }
 184
 185 static void fsmonitor_refresh_callback(struct index_state *istate, const char *name)
 186 {
 187         int pos = index_name_pos(istate, name, strlen(name));
 188
 189         if (pos >= 0) {
 190                 struct cache_entry *ce = istate->cache[pos];
 191                 ce->ce_flags &= ~CE_FSMONITOR_VALID;
 192         }
 193
 194         /*
 195          * Mark the untracked cache dirty even if it wasn't found in the index
 196          * as it could be a new untracked file.
 197          */
 198         trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
 199         untracked_cache_invalidate_path(istate, name, 0);
 200 }
 201
 202 void refresh_fsmonitor(struct index_state *istate)
 203 {
 204         struct strbuf query_result = STRBUF_INIT;
 205         int query_success = 0, hook_version = -1;
 206         size_t bol = 0; /* beginning of line */
 207         uint64_t last_update;
 208         struct strbuf last_update_token = STRBUF_INIT;
 209         char *buf;
 210         unsigned int i;
 211
 212         if (!core_fsmonitor || istate->fsmonitor_has_run_once)
 213                 return;
 214
 215         hook_version = fsmonitor_hook_version();
 216
 217         istate->fsmonitor_has_run_once = 1;
 218
 219         trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
 220         /*
 221          * This could be racy so save the date/time now and query_fsmonitor
 222          * should be inclusive to ensure we don't miss potential changes.
 223          */
 224         last_update = getnanotime();
 225         if (hook_version == HOOK_INTERFACE_VERSION1)
 226                 strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
 227
 228         /*
 229          * If we have a last update token, call query_fsmonitor for the set of
 230          * changes since that token, else assume everything is possibly dirty
 231          * and check it all.
 232          */
 233         if (istate->fsmonitor_last_update) {
 234                 if (hook_version == -1 || hook_version == HOOK_INTERFACE_VERSION2) {
 235                         query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION2,
 236                                 istate->fsmonitor_last_update, &query_result);
 237
 238                         if (query_success) {
 239                                 if (hook_version < 0)
 240                                         hook_version = HOOK_INTERFACE_VERSION2;
 241
 242                                 /*
 243                                  * First entry will be the last update token
 244                                  * Need to use a char * variable because static
 245                                  * analysis was suggesting to use strbuf_addbuf
 246                                  * but we don't want to copy the entire strbuf
 247                                  * only the chars up to the first NUL
 248                                  */
 249                                 buf = query_result.buf;
 250                                 strbuf_addstr(&last_update_token, buf);
 251                                 if (!last_update_token.len) {
 252                                         warning("Empty last update token.");
 253                                         query_success = 0;
 254                                 } else {
 255                                         bol = last_update_token.len + 1;
 256                                 }
 257                         } else if (hook_version < 0) {
 258                                 hook_version = HOOK_INTERFACE_VERSION1;
 259                                 if (!last_update_token.len)
 260                                         strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
 261                         }
 262                 }
 263
 264                 if (hook_version == HOOK_INTERFACE_VERSION1) {
 265                         query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
 266                                 istate->fsmonitor_last_update, &query_result);
 267                 }
 268
 269                 trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
 270                 trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
 271                         core_fsmonitor, query_success ? "success" : "failure");
 272         }
 273
 274         /* a fsmonitor process can return '/' to indicate all entries are invalid */
 275         if (query_success && query_result.buf[bol] != '/') {
 276                 /* Mark all entries returned by the monitor as dirty */
 277                 buf = query_result.buf;
 278                 for (i = bol; i < query_result.len; i++) {
 279                         if (buf[i] != '\0')
 280                                 continue;
 281                         fsmonitor_refresh_callback(istate, buf + bol);
 282                         bol = i + 1;
 283                 }
 284                 if (bol < query_result.len)
 285                         fsmonitor_refresh_callback(istate, buf + bol);
 286
 287                 /* Now mark the untracked cache for fsmonitor usage */
 288                 if (istate->untracked)
 289                         istate->untracked->use_fsmonitor = 1;
 290         } else {
 291
 292                 /* We only want to run the post index changed hook if we've actually changed entries, so keep track
 293                  * if we actually changed entries or not */
 294                 int is_cache_changed = 0;
 295                 /* Mark all entries invalid */
 296                 for (i = 0; i < istate->cache_nr; i++) {
 297                         if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
 298                                 is_cache_changed = 1;
 299                                 istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
 300                         }
 301                 }
 302
 303                 /* If we're going to check every file, ensure we save the results */
 304                 if (is_cache_changed)
 305                         istate->cache_changed |= FSMONITOR_CHANGED;
 306
 307                 if (istate->untracked)
 308                         istate->untracked->use_fsmonitor = 0;
 309         }
 310         strbuf_release(&query_result);
 311
 312         /* Now that we've updated istate, save the last_update_token */
 313         FREE_AND_NULL(istate->fsmonitor_last_update);
 314         istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
 315 }
 316
 317 void add_fsmonitor(struct index_state *istate)
 318 {
 319         unsigned int i;
 320         struct strbuf last_update = STRBUF_INIT;
 321
 322         if (!istate->fsmonitor_last_update) {
 323                 trace_printf_key(&trace_fsmonitor, "add fsmonitor");
 324                 istate->cache_changed |= FSMONITOR_CHANGED;
 325                 strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
 326                 istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
 327
 328                 /* reset the fsmonitor state */
 329                 for (i = 0; i < istate->cache_nr; i++)
 330                         istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
 331
 332                 /* reset the untracked cache */
 333                 if (istate->untracked) {
 334                         add_untracked_cache(istate);
 335                         istate->untracked->use_fsmonitor = 1;
 336                 }
 337
 338                 /* Update the fsmonitor state */
 339                 refresh_fsmonitor(istate);
 340         }
 341 }
 342
 343 void remove_fsmonitor(struct index_state *istate)
 344 {
 345         if (istate->fsmonitor_last_update) {
 346                 trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
 347                 istate->cache_changed |= FSMONITOR_CHANGED;
 348                 FREE_AND_NULL(istate->fsmonitor_last_update);
 349         }
 350 }
 351
 352 void tweak_fsmonitor(struct index_state *istate)
 353 {
 354         unsigned int i;
 355         int fsmonitor_enabled = git_config_get_fsmonitor();
 356
 357         if (istate->fsmonitor_dirty) {
 358                 if (fsmonitor_enabled) {
 359                         /* Mark all entries valid */
 360                         for (i = 0; i < istate->cache_nr; i++) {
 361                                 istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
 362                         }
 363
 364                         /* Mark all previously saved entries as dirty */
 365                         if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
 366                                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
 367                                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
 368                         ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
 369
 370                         refresh_fsmonitor(istate);
 371                 }
 372
 373                 ewah_free(istate->fsmonitor_dirty);
 374                 istate->fsmonitor_dirty = NULL;
 375         }
 376
 377         switch (fsmonitor_enabled) {
 378         case -1: /* keep: do nothing */
 379                 break;
 380         case 0: /* false */
 381                 remove_fsmonitor(istate);
 382                 break;
 383         case 1: /* true */
 384                 add_fsmonitor(istate);
 385                 break;
 386         default: /* unknown value: do nothing */
 387                 break;
 388         }
 389 }