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