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         argv_array_push(&cp.args, core_fsmonitor);
 150         argv_array_pushf(&cp.args, "%d", version);
 151         argv_array_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 }