From c8bae7493d2f2910b57f13ded012e86bdcfb0532 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 16:47:53 +0200 Subject: Adding upstream version 1:2.39.2. Signed-off-by: Daniel Baumann --- fsmonitor.c | 612 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 612 insertions(+) create mode 100644 fsmonitor.c (limited to 'fsmonitor.c') diff --git a/fsmonitor.c b/fsmonitor.c new file mode 100644 index 0000000..08af00c --- /dev/null +++ b/fsmonitor.c @@ -0,0 +1,612 @@ +#include "cache.h" +#include "config.h" +#include "dir.h" +#include "ewah/ewok.h" +#include "fsmonitor.h" +#include "fsmonitor-ipc.h" +#include "run-command.h" +#include "strbuf.h" + +#define INDEX_EXTENSION_VERSION1 (1) +#define INDEX_EXTENSION_VERSION2 (2) +#define HOOK_INTERFACE_VERSION1 (1) +#define HOOK_INTERFACE_VERSION2 (2) + +struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR); + +static void assert_index_minimum(struct index_state *istate, size_t pos) +{ + if (pos > istate->cache_nr) + BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)", + (uintmax_t)pos, istate->cache_nr); +} + +static void fsmonitor_ewah_callback(size_t pos, void *is) +{ + struct index_state *istate = (struct index_state *)is; + struct cache_entry *ce; + + assert_index_minimum(istate, pos + 1); + + ce = istate->cache[pos]; + ce->ce_flags &= ~CE_FSMONITOR_VALID; +} + +static int fsmonitor_hook_version(void) +{ + int hook_version; + + if (git_config_get_int("core.fsmonitorhookversion", &hook_version)) + return -1; + + if (hook_version == HOOK_INTERFACE_VERSION1 || + hook_version == HOOK_INTERFACE_VERSION2) + return hook_version; + + warning("Invalid hook version '%i' in core.fsmonitorhookversion. " + "Must be 1 or 2.", hook_version); + return -1; +} + +int read_fsmonitor_extension(struct index_state *istate, const void *data, + unsigned long sz) +{ + const char *index = data; + uint32_t hdr_version; + uint32_t ewah_size; + struct ewah_bitmap *fsmonitor_dirty; + int ret; + uint64_t timestamp; + struct strbuf last_update = STRBUF_INIT; + + if (sz < sizeof(uint32_t) + 1 + sizeof(uint32_t)) + return error("corrupt fsmonitor extension (too short)"); + + hdr_version = get_be32(index); + index += sizeof(uint32_t); + if (hdr_version == INDEX_EXTENSION_VERSION1) { + timestamp = get_be64(index); + strbuf_addf(&last_update, "%"PRIu64"", timestamp); + index += sizeof(uint64_t); + } else if (hdr_version == INDEX_EXTENSION_VERSION2) { + strbuf_addstr(&last_update, index); + index += last_update.len + 1; + } else { + return error("bad fsmonitor version %d", hdr_version); + } + + istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL); + + ewah_size = get_be32(index); + index += sizeof(uint32_t); + + fsmonitor_dirty = ewah_new(); + ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size); + if (ret != ewah_size) { + ewah_free(fsmonitor_dirty); + return error("failed to parse ewah bitmap reading fsmonitor index extension"); + } + istate->fsmonitor_dirty = fsmonitor_dirty; + + if (!istate->split_index) + assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size); + + trace2_data_string("index", NULL, "extension/fsmn/read/token", + istate->fsmonitor_last_update); + trace_printf_key(&trace_fsmonitor, + "read fsmonitor extension successful '%s'", + istate->fsmonitor_last_update); + return 0; +} + +void fill_fsmonitor_bitmap(struct index_state *istate) +{ + unsigned int i, skipped = 0; + istate->fsmonitor_dirty = ewah_new(); + for (i = 0; i < istate->cache_nr; i++) { + if (istate->cache[i]->ce_flags & CE_REMOVE) + skipped++; + else if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID)) + ewah_set(istate->fsmonitor_dirty, i - skipped); + } +} + +void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate) +{ + uint32_t hdr_version; + uint32_t ewah_start; + uint32_t ewah_size = 0; + int fixup = 0; + + if (!istate->split_index) + assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size); + + put_be32(&hdr_version, INDEX_EXTENSION_VERSION2); + strbuf_add(sb, &hdr_version, sizeof(uint32_t)); + + strbuf_addstr(sb, istate->fsmonitor_last_update); + strbuf_addch(sb, 0); /* Want to keep a NUL */ + + fixup = sb->len; + strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */ + + ewah_start = sb->len; + ewah_serialize_strbuf(istate->fsmonitor_dirty, sb); + ewah_free(istate->fsmonitor_dirty); + istate->fsmonitor_dirty = NULL; + + /* fix up size field */ + put_be32(&ewah_size, sb->len - ewah_start); + memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t)); + + trace2_data_string("index", NULL, "extension/fsmn/write/token", + istate->fsmonitor_last_update); + trace_printf_key(&trace_fsmonitor, + "write fsmonitor extension successful '%s'", + istate->fsmonitor_last_update); +} + +/* + * Call the query-fsmonitor hook passing the last update token of the saved results. + */ +static int query_fsmonitor_hook(struct repository *r, + int version, + const char *last_update, + struct strbuf *query_result) +{ + struct child_process cp = CHILD_PROCESS_INIT; + int result; + + if (fsm_settings__get_mode(r) != FSMONITOR_MODE_HOOK) + return -1; + + strvec_push(&cp.args, fsm_settings__get_hook_path(r)); + strvec_pushf(&cp.args, "%d", version); + strvec_pushf(&cp.args, "%s", last_update); + cp.use_shell = 1; + cp.dir = get_git_work_tree(); + + trace2_region_enter("fsm_hook", "query", NULL); + + result = capture_command(&cp, query_result, 1024); + + if (result) + trace2_data_intmax("fsm_hook", NULL, "query/failed", result); + else + trace2_data_intmax("fsm_hook", NULL, "query/response-length", + query_result->len); + + trace2_region_leave("fsm_hook", "query", NULL); + + return result; +} + +static void fsmonitor_refresh_callback(struct index_state *istate, char *name) +{ + int i, len = strlen(name); + int pos = index_name_pos(istate, name, len); + + trace_printf_key(&trace_fsmonitor, + "fsmonitor_refresh_callback '%s' (pos %d)", + name, pos); + + if (name[len - 1] == '/') { + /* + * The daemon can decorate directory events, such as + * moves or renames, with a trailing slash if the OS + * FS Event contains sufficient information, such as + * MacOS. + * + * Use this to invalidate the entire cone under that + * directory. + * + * We do not expect an exact match because the index + * does not normally contain directory entries, so we + * start at the insertion point and scan. + */ + if (pos < 0) + pos = -pos - 1; + + /* Mark all entries for the folder invalid */ + for (i = pos; i < istate->cache_nr; i++) { + if (!starts_with(istate->cache[i]->name, name)) + break; + istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID; + } + + /* + * We need to remove the traling "/" from the path + * for the untracked cache. + */ + name[len - 1] = '\0'; + } else if (pos >= 0) { + /* + * We have an exact match for this path and can just + * invalidate it. + */ + istate->cache[pos]->ce_flags &= ~CE_FSMONITOR_VALID; + } else { + /* + * The path is not a tracked file -or- it is a + * directory event on a platform that cannot + * distinguish between file and directory events in + * the event handler, such as Windows. + * + * Scan as if it is a directory and invalidate the + * cone under it. (But remember to ignore items + * between "name" and "name/", such as "name-" and + * "name.". + */ + pos = -pos - 1; + + for (i = pos; i < istate->cache_nr; i++) { + if (!starts_with(istate->cache[i]->name, name)) + break; + if ((unsigned char)istate->cache[i]->name[len] > '/') + break; + if (istate->cache[i]->name[len] == '/') + istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID; + } + } + + /* + * Mark the untracked cache dirty even if it wasn't found in the index + * as it could be a new untracked file. + */ + untracked_cache_invalidate_path(istate, name, 0); +} + +/* + * The number of pathnames that we need to receive from FSMonitor + * before we force the index to be updated. + * + * Note that any pathname within the set of received paths MAY cause + * cache-entry or istate flag bits to be updated and thus cause the + * index to be updated on disk. + * + * However, the response may contain many paths (such as ignored + * paths) that will not update any flag bits. And thus not force the + * index to be updated. (This is fine and normal.) It also means + * that the token will not be updated in the FSMonitor index + * extension. So the next Git command will find the same token in the + * index, make the same token-relative request, and receive the same + * response (plus any newly changed paths). If this response is large + * (and continues to grow), performance could be impacted. + * + * For example, if the user runs a build and it writes 100K object + * files but doesn't modify any source files, the index would not need + * to be updated. The FSMonitor response (after the build and + * relative to a pre-build token) might be 5MB. Each subsequent Git + * command will receive that same 100K/5MB response until something + * causes the index to be updated. And `refresh_fsmonitor()` will + * have to iterate over those 100K paths each time. + * + * Performance could be improved if we optionally force update the + * index after a very large response and get an updated token into + * the FSMonitor index extension. This should allow subsequent + * commands to get smaller and more current responses. + * + * The value chosen here does not need to be precise. The index + * will be updated automatically the first time the user touches + * a tracked file and causes a command like `git status` to + * update an mtime to be updated and/or set a flag bit. + */ +static int fsmonitor_force_update_threshold = 100; + +void refresh_fsmonitor(struct index_state *istate) +{ + static int warn_once = 0; + struct strbuf query_result = STRBUF_INIT; + int query_success = 0, hook_version = -1; + size_t bol = 0; /* beginning of line */ + uint64_t last_update; + struct strbuf last_update_token = STRBUF_INIT; + char *buf; + unsigned int i; + int is_trivial = 0; + struct repository *r = istate->repo ? istate->repo : the_repository; + enum fsmonitor_mode fsm_mode = fsm_settings__get_mode(r); + enum fsmonitor_reason reason = fsm_settings__get_reason(r); + + if (!warn_once && reason > FSMONITOR_REASON_OK) { + char *msg = fsm_settings__get_incompatible_msg(r, reason); + warn_once = 1; + warning("%s", msg); + free(msg); + } + + if (fsm_mode <= FSMONITOR_MODE_DISABLED || + istate->fsmonitor_has_run_once) + return; + + istate->fsmonitor_has_run_once = 1; + + trace_printf_key(&trace_fsmonitor, "refresh fsmonitor"); + + if (fsm_mode == FSMONITOR_MODE_IPC) { + query_success = !fsmonitor_ipc__send_query( + istate->fsmonitor_last_update ? + istate->fsmonitor_last_update : "builtin:fake", + &query_result); + if (query_success) { + /* + * The response contains a series of nul terminated + * strings. The first is the new token. + * + * Use `char *buf` as an interlude to trick the CI + * static analysis to let us use `strbuf_addstr()` + * here (and only copy the token) rather than + * `strbuf_addbuf()`. + */ + buf = query_result.buf; + strbuf_addstr(&last_update_token, buf); + bol = last_update_token.len + 1; + is_trivial = query_result.buf[bol] == '/'; + if (is_trivial) + trace2_data_intmax("fsm_client", NULL, + "query/trivial-response", 1); + } else { + /* + * The builtin daemon is not available on this + * platform -OR- we failed to get a response. + * + * Generate a fake token (rather than a V1 + * timestamp) for the index extension. (If + * they switch back to the hook API, we don't + * want ambiguous state.) + */ + strbuf_addstr(&last_update_token, "builtin:fake"); + } + + goto apply_results; + } + + assert(fsm_mode == FSMONITOR_MODE_HOOK); + + hook_version = fsmonitor_hook_version(); + + /* + * This could be racy so save the date/time now and query_fsmonitor_hook + * should be inclusive to ensure we don't miss potential changes. + */ + last_update = getnanotime(); + if (hook_version == HOOK_INTERFACE_VERSION1) + strbuf_addf(&last_update_token, "%"PRIu64"", last_update); + + /* + * If we have a last update token, call query_fsmonitor_hook for the set of + * changes since that token, else assume everything is possibly dirty + * and check it all. + */ + if (istate->fsmonitor_last_update) { + if (hook_version == -1 || hook_version == HOOK_INTERFACE_VERSION2) { + query_success = !query_fsmonitor_hook( + r, HOOK_INTERFACE_VERSION2, + istate->fsmonitor_last_update, &query_result); + + if (query_success) { + if (hook_version < 0) + hook_version = HOOK_INTERFACE_VERSION2; + + /* + * First entry will be the last update token + * Need to use a char * variable because static + * analysis was suggesting to use strbuf_addbuf + * but we don't want to copy the entire strbuf + * only the chars up to the first NUL + */ + buf = query_result.buf; + strbuf_addstr(&last_update_token, buf); + if (!last_update_token.len) { + warning("Empty last update token."); + query_success = 0; + } else { + bol = last_update_token.len + 1; + is_trivial = query_result.buf[bol] == '/'; + } + } else if (hook_version < 0) { + hook_version = HOOK_INTERFACE_VERSION1; + if (!last_update_token.len) + strbuf_addf(&last_update_token, "%"PRIu64"", last_update); + } + } + + if (hook_version == HOOK_INTERFACE_VERSION1) { + query_success = !query_fsmonitor_hook( + r, HOOK_INTERFACE_VERSION1, + istate->fsmonitor_last_update, &query_result); + if (query_success) + is_trivial = query_result.buf[0] == '/'; + } + + if (is_trivial) + trace2_data_intmax("fsm_hook", NULL, + "query/trivial-response", 1); + + trace_performance_since(last_update, "fsmonitor process '%s'", + fsm_settings__get_hook_path(r)); + trace_printf_key(&trace_fsmonitor, + "fsmonitor process '%s' returned %s", + fsm_settings__get_hook_path(r), + query_success ? "success" : "failure"); + } + +apply_results: + /* + * The response from FSMonitor (excluding the header token) is + * either: + * + * [a] a (possibly empty) list of NUL delimited relative + * pathnames of changed paths. This list can contain + * files and directories. Directories have a trailing + * slash. + * + * [b] a single '/' to indicate the provider had no + * information and that we should consider everything + * invalid. We call this a trivial response. + */ + trace2_region_enter("fsmonitor", "apply_results", istate->repo); + + if (query_success && !is_trivial) { + /* + * Mark all pathnames returned by the monitor as dirty. + * + * This updates both the cache-entries and the untracked-cache. + */ + int count = 0; + + buf = query_result.buf; + for (i = bol; i < query_result.len; i++) { + if (buf[i] != '\0') + continue; + fsmonitor_refresh_callback(istate, buf + bol); + bol = i + 1; + count++; + } + if (bol < query_result.len) { + fsmonitor_refresh_callback(istate, buf + bol); + count++; + } + + /* Now mark the untracked cache for fsmonitor usage */ + if (istate->untracked) + istate->untracked->use_fsmonitor = 1; + + if (count > fsmonitor_force_update_threshold) + istate->cache_changed |= FSMONITOR_CHANGED; + + trace2_data_intmax("fsmonitor", istate->repo, "apply_count", + count); + + } else { + /* + * We failed to get a response or received a trivial response, + * so invalidate everything. + * + * We only want to run the post index changed hook if + * we've actually changed entries, so keep track if we + * actually changed entries or not. + */ + int is_cache_changed = 0; + + for (i = 0; i < istate->cache_nr; i++) { + if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) { + is_cache_changed = 1; + istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID; + } + } + + /* + * If we're going to check every file, ensure we save + * the results. + */ + if (is_cache_changed) + istate->cache_changed |= FSMONITOR_CHANGED; + + if (istate->untracked) + istate->untracked->use_fsmonitor = 0; + } + trace2_region_leave("fsmonitor", "apply_results", istate->repo); + + strbuf_release(&query_result); + + /* Now that we've updated istate, save the last_update_token */ + FREE_AND_NULL(istate->fsmonitor_last_update); + istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL); +} + +/* + * The caller wants to turn on FSMonitor. And when the caller writes + * the index to disk, a FSMonitor extension should be included. This + * requires that `istate->fsmonitor_last_update` not be NULL. But we + * have not actually talked to a FSMonitor process yet, so we don't + * have an initial value for this field. + * + * For a protocol V1 FSMonitor process, this field is a formatted + * "nanoseconds since epoch" field. However, for a protocol V2 + * FSMonitor process, this field is an opaque token. + * + * Historically, `add_fsmonitor()` has initialized this field to the + * current time for protocol V1 processes. There are lots of race + * conditions here, but that code has shipped... + * + * The only true solution is to use a V2 FSMonitor and get a current + * or default token value (that it understands), but we cannot do that + * until we have actually talked to an instance of the FSMonitor process + * (but the protocol requires that we send a token first...). + * + * For simplicity, just initialize like we have a V1 process and require + * that V2 processes adapt. + */ +static void initialize_fsmonitor_last_update(struct index_state *istate) +{ + struct strbuf last_update = STRBUF_INIT; + + strbuf_addf(&last_update, "%"PRIu64"", getnanotime()); + istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL); +} + +void add_fsmonitor(struct index_state *istate) +{ + unsigned int i; + + if (!istate->fsmonitor_last_update) { + trace_printf_key(&trace_fsmonitor, "add fsmonitor"); + istate->cache_changed |= FSMONITOR_CHANGED; + initialize_fsmonitor_last_update(istate); + + /* reset the fsmonitor state */ + for (i = 0; i < istate->cache_nr; i++) + istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID; + + /* reset the untracked cache */ + if (istate->untracked) { + add_untracked_cache(istate); + istate->untracked->use_fsmonitor = 1; + } + + /* Update the fsmonitor state */ + refresh_fsmonitor(istate); + } +} + +void remove_fsmonitor(struct index_state *istate) +{ + if (istate->fsmonitor_last_update) { + trace_printf_key(&trace_fsmonitor, "remove fsmonitor"); + istate->cache_changed |= FSMONITOR_CHANGED; + FREE_AND_NULL(istate->fsmonitor_last_update); + } +} + +void tweak_fsmonitor(struct index_state *istate) +{ + unsigned int i; + int fsmonitor_enabled = (fsm_settings__get_mode(istate->repo) + > FSMONITOR_MODE_DISABLED); + + if (istate->fsmonitor_dirty) { + if (fsmonitor_enabled) { + /* Mark all entries valid */ + for (i = 0; i < istate->cache_nr; i++) { + if (S_ISGITLINK(istate->cache[i]->ce_mode)) + continue; + istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID; + } + + /* Mark all previously saved entries as dirty */ + assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size); + ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate); + + refresh_fsmonitor(istate); + } + + ewah_free(istate->fsmonitor_dirty); + istate->fsmonitor_dirty = NULL; + } + + if (fsmonitor_enabled) + add_fsmonitor(istate); + else + remove_fsmonitor(istate); +} -- cgit v1.2.3