untracked cache: guard and disable on system changes If the user enables untracked cache, then - move worktree to an unsupported filesystem - or simply upgrade OS - or move the whole (portable) disk from one machine to another - or access a shared fs from another machine there's no guarantee that untracked cache can still function properly. Record the worktree location and OS footprint in the cache. If it changes, err on the safe side and disable the cache. The user can 'update-index --untracked-cache' again to make sure all conditions are met. This adds a new requirement that setup_git_directory* must be called before read_cache() because we need worktree location by then, or the cache is dropped. This change does not cover all bases, you can fool it if you try hard. The point is to stop accidents. Helped-by: Eric Sunshine <sunshine@sunshineco.com> Helped-by: brian m. carlson <sandals@crustytoothpaste.net> Helped-by: Torsten Bögershausen <tboegi@web.de> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt index db59a13..b7093af 100644 --- a/Documentation/technical/index-format.txt +++ b/Documentation/technical/index-format.txt
@@ -242,6 +242,10 @@ The extension starts with + - A sequence of NUL-terminated strings, preceded by the size of the + sequence in variable width encoding. Each string describes the + environment where the cache can be used. + - Stat data of $GIT_DIR/info/exclude. See "Index entry" section from ctime field until "file size".
diff --git a/builtin/update-index.c b/builtin/update-index.c index c6951ad..790a6aa 100644 --- a/builtin/update-index.c +++ b/builtin/update-index.c
@@ -1104,7 +1104,7 @@ the_index.split_index = NULL; the_index.cache_changed |= SOMETHING_CHANGED; } - if (untracked_cache > 0 && !the_index.untracked) { + if (untracked_cache > 0) { struct untracked_cache *uc; if (untracked_cache < 2) { @@ -1112,11 +1112,15 @@ if (!test_if_untracked_cache_is_supported()) return 1; } - uc = xcalloc(1, sizeof(*uc)); - uc->exclude_per_dir = ".gitignore"; - /* should be the same flags used by git-status */ - uc->dir_flags = DIR_SHOW_OTHER_DIRECTORIES | DIR_HIDE_EMPTY_DIRECTORIES; - the_index.untracked = uc; + if (!the_index.untracked) { + uc = xcalloc(1, sizeof(*uc)); + strbuf_init(&uc->ident, 100); + uc->exclude_per_dir = ".gitignore"; + /* should be the same flags used by git-status */ + uc->dir_flags = DIR_SHOW_OTHER_DIRECTORIES | DIR_HIDE_EMPTY_DIRECTORIES; + the_index.untracked = uc; + } + add_untracked_ident(the_index.untracked); the_index.cache_changed |= UNTRACKED_CHANGED; } else if (!untracked_cache && the_index.untracked) { the_index.untracked = NULL;
diff --git a/dir.c b/dir.c index 2cf8f35..e9eaf97 100644 --- a/dir.c +++ b/dir.c
@@ -1794,6 +1794,40 @@ return rc; } +static const char *get_ident_string(void) +{ + static struct strbuf sb = STRBUF_INIT; + struct utsname uts; + + if (sb.len) + return sb.buf; + if (uname(&uts)) + die_errno(_("failed to get kernel name and information")); + strbuf_addf(&sb, "Location %s, system %s %s %s", get_git_work_tree(), + uts.sysname, uts.release, uts.version); + return sb.buf; +} + +static int ident_in_untracked(const struct untracked_cache *uc) +{ + const char *end = uc->ident.buf + uc->ident.len; + const char *p = uc->ident.buf; + + for (p = uc->ident.buf; p < end; p += strlen(p) + 1) + if (!strcmp(p, get_ident_string())) + return 1; + return 0; +} + +void add_untracked_ident(struct untracked_cache *uc) +{ + if (ident_in_untracked(uc)) + return; + strbuf_addstr(&uc->ident, get_ident_string()); + /* this strbuf contains a list of strings, save NUL too */ + strbuf_addch(&uc->ident, 0); +} + static struct untracked_cache_dir *validate_untracked_cache(struct dir_struct *dir, int base_len, const struct pathspec *pathspec) @@ -1860,6 +1894,11 @@ if (ce_skip_worktree(active_cache[i])) return NULL; + if (!ident_in_untracked(dir->untracked)) { + warning(_("Untracked cache is disabled on this system.")); + return NULL; + } + if (!dir->untracked->root) { const int len = sizeof(*dir->untracked->root); dir->untracked->root = xmalloc(len); @@ -2268,6 +2307,11 @@ hashcpy(ouc->excludes_file_sha1, untracked->ss_excludes_file.sha1); ouc->dir_flags = htonl(untracked->dir_flags); memcpy(ouc->exclude_per_dir, untracked->exclude_per_dir, len + 1); + + varint_len = encode_varint(untracked->ident.len, varbuf); + strbuf_add(out, varbuf, varint_len); + strbuf_add(out, untracked->ident.buf, untracked->ident.len); + strbuf_add(out, ouc, ouc_size(len)); free(ouc); ouc = NULL; @@ -2453,17 +2497,26 @@ struct untracked_cache *uc; struct read_data rd; const unsigned char *next = data, *end = (const unsigned char *)data + sz; - int len; + const char *ident; + int ident_len, len; if (sz <= 1 || end[-1] != '\0') return NULL; end--; + ident_len = decode_varint(&next); + if (next + ident_len > end) + return NULL; + ident = (const char *)next; + next += ident_len; + ouc = (const struct ondisk_untracked_cache *)next; if (next + ouc_size(0) > end) return NULL; uc = xcalloc(1, sizeof(*uc)); + strbuf_init(&uc->ident, ident_len); + strbuf_add(&uc->ident, ident, ident_len); load_sha1_stat(&uc->ss_info_exclude, &ouc->info_exclude_stat, ouc->info_exclude_sha1); load_sha1_stat(&uc->ss_excludes_file, &ouc->excludes_file_stat,
diff --git a/dir.h b/dir.h index 2ce7dd3..6ccbc45 100644 --- a/dir.h +++ b/dir.h
@@ -127,6 +127,7 @@ struct sha1_stat ss_info_exclude; struct sha1_stat ss_excludes_file; const char *exclude_per_dir; + struct strbuf ident; /* * dir_struct#flags must match dir_flags or the untracked * cache is ignored. @@ -305,4 +306,5 @@ void free_untracked_cache(struct untracked_cache *); struct untracked_cache *read_untracked_extension(const void *data, unsigned long sz); void write_untracked_extension(struct strbuf *out, struct untracked_cache *untracked); +void add_untracked_ident(struct untracked_cache *); #endif
diff --git a/git-compat-util.h b/git-compat-util.h index a3095be..1663537 100644 --- a/git-compat-util.h +++ b/git-compat-util.h
@@ -134,6 +134,7 @@ #elif defined(_MSC_VER) #include "compat/msvc.h" #else +#include <sys/utsname.h> #include <sys/wait.h> #include <sys/resource.h> #include <sys/socket.h>
diff --git a/test-dump-untracked-cache.c b/test-dump-untracked-cache.c index 710441e..25d855d 100644 --- a/test-dump-untracked-cache.c +++ b/test-dump-untracked-cache.c
@@ -44,6 +44,7 @@ { struct untracked_cache *uc; struct strbuf base = STRBUF_INIT; + setup_git_directory(); if (read_cache() < 0) die("unable to read index file"); uc = the_index.untracked;