untracked cache: guard and disable on system changes

[thirdparty/git.git] / dir.c

diff --git a/dir.c b/dir.c
index 2cf8f35cc789f241163ebb127183be172a517c7c..e9eaf97efec17e4e96c3ee6cc09e7d4a74304f6d 100644 (file)
--- a/dir.c
+++ b/dir.c
@@ -1794,6 +1794,40 @@ static int treat_leading_path(struct dir_struct *dir,
        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 @@ static struct untracked_cache_dir *validate_untracked_cache(struct dir_struct *d
                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 @@ void write_untracked_extension(struct strbuf *out, struct untracked_cache *untra
        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 *read_untracked_extension(const void *data, unsigned long
        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,