git-tar-tree: no more void pointer arithmetic

[git.git] / read-cache.c

diff --git a/read-cache.c b/read-cache.c
index b95edcc..c499c51 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -4,11 +4,26 @@
  * Copyright (C) Linus Torvalds, 2005
  */
 #include "cache.h"
+#include "cache-tree.h"
+
+/* Index extensions.
+ *
+ * The first letter should be 'A'..'Z' for extensions that are not
+ * necessary for a correct operation (i.e. optimization data).
+ * When new extensions are added that _needs_ to be understood in
+ * order to correctly interpret the index file, pick character that
+ * is outside the range, to cause the reader to abort.
+ */
+
+#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
+#define CACHE_EXT_TREE 0x54524545      /* "TREE" */
 
 struct cache_entry **active_cache = NULL;
 static time_t index_file_timestamp;
 unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0;
 
+struct cache_tree *active_cache_tree = NULL;
+
 /*
  * This only updates the "non-critical" parts of the directory
  * cache, ie the parts that aren't tracked by GIT, and only used
@@ -332,6 +347,70 @@ int ce_path_match(const struct cache_entry *ce, const char **pathspec)
 }
 
 /*
+ * We fundamentally don't like some paths: we don't want
+ * dot or dot-dot anywhere, and for obvious reasons don't
+ * want to recurse into ".git" either.
+ *
+ * Also, we don't want double slashes or slashes at the
+ * end that can make pathnames ambiguous.
+ */
+static int verify_dotfile(const char *rest)
+{
+       /*
+        * The first character was '.', but that
+        * has already been discarded, we now test
+        * the rest.
+        */
+       switch (*rest) {
+       /* "." is not allowed */
+       case '\0': case '/':
+               return 0;
+
+       /*
+        * ".git" followed by  NUL or slash is bad. This
+        * shares the path end test with the ".." case.
+        */
+       case 'g':
+               if (rest[1] != 'i')
+                       break;
+               if (rest[2] != 't')
+                       break;
+               rest += 2;
+       /* fallthrough */
+       case '.':
+               if (rest[1] == '\0' || rest[1] == '/')
+                       return 0;
+       }
+       return 1;
+}
+
+int verify_path(const char *path)
+{
+       char c;
+
+       goto inside;
+       for (;;) {
+               if (!c)
+                       return 1;
+               if (c == '/') {
+inside:
+                       c = *path++;
+                       switch (c) {
+                       default:
+                               continue;
+                       case '/': case '\0':
+                               break;
+                       case '.':
+                               if (verify_dotfile(path))
+                                       continue;
+                       }
+                       return 0;
+               }
+               c = *path++;
+       }
+}
+
+/*
  * Do we have another file that has the beginning components being a
  * proper superset of the name we're trying to add?
  */
@@ -472,6 +551,8 @@ int add_cache_entry(struct cache_entry *ce, int option)
 
        if (!ok_to_add)
                return -1;
+       if (!verify_path(ce->name))
+               return -1;
 
        if (!skip_df_check &&
            check_file_directory_conflict(ce, pos, ok_to_replace)) {
@@ -630,6 +711,22 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size)
        return 0;
 }
 
+static int read_index_extension(const char *ext, void *data, unsigned long sz)
+{
+       switch (CACHE_EXT(ext)) {
+       case CACHE_EXT_TREE:
+               active_cache_tree = cache_tree_read(data, sz);
+               break;
+       default:
+               if (*ext < 'A' || 'Z' < *ext)
+                       return error("index uses %.4s extension, which we do not understand",
+                                    ext);
+               fprintf(stderr, "ignoring %.4s extension\n", ext);
+               break;
+       }
+       return 0;
+}
+
 int read_cache(void)
 {
        int fd, i;
@@ -678,6 +775,22 @@ int read_cache(void)
                active_cache[i] = ce;
        }
        index_file_timestamp = st.st_mtime;
+       while (offset <= size - 20 - 8) {
+               /* After an array of active_nr index entries,
+                * there can be arbitrary number of extended
+                * sections, each of which is prefixed with
+                * extension name (4-byte) and section length
+                * in 4-byte network byte order.
+                */
+               unsigned long extsize;
+               memcpy(&extsize, map + offset + 4, 4);
+               extsize = ntohl(extsize);
+               if (read_index_extension(map + offset,
+                                        map + offset + 8, extsize) < 0)
+                       goto unmap;
+               offset += 8;
+               offset += extsize;
+       }
        return active_nr;
 
 unmap:
@@ -712,6 +825,17 @@ static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
        return 0;
 }
 
+static int write_index_ext_header(SHA_CTX *context, int fd,
+                                 unsigned int ext, unsigned int sz)
+{
+       ext = htonl(ext);
+       sz = htonl(sz);
+       if ((ce_write(context, fd, &ext, 4) < 0) ||
+           (ce_write(context, fd, &sz, 4) < 0))
+               return -1;
+       return 0;
+}
+
 static int ce_flush(SHA_CTX *context, int fd)
 {
        unsigned int left = write_buffer_len;
@@ -808,5 +932,19 @@ int write_cache(int newfd, struct cache_entry **cache, int entries)
                if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
                        return -1;
        }
+
+       /* Write extension data here */
+       if (active_cache_tree) {
+               unsigned long sz;
+               void *data = cache_tree_write(active_cache_tree, &sz);
+               if (data &&
+                   !write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sz) &&
+                   !ce_write(&c, newfd, data, sz))
+                       ;
+               else {
+                       free(data);
+                       return -1;
+               }
+       }
        return ce_flush(&c, newfd);
 }