Merge branch 'jc/maint-doc-git-add-example' into maint
[gitweb.git] / sha1_file.c
index bcfcab351dd9f8d5b4e1cc0d86ecd2162f46cf94..63981fb3fd9cfa6cca4126eba5a964b449c62444 100644 (file)
@@ -99,7 +99,11 @@ int safe_create_leading_directories(char *path)
                pos = strchr(pos, '/');
                if (!pos)
                        break;
-               *pos = 0;
+               while (*++pos == '/')
+                       ;
+               if (!*pos)
+                       break;
+               *--pos = '\0';
                if (!stat(path, &st)) {
                        /* path exists */
                        if (!S_ISDIR(st.st_mode)) {
@@ -250,7 +254,6 @@ static void read_info_alternates(const char * alternates, int depth);
  */
 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 {
-       struct stat st;
        const char *objdir = get_object_directory();
        struct alternate_object_database *ent;
        struct alternate_object_database *alt;
@@ -281,7 +284,7 @@ static int link_alt_odb_entry(const char * entry, int len, const char * relative
        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 
        /* Detect cases where alternate disappeared */
-       if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
+       if (!is_directory(ent->base)) {
                error("object directory %s does not exist; "
                      "check .git/objects/info/alternates.",
                      ent->base);
@@ -394,6 +397,16 @@ void add_to_alternates_file(const char *reference)
                link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0);
 }
 
+void foreach_alt_odb(alt_odb_fn fn, void *cb)
+{
+       struct alternate_object_database *ent;
+
+       prepare_alt_odb();
+       for (ent = alt_odb_list; ent; ent = ent->next)
+               if (fn(ent, cb))
+                       return;
+}
+
 void prepare_alt_odb(void)
 {
        const char *alt;
@@ -707,6 +720,8 @@ static int open_packed_git_1(struct packed_git *p)
                return error("packfile %s index unavailable", p->pack_name);
 
        p->pack_fd = open(p->pack_name, O_RDONLY);
+       while (p->pack_fd < 0 && errno == EMFILE && unuse_one_window(p, -1))
+               p->pack_fd = open(p->pack_name, O_RDONLY);
        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
                return -1;
 
@@ -778,7 +793,7 @@ static int in_window(struct pack_window *win, off_t offset)
                && (offset + 20) <= (win_off + win->len);
 }
 
-unsigned charuse_pack(struct packed_git *p,
+unsigned char *use_pack(struct packed_git *p,
                struct pack_window **w_cursor,
                off_t offset,
                unsigned int *left)
@@ -788,7 +803,7 @@ unsigned char* use_pack(struct packed_git *p,
        if (p->pack_fd == -1 && open_packed_git(p))
                die("packfile %s cannot be accessed", p->pack_name);
 
-       /* Since packfiles end in a hash of their content and its
+       /* Since packfiles end in a hash of their content and it's
         * pointless to ask for an offset into the middle of that
         * hash, and the in_window function above wouldn't match
         * don't allow an offset too close to the end of the file.
@@ -924,6 +939,8 @@ static void prepare_packed_git_one(char *objdir, int local)
        sprintf(path, "%s/pack", objdir);
        len = strlen(path);
        dir = opendir(path);
+       while (!dir && errno == EMFILE && unuse_one_window(packed_git, -1))
+               dir = opendir(path);
        if (!dir) {
                if (errno != ENOENT)
                        error("unable to open object pack directory: %s: %s",
@@ -1141,11 +1158,11 @@ static int legacy_loose_object(unsigned char *map)
                return 0;
 }
 
-unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
+unsigned long unpack_object_header_buffer(const unsigned char *buf,
+               unsigned long len, enum object_type *type, unsigned long *sizep)
 {
        unsigned shift;
-       unsigned char c;
-       unsigned long size;
+       unsigned long size, c;
        unsigned long used = 0;
 
        c = buf[used++];
@@ -1153,10 +1170,10 @@ unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned lon
        size = c & 15;
        shift = 4;
        while (c & 0x80) {
-               if (len <= used)
-                       return 0;
-               if (sizeof(long) * 8 <= shift)
+               if (len <= used || bitsizeof(long) <= shift) {
+                       error("bad object header");
                        return 0;
+               }
                c = buf[used++];
                size += (c & 0x7f) << shift;
                shift += 7;
@@ -1183,8 +1200,8 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
        stream->avail_out = bufsiz;
 
        if (legacy_loose_object(map)) {
-               inflateInit(stream);
-               return inflate(stream, 0);
+               git_inflate_init(stream);
+               return git_inflate(stream, 0);
        }
 
 
@@ -1195,7 +1212,7 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
         * really worth it and we don't write it any longer.  But we
         * can still read it.
         */
-       used = unpack_object_header_gently(map, mapsize, &type, &size);
+       used = unpack_object_header_buffer(map, mapsize, &type, &size);
        if (!used || !valid_loose_object_type[type])
                return -1;
        map += used;
@@ -1204,7 +1221,7 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
        /* Set up the stream for the rest.. */
        stream->next_in = map;
        stream->avail_in = mapsize;
-       inflateInit(stream);
+       git_inflate_init(stream);
 
        /* And generate the fake traditional header */
        stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
@@ -1241,11 +1258,11 @@ static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size
                stream->next_out = buf + bytes;
                stream->avail_out = size - bytes;
                while (status == Z_OK)
-                       status = inflate(stream, Z_FINISH);
+                       status = git_inflate(stream, Z_FINISH);
        }
        buf[size] = 0;
        if (status == Z_STREAM_END && !stream->avail_in) {
-               inflateEnd(stream);
+               git_inflate_end(stream);
                return buf;
        }
 
@@ -1335,17 +1352,19 @@ unsigned long get_size_from_delta(struct packed_git *p,
        stream.next_out = delta_head;
        stream.avail_out = sizeof(delta_head);
 
-       inflateInit(&stream);
+       git_inflate_init(&stream);
        do {
                in = use_pack(p, w_curs, curpos, &stream.avail_in);
                stream.next_in = in;
-               st = inflate(&stream, Z_FINISH);
+               st = git_inflate(&stream, Z_FINISH);
                curpos += stream.next_in - in;
        } while ((st == Z_OK || st == Z_BUF_ERROR) &&
                 stream.total_out < sizeof(delta_head));
-       inflateEnd(&stream);
-       if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head))
-               die("delta data unpack-initial failed");
+       git_inflate_end(&stream);
+       if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
+               error("delta data unpack-initial failed");
+               return 0;
+       }
 
        /* Examine the initial part of the delta to figure out
         * the result size.
@@ -1386,7 +1405,7 @@ static off_t get_delta_base(struct packed_git *p,
                        base_offset = (base_offset << 7) + (c & 127);
                }
                base_offset = delta_obj_offset - base_offset;
-               if (base_offset >= delta_obj_offset)
+               if (base_offset <= 0 || base_offset >= delta_obj_offset)
                        return 0;  /* out of bound */
                *curpos += used;
        } else if (type == OBJ_REF_DELTA) {
@@ -1412,15 +1431,32 @@ static int packed_delta_info(struct packed_git *p,
        off_t base_offset;
 
        base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
+       if (!base_offset)
+               return OBJ_BAD;
        type = packed_object_info(p, base_offset, NULL);
+       if (type <= OBJ_NONE) {
+               struct revindex_entry *revidx;
+               const unsigned char *base_sha1;
+               revidx = find_pack_revindex(p, base_offset);
+               if (!revidx)
+                       return OBJ_BAD;
+               base_sha1 = nth_packed_object_sha1(p, revidx->nr);
+               mark_bad_packed_object(p, base_sha1);
+               type = sha1_object_info(base_sha1, NULL);
+               if (type <= OBJ_NONE)
+                       return OBJ_BAD;
+       }
 
        /* We choose to only get the type of the base object and
         * ignore potentially corrupt pack file that expects the delta
         * based on a base with a wrong size.  This saves tons of
         * inflate() calls.
         */
-       if (sizep)
+       if (sizep) {
                *sizep = get_size_from_delta(p, w_curs, curpos);
+               if (*sizep == 0)
+                       type = OBJ_BAD;
+       }
 
        return type;
 }
@@ -1442,10 +1478,11 @@ static int unpack_object_header(struct packed_git *p,
         * insane, so we know won't exceed what we have been given.
         */
        base = use_pack(p, w_curs, *curpos, &left);
-       used = unpack_object_header_gently(base, left, &type, sizep);
-       if (!used)
-               die("object offset outside of pack file");
-       *curpos += used;
+       used = unpack_object_header_buffer(base, left, &type, sizep);
+       if (!used) {
+               type = OBJ_BAD;
+       } else
+               *curpos += used;
 
        return type;
 }
@@ -1529,8 +1566,9 @@ static int packed_object_info(struct packed_git *p, off_t obj_offset,
                        *sizep = size;
                break;
        default:
-               die("pack %s contains unknown object type %d",
-                   p->pack_name, type);
+               error("unknown object type %i at offset %"PRIuMAX" in %s",
+                     type, (uintmax_t)obj_offset, p->pack_name);
+               type = OBJ_BAD;
        }
        unuse_pack(&w_curs);
        return type;
@@ -1549,16 +1587,18 @@ static void *unpack_compressed_entry(struct packed_git *p,
        buffer[size] = 0;
        memset(&stream, 0, sizeof(stream));
        stream.next_out = buffer;
-       stream.avail_out = size;
+       stream.avail_out = size + 1;
 
-       inflateInit(&stream);
+       git_inflate_init(&stream);
        do {
                in = use_pack(p, w_curs, curpos, &stream.avail_in);
                stream.next_in = in;
-               st = inflate(&stream, Z_FINISH);
+               st = git_inflate(&stream, Z_FINISH);
+               if (!stream.avail_out)
+                       break; /* the payload is larger than it should be */
                curpos += stream.next_in - in;
        } while (st == Z_OK || st == Z_BUF_ERROR);
-       inflateEnd(&stream);
+       git_inflate_end(&stream);
        if ((st != Z_STREAM_END) || stream.total_out != size) {
                free(buffer);
                return NULL;
@@ -1602,11 +1642,9 @@ static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
        struct delta_base_cache_entry *ent = delta_base_cache + hash;
 
        ret = ent->data;
-       if (ret && ent->p == p && ent->base_offset == base_offset)
-               goto found_cache_entry;
-       return unpack_entry(p, base_offset, type, base_size);
+       if (!ret || ent->p != p || ent->base_offset != base_offset)
+               return unpack_entry(p, base_offset, type, base_size);
 
-found_cache_entry:
        if (!keep_cache) {
                ent->data = NULL;
                ent->lru.next->prev = ent->lru.prev;
@@ -1675,6 +1713,9 @@ static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
        delta_base_cache_lru.prev = &ent->lru;
 }
 
+static void *read_object(const unsigned char *sha1, enum object_type *type,
+                        unsigned long *size);
+
 static void *unpack_delta_entry(struct packed_git *p,
                                struct pack_window **w_curs,
                                off_t curpos,
@@ -1703,9 +1744,12 @@ static void *unpack_delta_entry(struct packed_git *p,
                 * This is costly but should happen only in the presence
                 * of a corrupted pack, and is better than failing outright.
                 */
-               struct revindex_entry *revidx = find_pack_revindex(p, base_offset);
-               const unsigned char *base_sha1 =
-                                       nth_packed_object_sha1(p, revidx->nr);
+               struct revindex_entry *revidx;
+               const unsigned char *base_sha1;
+               revidx = find_pack_revindex(p, base_offset);
+               if (!revidx)
+                       return NULL;
+               base_sha1 = nth_packed_object_sha1(p, revidx->nr);
                error("failed to read delta base object %s"
                      " at offset %"PRIuMAX" from %s",
                      sha1_to_hex(base_sha1), (uintmax_t)base_offset,
@@ -1734,6 +1778,8 @@ static void *unpack_delta_entry(struct packed_git *p,
        return result;
 }
 
+int do_check_packed_object_crc;
+
 void *unpack_entry(struct packed_git *p, off_t obj_offset,
                   enum object_type *type, unsigned long *sizep)
 {
@@ -1741,6 +1787,20 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
        off_t curpos = obj_offset;
        void *data;
 
+       if (do_check_packed_object_crc && p->index_version > 1) {
+               struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
+               unsigned long len = revidx[1].offset - obj_offset;
+               if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
+                       const unsigned char *sha1 =
+                               nth_packed_object_sha1(p, revidx->nr);
+                       error("bad packed object CRC for %s",
+                             sha1_to_hex(sha1));
+                       mark_bad_packed_object(p, sha1);
+                       unuse_pack(&w_curs);
+                       return NULL;
+               }
+       }
+
        *type = unpack_object_header(p, &w_curs, &curpos, sizep);
        switch (*type) {
        case OBJ_OFS_DELTA:
@@ -1864,25 +1924,7 @@ off_t find_pack_entry_one(const unsigned char *sha1,
        return 0;
 }
 
-int matches_pack_name(struct packed_git *p, const char *name)
-{
-       const char *last_c, *c;
-
-       if (!strcmp(p->pack_name, name))
-               return 1;
-
-       for (c = p->pack_name, last_c = c; *c;)
-               if (*c == '/')
-                       last_c = ++c;
-               else
-                       ++c;
-       if (!strcmp(last_c, name))
-               return 1;
-
-       return 0;
-}
-
-static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
+static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 {
        static struct packed_git *last_found = (void *)1;
        struct packed_git *p;
@@ -1894,15 +1936,6 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, cons
        p = (last_found == (void *)1) ? packed_git : last_found;
 
        do {
-               if (ignore_packed) {
-                       const char **ig;
-                       for (ig = ignore_packed; *ig; ig++)
-                               if (matches_pack_name(p, *ig))
-                                       break;
-                       if (*ig)
-                               goto next;
-               }
-
                if (p->num_bad_objects) {
                        unsigned i;
                        for (i = 0; i < p->num_bad_objects; i++)
@@ -1973,7 +2006,7 @@ static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *size
                status = error("unable to parse %s header", sha1_to_hex(sha1));
        else if (sizep)
                *sizep = size;
-       inflateEnd(&stream);
+       git_inflate_end(&stream);
        munmap(map, mapsize);
        return status;
 }
@@ -1983,7 +2016,7 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
        struct pack_entry e;
        int status;
 
-       if (!find_pack_entry(sha1, &e, NULL)) {
+       if (!find_pack_entry(sha1, &e)) {
                /* Most likely it's a loose object. */
                status = sha1_loose_object_info(sha1, sizep);
                if (status >= 0)
@@ -1991,10 +2024,17 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 
                /* Not a loose object; someone else may have just packed it. */
                reprepare_packed_git();
-               if (!find_pack_entry(sha1, &e, NULL))
+               if (!find_pack_entry(sha1, &e))
                        return status;
        }
-       return packed_object_info(e.p, e.offset, sizep);
+
+       status = packed_object_info(e.p, e.offset, sizep);
+       if (status < 0) {
+               mark_bad_packed_object(e.p, sha1);
+               status = sha1_object_info(sha1, sizep);
+       }
+
+       return status;
 }
 
 static void *read_packed_sha1(const unsigned char *sha1,
@@ -2003,7 +2043,7 @@ static void *read_packed_sha1(const unsigned char *sha1,
        struct pack_entry e;
        void *data;
 
-       if (!find_pack_entry(sha1, &e, NULL))
+       if (!find_pack_entry(sha1, &e))
                return NULL;
        data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
        if (!data) {
@@ -2036,9 +2076,7 @@ static struct cached_object {
 static int cached_object_nr, cached_object_alloc;
 
 static struct cached_object empty_tree = {
-       /* empty tree sha1: 4b825dc642cb6eb9a060e54bf8d69288fbee4904 */
-       "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60"
-       "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04",
+       EMPTY_TREE_SHA1_BIN,
        OBJ_TREE,
        "",
        0
@@ -2081,8 +2119,8 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
        return 0;
 }
 
-void *read_object(const unsigned char *sha1, enum object_type *type,
-                 unsigned long *size)
+static void *read_object(const unsigned char *sha1, enum object_type *type,
+                        unsigned long *size)
 {
        unsigned long mapsize;
        void *map, *buf;
@@ -2108,13 +2146,26 @@ void *read_object(const unsigned char *sha1, enum object_type *type,
        return read_packed_sha1(sha1, type, size);
 }
 
-void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
-                    unsigned long *size)
+void *read_sha1_file_repl(const unsigned char *sha1,
+                         enum object_type *type,
+                         unsigned long *size,
+                         const unsigned char **replacement)
 {
-       void *data = read_object(sha1, type, size);
+       const unsigned char *repl = lookup_replace_object(sha1);
+       void *data = read_object(repl, type, size);
+
+       /* die if we replaced an object with one that does not exist */
+       if (!data && repl != sha1)
+               die("replacement %s not found for %s",
+                   sha1_to_hex(repl), sha1_to_hex(sha1));
+
        /* legacy behavior is to die on corrupted objects */
-       if (!data && (has_loose_object(sha1) || has_packed_and_bad(sha1)))
-               die("object %s is corrupted", sha1_to_hex(sha1));
+       if (!data && (has_loose_object(repl) || has_packed_and_bad(repl)))
+               die("object %s is corrupted", sha1_to_hex(repl));
+
+       if (replacement)
+               *replacement = repl;
+
        return data;
 }
 
@@ -2170,25 +2221,31 @@ static void write_sha1_file_prepare(const void *buf, unsigned long len,
                                     const char *type, unsigned char *sha1,
                                     char *hdr, int *hdrlen)
 {
-       SHA_CTX c;
+       git_SHA_CTX c;
 
        /* Generate the header */
        *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
 
        /* Sha1.. */
-       SHA1_Init(&c);
-       SHA1_Update(&c, hdr, *hdrlen);
-       SHA1_Update(&c, buf, len);
-       SHA1_Final(sha1, &c);
+       git_SHA1_Init(&c);
+       git_SHA1_Update(&c, hdr, *hdrlen);
+       git_SHA1_Update(&c, buf, len);
+       git_SHA1_Final(sha1, &c);
 }
 
 /*
- * Move the just written object into its final resting place
+ * Move the just written object into its final resting place.
+ * NEEDSWORK: this should be renamed to finalize_temp_file() as
+ * "moving" is only a part of what it does, when no patch between
+ * master to pu changes the call sites of this function.
  */
 int move_temp_to_file(const char *tmpfile, const char *filename)
 {
        int ret = 0;
-       if (link(tmpfile, filename))
+
+       if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
+               goto try_rename;
+       else if (link(tmpfile, filename))
                ret = errno;
 
        /*
@@ -2199,15 +2256,16 @@ int move_temp_to_file(const char *tmpfile, const char *filename)
         *
         * The same holds for FAT formatted media.
         *
-        * When this succeeds, we just return 0. We have nothing
+        * When this succeeds, we just return We have nothing
         * left to unlink.
         */
        if (ret && ret != EEXIST) {
+       try_rename:
                if (!rename(tmpfile, filename))
-                       return 0;
+                       goto out;
                ret = errno;
        }
-       unlink(tmpfile);
+       unlink_or_warn(tmpfile);
        if (ret) {
                if (ret != EEXIST) {
                        return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
@@ -2215,6 +2273,9 @@ int move_temp_to_file(const char *tmpfile, const char *filename)
                /* FIXME!!! Collision check here ? */
        }
 
+out:
+       if (set_shared_perm(filename, (S_IFREG|0444)))
+               return error("unable to set permission to '%s'", filename);
        return 0;
 }
 
@@ -2239,9 +2300,8 @@ static void close_sha1_file(int fd)
 {
        if (fsync_object_files)
                fsync_or_die(fd, "sha1 file");
-       fchmod(fd, 0444);
        if (close(fd) != 0)
-               die("error when closing sha1 file (%s)", strerror(errno));
+               die_errno("error when closing sha1 file");
 }
 
 /* Size of directory component, including the ending '/' */
@@ -2297,6 +2357,8 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 
        filename = sha1_file_name(sha1);
        fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
+       while (fd < 0 && errno == EMFILE && unuse_one_window(packed_git, -1))
+               fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
        if (fd < 0) {
                if (errno == EACCES)
                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
@@ -2404,66 +2466,36 @@ int has_pack_file(const unsigned char *sha1)
        return 1;
 }
 
-int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
+int has_sha1_pack(const unsigned char *sha1)
 {
        struct pack_entry e;
-       return find_pack_entry(sha1, &e, ignore_packed);
+       return find_pack_entry(sha1, &e);
 }
 
 int has_sha1_file(const unsigned char *sha1)
 {
        struct pack_entry e;
 
-       if (find_pack_entry(sha1, &e, NULL))
+       if (find_pack_entry(sha1, &e))
                return 1;
        return has_loose_object(sha1);
 }
 
-int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
-{
-       struct strbuf buf;
-       int ret;
-
-       strbuf_init(&buf, 0);
-       if (strbuf_read(&buf, fd, 4096) < 0) {
-               strbuf_release(&buf);
-               return -1;
-       }
-
-       if (!type)
-               type = blob_type;
-       if (write_object)
-               ret = write_sha1_file(buf.buf, buf.len, type, sha1);
-       else
-               ret = hash_sha1_file(buf.buf, buf.len, type, sha1);
-       strbuf_release(&buf);
-
-       return ret;
-}
-
-int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
-            enum object_type type, const char *path)
+static int index_mem(unsigned char *sha1, void *buf, size_t size,
+                    int write_object, enum object_type type, const char *path)
 {
-       size_t size = xsize_t(st->st_size);
-       void *buf = NULL;
        int ret, re_allocated = 0;
 
-       if (size)
-               buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
-       close(fd);
-
        if (!type)
                type = OBJ_BLOB;
 
        /*
         * Convert blobs to git internal format
         */
-       if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
-               struct strbuf nbuf;
-               strbuf_init(&nbuf, 0);
+       if ((type == OBJ_BLOB) && path) {
+               struct strbuf nbuf = STRBUF_INIT;
                if (convert_to_git(path, buf, size, &nbuf,
                                   write_object ? safe_crlf : 0)) {
-                       munmap(buf, size);
                        buf = strbuf_detach(&nbuf, &size);
                        re_allocated = 1;
                }
@@ -2473,20 +2505,39 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
                ret = write_sha1_file(buf, size, typename(type), sha1);
        else
                ret = hash_sha1_file(buf, size, typename(type), sha1);
-       if (re_allocated) {
+       if (re_allocated)
                free(buf);
-               return ret;
-       }
-       if (size)
+       return ret;
+}
+
+int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
+            enum object_type type, const char *path)
+{
+       int ret;
+       size_t size = xsize_t(st->st_size);
+
+       if (!S_ISREG(st->st_mode)) {
+               struct strbuf sbuf = STRBUF_INIT;
+               if (strbuf_read(&sbuf, fd, 4096) >= 0)
+                       ret = index_mem(sha1, sbuf.buf, sbuf.len, write_object,
+                                       type, path);
+               else
+                       ret = -1;
+               strbuf_release(&sbuf);
+       } else if (size) {
+               void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+               ret = index_mem(sha1, buf, size, write_object, type, path);
                munmap(buf, size);
+       } else
+               ret = index_mem(sha1, NULL, size, write_object, type, path);
+       close(fd);
        return ret;
 }
 
 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
 {
        int fd;
-       char *target;
-       size_t len;
+       struct strbuf sb = STRBUF_INIT;
 
        switch (st->st_mode & S_IFMT) {
        case S_IFREG:
@@ -2499,20 +2550,17 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
                                     path);
                break;
        case S_IFLNK:
-               len = xsize_t(st->st_size);
-               target = xmalloc(len + 1);
-               if (readlink(path, target, len + 1) != st->st_size) {
+               if (strbuf_readlink(&sb, path, st->st_size)) {
                        char *errstr = strerror(errno);
-                       free(target);
                        return error("readlink(\"%s\"): %s", path,
                                     errstr);
                }
                if (!write_object)
-                       hash_sha1_file(target, len, blob_type, sha1);
-               else if (write_sha1_file(target, len, blob_type, sha1))
+                       hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
+               else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
                        return error("%s: failed to insert into database",
                                     path);
-               free(target);
+               strbuf_release(&sb);
                break;
        case S_IFDIR:
                return resolve_gitlink_ref(path, "HEAD", sha1);