fast-import: prevent producing bad delta
[gitweb.git] / sha1_file.c
index 006321e009b321db6cf4f7bf35d8385017a7076a..697f4a43c5ef0bdc220a15545d94bc31ad1f248e 100644 (file)
 #include "pack.h"
 #include "blob.h"
 #include "commit.h"
+#include "run-command.h"
 #include "tag.h"
 #include "tree.h"
+#include "tree-walk.h"
 #include "refs.h"
 #include "pack-revindex.h"
 #include "sha1-lookup.h"
 #endif
 #endif
 
-#ifdef NO_C99_FORMAT
-#define SZ_FMT "lu"
-static unsigned long sz_fmt(size_t s) { return (unsigned long)s; }
-#else
-#define SZ_FMT "zu"
-static size_t sz_fmt(size_t s) { return s; }
-#endif
+#define SZ_FMT PRIuMAX
+static inline uintmax_t sz_fmt(size_t s) { return s; }
 
 const unsigned char null_sha1[20];
 
-static inline int offset_1st_component(const char *path)
+/*
+ * This is meant to hold a *small* number of objects that you would
+ * want read_sha1_file() to be able to return, but yet you do not want
+ * to write them into the object store (e.g. a browse-only
+ * application).
+ */
+static struct cached_object {
+       unsigned char sha1[20];
+       enum object_type type;
+       void *buf;
+       unsigned long size;
+} *cached_objects;
+static int cached_object_nr, cached_object_alloc;
+
+static struct cached_object empty_tree = {
+       EMPTY_TREE_SHA1_BIN_LITERAL,
+       OBJ_TREE,
+       "",
+       0
+};
+
+static struct cached_object *find_cached_object(const unsigned char *sha1)
+{
+       int i;
+       struct cached_object *co = cached_objects;
+
+       for (i = 0; i < cached_object_nr; i++, co++) {
+               if (!hashcmp(co->sha1, sha1))
+                       return co;
+       }
+       if (!hashcmp(sha1, empty_tree.sha1))
+               return &empty_tree;
+       return NULL;
+}
+
+int mkdir_in_gitdir(const char *path)
 {
-       if (has_dos_drive_prefix(path))
-               return 2 + (path[2] == '/');
-       return *path == '/';
+       if (mkdir(path, 0777)) {
+               int saved_errno = errno;
+               struct stat st;
+               struct strbuf sb = STRBUF_INIT;
+
+               if (errno != EEXIST)
+                       return -1;
+               /*
+                * Are we looking at a path in a symlinked worktree
+                * whose original repository does not yet have it?
+                * e.g. .git/rr-cache pointing at its original
+                * repository in which the user hasn't performed any
+                * conflict resolution yet?
+                */
+               if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
+                   strbuf_readlink(&sb, path, st.st_size) ||
+                   !is_absolute_path(sb.buf) ||
+                   mkdir(sb.buf, 0777)) {
+                       strbuf_release(&sb);
+                       errno = saved_errno;
+                       return -1;
+               }
+               strbuf_release(&sb);
+       }
+       return adjust_shared_perm(path);
 }
 
 int safe_create_leading_directories(char *path)
@@ -109,20 +163,22 @@ static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
  */
 char *sha1_file_name(const unsigned char *sha1)
 {
-       static char *name, *base;
+       static char buf[PATH_MAX];
+       const char *objdir;
+       int len;
 
-       if (!base) {
-               const char *sha1_file_directory = get_object_directory();
-               int len = strlen(sha1_file_directory);
-               base = xmalloc(len + 60);
-               memcpy(base, sha1_file_directory, len);
-               memset(base+len, 0, 60);
-               base[len] = '/';
-               base[len+3] = '/';
-               name = base + len + 1;
-       }
-       fill_sha1_path(name, sha1);
-       return base;
+       objdir = get_object_directory();
+       len = strlen(objdir);
+
+       /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
+       if (len + 43 > PATH_MAX)
+               die("insanely long object directory %s", objdir);
+       memcpy(buf, objdir, len);
+       buf[len] = '/';
+       buf[len+3] = '/';
+       buf[len+42] = '\0';
+       fill_sha1_path(buf + len + 1, sha1);
+       return buf;
 }
 
 static char *sha1_get_pack_name(const unsigned char *sha1,
@@ -170,6 +226,7 @@ struct alternate_object_database *alt_odb_list;
 static struct alternate_object_database **alt_odb_tail;
 
 static void read_info_alternates(const char * alternates, int depth);
+static int git_open_noatime(const char *name);
 
 /*
  * Prepare alternate object database registry.
@@ -303,7 +360,7 @@ static void read_info_alternates(const char * relative_base, int depth)
        int fd;
 
        sprintf(path, "%s/%s", relative_base, alt_file_name);
-       fd = open(path, O_RDONLY);
+       fd = git_open_noatime(path);
        if (fd < 0)
                return;
        if (fstat(fd, &st) || (st.st_size == 0)) {
@@ -385,6 +442,8 @@ static unsigned int pack_used_ctr;
 static unsigned int pack_mmap_calls;
 static unsigned int peak_pack_open_windows;
 static unsigned int pack_open_windows;
+static unsigned int pack_open_fds;
+static unsigned int pack_max_fds;
 static size_t peak_pack_mapped;
 static size_t pack_mapped;
 struct packed_git *packed_git;
@@ -416,7 +475,7 @@ static int check_packed_git_idx(const char *path,  struct packed_git *p)
        struct pack_idx_header *hdr;
        size_t idx_size;
        uint32_t version, nr, i, *index;
-       int fd = open(path, O_RDONLY);
+       int fd = git_open_noatime(path);
        struct stat st;
 
        if (fd < 0)
@@ -562,8 +621,10 @@ static int unuse_one_window(struct packed_git *current, int keep_fd)
                        lru_l->next = lru_w->next;
                else {
                        lru_p->windows = lru_w->next;
-                       if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
+                       if (!lru_p->windows && lru_p->pack_fd != -1
+                               && lru_p->pack_fd != keep_fd) {
                                close(lru_p->pack_fd);
+                               pack_open_fds--;
                                lru_p->pack_fd = -1;
                        }
                }
@@ -581,6 +642,21 @@ void release_pack_memory(size_t need, int fd)
                ; /* nothing */
 }
 
+void *xmmap(void *start, size_t length,
+       int prot, int flags, int fd, off_t offset)
+{
+       void *ret = mmap(start, length, prot, flags, fd, offset);
+       if (ret == MAP_FAILED) {
+               if (!length)
+                       return NULL;
+               release_pack_memory(length, fd);
+               ret = mmap(start, length, prot, flags, fd, offset);
+               if (ret == MAP_FAILED)
+                       die_errno("Out of memory? mmap failed");
+       }
+       return ret;
+}
+
 void close_pack_windows(struct packed_git *p)
 {
        while (p->windows) {
@@ -606,6 +682,14 @@ void unuse_pack(struct pack_window **w_cursor)
        }
 }
 
+void close_pack_index(struct packed_git *p)
+{
+       if (p->index_data) {
+               munmap((void *)p->index_data, p->index_size);
+               p->index_data = NULL;
+       }
+}
+
 /*
  * This is used by git-repack in case a newly created pack happens to
  * contain the same set of objects as an existing one.  In that case
@@ -625,10 +709,11 @@ void free_pack_by_name(const char *pack_name)
                if (strcmp(pack_name, p->pack_name) == 0) {
                        clear_delta_base_cache();
                        close_pack_windows(p);
-                       if (p->pack_fd != -1)
+                       if (p->pack_fd != -1) {
                                close(p->pack_fd);
-                       if (p->index_data)
-                               munmap((void *)p->index_data, p->index_size);
+                               pack_open_fds--;
+                       }
+                       close_pack_index(p);
                        free(p->bad_object_sha1);
                        *pp = p->next;
                        free(p);
@@ -653,11 +738,29 @@ static int open_packed_git_1(struct packed_git *p)
        if (!p->index_data && open_pack_index(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 (!pack_max_fds) {
+               struct rlimit lim;
+               unsigned int max_fds;
+
+               if (getrlimit(RLIMIT_NOFILE, &lim))
+                       die_errno("cannot get RLIMIT_NOFILE");
+
+               max_fds = lim.rlim_cur;
+
+               /* Save 3 for stdin/stdout/stderr, 22 for work */
+               if (25 < max_fds)
+                       pack_max_fds = max_fds - 25;
+               else
+                       pack_max_fds = 1;
+       }
+
+       while (pack_max_fds <= pack_open_fds && unuse_one_window(NULL, -1))
+               ; /* nothing */
+
+       p->pack_fd = git_open_noatime(p->pack_name);
        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
                return -1;
+       pack_open_fds++;
 
        /* If we created the struct before we had the pack we lack size. */
        if (!p->pack_size) {
@@ -709,6 +812,7 @@ static int open_packed_git(struct packed_git *p)
                return 0;
        if (p->pack_fd != -1) {
                close(p->pack_fd);
+               pack_open_fds--;
                p->pack_fd = -1;
        }
        return -1;
@@ -734,14 +838,13 @@ unsigned char *use_pack(struct packed_git *p,
 {
        struct pack_window *win = *w_cursor;
 
-       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 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.
         */
+       if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
+               die("packfile %s cannot be accessed", p->pack_name);
        if (offset > (p->pack_size - 20))
                die("offset beyond end of packfile (truncated pack?)");
 
@@ -755,6 +858,10 @@ unsigned char *use_pack(struct packed_git *p,
                if (!win) {
                        size_t window_align = packed_git_window_size / 2;
                        off_t len;
+
+                       if (p->pack_fd == -1 && open_packed_git(p))
+                               die("packfile %s cannot be accessed", p->pack_name);
+
                        win = xcalloc(1, sizeof(*win));
                        win->offset = (offset / window_align) * window_align;
                        len = p->pack_size - win->offset;
@@ -772,6 +879,12 @@ unsigned char *use_pack(struct packed_git *p,
                                die("packfile %s cannot be mapped: %s",
                                        p->pack_name,
                                        strerror(errno));
+                       if (!win->offset && win->len == p->pack_size
+                               && !p->do_not_close) {
+                               close(p->pack_fd);
+                               pack_open_fds--;
+                               p->pack_fd = -1;
+                       }
                        pack_mmap_calls++;
                        pack_open_windows++;
                        if (pack_mapped > peak_pack_mapped)
@@ -801,11 +914,22 @@ static struct packed_git *alloc_packed_git(int extra)
        return p;
 }
 
+static void try_to_free_pack_memory(size_t size)
+{
+       release_pack_memory(size, -1);
+}
+
 struct packed_git *add_packed_git(const char *path, int path_len, int local)
 {
+       static int have_set_try_to_free_routine;
        struct stat st;
        struct packed_git *p = alloc_packed_git(path_len + 2);
 
+       if (!have_set_try_to_free_routine) {
+               have_set_try_to_free_routine = 1;
+               set_try_to_free_routine(try_to_free_pack_memory);
+       }
+
        /*
         * Make sure a corresponding .pack file exists and that
         * the index looks sane.
@@ -838,9 +962,8 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
        return p;
 }
 
-struct packed_git *parse_pack_index(unsigned char *sha1)
+struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 {
-       const char *idx_path = sha1_pack_index_name(sha1);
        const char *path = sha1_pack_name(sha1);
        struct packed_git *p = alloc_packed_git(strlen(path) + 1);
 
@@ -856,6 +979,9 @@ struct packed_git *parse_pack_index(unsigned char *sha1)
 
 void install_packed_git(struct packed_git *pack)
 {
+       if (pack->pack_fd != -1)
+               pack_open_fds++;
+
        pack->next = packed_git;
        packed_git = pack;
 }
@@ -873,8 +999,6 @@ 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",
@@ -1002,7 +1126,7 @@ static void mark_bad_packed_object(struct packed_git *p,
        p->num_bad_objects++;
 }
 
-static int has_packed_and_bad(const unsigned char *sha1)
+static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
 {
        struct packed_git *p;
        unsigned i;
@@ -1010,8 +1134,8 @@ static int has_packed_and_bad(const unsigned char *sha1)
        for (p = packed_git; p; p = p->next)
                for (i = 0; i < p->num_bad_objects; i++)
                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
-                               return 1;
-       return 0;
+                               return p;
+       return NULL;
 }
 
 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
@@ -1024,15 +1148,20 @@ int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long siz
 static int git_open_noatime(const char *name)
 {
        static int sha1_file_open_flag = O_NOATIME;
-       int fd = open(name, O_RDONLY | sha1_file_open_flag);
 
-       /* Might the failure be due to O_NOATIME? */
-       if (fd < 0 && errno != ENOENT && sha1_file_open_flag) {
-               fd = open(name, O_RDONLY);
+       for (;;) {
+               int fd = open(name, O_RDONLY | sha1_file_open_flag);
                if (fd >= 0)
+                       return fd;
+
+               /* Might the failure be due to O_NOATIME? */
+               if (errno != ENOENT && sha1_file_open_flag) {
                        sha1_file_open_flag = 0;
+                       continue;
+               }
+
+               return -1;
        }
-       return fd;
 }
 
 static int open_sha1_file(const unsigned char *sha1)
@@ -1076,20 +1205,29 @@ static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
        return map;
 }
 
-static int legacy_loose_object(unsigned char *map)
+/*
+ * There used to be a second loose object header format which
+ * was meant to mimic the in-pack format, allowing for direct
+ * copy of the object data.  This format turned up not to be
+ * really worth it and we no longer write loose objects in that
+ * format.
+ */
+static int experimental_loose_object(unsigned char *map)
 {
        unsigned int word;
 
        /*
         * Is it a zlib-compressed buffer? If so, the first byte
         * must be 0x78 (15-bit window size, deflated), and the
-        * first 16-bit word is evenly divisible by 31
+        * first 16-bit word is evenly divisible by 31. If so,
+        * we are looking at the official format, not the experimental
+        * one.
         */
        word = (map[0] << 8) + map[1];
        if (map[0] == 0x78 && !(word % 31))
-               return 1;
-       else
                return 0;
+       else
+               return 1;
 }
 
 unsigned long unpack_object_header_buffer(const unsigned char *buf,
@@ -1133,34 +1271,29 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
        stream->next_out = buffer;
        stream->avail_out = bufsiz;
 
-       if (legacy_loose_object(map)) {
-               git_inflate_init(stream);
-               return git_inflate(stream, 0);
-       }
-
+       if (experimental_loose_object(map)) {
+               /*
+                * The old experimental format we no longer produce;
+                * we can still read it.
+                */
+               used = unpack_object_header_buffer(map, mapsize, &type, &size);
+               if (!used || !valid_loose_object_type[type])
+                       return -1;
+               map += used;
+               mapsize -= used;
 
-       /*
-        * There used to be a second loose object header format which
-        * was meant to mimic the in-pack format, allowing for direct
-        * copy of the object data.  This format turned up not to be
-        * really worth it and we don't write it any longer.  But we
-        * can still read it.
-        */
-       used = unpack_object_header_buffer(map, mapsize, &type, &size);
-       if (!used || !valid_loose_object_type[type])
-               return -1;
-       map += used;
-       mapsize -= used;
+               /* Set up the stream for the rest.. */
+               stream->next_in = map;
+               stream->avail_in = mapsize;
+               git_inflate_init(stream);
 
-       /* Set up the stream for the rest.. */
-       stream->next_in = map;
-       stream->avail_in = mapsize;
+               /* And generate the fake traditional header */
+               stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
+                                                typename(type), size);
+               return 0;
+       }
        git_inflate_init(stream);
-
-       /* And generate the fake traditional header */
-       stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
-                                        typename(type), size);
-       return 0;
+       return git_inflate(stream, 0);
 }
 
 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
@@ -1179,7 +1312,7 @@ static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size
                /*
                 * The above condition must be (bytes <= size), not
                 * (bytes < size).  In other words, even though we
-                * expect no more output and set avail_out to zer0,
+                * expect no more output and set avail_out to zero,
                 * the input zlib stream may have bytes that express
                 * "this concludes the stream", and we *do* want to
                 * eat that input.
@@ -1405,7 +1538,7 @@ static int unpack_object_header(struct packed_git *p,
        enum object_type type;
 
        /* use_pack() assures us we have [base, base + 20) available
-        * as a range that we can look at at.  (Its actually the hash
+        * as a range that we can look at.  (Its actually the hash
         * size that is assured.)  With our object header encoding
         * the maximum deflated object size is 2^137, which is just
         * insane, so we know won't exceed what we have been given.
@@ -1856,6 +1989,27 @@ off_t find_pack_entry_one(const unsigned char *sha1,
        return 0;
 }
 
+static int is_pack_valid(struct packed_git *p)
+{
+       /* An already open pack is known to be valid. */
+       if (p->pack_fd != -1)
+               return 1;
+
+       /* If the pack has one window completely covering the
+        * file size, the pack is known to be valid even if
+        * the descriptor is not currently open.
+        */
+       if (p->windows) {
+               struct pack_window *w = p->windows;
+
+               if (!w->offset && w->len == p->pack_size)
+                       return 1;
+       }
+
+       /* Force the pack to open to prove its valid. */
+       return !open_packed_git(p);
+}
+
 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 {
        static struct packed_git *last_found = (void *)1;
@@ -1885,7 +2039,7 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
                         * it may have been deleted since the index
                         * was loaded!
                         */
-                       if (p->pack_fd == -1 && open_packed_git(p)) {
+                       if (!is_pack_valid(p)) {
                                error("packfile %s cannot be accessed", p->pack_name);
                                goto next;
                        }
@@ -1945,9 +2099,17 @@ static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *size
 
 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 {
+       struct cached_object *co;
        struct pack_entry e;
        int status;
 
+       co = find_cached_object(sha1);
+       if (co) {
+               if (sizep)
+                       *sizep = co->size;
+               return co->type;
+       }
+
        if (!find_pack_entry(sha1, &e)) {
                /* Most likely it's a loose object. */
                status = sha1_loose_object_info(sha1, sizep);
@@ -1993,41 +2155,6 @@ static void *read_packed_sha1(const unsigned char *sha1,
        return data;
 }
 
-/*
- * This is meant to hold a *small* number of objects that you would
- * want read_sha1_file() to be able to return, but yet you do not want
- * to write them into the object store (e.g. a browse-only
- * application).
- */
-static struct cached_object {
-       unsigned char sha1[20];
-       enum object_type type;
-       void *buf;
-       unsigned long size;
-} *cached_objects;
-static int cached_object_nr, cached_object_alloc;
-
-static struct cached_object empty_tree = {
-       EMPTY_TREE_SHA1_BIN,
-       OBJ_TREE,
-       "",
-       0
-};
-
-static struct cached_object *find_cached_object(const unsigned char *sha1)
-{
-       int i;
-       struct cached_object *co = cached_objects;
-
-       for (i = 0; i < cached_object_nr; i++, co++) {
-               if (!hashcmp(co->sha1, sha1))
-                       return co;
-       }
-       if (!hashcmp(sha1, empty_tree.sha1))
-               return &empty_tree;
-       return NULL;
-}
-
 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
                      unsigned char *sha1)
 {
@@ -2078,27 +2205,46 @@ static void *read_object(const unsigned char *sha1, enum object_type *type,
        return read_packed_sha1(sha1, type, size);
 }
 
-void *read_sha1_file_repl(const unsigned char *sha1,
-                         enum object_type *type,
-                         unsigned long *size,
-                         const unsigned char **replacement)
+/*
+ * This function dies on corrupt objects; the callers who want to
+ * deal with them should arrange to call read_object() and give error
+ * messages themselves.
+ */
+void *read_sha1_file_extended(const unsigned char *sha1,
+                             enum object_type *type,
+                             unsigned long *size,
+                             unsigned flag)
 {
-       const unsigned char *repl = lookup_replace_object(sha1);
-       void *data = read_object(repl, type, size);
+       void *data;
+       char *path;
+       const struct packed_git *p;
+       const unsigned char *repl = (flag & READ_SHA1_FILE_REPLACE)
+               ? lookup_replace_object(sha1) : sha1;
+
+       errno = 0;
+       data = read_object(repl, type, size);
+       if (data)
+               return data;
+
+       if (errno && errno != ENOENT)
+               die_errno("failed to read object %s", sha1_to_hex(sha1));
 
        /* die if we replaced an object with one that does not exist */
-       if (!data && repl != sha1)
+       if (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(repl) || has_packed_and_bad(repl)))
-               die("object %s is corrupted", sha1_to_hex(repl));
+       if (has_loose_object(repl)) {
+               path = sha1_file_name(sha1);
+               die("loose object %s (stored in %s) is corrupt",
+                   sha1_to_hex(repl), path);
+       }
 
-       if (replacement)
-               *replacement = repl;
+       if ((p = has_packed_and_bad(repl)) != NULL)
+               die("packed object %s (stored in %s) is corrupt",
+                   sha1_to_hex(repl), p->pack_name);
 
-       return data;
+       return NULL;
 }
 
 void *read_object_with_reference(const unsigned char *sha1,
@@ -2206,7 +2352,7 @@ int move_temp_to_file(const char *tmpfile, const char *filename)
        }
 
 out:
-       if (set_shared_perm(filename, (S_IFREG|0444)))
+       if (adjust_shared_perm(filename))
                return error("unable to set permission to '%s'", filename);
        return 0;
 }
@@ -2262,7 +2408,7 @@ static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
        }
        memcpy(buffer, filename, dirlen);
        strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
-       fd = mkstemp(buffer);
+       fd = git_mkstemp_mode(buffer, 0444);
        if (fd < 0 && dirlen && errno == ENOENT) {
                /* Make sure the directory exists */
                memcpy(buffer, filename, dirlen);
@@ -2272,13 +2418,13 @@ static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
 
                /* Try again */
                strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
-               fd = mkstemp(buffer);
+               fd = git_mkstemp_mode(buffer, 0444);
        }
        return fd;
 }
 
 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
-                             void *buf, unsigned long len, time_t mtime)
+                             const void *buf, unsigned long len, time_t mtime)
 {
        int fd, ret;
        unsigned char compressed[4096];
@@ -2290,8 +2436,6 @@ 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());
@@ -2314,7 +2458,7 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
        git_SHA1_Update(&c, hdr, hdrlen);
 
        /* Then the data itself.. */
-       stream.next_in = buf;
+       stream.next_in = (void *)buf;
        stream.avail_in = len;
        do {
                unsigned char *in0 = stream.next_in;
@@ -2349,7 +2493,7 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
        return move_temp_to_file(tmpfile, filename);
 }
 
-int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
+int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
        unsigned char sha1[20];
        char hdr[32];
@@ -2410,10 +2554,40 @@ int has_sha1_file(const unsigned char *sha1)
        return has_loose_object(sha1);
 }
 
+static void check_tree(const void *buf, size_t size)
+{
+       struct tree_desc desc;
+       struct name_entry entry;
+
+       init_tree_desc(&desc, buf, size);
+       while (tree_entry(&desc, &entry))
+               /* do nothing
+                * tree_entry() will die() on malformed entries */
+               ;
+}
+
+static void check_commit(const void *buf, size_t size)
+{
+       struct commit c;
+       memset(&c, 0, sizeof(c));
+       if (parse_commit_buffer(&c, buf, size))
+               die("corrupt commit");
+}
+
+static void check_tag(const void *buf, size_t size)
+{
+       struct tag t;
+       memset(&t, 0, sizeof(t));
+       if (parse_tag_buffer(&t, buf, size))
+               die("corrupt tag");
+}
+
 static int index_mem(unsigned char *sha1, void *buf, size_t size,
-                    int write_object, enum object_type type, const char *path)
+                    enum object_type type,
+                    const char *path, unsigned flags)
 {
        int ret, re_allocated = 0;
+       int write_object = flags & HASH_WRITE_OBJECT;
 
        if (!type)
                type = OBJ_BLOB;
@@ -2429,6 +2603,14 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
                        re_allocated = 1;
                }
        }
+       if (flags & HASH_FORMAT_CHECK) {
+               if (type == OBJ_TREE)
+                       check_tree(buf, size);
+               if (type == OBJ_COMMIT)
+                       check_commit(buf, size);
+               if (type == OBJ_TAG)
+                       check_tag(buf, size);
+       }
 
        if (write_object)
                ret = write_sha1_file(buf, size, typename(type), sha1);
@@ -2439,41 +2621,141 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
        return ret;
 }
 
+static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
+                     const char *path, unsigned flags)
+{
+       struct strbuf sbuf = STRBUF_INIT;
+       int ret;
+
+       if (strbuf_read(&sbuf, fd, 4096) >= 0)
+               ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
+       else
+               ret = -1;
+       strbuf_release(&sbuf);
+       return ret;
+}
+
 #define SMALL_FILE_SIZE (32*1024)
 
-int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
-            enum object_type type, const char *path)
+static int index_core(unsigned char *sha1, int fd, size_t size,
+                     enum object_type type, const char *path,
+                     unsigned flags)
 {
        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);
+       if (!size) {
+               ret = index_mem(sha1, NULL, size, type, path, flags);
        } else if (size <= SMALL_FILE_SIZE) {
                char *buf = xmalloc(size);
                if (size == read_in_full(fd, buf, size))
-                       ret = index_mem(sha1, buf, size, write_object, type,
-                                       path);
+                       ret = index_mem(sha1, buf, size, type, path, flags);
                else
                        ret = error("short read %s", strerror(errno));
                free(buf);
-       } else if (size) {
+       } else {
                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
-               ret = index_mem(sha1, buf, size, write_object, type, path);
+               ret = index_mem(sha1, buf, size, type, path, flags);
                munmap(buf, size);
-       } else
-               ret = index_mem(sha1, NULL, size, write_object, type, path);
+       }
+       return ret;
+}
+
+/*
+ * This creates one packfile per large blob, because the caller
+ * immediately wants the result sha1, and fast-import can report the
+ * object name via marks mechanism only by closing the created
+ * packfile.
+ *
+ * This also bypasses the usual "convert-to-git" dance, and that is on
+ * purpose. We could write a streaming version of the converting
+ * functions and insert that before feeding the data to fast-import
+ * (or equivalent in-core API described above), but the primary
+ * motivation for trying to stream from the working tree file and to
+ * avoid mmaping it in core is to deal with large binary blobs, and
+ * by definition they do _not_ want to get any conversion.
+ */
+static int index_stream(unsigned char *sha1, int fd, size_t size,
+                       enum object_type type, const char *path,
+                       unsigned flags)
+{
+       struct child_process fast_import;
+       char export_marks[512];
+       const char *argv[] = { "fast-import", "--quiet", export_marks, NULL };
+       char tmpfile[512];
+       char fast_import_cmd[512];
+       char buf[512];
+       int len, tmpfd;
+
+       strcpy(tmpfile, git_path("hashstream_XXXXXX"));
+       tmpfd = git_mkstemp_mode(tmpfile, 0600);
+       if (tmpfd < 0)
+               die_errno("cannot create tempfile: %s", tmpfile);
+       if (close(tmpfd))
+               die_errno("cannot close tempfile: %s", tmpfile);
+       sprintf(export_marks, "--export-marks=%s", tmpfile);
+
+       memset(&fast_import, 0, sizeof(fast_import));
+       fast_import.in = -1;
+       fast_import.argv = argv;
+       fast_import.git_cmd = 1;
+       if (start_command(&fast_import))
+               die_errno("index-stream: git fast-import failed");
+
+       len = sprintf(fast_import_cmd, "blob\nmark :1\ndata %lu\n",
+                     (unsigned long) size);
+       write_or_whine(fast_import.in, fast_import_cmd, len,
+                      "index-stream: feeding fast-import");
+       while (size) {
+               char buf[10240];
+               size_t sz = size < sizeof(buf) ? size : sizeof(buf);
+               size_t actual;
+
+               actual = read_in_full(fd, buf, sz);
+               if (actual < 0)
+                       die_errno("index-stream: reading input");
+               if (write_in_full(fast_import.in, buf, actual) != actual)
+                       die_errno("index-stream: feeding fast-import");
+               size -= actual;
+       }
+       if (close(fast_import.in))
+               die_errno("index-stream: closing fast-import");
+       if (finish_command(&fast_import))
+               die_errno("index-stream: finishing fast-import");
+
+       tmpfd = open(tmpfile, O_RDONLY);
+       if (tmpfd < 0)
+               die_errno("index-stream: cannot open fast-import mark");
+       len = read(tmpfd, buf, sizeof(buf));
+       if (len < 0)
+               die_errno("index-stream: reading fast-import mark");
+       if (close(tmpfd) < 0)
+               die_errno("index-stream: closing fast-import mark");
+       if (unlink(tmpfile))
+               die_errno("index-stream: unlinking fast-import mark");
+       if (len != 44 ||
+           memcmp(":1 ", buf, 3) ||
+           get_sha1_hex(buf + 3, sha1))
+               die_errno("index-stream: unexpected fast-import mark: <%s>", buf);
+       return 0;
+}
+
+int index_fd(unsigned char *sha1, int fd, struct stat *st,
+            enum object_type type, const char *path, unsigned flags)
+{
+       int ret;
+       size_t size = xsize_t(st->st_size);
+
+       if (!S_ISREG(st->st_mode))
+               ret = index_pipe(sha1, fd, type, path, flags);
+       else if (size <= big_file_threshold || type != OBJ_BLOB)
+               ret = index_core(sha1, fd, size, type, path, flags);
+       else
+               ret = index_stream(sha1, fd, size, type, path, flags);
        close(fd);
        return ret;
 }
 
-int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
+int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
 {
        int fd;
        struct strbuf sb = STRBUF_INIT;
@@ -2484,7 +2766,7 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
                if (fd < 0)
                        return error("open(\"%s\"): %s", path,
                                     strerror(errno));
-               if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
+               if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
                        return error("%s: failed to insert into database",
                                     path);
                break;
@@ -2494,7 +2776,7 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
                        return error("readlink(\"%s\"): %s", path,
                                     errstr);
                }
-               if (!write_object)
+               if (!(flags & HASH_WRITE_OBJECT))
                        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",
@@ -2523,3 +2805,13 @@ int read_pack_header(int fd, struct pack_header *header)
                return PH_ERROR_PROTOCOL;
        return 0;
 }
+
+void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
+{
+       enum object_type type = sha1_object_info(sha1, NULL);
+       if (type < 0)
+               die("%s is not a valid object", sha1_to_hex(sha1));
+       if (type != expect)
+               die("%s is not a valid '%s' object", sha1_to_hex(sha1),
+                   typename(expect));
+}