unpack-objects: prevent writing of inconsistent objects

[thirdparty/git.git] / builtin-unpack-objects.c

diff --git a/builtin-unpack-objects.c b/builtin-unpack-objects.c
index 50e07faa12f495b3270e1446573b88a255336877..9d2a8549509658d32f25a1bc6af0552dc8380988 100644 (file)
--- a/builtin-unpack-objects.c
+++ b/builtin-unpack-objects.c
@@ -7,11 +7,13 @@
 #include "commit.h"
 #include "tag.h"
 #include "tree.h"
+#include "tree-walk.h"
 #include "progress.h"
 #include "decorate.h"
+#include "fsck.h"
 
-static int dry_run, quiet, recover, has_errors;
-static const char unpack_usage[] = "git-unpack-objects [-n] [-q] [-r] < pack-file";
+static int dry_run, quiet, recover, has_errors, strict;
+static const char unpack_usage[] = "git-unpack-objects [-n] [-q] [-r] [--strict] < pack-file";
 
 /* We always read in 4kB chunks. */
 static unsigned char buffer[4096];
@@ -31,6 +33,16 @@ static struct obj_buffer *lookup_object_buffer(struct object *base)
        return lookup_decoration(&obj_decorate, base);
 }
 
+static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
+{
+       struct obj_buffer *obj;
+       obj = xcalloc(1, sizeof(struct obj_buffer));
+       obj->buffer = buffer;
+       obj->size = size;
+       if (add_decoration(&obj_decorate, object, obj))
+               die("object %s tried to add buffer twice!", sha1_to_hex(object->sha1));
+}
+
 /*
  * Make sure at least "min" bytes are available in the buffer, and
  * return the pointer to the buffer.
@@ -134,9 +146,58 @@ static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1,
 struct obj_info {
        off_t offset;
        unsigned char sha1[20];
+       struct object *obj;
 };
 
+#define FLAG_OPEN (1u<<20)
+#define FLAG_WRITTEN (1u<<21)
+
 static struct obj_info *obj_list;
+unsigned nr_objects;
+
+static void write_cached_object(struct object *obj)
+{
+       unsigned char sha1[20];
+       struct obj_buffer *obj_buf = lookup_object_buffer(obj);
+       if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type), sha1) < 0)
+               die("failed to write object %s", sha1_to_hex(obj->sha1));
+       obj->flags |= FLAG_WRITTEN;
+}
+
+static int check_object(struct object *obj, int type, void *data)
+{
+       if (!obj)
+               return 0;
+
+       if (obj->flags & FLAG_WRITTEN)
+               return 1;
+
+       if (type != OBJ_ANY && obj->type != type)
+               die("object type mismatch");
+
+       if (!(obj->flags & FLAG_OPEN)) {
+               unsigned long size;
+               int type = sha1_object_info(obj->sha1, &size);
+               if (type != obj->type || type <= 0)
+                       die("object of unexpected type");
+               obj->flags |= FLAG_WRITTEN;
+               return 1;
+       }
+
+       if (fsck_object(obj, 1, fsck_error_function))
+               die("Error in object");
+       if (!fsck_walk(obj, check_object, 0))
+               die("Error on reachable objects of %s", sha1_to_hex(obj->sha1));
+       write_cached_object(obj);
+       return 1;
+}
+
+static void write_rest(void)
+{
+       unsigned i;
+       for (i = 0; i < nr_objects; i++)
+               check_object(obj_list[i].obj, OBJ_ANY, 0);
+}
 
 static void added_object(unsigned nr, enum object_type type,
                         void *data, unsigned long size);
@@ -144,9 +205,36 @@ static void added_object(unsigned nr, enum object_type type,
 static void write_object(unsigned nr, enum object_type type,
                         void *buf, unsigned long size)
 {
-       if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
-               die("failed to write object");
        added_object(nr, type, buf, size);
+       if (!strict) {
+               if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
+                       die("failed to write object");
+               free(buf);
+               obj_list[nr].obj = 0;
+       } else if (type == OBJ_BLOB) {
+               struct blob *blob;
+               if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
+                       die("failed to write object");
+               free(buf);
+
+               blob = lookup_blob(obj_list[nr].sha1);
+               if (blob)
+                       blob->object.flags |= FLAG_WRITTEN;
+               else
+                       die("invalid blob object");
+               obj_list[nr].obj = 0;
+       } else {
+               struct object *obj;
+               int eaten;
+               hash_sha1_file(buf, size, typename(type), obj_list[nr].sha1);
+               obj = parse_object_buffer(obj_list[nr].sha1, type, size, buf, &eaten);
+               if (!obj)
+                       die("invalid %s", typename(type));
+               /* buf is stored via add_object_buffer and in obj, if its a tree or commit */
+               add_object_buffer(obj, buf, size);
+               obj->flags |= FLAG_OPEN;
+               obj_list[nr].obj = obj;
+       }
 }
 
 static void resolve_delta(unsigned nr, enum object_type type,
@@ -163,7 +251,6 @@ static void resolve_delta(unsigned nr, enum object_type type,
                die("failed to apply delta");
        free(delta);
        write_object(nr, type, result, result_size);
-       free(result);
 }
 
 static void added_object(unsigned nr, enum object_type type,
@@ -193,7 +280,8 @@ static void unpack_non_delta_entry(enum object_type type, unsigned long size,
 
        if (!dry_run && buf)
                write_object(nr, type, buf, size);
-       free(buf);
+       else
+               free(buf);
 }
 
 static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
@@ -336,7 +424,8 @@ static void unpack_all(void)
        int i;
        struct progress *progress = NULL;
        struct pack_header *hdr = fill(sizeof(struct pack_header));
-       unsigned nr_objects = ntohl(hdr->hdr_entries);
+
+       nr_objects = ntohl(hdr->hdr_entries);
 
        if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
                die("bad pack file");
@@ -347,6 +436,7 @@ static void unpack_all(void)
        if (!quiet)
                progress = start_progress("Unpacking objects", nr_objects);
        obj_list = xmalloc(nr_objects * sizeof(*obj_list));
+       memset(obj_list, 0, nr_objects * sizeof(*obj_list));
        for (i = 0; i < nr_objects; i++) {
                unpack_one(i);
                display_progress(progress, i + 1);
@@ -382,6 +472,10 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
                                recover = 1;
                                continue;
                        }
+                       if (!strcmp(arg, "--strict")) {
+                               strict = 1;
+                               continue;
+                       }
                        if (!prefixcmp(arg, "--pack_header=")) {
                                struct pack_header *hdr;
                                char *c;
@@ -407,6 +501,8 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
        unpack_all();
        SHA1_Update(&ctx, buffer, offset);
        SHA1_Final(sha1, &ctx);
+       if (strict)
+               write_rest();
        if (hashcmp(fill(20), sha1))
                die("final sha1 did not match");
        use(20);