Allow the user to specify the hash algorithm on the command line by
using the --object-format option to git init. Validate that the user is
not attempting to reinitialize a repository with a different hash
algorithm. Ensure that if we are writing a non-SHA-1 repository that we
set the repository version to 1 and write the objectFormat extension.
Restrict this option to work only when ENABLE_SHA256 is set until the
codebase is in a situation to fully support this.
Signed-off-by: brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/git-init.txt | 7 ++++-
builtin/clone.c | 2 +-
builtin/init-db.c | 52 +++++++++++++++++++++++++++++++++-----
cache.h | 3 ++-
4 files changed, 55 insertions(+), 9 deletions(-)
diff --git a/Documentation/git-init.txt b/Documentation/git-init.txt
index 32880aafb0..adc6adfd38 100644
--- a/Documentation/git-init.txt
+++ b/Documentation/git-init.txt
@@ -10,7 +10,7 @@ SYNOPSIS
--------
[verse]
'git init' [-q | --quiet] [--bare] [--template=<template_directory>]
- [--separate-git-dir <git dir>]
+ [--separate-git-dir <git dir>] [--object-format=<format]
[--shared[=<permissions>]] [directory]
@@ -48,6 +48,11 @@ Only print error and warning messages; all other output will be suppressed.
Create a bare repository. If `GIT_DIR` environment is not set, it is set to the
current working directory.
+--object-format=<format>::
+
+Specify the given object format (hash algorithm) for the repository. The valid
+values are 'sha1' and (if enabled) 'sha256'. 'sha1' is the default.
+
--template=<template_directory>::
Specify the directory from which templates will be used. (See the "TEMPLATE
diff --git a/builtin/clone.c b/builtin/clone.c
index 4f6150c55c..961996a110 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -1097,7 +1097,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
}
}
- init_db(git_dir, real_git_dir, option_template, INIT_DB_QUIET);
+ init_db(git_dir, real_git_dir, option_template, GIT_HASH_UNKNOWN, INIT_DB_QUIET);
if (real_git_dir)
git_dir = real_git_dir;
diff --git a/builtin/init-db.c b/builtin/init-db.c
index b11f07064d..d05552f0ae 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -177,7 +177,8 @@ static int needs_work_tree_config(const char *git_dir, const char *work_tree)
}
static int create_default_files(const char *template_path,
- const char *original_git_dir)
+ const char *original_git_dir,
+ const struct repository_format *fmt)
{
struct stat st1;
struct strbuf buf = STRBUF_INIT;
@@ -187,6 +188,7 @@ static int create_default_files(const char *template_path,
int reinit;
int filemode;
struct strbuf err = STRBUF_INIT;
+ int repo_version = GIT_REPO_VERSION;
/* Just look for `init.templatedir` */
init_db_template_dir = NULL; /* re-set in case it was set before */
@@ -244,11 +246,23 @@ static int create_default_files(const char *template_path,
exit(1);
}
+#ifndef ENABLE_SHA256
+ if (fmt->hash_algo != GIT_HASH_SHA1)
+ die(_("The hash algorithm %s is not supported in this build."), hash_algos[fmt->hash_algo].name);
+#endif
+
+ if (fmt->hash_algo != GIT_HASH_SHA1)
+ repo_version = GIT_REPO_VERSION_READ;
+
/* This forces creation of new config file */
xsnprintf(repo_version_string, sizeof(repo_version_string),
- "%d", GIT_REPO_VERSION);
+ "%d", repo_version);
git_config_set("core.repositoryformatversion", repo_version_string);
+ if (fmt->hash_algo != GIT_HASH_SHA1)
+ git_config_set("extensions.objectformat",
+ hash_algos[fmt->hash_algo].name);
+
/* Check filemode trustability */
path = git_path_buf(&buf, "config");
filemode = TEST_FILEMODE;
@@ -340,12 +354,26 @@ static void separate_git_dir(const char *git_dir, const char *git_link)
write_file(git_link, "gitdir: %s", git_dir);
}
+static void validate_hash_algorithm(struct repository_format *repo_fmt, int hash)
+{
+ /*
+ * If we already have an initialized repo, don't allow the user to
+ * specify a different algorithm, as that could cause corruption.
+ * Otherwise, if the user has specified one on the command line, use it.
+ */
+ if (repo_fmt->version >= 0 && hash != GIT_HASH_UNKNOWN && hash != repo_fmt->hash_algo)
+ die(_("attempt to reinitialize repository with different hash"));
+ else if (hash != GIT_HASH_UNKNOWN)
+ repo_fmt->hash_algo = hash;
+}
+
int init_db(const char *git_dir, const char *real_git_dir,
- const char *template_dir, unsigned int flags)
+ const char *template_dir, int hash, unsigned int flags)
{
int reinit;
int exist_ok = flags & INIT_DB_EXIST_OK;
char *original_git_dir = real_pathdup(git_dir, 1);
+ struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
if (real_git_dir) {
struct stat st;
@@ -378,9 +406,11 @@ int init_db(const char *git_dir, const char *real_git_dir,
* config file, so this will not fail. What we are catching
* is an attempt to reinitialize new repository with an old tool.
*/
- check_repository_format(NULL);
+ check_repository_format(&repo_fmt);
- reinit = create_default_files(template_dir, original_git_dir);
+ validate_hash_algorithm(&repo_fmt, hash);
+
+ reinit = create_default_files(template_dir, original_git_dir, &repo_fmt);
create_object_directory();
@@ -482,6 +512,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
const char *work_tree;
const char *template_dir = NULL;
unsigned int flags = 0;
+ const char *object_format = NULL;
+ int hash_algo = GIT_HASH_UNKNOWN;
const struct option init_db_options[] = {
OPT_STRING(0, "template", &template_dir, N_("template-directory"),
N_("directory from which templates will be used")),
@@ -494,6 +526,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
OPT_BIT('q', "quiet", &flags, N_("be quiet"), INIT_DB_QUIET),
OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
N_("separate git dir from working tree")),
+ OPT_STRING(0, "object-format", &object_format, N_("hash"),
+ N_("specify the hash algorithm to use")),
OPT_END()
};
@@ -546,6 +580,12 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
free(cwd);
}
+ if (object_format) {
+ hash_algo = hash_algo_by_name(object_format);
+ if (hash_algo == GIT_HASH_UNKNOWN)
+ die(_("unknown hash algorithm '%s'"), object_format);
+ }
+
if (init_shared_repository != -1)
set_shared_repository(init_shared_repository);
@@ -597,5 +637,5 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
UNLEAK(work_tree);
flags |= INIT_DB_EXIST_OK;
- return init_db(git_dir, real_git_dir, template_dir, flags);
+ return init_db(git_dir, real_git_dir, template_dir, hash_algo, flags);
}
diff --git a/cache.h b/cache.h
index 29ee02a8d4..7a47e023ba 100644
--- a/cache.h
+++ b/cache.h
@@ -627,7 +627,8 @@ int path_inside_repo(const char *prefix, const char *path);
#define INIT_DB_EXIST_OK 0x0002
int init_db(const char *git_dir, const char *real_git_dir,
- const char *template_dir, unsigned int flags);
+ const char *template_dir, int hash_algo,
+ unsigned int flags);
void sanitize_stdfds(void);
int daemonize(void);
