builtin/init-db: allow specifying hash algorithm on command line
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@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
brian m. carlson committed
Feb 22, 2020 at 20:17 UTC
8b8f7189dff1f9ee2e3d65dfaafc2fc9f4956232
4 files changed
+55
-9
Documentation/git-init.txt
+6
-1
@@ -10,7 +10,7 @@ SYNOPSIS
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--------
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[verse]
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'git init' [-q | --quiet] [--bare] [--template=<template_directory>]
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- [--separate-git-dir <git dir>]
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+ [--separate-git-dir <git dir>] [--object-format=<format]
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[--shared[=<permissions>]] [directory]
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@@ -48,6 +48,11 @@ Only print error and warning messages; all other output will be suppressed.
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Create a bare repository. If `GIT_DIR` environment is not set, it is set to the
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current working directory.
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+--object-format=<format>::
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+
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+Specify the given object format (hash algorithm) for the repository. The valid
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+values are 'sha1' and (if enabled) 'sha256'. 'sha1' is the default.
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+
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--template=<template_directory>::
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Specify the directory from which templates will be used. (See the "TEMPLATE
builtin/clone.c
+1
-1
@@ -1097,7 +1097,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
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}
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}
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- init_db(git_dir, real_git_dir, option_template, INIT_DB_QUIET);
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+ init_db(git_dir, real_git_dir, option_template, GIT_HASH_UNKNOWN, INIT_DB_QUIET);
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if (real_git_dir)
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git_dir = real_git_dir;
builtin/init-db.c
+46
-6
@@ -177,7 +177,8 @@ static int needs_work_tree_config(const char *git_dir, const char *work_tree)
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}
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static int create_default_files(const char *template_path,
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- const char *original_git_dir)
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+ const char *original_git_dir,
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+ const struct repository_format *fmt)
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{
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struct stat st1;
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struct strbuf buf = STRBUF_INIT;
@@ -187,6 +188,7 @@ static int create_default_files(const char *template_path,
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int reinit;
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int filemode;
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struct strbuf err = STRBUF_INIT;
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+ int repo_version = GIT_REPO_VERSION;
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/* Just look for `init.templatedir` */
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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,
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exit(1);
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}
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+#ifndef ENABLE_SHA256
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+ if (fmt->hash_algo != GIT_HASH_SHA1)
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+ die(_("The hash algorithm %s is not supported in this build."), hash_algos[fmt->hash_algo].name);
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+#endif
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+
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+ if (fmt->hash_algo != GIT_HASH_SHA1)
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+ repo_version = GIT_REPO_VERSION_READ;
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+
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/* This forces creation of new config file */
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xsnprintf(repo_version_string, sizeof(repo_version_string),
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- "%d", GIT_REPO_VERSION);
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+ "%d", repo_version);
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git_config_set("core.repositoryformatversion", repo_version_string);
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+ if (fmt->hash_algo != GIT_HASH_SHA1)
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+ git_config_set("extensions.objectformat",
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+ hash_algos[fmt->hash_algo].name);
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+
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/* Check filemode trustability */
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path = git_path_buf(&buf, "config");
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filemode = TEST_FILEMODE;
@@ -340,12 +354,26 @@ static void separate_git_dir(const char *git_dir, const char *git_link)
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write_file(git_link, "gitdir: %s", git_dir);
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}
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+static void validate_hash_algorithm(struct repository_format *repo_fmt, int hash)
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+{
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+ /*
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+ * If we already have an initialized repo, don't allow the user to
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+ * specify a different algorithm, as that could cause corruption.
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+ * Otherwise, if the user has specified one on the command line, use it.
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+ */
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+ if (repo_fmt->version >= 0 && hash != GIT_HASH_UNKNOWN && hash != repo_fmt->hash_algo)
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+ die(_("attempt to reinitialize repository with different hash"));
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+ else if (hash != GIT_HASH_UNKNOWN)
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+ repo_fmt->hash_algo = hash;
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+}
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+
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int init_db(const char *git_dir, const char *real_git_dir,
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- const char *template_dir, unsigned int flags)
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+ const char *template_dir, int hash, unsigned int flags)
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{
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int reinit;
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int exist_ok = flags & INIT_DB_EXIST_OK;
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char *original_git_dir = real_pathdup(git_dir, 1);
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+ struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
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if (real_git_dir) {
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struct stat st;
@@ -378,9 +406,11 @@ int init_db(const char *git_dir, const char *real_git_dir,
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* config file, so this will not fail. What we are catching
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* is an attempt to reinitialize new repository with an old tool.
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*/
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- check_repository_format(NULL);
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+ check_repository_format(&repo_fmt);
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- reinit = create_default_files(template_dir, original_git_dir);
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+ validate_hash_algorithm(&repo_fmt, hash);
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+
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+ reinit = create_default_files(template_dir, original_git_dir, &repo_fmt);
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create_object_directory();
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@@ -482,6 +512,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
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const char *work_tree;
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const char *template_dir = NULL;
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unsigned int flags = 0;
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+ const char *object_format = NULL;
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+ int hash_algo = GIT_HASH_UNKNOWN;
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const struct option init_db_options[] = {
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OPT_STRING(0, "template", &template_dir, N_("template-directory"),
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N_("directory from which templates will be used")),
@@ -494,6 +526,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
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OPT_BIT('q', "quiet", &flags, N_("be quiet"), INIT_DB_QUIET),
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OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
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N_("separate git dir from working tree")),
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+ OPT_STRING(0, "object-format", &object_format, N_("hash"),
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+ N_("specify the hash algorithm to use")),
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OPT_END()
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};
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@@ -546,6 +580,12 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
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free(cwd);
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}
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+ if (object_format) {
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+ hash_algo = hash_algo_by_name(object_format);
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+ if (hash_algo == GIT_HASH_UNKNOWN)
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+ die(_("unknown hash algorithm '%s'"), object_format);
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+ }
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+
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if (init_shared_repository != -1)
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set_shared_repository(init_shared_repository);
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@@ -597,5 +637,5 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
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UNLEAK(work_tree);
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flags |= INIT_DB_EXIST_OK;
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- return init_db(git_dir, real_git_dir, template_dir, flags);
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+ return init_db(git_dir, real_git_dir, template_dir, hash_algo, flags);
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}
cache.h
+2
-1
@@ -627,7 +627,8 @@ int path_inside_repo(const char *prefix, const char *path);
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#define INIT_DB_EXIST_OK 0x0002
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int init_db(const char *git_dir, const char *real_git_dir,
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- const char *template_dir, unsigned int flags);
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+ const char *template_dir, int hash_algo,
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+ unsigned int flags);
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void sanitize_stdfds(void);
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int daemonize(void);