While it's already possible to pass runtime configuration via `git -c
<key>=<value>`, it may be undesirable to use when the value contains
sensitive information. E.g. if one wants to set `http.extraHeader` to
contain an authentication token, doing so via `-c` would trivially leak
those credentials via e.g. ps(1), which typically also shows command
arguments.
To enable this usecase without leaking credentials, this commit
introduces a new switch `--config-env=<key>=<envvar>`. Instead of
directly passing a value for the given key, it instead allows the user
to specify the name of an environment variable. The value of that
variable will then be used as value of the key.
Co-authored-by: Jeff King <peff@xxxxxxxx>
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
Documentation/git.txt | 11 ++++++++++-
config.c | 21 ++++++++++++++++++++
config.h | 1 +
git.c | 4 +++-
t/t1300-config.sh | 45 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 80 insertions(+), 2 deletions(-)
diff --git a/Documentation/git.txt b/Documentation/git.txt
index c463b937a8..9061c54792 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -13,7 +13,7 @@ SYNOPSIS
[--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
[-p|--paginate|-P|--no-pager] [--no-replace-objects] [--bare]
[--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
- [--super-prefix=<path>]
+ [--super-prefix=<path>] [--config-env <name>=<envvar>]
<command> [<args>]
DESCRIPTION
@@ -80,6 +80,15 @@ config file). Including the equals but with an empty value (like `git -c
foo.bar= ...`) sets `foo.bar` to the empty string which `git config
--type=bool` will convert to `false`.
+--config-env=<name>=<envvar>::
+ Pass a configuration parameter to the command. The <envvar>
+ given will be replaced with the contents of the environment
+ variable of that name. In contrast to `-c`, an envvar must
+ always be given and exist in the environment. Passing an
+ environment variable with empty value will set <name> to the
+ empty string which `git config --type=bool` will convert to
+ `false`.
+
--exec-path[=<path>]::
Path to wherever your core Git programs are installed.
This can also be controlled by setting the GIT_EXEC_PATH
diff --git a/config.c b/config.c
index 1137bd73af..cde3511110 100644
--- a/config.c
+++ b/config.c
@@ -345,6 +345,27 @@ void git_config_push_parameter(const char *text)
strbuf_release(&env);
}
+void git_config_push_env(const char *spec)
+{
+ struct strbuf buf = STRBUF_INIT;
+ const char *env_name;
+ const char *env_value;
+
+ env_name = strrchr(spec, '=');
+ if (!env_name)
+ die("invalid config format: %s", spec);
+ env_name++;
+
+ env_value = getenv(env_name);
+ if (!env_value)
+ die("config variable missing for '%s'", env_name);
+
+ strbuf_add(&buf, spec, env_name - spec);
+ strbuf_addstr(&buf, env_value);
+ git_config_push_parameter(buf.buf);
+ strbuf_release(&buf);
+}
+
static inline int iskeychar(int c)
{
return isalnum(c) || c == '-';
diff --git a/config.h b/config.h
index c1449bb790..19a9adbaa9 100644
--- a/config.h
+++ b/config.h
@@ -138,6 +138,7 @@ int git_config_from_mem(config_fn_t fn,
int git_config_from_blob_oid(config_fn_t fn, const char *name,
const struct object_id *oid, void *data);
void git_config_push_parameter(const char *text);
+void git_config_push_env(const char *spec);
int git_config_from_parameters(config_fn_t fn, void *data);
void read_early_config(config_fn_t cb, void *data);
void read_very_early_config(config_fn_t cb, void *data);
diff --git a/git.c b/git.c
index 5a8ff12f87..b5f63d346b 100644
--- a/git.c
+++ b/git.c
@@ -29,7 +29,7 @@ const char git_usage_string[] =
" [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
" [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]\n"
" [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
- " [--super-prefix=<path>]\n"
+ " [--super-prefix=<path>] [--config-env=<name>=<envvar>]\n"
" <command> [<args>]");
const char git_more_info_string[] =
@@ -255,6 +255,8 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
git_config_push_parameter((*argv)[1]);
(*argv)++;
(*argc)--;
+ } else if (skip_prefix(cmd, "--config-env=", &cmd)) {
+ git_config_push_env(cmd);
} else if (!strcmp(cmd, "--literal-pathspecs")) {
setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
if (envchanged)
diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index 97a04c6cc2..46a94814d5 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -1316,6 +1316,51 @@ test_expect_success 'detect bogus GIT_CONFIG_PARAMETERS' '
git config --get-regexp "env.*"
'
+test_expect_success 'git --config-env=key=envvar support' '
+ cat >expect <<-\EOF &&
+ value
+ value
+ false
+ EOF
+ {
+ env ENVVAR=value git --config-env=core.name=ENVVAR config core.name &&
+ env ENVVAR=value git --config-env=foo.CamelCase=ENVVAR config foo.camelcase &&
+ env ENVVAR= git --config-env=foo.flag=ENVVAR config --bool foo.flag
+ } >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'git --config-env fails with invalid parameters' '
+ test_must_fail git --config-env=foo.flag config --bool foo.flag 2>error &&
+ test_i18ngrep "invalid config format" error &&
+ test_must_fail git --config-env=foo.flag=NONEXISTENT config --bool foo.flag 2>error &&
+ test_i18ngrep "config variable missing" error
+'
+
+test_expect_success 'git -c and --config-env work together' '
+ cat >expect <<-\EOF &&
+ bar.cmd cmd-value
+ bar.env env-value
+ EOF
+ env ENVVAR=env-value git \
+ -c bar.cmd=cmd-value \
+ --config-env=bar.env=ENVVAR \
+ config --get-regexp "^bar.*" >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'git -c and --config-env override each other' '
+ cat >expect <<-\EOF &&
+ env
+ cmd
+ EOF
+ {
+ env ENVVAR=env git -c bar.bar=cmd --config-env=bar.bar=ENVVAR config bar.bar &&
+ env ENVVAR=env git --config-env=bar.bar=ENVVAR -c bar.bar=cmd config bar.bar
+ } >actual &&
+ test_cmp expect actual
+'
+
test_expect_success 'git config --edit works' '
git config -f tmp test.value no &&
echo test.value=yes >expect &&
--
2.29.2
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