Merge branch 'program-data-config'

This branch introduces support for reading the "Windows-wide" Git
configuration from `%PROGRAMDATA%\Git\config`. As these settings are
intended to be shared between *all* Git-related software, that config
file takes an even lower precedence than `$(prefix)/etc/gitconfig`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Documentation/config.txt

@@ -6,7 +6,9 @@ the Git commands' behavior. The `.git/config` file in each repository
 is used to store the configuration for that repository, and
 `$HOME/.gitconfig` is used to store a per-user configuration as
 fallback values for the `.git/config` file. The file `/etc/gitconfig`
-can be used to store a system-wide default configuration.
+can be used to store a system-wide default configuration. On Windows,
+configuration can also be stored in `C:\ProgramData\Git\config`; This
+file will be used also by libgit2-based software.
 
 The configuration variables are used by both the Git plumbing
 and the porcelains. The variables are divided into sections, wherein

Documentation/git-config.txt

@@ -253,6 +253,14 @@ $XDG_CONFIG_HOME/git/config::
 $GIT_DIR/config::
 	Repository specific configuration file.
 
+On Windows, as there is no central `/etc/` directory, there is yet another
+config file (located at `$PROGRAMDATA/Git/config`), intended to contain
+settings for *all* Git-related software running on the machine. Consequently,
+this config file takes an even lower precedence than the
+`$(prefix)/etc/gitconfig` file. Typically `$PROGRAMDATA` points to
+`C:\ProgramData` (on Windows XP the equivalent in `$ALLUSERSPROFILE` is used,
+i.e. `C:\Documents and Settings\All Users\Application Data\Git\config`).
+
 If no further options are given, all reading options will read all of these
 files that are available. If the global or the system-wide configuration
 file are not available they will be ignored. If the repository configuration

Documentation/git.txt

@@ -1026,7 +1026,8 @@ for further details.
 
 `GIT_CONFIG_NOSYSTEM`::
 	Whether to skip reading settings from the system-wide
-	`$(prefix)/etc/gitconfig` file.  This environment variable can
+	`$(prefix)/etc/gitconfig` file (and on Windows, also from the
+	`%PROGRAMDATA%\Git\config` file).  This environment variable can
 	be used along with `$HOME` and `$XDG_CONFIG_HOME` to create a
 	predictable environment for a picky script, or you can set it
 	temporarily to avoid using a buggy `/etc/gitconfig` file while

compat/mingw.c

@@ -2838,3 +2838,22 @@ int uname(struct utsname *buf)
 		  "%u", (v >> 16) & 0x7fff);
 	return 0;
 }
+
+const char *program_data_config(void)
+{
+	static struct strbuf path = STRBUF_INIT;
+	static unsigned initialized;
+
+	if (!initialized) {
+		const char *env = mingw_getenv("PROGRAMDATA");
+		const char *extra = "";
+		if (!env) {
+			env = mingw_getenv("ALLUSERSPROFILE");
+			extra = "/Application Data";
+		}
+		if (env)
+			strbuf_addf(&path, "%s%s/Git/config", env, extra);
+		initialized = 1;
+	}
+	return *path.buf ? path.buf : NULL;
+}

compat/mingw.h

@@ -458,6 +458,8 @@ int mingw_offset_1st_component(const char *path);
 #define PATH_SEP ';'
 extern char *mingw_query_user_email(void);
 #define query_user_email mingw_query_user_email
+extern const char *program_data_config(void);
+#define git_program_data_config program_data_config
 #if !defined(__MINGW64_VERSION_MAJOR) && (!defined(_MSC_VER) || _MSC_VER < 1800)
 #define PRIuMAX "I64u"
 #define PRId64 "I64d"

config.c

@@ -1284,9 +1284,16 @@ static int do_git_config_sequence(config_fn_t fn, void *data)
 	char *repo_config = have_git_dir() ? git_pathdup("config") : NULL;
 
 	current_parsing_scope = CONFIG_SCOPE_SYSTEM;
-	if (git_config_system() && !access_or_die(git_etc_gitconfig(), R_OK, 0))
-		ret += git_config_from_file(fn, git_etc_gitconfig(),
-					    data);
+	if (git_config_system()) {
+		if (git_program_data_config() &&
+		    !access_or_die(git_program_data_config(), R_OK, 0))
+			ret += git_config_from_file(fn,
+						    git_program_data_config(),
+						    data);
+		if (!access_or_die(git_etc_gitconfig(), R_OK, 0))
+			ret += git_config_from_file(fn, git_etc_gitconfig(),
+						    data);
+	}
 
 	current_parsing_scope = CONFIG_SCOPE_GLOBAL;
 	if (xdg_config && !access_or_die(xdg_config, R_OK, ACCESS_EACCES_OK))
@@ -2041,6 +2048,20 @@ int git_config_key_is_valid(const char *key)
 	return !git_config_parse_key_1(key, NULL, NULL, 1);
 }
 
+static int lock_config_file(const char *config_filename,
+		struct lock_file **result)
+{
+	int fd;
+
+	*result = xcalloc(1, sizeof(struct lock_file));
+	fd = hold_lock_file_for_update(*result, config_filename, 0);
+	if (fd < 0)
+		error("could not lock config file %s: %s", config_filename,
+				strerror(errno));
+
+	return fd;
+}
+
 /*
  * If value==NULL, unset in (remove from) config,
  * if value_regex!=NULL, disregard key/value pairs where value does not match.
@@ -2092,8 +2113,7 @@ int git_config_set_multivar_in_file_gently(const char *config_filename,
 	 * The lock serves a purpose in addition to locking: the new
 	 * contents of .git/config will be written into it.
 	 */
-	lock = xcalloc(1, sizeof(struct lock_file));
-	fd = hold_lock_file_for_update(lock, config_filename, 0);
+	fd = lock_config_file(config_filename, &lock);
 	if (fd < 0) {
 		error_errno("could not lock config file %s", config_filename);
 		free(store.key);
@@ -2394,12 +2414,9 @@ int git_config_rename_section_in_file(const char *config_filename,
 	if (!config_filename)
 		config_filename = filename_buf = git_pathdup("config");
 
-	lock = xcalloc(1, sizeof(struct lock_file));
-	out_fd = hold_lock_file_for_update(lock, config_filename, 0);
-	if (out_fd < 0) {
-		ret = error("could not lock config file %s", config_filename);
+	out_fd = lock_config_file(config_filename, &lock);
+	if (out_fd < 0)
 		goto out;
-	}
 
 	if (!(config_file = fopen(config_filename, "rb"))) {
 		/* no config file means nothing to rename, no error */

git-compat-util.h

@@ -384,6 +384,10 @@ static inline char *git_find_last_dir_sep(const char *path)
 #define query_user_email() NULL
 #endif
 
+#ifndef git_program_data_config
+#define git_program_data_config() NULL
+#endif
+
 #if defined(__HP_cc) && (__HP_cc >= 61000)
 #define NORETURN __attribute__((noreturn))
 #define NORETURN_PTR