Read /etc/locale.conf when configuring the distro locale (#40940)
* Read /etc/locale.conf when configuring the distro locale ConfigUpdateLanguage only read /etc/default/locale to populate the $LANG environment variable. That path is used by Debian/Ubuntu, but systemd-based distributions (Fedora, Arch, openSUSE, ...) store the locale in /etc/locale.conf instead, so $LANG was never set on those distros. Check both locations and use the first one that exists. Both files share the same "LANG=" line format, so the existing parsing is reused unchanged. Fixes #13207 * Add unit test for distro locale configuration Cover the ConfigUpdateLanguage code path that populates $LANG from the distro locale file. The test creates the locale files in the test distro and verifies that $LANG is set correctly for each supported layout: - only /etc/default/locale present (Debian/Ubuntu) - only /etc/locale.conf present (Fedora, Arch, openSUSE, ...) - both present, confirming /etc/default/locale takes precedence
i4M1k0SU committed
Jul 10, 2026 at 10:30 UTC
3dbf5c1ad9b54938f3381214b0935d8a5e0e9aa7
2 files changed
+64
-7
src/linux/init/config.cpp
+24
-7
@@ -53,6 +53,7 @@ Abstract:
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#define HOSTS_FILE_PATH ETC_FOLDER "hosts"
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#define LANG_ENV "LANG"
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#define LOCALE_FILE_PATH ETC_DEFAULT_FOLDER "locale"
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+#define LOCALE_CONF_FILE_PATH ETC_FOLDER "locale.conf"
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#define PATH_ENV "PATH"
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#define RESOLV_CONF_DIRECTORY_MODE 0755
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#define RESOLV_CONF_FILE_MODE 0644
@@ -2514,9 +2515,14 @@ void ConfigUpdateLanguage(EnvironmentBlock& Environment)
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Routine Description:
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- This routine queries the contents of the /etc/default/locale text file and
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+ This routine queries the contents of the locale configuration file and
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if present updates the $LANG environment variable in the environment block.
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+ Different distributions store this file in different locations:
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+ - /etc/default/locale
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+ - /etc/locale.conf
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+ Both share the same "LANG=" line format, so the first file that exists is used.
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+
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Arguments:
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Environment - Supplies the environment block pointer to update.
@@ -2530,22 +2536,33 @@ Return Value:
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try
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{
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//
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- // Attempt to open the /etc/default/locale file. If the file does not exist
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- // then the $LANG environment variable will not be updated.
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+ // Attempt to open the locale configuration file, trying each known path in turn.
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+ // If none of the files exist then the $LANG environment variable will not be updated.
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//
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- // N.B. This file is being opened by root. The only user-visible content
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+ // N.B. These files are being opened by root. The only user-visible content
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// will be the contents of the last line of the file that contains
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// "LANG=".
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//
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- wil::unique_file LocaleFile{fopen(LOCALE_FILE_PATH, "r")};
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- if (!LocaleFile)
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+ constexpr const char* LocaleFilePaths[] = {LOCALE_FILE_PATH, LOCALE_CONF_FILE_PATH};
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+
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+ wil::unique_file LocaleFile;
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+ for (const auto* Path : LocaleFilePaths)
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{
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+ LocaleFile.reset(fopen(Path, "r"));
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+ if (LocaleFile)
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+ {
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+ break;
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+ }
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+
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if (errno != ENOENT)
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{
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- LOG_ERROR("fopen({}) failed {}", LOCALE_FILE_PATH, errno);
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+ LOG_ERROR("fopen({}) failed {}", Path, errno);
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}
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+ }
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+ if (!LocaleFile)
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+ {
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return;
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}
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test/windows/UnitTests.cpp
+40
@@ -516,6 +516,46 @@ class UnitTests
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}
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}
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+ WSL2_TEST_METHOD(ConfigUpdateLanguage)
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+ {
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+ // Validates that init populates $LANG from the distro locale configuration file.
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+ // ConfigUpdateLanguage reads /etc/default/locale first, then /etc/locale.conf, and uses
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+ // the first file that exists. See ConfigUpdateLanguage in src/linux/init/config.cpp.
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+
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+ DistroFileChange defaultLocale(L"/etc/default/locale", LxsstuLaunchWsl(L"test -f /etc/default/locale") == 0);
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+ DistroFileChange localeConf(L"/etc/locale.conf", LxsstuLaunchWsl(L"test -f /etc/locale.conf") == 0);
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+
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+ const auto readLang = []() { return LxsstuLaunchWslAndCaptureOutput(L"echo $LANG").first; };
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+
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+ // Only /etc/default/locale is present (Debian/Ubuntu).
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+ {
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+ defaultLocale.Delete();
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+ localeConf.Delete();
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+ defaultLocale.SetContent(L"LANG=de_DE.UTF-8\n");
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+ TerminateDistribution();
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+ VERIFY_ARE_EQUAL(readLang(), L"de_DE.UTF-8\n");
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+ }
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+
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+ // Only /etc/locale.conf is present (Fedora, Arch, openSUSE, ...).
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+ {
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+ defaultLocale.Delete();
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+ localeConf.Delete();
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+ localeConf.SetContent(L"LANG=fr_FR.UTF-8\n");
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+ TerminateDistribution();
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+ VERIFY_ARE_EQUAL(readLang(), L"fr_FR.UTF-8\n");
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+ }
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+
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+ // Both files are present: /etc/default/locale takes precedence because it is read first.
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+ {
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+ defaultLocale.Delete();
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+ localeConf.Delete();
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+ defaultLocale.SetContent(L"LANG=ja_JP.UTF-8\n");
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+ localeConf.SetContent(L"LANG=en_US.UTF-8\n");
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+ TerminateDistribution();
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+ VERIFY_ARE_EQUAL(readLang(), L"ja_JP.UTF-8\n");
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+ }
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+ }
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+
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TEST_METHOD(Dup)
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{
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VERIFY_NO_THROW(LxsstuRunTest(L"/data/test/wsl_unit_tests dup", L"Dup"));