From 2f25971d4ba8906d65515555ecffc79dcb1c395e Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Sat, 1 Feb 2020 00:31:16 +0100 Subject: [PATCH] mingw: allow `git.exe` to be used instead of the "Git wrapper" Git for Windows wants to add `git.exe` to the users' `PATH`, without cluttering the latter with unnecessary executables such as `wish.exe`. To that end, it invented the concept of its "Git wrapper", i.e. a tiny executable located in `C:\Program Files\Git\cmd\git.exe` (originally a CMD script) whose sole purpose is to set up a couple of environment variables and then spawn the _actual_ `git.exe` (which nowadays lives in `C:\Program Files\Git\mingw64\bin\git.exe` for 64-bit, and the obvious equivalent for 32-bit installations). Currently, the following environment variables are set unless already initialized: - `MSYSTEM`, to make sure that the MSYS2 Bash and the MSYS2 Perl interpreter behave as expected, and - `PLINK_PROTOCOL`, to force PuTTY's `plink.exe` to use the SSH protocol instead of Telnet, - `PATH`, to make sure that the `bin` folder in the user's home directory, as well as the `/mingw64/bin` and the `/usr/bin` directories are included. The trick here is that the `/mingw64/bin/` and `/usr/bin/` directories are relative to the top-level installation directory of Git for Windows (which the included Bash interprets as `/`, i.e. as the MSYS pseudo root directory). Using the absence of `MSYSTEM` as a tell-tale, we can detect in `git.exe` whether these environment variables have been initialized properly. Therefore we can call `C:\Program Files\Git\mingw64\bin\git` in-place after this change, without having to call Git through the Git wrapper. Obviously, above-mentioned directories must be _prepended_ to the `PATH` variable, otherwise we risk picking up executables from unrelated Git installations. We do that by constructing the new `PATH` value from scratch, appending `$HOME/bin` (if `HOME` is set), then the MSYS2 system directories, and then appending the original `PATH`. Side note: this modification of the `PATH` variable is independent of the modification necessary to reach the executables and scripts in `/mingw64/libexec/git-core/`, i.e. the `GIT_EXEC_PATH`. That modification is still performed by Git, elsewhere, long after making the changes described above. While we _still_ cannot simply hard-link `mingw64\bin\git.exe` to `cmd` (because the former depends on a couple of `.dll` files that are only in `mingw64\bin`, i.e. calling `...\cmd\git.exe` would fail to load due to missing dependencies), at least we can now avoid that extra process of running the Git wrapper (which then has to wait for the spawned `git.exe` to finish) by calling `...\mingw64\bin\git.exe` directly, via its absolute path. Testing this is in Git's test suite tricky: we set up a "new" MSYS pseudo-root and copy the `git.exe` file into the appropriate location, then verify that `MSYSTEM` is set properly, and also that the `PATH` is modified so that scripts can be found in `$HOME/bin`, `/mingw64/bin/` and `/usr/bin/`. This addresses https://github.com/git-for-windows/git/issues/2283 Signed-off-by: Johannes Schindelin --- compat/mingw.c | 69 +++++++++++++++++++++++++++++++++++++++++++ config.mak.uname | 4 +-- t/t0060-path-utils.sh | 31 ++++++++++++++++++- 3 files changed, 101 insertions(+), 3 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index f20d36a04113eb..3ec814aa1e8f2a 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -2618,6 +2618,47 @@ int xwcstoutf(char *utf, const wchar_t *wcs, size_t utflen) return -1; } +#ifdef ENSURE_MSYSTEM_IS_SET +static size_t append_system_bin_dirs(char *path, size_t size) +{ +#if !defined(RUNTIME_PREFIX) || !defined(HAVE_WPGMPTR) + return 0; +#else + char prefix[32768]; + const char *slash; + size_t len = xwcstoutf(prefix, _wpgmptr, sizeof(prefix)), off = 0; + + if (len == 0 || len >= sizeof(prefix) || + !(slash = find_last_dir_sep(prefix))) + return 0; + /* strip trailing `git.exe` */ + len = slash - prefix; + + /* strip trailing `cmd` or `mingw64\bin` or `mingw32\bin` or `bin` or `libexec\git-core` */ + if (strip_suffix_mem(prefix, &len, "\\mingw64\\libexec\\git-core") || + strip_suffix_mem(prefix, &len, "\\mingw64\\bin")) + off += xsnprintf(path + off, size - off, + "%.*s\\mingw64\\bin;", (int)len, prefix); + else if (strip_suffix_mem(prefix, &len, "\\mingw32\\libexec\\git-core") || + strip_suffix_mem(prefix, &len, "\\mingw32\\bin")) + off += xsnprintf(path + off, size - off, + "%.*s\\mingw32\\bin;", (int)len, prefix); + else if (strip_suffix_mem(prefix, &len, "\\cmd") || + strip_suffix_mem(prefix, &len, "\\bin") || + strip_suffix_mem(prefix, &len, "\\libexec\\git-core")) + off += xsnprintf(path + off, size - off, + "%.*s\\mingw%d\\bin;", (int)len, prefix, + (int)(sizeof(void *) * 8)); + else + return 0; + + off += xsnprintf(path + off, size - off, + "%.*s\\usr\\bin;", (int)len, prefix); + return off; +#endif +} +#endif + static void setup_windows_environment(void) { char *tmp = getenv("TMPDIR"); @@ -2670,6 +2711,34 @@ static void setup_windows_environment(void) setenv("HOME", tmp, 1); } + if (!getenv("PLINK_PROTOCOL")) + setenv("PLINK_PROTOCOL", "ssh", 0); + +#ifdef ENSURE_MSYSTEM_IS_SET + if (!(tmp = getenv("MSYSTEM")) || !tmp[0]) { + const char *home = getenv("HOME"), *path = getenv("PATH"); + char buf[32768]; + size_t off = 0; + + xsnprintf(buf, sizeof(buf), + "MINGW%d", (int)(sizeof(void *) * 8)); + setenv("MSYSTEM", buf, 1); + + if (home) + off += xsnprintf(buf + off, sizeof(buf) - off, + "%s\\bin;", home); + off += append_system_bin_dirs(buf + off, sizeof(buf) - off); + if (path) + off += xsnprintf(buf + off, sizeof(buf) - off, + "%s", path); + else if (off > 0) + buf[off - 1] = '\0'; + else + buf[0] = '\0'; + setenv("PATH", buf, 1); + } +#endif + if (!getenv("LC_ALL") && !getenv("LC_CTYPE") && !getenv("LANG")) setenv("LC_CTYPE", "C.UTF-8", 1); } diff --git a/config.mak.uname b/config.mak.uname index 85d63821ec95f6..e91b9beafe0a01 100644 --- a/config.mak.uname +++ b/config.mak.uname @@ -501,7 +501,7 @@ endif compat/win32/pthread.o compat/win32/syslog.o \ compat/win32/trace2_win32_process_info.o \ compat/win32/dirent.o - COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DDETECT_MSYS_TTY -DNOGDI -DHAVE_STRING_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\" + COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DDETECT_MSYS_TTY -DENSURE_MSYSTEM_IS_SET -DNOGDI -DHAVE_STRING_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\" BASIC_LDFLAGS = -IGNORE:4217 -IGNORE:4049 -NOLOGO -ENTRY:wmainCRTStartup -SUBSYSTEM:CONSOLE # invalidcontinue.obj allows Git's source code to close the same file # handle twice, or to access the osfhandle of an already-closed stdout @@ -729,7 +729,7 @@ ifeq ($(uname_S),MINGW) endif CC = gcc COMPAT_CFLAGS += -D__USE_MINGW_ANSI_STDIO=0 -DDETECT_MSYS_TTY \ - -fstack-protector-strong + -DENSURE_MSYSTEM_IS_SET -fstack-protector-strong EXTLIBS += -lntdll EXTRA_PROGRAMS += headless-git$X INSTALL = /bin/install diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh index 0afa3d0d312ca6..e73835e41b96e4 100755 --- a/t/t0060-path-utils.sh +++ b/t/t0060-path-utils.sh @@ -599,7 +599,8 @@ test_expect_success !VALGRIND,RUNTIME_PREFIX,CAN_EXEC_IN_PWD 'RUNTIME_PREFIX wor cp "$GIT_EXEC_PATH"/git$X pretend/bin/ && GIT_EXEC_PATH= ./pretend/bin/git here >actual && echo HERE >expect && - test_cmp expect actual' + test_cmp expect actual +' test_expect_success !VALGRIND,RUNTIME_PREFIX,CAN_EXEC_IN_PWD '%(prefix)/ works' ' mkdir -p pretend/bin && @@ -610,4 +611,32 @@ test_expect_success !VALGRIND,RUNTIME_PREFIX,CAN_EXEC_IN_PWD '%(prefix)/ works' test_cmp expect actual ' +test_expect_success MINGW 'MSYSTEM/PATH is adjusted if necessary' ' + mkdir -p "$HOME"/bin pretend/mingw64/bin \ + pretend/mingw64/libexec/git-core pretend/usr/bin && + cp "$GIT_EXEC_PATH"/git.exe pretend/mingw64/bin/ && + cp "$GIT_EXEC_PATH"/git.exe pretend/mingw64/libexec/git-core/ && + # copy the .dll files, if any (happens when building via CMake) + case "$GIT_EXEC_PATH"/*.dll in + */"*.dll") ;; # no `.dll` files to be copied + *) + cp "$GIT_EXEC_PATH"/*.dll pretend/mingw64/bin/ && + cp "$GIT_EXEC_PATH"/*.dll pretend/mingw64/libexec/git-core/ + ;; + esac && + echo "env | grep MSYSTEM=" | write_script "$HOME"/bin/git-test-home && + echo "echo mingw64" | write_script pretend/mingw64/bin/git-test-bin && + echo "echo usr" | write_script pretend/usr/bin/git-test-bin2 && + + ( + MSYSTEM= && + GIT_EXEC_PATH= && + pretend/mingw64/libexec/git-core/git.exe test-home >actual && + pretend/mingw64/libexec/git-core/git.exe test-bin >>actual && + pretend/mingw64/bin/git.exe test-bin2 >>actual + ) && + test_write_lines MSYSTEM=$MSYSTEM mingw64 usr >expect && + test_cmp expect actual +' + test_done