From 994379ee92d46589e226d1a1b765f1bf1255f50d Mon Sep 17 00:00:00 2001 From: Tian Yuchen Date: Mon, 23 Feb 2026 15:44:10 +0800 Subject: [PATCH] setup: improve error diagnosis for invalid .git files 'read_gitfile_gently()' treats any non-regular file as 'READ_GITFILE_ERR_NOT_A_FILE' and fails to discern between 'ENOENT' and other stat failures. This flawed error reporting is noted by two 'NEEDSWORK' comments. Address these comments by introducing two new error codes: 'READ_GITFILE_ERR_MISSING'(which groups the "file missing" scenarios together) and 'READ_GITFILE_ERR_IS_A_DIR'. To preserve the original intent of the setup process: 1. Update 'read_gitfile_error_die()' to treat both 'IS_A_DIR' and 'MISSING' as no-ops, while continuing to call 'die()' on true 'NOT_A_FILE' errors to prevent security hazards (like FIFOs). 2. Unconditionally pass '&error_code' to 'read_gitfile_gently()'. 3. Only invoke 'is_git_directory()' when we explicitly receive 'READ_GITFILE_ERR_IS_A_DIR', avoiding redundant filesystem checks. 4. Correctly return 'GIT_DIR_INVALID_GITFILE' on unrecognized errors when 'die_on_error' is false. Additionally, audit external callers of 'read_gitfile_gently()' in 'submodule.c' and 'worktree.c' to accommodate the refined error codes. Signed-off-by: Tian Yuchen Signed-off-by: Junio C Hamano --- setup.c | 45 ++++++++++++++------ setup.h | 2 + submodule.c | 2 +- t/meson.build | 1 + t/t0009-git-dir-validation.sh | 77 +++++++++++++++++++++++++++++++++++ worktree.c | 6 ++- 6 files changed, 118 insertions(+), 15 deletions(-) create mode 100755 t/t0009-git-dir-validation.sh diff --git a/setup.c b/setup.c index b723f8b339..ff3af0da3c 100644 --- a/setup.c +++ b/setup.c @@ -895,10 +895,14 @@ int verify_repository_format(const struct repository_format *format, void read_gitfile_error_die(int error_code, const char *path, const char *dir) { switch (error_code) { - case READ_GITFILE_ERR_STAT_FAILED: - case READ_GITFILE_ERR_NOT_A_FILE: + case READ_GITFILE_ERR_MISSING: + case READ_GITFILE_ERR_IS_A_DIR: /* non-fatal; follow return path */ break; + case READ_GITFILE_ERR_STAT_FAILED: + die(_("error reading '%s'"), path); + case READ_GITFILE_ERR_NOT_A_FILE: + die(_("not a regular file: '%s'"), path); case READ_GITFILE_ERR_OPEN_FAILED: die_errno(_("error opening '%s'"), path); case READ_GITFILE_ERR_TOO_LARGE: @@ -939,8 +943,14 @@ const char *read_gitfile_gently(const char *path, int *return_error_code) static struct strbuf realpath = STRBUF_INIT; if (stat(path, &st)) { - /* NEEDSWORK: discern between ENOENT vs other errors */ - error_code = READ_GITFILE_ERR_STAT_FAILED; + if (errno == ENOENT || errno == ENOTDIR) + error_code = READ_GITFILE_ERR_MISSING; + else + error_code = READ_GITFILE_ERR_STAT_FAILED; + goto cleanup_return; + } + if (S_ISDIR(st.st_mode)) { + error_code = READ_GITFILE_ERR_IS_A_DIR; goto cleanup_return; } if (!S_ISREG(st.st_mode)) { @@ -1576,20 +1586,31 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir, if (offset > min_offset) strbuf_addch(dir, '/'); strbuf_addstr(dir, DEFAULT_GIT_DIR_ENVIRONMENT); - gitdirenv = read_gitfile_gently(dir->buf, die_on_error ? - NULL : &error_code); + gitdirenv = read_gitfile_gently(dir->buf, &error_code); if (!gitdirenv) { - if (die_on_error || - error_code == READ_GITFILE_ERR_NOT_A_FILE) { - /* NEEDSWORK: fail if .git is not file nor dir */ + switch (error_code) { + case READ_GITFILE_ERR_MISSING: + /* no .git in this directory, move on */ + break; + case READ_GITFILE_ERR_IS_A_DIR: if (is_git_directory(dir->buf)) { gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT; gitdir_path = xstrdup(dir->buf); } - } else if (error_code != READ_GITFILE_ERR_STAT_FAILED) - return GIT_DIR_INVALID_GITFILE; - } else + /* + * NEEDSWORK: should we catch a directory .git + * that is not a git directory here? + */ + break; + default: + if (die_on_error || error_code == READ_GITFILE_ERR_NOT_A_FILE) + read_gitfile_error_die(error_code, dir->buf, NULL); + else + return GIT_DIR_INVALID_GITFILE; + } + } else { gitfile = xstrdup(dir->buf); + } /* * Earlier, we tentatively added DEFAULT_GIT_DIR_ENVIRONMENT * to check that directory for a repository. diff --git a/setup.h b/setup.h index d55dcc6608..1a0d010b5d 100644 --- a/setup.h +++ b/setup.h @@ -36,6 +36,8 @@ int is_nonbare_repository_dir(struct strbuf *path); #define READ_GITFILE_ERR_NO_PATH 6 #define READ_GITFILE_ERR_NOT_A_REPO 7 #define READ_GITFILE_ERR_TOO_LARGE 8 +#define READ_GITFILE_ERR_MISSING 9 +#define READ_GITFILE_ERR_IS_A_DIR 10 void read_gitfile_error_die(int error_code, const char *path, const char *dir); const char *read_gitfile_gently(const char *path, int *return_error_code); #define read_gitfile(path) read_gitfile_gently((path), NULL) diff --git a/submodule.c b/submodule.c index 40a5c6fb9d..e733f8a669 100644 --- a/submodule.c +++ b/submodule.c @@ -2413,7 +2413,7 @@ void absorb_git_dir_into_superproject(const char *path, const struct submodule *sub; struct strbuf sub_gitdir = STRBUF_INIT; - if (err_code == READ_GITFILE_ERR_STAT_FAILED) { + if (err_code == READ_GITFILE_ERR_MISSING) { /* unpopulated as expected */ strbuf_release(&gitdir); return; diff --git a/t/meson.build b/t/meson.build index 459c52a489..71a6f07a11 100644 --- a/t/meson.build +++ b/t/meson.build @@ -80,6 +80,7 @@ integration_tests = [ 't0006-date.sh', 't0007-git-var.sh', 't0008-ignores.sh', + 't0009-git-dir-validation.sh', 't0010-racy-git.sh', 't0012-help.sh', 't0013-sha1dc.sh', diff --git a/t/t0009-git-dir-validation.sh b/t/t0009-git-dir-validation.sh new file mode 100755 index 0000000000..7e2c711a63 --- /dev/null +++ b/t/t0009-git-dir-validation.sh @@ -0,0 +1,77 @@ +#!/bin/sh + +test_description='setup: validation of .git file/directory types + +Verify that setup_git_directory() correctly handles: +1. Valid .git directories (including symlinks to them). +2. Invalid .git files (FIFOs, sockets) by erroring out. +3. Invalid .git files (garbage) by erroring out. +' + +. ./test-lib.sh + +test_expect_success 'setup: create parent git repository' ' + git init parent && + test_commit -C parent "root-commit" +' + +test_expect_success SYMLINKS 'setup: .git as a symlink to a directory is valid' ' + test_when_finished "rm -rf parent/link-to-dir" && + mkdir -p parent/link-to-dir && + ( + cd parent/link-to-dir && + git init real-repo && + ln -s real-repo/.git .git && + git rev-parse --git-dir >actual && + echo .git >expect && + test_cmp expect actual + ) +' + +test_expect_success PIPE 'setup: .git as a FIFO (named pipe) is rejected' ' + test_when_finished "rm -rf parent/fifo-trap" && + mkdir -p parent/fifo-trap && + ( + cd parent/fifo-trap && + mkfifo .git && + test_must_fail git rev-parse --git-dir 2>stderr && + grep "not a regular file" stderr + ) +' + +test_expect_success SYMLINKS,PIPE 'setup: .git as a symlink to a FIFO is rejected' ' + test_when_finished "rm -rf parent/symlink-fifo-trap" && + mkdir -p parent/symlink-fifo-trap && + ( + cd parent/symlink-fifo-trap && + mkfifo target-fifo && + ln -s target-fifo .git && + test_must_fail git rev-parse --git-dir 2>stderr && + grep "not a regular file" stderr + ) +' + +test_expect_success 'setup: .git with garbage content is rejected' ' + test_when_finished "rm -rf parent/garbage-trap" && + mkdir -p parent/garbage-trap && + ( + cd parent/garbage-trap && + echo "garbage" >.git && + test_must_fail git rev-parse --git-dir 2>stderr && + grep "invalid gitfile format" stderr + ) +' + +test_expect_success 'setup: .git as an empty directory is ignored' ' + test_when_finished "rm -rf parent/empty-dir" && + mkdir -p parent/empty-dir && + ( + cd parent/empty-dir && + mkdir .git && + git rev-parse --git-dir >actual && + echo "$TRASH_DIRECTORY/parent/.git" >expect && + test_cmp expect actual + ) +' + +test_done diff --git a/worktree.c b/worktree.c index 9308389cb6..d1165e1d1c 100644 --- a/worktree.c +++ b/worktree.c @@ -653,7 +653,8 @@ static void repair_gitfile(struct worktree *wt, } } - if (err == READ_GITFILE_ERR_NOT_A_FILE) + if (err == READ_GITFILE_ERR_NOT_A_FILE || + err == READ_GITFILE_ERR_IS_A_DIR) fn(1, wt->path, _(".git is not a file"), cb_data); else if (err) repair = _(".git file broken"); @@ -833,7 +834,8 @@ void repair_worktree_at_path(const char *path, strbuf_addstr(&backlink, dotgit_contents); strbuf_realpath_forgiving(&backlink, backlink.buf, 0); } - } else if (err == READ_GITFILE_ERR_NOT_A_FILE) { + } else if (err == READ_GITFILE_ERR_NOT_A_FILE || + err == READ_GITFILE_ERR_IS_A_DIR) { fn(1, dotgit.buf, _("unable to locate repository; .git is not a file"), cb_data); goto done; } else if (err == READ_GITFILE_ERR_NOT_A_REPO) {