Revision 05d1ed6148305d299693000856e4971e9f642662 authored by Ben Wijen on 22 August 2016, 12:47:55 UTC, committed by Junio C Hamano on 23 August 2016, 16:09:55 UTC
When the index is locked and child processes inherit the handle to
said lock and the parent process wants to remove the lock before the
child process exits, on Windows there is a problem: it won't work
because files cannot be deleted if a process holds a handle on them.
The symptom:

    Rename from 'xxx/.git/index.lock' to 'xxx/.git/index' failed.
    Should I try again? (y/n)

Spawning child processes with bInheritHandles==FALSE would not work
because no file handles would be inherited, not even the hStdXxx
handles in STARTUPINFO (stdin/stdout/stderr).

Opening every file with O_NOINHERIT does not work, either, as e.g.
git-upload-pack expects inherited file handles.

This leaves us with the only way out: creating temp files with the
O_NOINHERIT flag. This flag is Windows-specific, however. For our
purposes, it is equivalent to O_CLOEXEC (which does not exist on
Windows), so let's just open temporary files with the O_CLOEXEC flag and
map that flag to O_NOINHERIT on Windows.

As Eric Wong pointed out, we need to be careful to handle the case where
the Linux headers used to compile Git support O_CLOEXEC but the Linux
kernel used to run Git does not: it returns an EINVAL.

This fixes the test that we just introduced to demonstrate the problem.

Signed-off-by: Ben Wijen <ben@wijen.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Raw File
sequencer.h
#ifndef SEQUENCER_H
#define SEQUENCER_H

#define SEQ_DIR		"sequencer"
#define SEQ_HEAD_FILE	"sequencer/head"
#define SEQ_TODO_FILE	"sequencer/todo"
#define SEQ_OPTS_FILE	"sequencer/opts"

#define APPEND_SIGNOFF_DEDUP (1u << 0)

enum replay_action {
	REPLAY_REVERT,
	REPLAY_PICK
};

enum replay_subcommand {
	REPLAY_NONE,
	REPLAY_REMOVE_STATE,
	REPLAY_CONTINUE,
	REPLAY_ROLLBACK
};

struct replay_opts {
	enum replay_action action;
	enum replay_subcommand subcommand;

	/* Boolean options */
	int edit;
	int record_origin;
	int no_commit;
	int signoff;
	int allow_ff;
	int allow_rerere_auto;
	int allow_empty;
	int allow_empty_message;
	int keep_redundant_commits;

	int mainline;

	const char *gpg_sign;

	/* Merge strategy */
	const char *strategy;
	const char **xopts;
	size_t xopts_nr, xopts_alloc;

	/* Only used by REPLAY_NONE */
	struct rev_info *revs;
};

int sequencer_pick_revisions(struct replay_opts *opts);

extern const char sign_off_header[];

void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag);
void append_conflicts_hint(struct strbuf *msgbuf);

#endif
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