config: allow inaccessible configuration under $HOME

The changes v1.7.12.1~2^2~4 (config: warn on inaccessible files,
2012-08-21) and v1.8.1.1~22^2~2 (config: treat user and xdg config
permission problems as errors, 2012-10-13) were intended to prevent
important configuration (think "[transfer] fsckobjects") from being
ignored when the configuration is unintentionally unreadable (for
example with EIO on a flaky filesystem, or with ENOMEM due to a DoS
attack).  Usually ~/.gitconfig and ~/.config/git are readable by the
current user, and if they aren't then it would be easy to fix those
permissions, so the damage from adding this check should have been
minimal.

Unfortunately the access() check often trips when git is being run as
a server.  A daemon (such as inetd or git-daemon) starts as "root",
creates a listening socket, and then drops privileges, meaning that
when git commands are invoked they cannot access $HOME and die with

 fatal: unable to access '/root/.config/git/config': Permission denied

Any patch to fix this would have one of three problems:

  1. We annoy sysadmins who need to take an extra step to handle HOME
     when dropping privileges (the current behavior, or any other
     proposal that they have to opt into).

  2. We annoy sysadmins who want to set HOME when dropping privileges,
     either by making what they want to do impossible, or making them
     set an extra variable or option to accomplish what used to work
     (e.g., a patch to git-daemon to set HOME when --user is passed).

  3. We loosen the check, so some cases which might be noteworthy are
     not caught.

This patch is of type (3).

Treat user and xdg configuration that are inaccessible due to
permissions (EACCES) as though no user configuration was provided at
all.

An alternative method would be to check if $HOME is readable, but that
would not help in cases where the user who dropped privileges had a
globally readable HOME with only .config or .gitconfig being private.

This does not change the behavior when /etc/gitconfig or .git/config
is unreadable (since those are more serious configuration errors),
nor when ~/.gitconfig or ~/.config/git is unreadable due to problems
other than permissions.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Improved-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
dir.c: fix ignore processing within not-ignored directories

As of 95c6f271 "dir.c: unify is_excluded and is_path_excluded APIs", the
is_excluded API no longer recurses into directories that match an ignore
pattern, and returns the directory's ignored state for all contained paths.

This is OK for normal ignore patterns, i.e. ignoring a directory affects
the entire contents recursively.

Unfortunately, this also "works" for negated ignore patterns ('!dir'), i.e.
the entire contents is "not-ignored" recursively, regardless of ignore
patterns that match the contents directly.

In prep_exclude, skip recursing into a directory only if it is really
ignored (i.e. the ignore pattern is not negated).

Signed-off-by: Karsten Blees <blees@dcon.de>
Tested-by: Øystein Walle <oystwa@gmail.com>
Reviewed-by: Duy Nguyen <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Document .git/modules

A note in the beginning of this document describes the behavior already.
This patch just adds where to find the repositories.

Signed-off-by: Fredrik Gustafsson <iveqy@iveqy.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
submodule: remove redundant check for the_index.initialized

read_cache already performs the same check and returns immediately if
the cache has already been loaded.

Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'kb/status-ignored-optim-2' into maint

Fix recent regression of .gitignore files that list !directory to
mark it not-ignored.

* kb/status-ignored-optim-2:
  dir.c: fix ignore processing within not-ignored directories
Merge branch 'jn/config-ignore-inaccessible' into maint

A git daemon that starts as "root" and then drops privilege often
leaves $HOME set to that of the root user, which is unreadable by
the daemon process, which was diagnosed as a configuration error.

Make per-user configuration files that are inaccessible due to
EACCES as though these files do not exist to avoid this issue, as
the tightening which was originally meant as an additional security
has annoyed enough sysadmins.

* jn/config-ignore-inaccessible:
  config: allow inaccessible configuration under $HOME
mingw: make mingw_signal return the correct handler

Returning the SIGALRM handler for SIGINT is not very useful.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git 1.8.3.1

Primarily to push out two regression issues that seem to affect many
people, namely, the ".gitignore !directory" bug and "daemon cannot
read from $HOME owned by root" bug.

Signed-off-by: Junio C Hamano <gitster@pobox.com>