credentials: add "store" helper

This is like "cache", except that we actually put the
credentials on disk. This can be terribly insecure, of
course, but we do what we can to protect them by filesystem
permissions, and we warn the user in the documentation.

This is not unlike using .netrc to store entries, but it's a
little more user-friendly. Instead of putting credentials in
place ahead of time, we transparently store them after
prompting the user for them once.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 80 insertions, 0 deletions

diff --git a/Documentation/git-credential-store.txt b/Documentation/git-credential-store.txt
new file mode 100644
index 0000000000..31093467d1
--- /dev/null
+++ b/Documentation/git-credential-store.txt
@@ -0,0 +1,75 @@
+git-credential-store(1)
+=======================
+
+NAME
+----
+git-credential-store - helper to store credentials on disk
+
+SYNOPSIS
+--------
+-------------------
+git config credential.helper 'store [options]'
+-------------------
+
+DESCRIPTION
+-----------
+
+NOTE: Using this helper will store your passwords unencrypted on disk,
+protected only by filesystem permissions. If this is not an acceptable
+security tradeoff, try linkgit:git-credential-cache[1], or find a helper
+that integrates with secure storage provided by your operating system.
+
+This command stores credentials indefinitely on disk for use by future
+git programs.
+
+You probably don't want to invoke this command directly; it is meant to
+be used as a credential helper by other parts of git. See
+linkgit:gitcredentials[7] or `EXAMPLES` below.
+
+OPTIONS
+-------
+
+--store=<path>::
+
+	Use `<path>` to store credentials. The file will have its
+	filesystem permissions set to prevent other users on the system
+	from reading it, but will not be encrypted or otherwise
+	protected. Defaults to `~/.git-credentials`.
+
+EXAMPLES
+--------
+
+The point of this helper is to reduce the number of times you must type
+your username or password. For example:
+
+------------------------------------------
+$ git config credential.helper store
+$ git push http://example.com/repo.git
+Username: <type your username>
+Password: <type your password>
+
+[several days later]
+$ git push http://example.com/repo.git
+[your credentials are used automatically]
+------------------------------------------
+
+STORAGE FORMAT
+--------------
+
+The `.git-credentials` file is stored in plaintext. Each credential is
+stored on its own line as a URL like:
+
+------------------------------
+https://user:pass@example.com
+------------------------------
+
+When git needs authentication for a particular URL context,
+credential-store will consider that context a pattern to match against
+each entry in the credentials file.  If the protocol, hostname, and
+username (if we already have one) match, then the password is returned
+to git. See the discussion of configuration in linkgit:gitcredentials[7]
+for more information.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index 4e3f860ea9..066f825f2e 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -71,6 +71,11 @@ cache::
 	Cache credentials in memory for a short period of time. See
 	linkgit:git-credential-cache[1] for details.
 
+store::
+
+	Store credentials indefinitely on disk. See
+	linkgit:git-credential-store[1] for details.
+
 You may also have third-party helpers installed; search for
 `credential-*` in the output of `git help -a`, and consult the
 documentation of individual helpers.  Once you have selected a helper,