apt/apt-pkg/deb/debsystem.cc, branch 1.9.12

apt(8): Wait for frontend and cache lock

2020-02-26T19:36:52Z

This is a rework of !6 with additional stuff for the frontend lock, so we can lock the frontend lock and then keep looping over dpkg lock.

pkgsystem: Drop more virtual workaround shenanigans

2020-02-26T13:30:03Z

Unlock dpkg locks in reverse locking order

2019-05-21T12:53:13Z

We need to unlock in the reverse order of locking in order to get useful behavior. LP: #1829860

Set PATH=/usr/sbin:/usr/bin:/sbin:/bin when running dpkg

2018-12-10T16:31:24Z

This avoids a lot of problems from local installations of scripting languages and other stuff in /usr/local for which maintainer scripts are not prepared. [v3: Inherit PATH during tests, check overrides work] [v2: Add testing]

Set DPKG_FRONTEND_LOCKED as needed when doing selection changes

2018-08-08T13:20:44Z

We forgot to set the variable for the selection changes. Let's set it for that and some other dpkg calls. Regression-Of: c2c8b4787b0882234ba2772ec7513afbf97b563a

Add support for dpkg frontend lock

2018-08-07T13:07:52Z

The dpkg frontend lock is a lock dpkg tries to acquire except if the frontend already acquires it. This fixes a race condition in the install command where the dpkg lock is not held for a short period of time between different dpkg invocations. For this reason we also define an environment variable DPKG_FRONTEND_LOCKED for dpkg invocations so dpkg knows not to try to acquire the frontend lock because it's held by a parent process. We can set DPKG_FRONTEND_LOCKED only if the frontend lock really is held; that is, if our lock count is greater than 0 - otherwise an apt client not using the LockInner family of functions would run dpkg without the frontend lock set, but with DPKG_FRONTEND_LOCKED set. Such a process has a weaker guarantee: Because dpkg would not lock the frontend lock either, the process is prone to the existing races, and, more importantly, so is a new style process. Closes: #869546 [fixups: fix error messages, add public IsLocked() method, and make {Un,}LockInner return an error on !debSystem]

Fix lock counting in debSystem

2018-06-13T21:36:08Z

debSystem uses a reference counted lock, so you can acquire it multiple times in your applications, possibly nested. Nesting locks causes a fd leak, though, as we only increment the lock count when we already have locked twice, rather than once, and hence when we call lock the second time, instead of increasing the lock count, we open another lock fd. This fixes the code to check if we have locked at all (> 0). There is no practical problem here aside from the fd leak, as closing the new fd releases the lock on the old one due to the weird semantics of fcntl locks.

Remove obsolete RCS keywords

2018-05-07T11:41:31Z

Prompted-by: Jakub Wilk

Reformat and sort all includes with clang-format

2017-07-12T11:57:51Z

This makes it easier to see which headers includes what. The changes were done by running git grep -l '#\s*include' \ | grep -E '.(cc|h)$' \ | xargs sed -i -E 's/(^\s*)#(\s*)include/\1#\2 include/' To modify all include lines by adding a space, and then running ./git-clang-format.sh.

Drop cacheiterators.h include

2017-07-12T11:56:05Z

Including cacheiterators.h before pkgcache.h fails because pkgcache.h depends on cacheiterators.h.