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f87d06ed85
Several packages are only used while running the e2e suite. These packages are less important to update, as the they can not influence the final executable that is part of the Ceph-CSI container-image. By moving these dependencies out of the main Ceph-CSI go.mod, it is easier to identify if a reported CVE affects Ceph-CSI, or only the testing (like most of the Kubernetes CVEs). Signed-off-by: Niels de Vos <ndevos@ibm.com>
45 lines
2.7 KiB
Go
45 lines
2.7 KiB
Go
// Package mountinfo provides a set of functions to retrieve information about OS mounts.
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//
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// Currently it supports Linux. For historical reasons, there is also some support for FreeBSD and OpenBSD,
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// and a shallow implementation for Windows, but in general this is Linux-only package, so
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// the rest of the document only applies to Linux, unless explicitly specified otherwise.
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//
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// In Linux, information about mounts seen by the current process is available from
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// /proc/self/mountinfo. Note that due to mount namespaces, different processes can
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// see different mounts. A per-process mountinfo table is available from /proc/<PID>/mountinfo,
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// where <PID> is a numerical process identifier.
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//
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// In general, /proc is not a very efficient interface, and mountinfo is not an exception.
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// For example, there is no way to get information about a specific mount point (i.e. it
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// is all-or-nothing). This package tries to hide the /proc ineffectiveness by using
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// parse filters while reading mountinfo. A filter can skip some entries, or stop
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// processing the rest of the file once the needed information is found.
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//
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// For mountinfo filters that accept path as an argument, the path must be absolute,
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// having all symlinks resolved, and being cleaned (i.e. no extra slashes or dots).
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// One way to achieve all of the above is to employ filepath.Abs followed by
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// filepath.EvalSymlinks (the latter calls filepath.Clean on the result so
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// there is no need to explicitly call filepath.Clean).
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//
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// NOTE that in many cases there is no need to consult mountinfo at all. Here are some
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// of the cases where mountinfo should not be parsed:
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//
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// 1. Before performing a mount. Usually, this is not needed, but if required (say to
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// prevent over-mounts), to check whether a directory is mounted, call os.Lstat
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// on it and its parent directory, and compare their st.Sys().(*syscall.Stat_t).Dev
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// fields -- if they differ, then the directory is the mount point. NOTE this does
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// not work for bind mounts. Optionally, the filesystem type can also be checked
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// by calling unix.Statfs and checking the Type field (i.e. filesystem type).
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//
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// 2. After performing a mount. If there is no error returned, the mount succeeded;
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// checking the mount table for a new mount is redundant and expensive.
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//
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// 3. Before performing an unmount. It is more efficient to do an unmount and ignore
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// a specific error (EINVAL) which tells the directory is not mounted.
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//
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// 4. After performing an unmount. If there is no error returned, the unmount succeeded.
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//
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// 5. To find the mount point root of a specific directory. You can perform os.Stat()
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// on the directory and traverse up until the Dev field of a parent directory differs.
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package mountinfo
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