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d715ccc391
Since https://github.com/weaveworks/tcptracer-bpf/pull/39, tcptracer-bpf can generate "fd_install" events when a process installs a new file descriptor in its fd table. Those events must be requested explicitely on a per-pid basis with tracer.AddFdInstallWatcher(pid). This is useful to know about "accept" events that would otherwise be missed because kretprobes are not triggered for functions that were called before the installation of the kretprobe. This patch find all the processes that are currently blocked on an accept() syscall during the EbpfTracker initialization. feedInitialConnections() will use tracer.AddFdInstallWatcher() to subscribe to fd_install events. When a fd_install event is received, synthesise an accept event with the connection tuple and the network namespace (from /proc).
68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
package process
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import "sync"
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// Process represents a single process.
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type Process struct {
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PID, PPID int
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Name string
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Cmdline string
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Threads int
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Jiffies uint64
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RSSBytes uint64
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RSSBytesLimit uint64
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OpenFilesCount int
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OpenFilesLimit uint64
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IsWaitingInAccept bool
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}
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// Walker is something that walks the /proc directory
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type Walker interface {
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Walk(func(Process, Process)) error
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}
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// CachingWalker is a walker than caches a copy of the output from another
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// Walker, and then allows other concurrent readers to Walk that copy.
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type CachingWalker struct {
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cache map[int]Process
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previousByPID map[int]Process
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cacheLock sync.RWMutex
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source Walker
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}
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// NewCachingWalker returns a new CachingWalker
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func NewCachingWalker(source Walker) *CachingWalker {
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return &CachingWalker{source: source}
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}
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// Name of this ticker, for metrics gathering
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func (*CachingWalker) Name() string { return "Process" }
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// Walk walks a cached copy of process list
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func (c *CachingWalker) Walk(f func(Process, Process)) error {
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c.cacheLock.RLock()
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defer c.cacheLock.RUnlock()
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for _, p := range c.cache {
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f(p, c.previousByPID[p.PID])
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}
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return nil
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}
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// Tick updates cached copy of process list
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func (c *CachingWalker) Tick() error {
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newCache := map[int]Process{}
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err := c.source.Walk(func(p, _ Process) {
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newCache[p.PID] = p
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})
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if err != nil {
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return err
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}
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c.cacheLock.Lock()
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defer c.cacheLock.Unlock()
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c.previousByPID = c.cache
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c.cache = newCache
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return nil
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}
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