// sockets recursively finds all unix sockets under the path provided
func (r *Registry) sockets(path string) ([]string, error) {
var (
result []string
statT syscall.Stat_t
)
// TODO: use of fs.Stat (which is syscall.Stat) here makes this linux specific.
if err := fs.Stat(path, &statT); err != nil {
return nil, err
}
switch statT.Mode & syscall.S_IFMT {
case syscall.S_IFDIR:
files, err := fs.ReadDir(path)
if err != nil {
return nil, err
}
for _, file := range files {
fpath := filepath.Join(path, file.Name())
s, err := r.sockets(fpath)
if err != nil {
log.Warningf("plugins: error loading path %s: %v", fpath, err)
}
result = append(result, s...)
}
case syscall.S_IFSOCK:
result = append(result, path)
}
return result, nil
}
func (p dir) Stat(path string, stat *syscall.Stat_t) error {
if path == "/" {
*stat = syscall.Stat_t{Mode: syscall.S_IFDIR}
return nil
}
head, tail := split(path)
fs, ok := p.entries[head]
if !ok {
return fmt.Errorf("Not found: %s", path)
}
return fs.Stat(tail, stat)
}
// walk walks over all numerical (PID) /proc entries. It reads
// /proc/PID/net/tcp{,6} for each namespace and sees if the ./fd/* files of each
// process in that namespace are symlinks to sockets. Returns a map from socket
// ID (inode) to PID.
func (w pidWalker) walk(buf *bytes.Buffer) (map[uint64]*Proc, error) {
var (
sockets = map[uint64]*Proc{} // map socket inode -> process
namespaces = map[uint64][]*process.Process{} // map network namespace id -> processes
statT syscall.Stat_t
)
// We do two process traversals: One to group processes by namespace and
// another one to obtain their connections.
//
// The first traversal is needed to allow obtaining the connections on a
// per-namespace basis. This is done to minimize the race condition
// between reading /net/tcp{,6} of each namespace and /proc/PID/fd/* for
// the processes living in that namespace.
w.walker.Walk(func(p, _ process.Process) {
dirName := strconv.Itoa(p.PID)
netNamespacePath := filepath.Join(procRoot, dirName, getNetNamespacePathSuffix())
if err := fs.Stat(netNamespacePath, &statT); err != nil {
return
}
namespaceID := statT.Ino
namespaces[namespaceID] = append(namespaces[namespaceID], &p)
})
for _, procs := range namespaces {
select {
case <-w.tickc:
w.walkNamespace(buf, sockets, procs)
case <-w.stopc:
break // abort
}
}
metrics.SetGauge(namespaceKey, float32(len(namespaces)))
return sockets, nil
}
// walkNamespace does the work of walk for a single namespace
func (w pidWalker) walkNamespace(buf *bytes.Buffer, sockets map[uint64]*Proc, namespaceProcs []*process.Process) error {
if found, err := readProcessConnections(buf, namespaceProcs); err != nil || !found {
return err
}
var statT syscall.Stat_t
var fdBlockCount uint64
for i, p := range namespaceProcs {
// Get the sockets for all the processes in the namespace
dirName := strconv.Itoa(p.PID)
fdBase := filepath.Join(procRoot, dirName, "fd")
if fdBlockCount > w.fdBlockSize {
// we surpassed the filedescriptor rate limit
select {
case <-w.tickc:
case <-w.stopc:
return nil // abort
}
fdBlockCount = 0
// read the connections again to
// avoid the race between between /net/tcp{,6} and /proc/PID/fd/*
if found, err := readProcessConnections(buf, namespaceProcs[i:]); err != nil || !found {
return err
}
}
fds, err := fs.ReadDirNames(fdBase)
if err != nil {
// Process is gone by now, or we don't have access.
continue
}
var proc *Proc
for _, fd := range fds {
fdBlockCount++
// Direct use of syscall.Stat() to save garbage.
err = fs.Stat(filepath.Join(fdBase, fd), &statT)
if err != nil {
continue
}
// We want sockets only.
if statT.Mode&syscall.S_IFMT != syscall.S_IFSOCK {
continue
}
// Initialize proc lazily to avoid creating unnecessary
// garbage
if proc == nil {
proc = &Proc{
PID: uint(p.PID),
Name: p.Name,
}
}
sockets[statT.Ino] = proc
}
}
return nil
}