in sigar_linux_common.go [160:222]
func (self *ProcState) Get(pid int) error {
data, err := readProcFile(pid, "stat")
if err != nil {
return err
}
// Extract the comm value with is surrounded by parentheses.
lIdx := bytes.Index(data, []byte("("))
rIdx := bytes.LastIndex(data, []byte(")"))
if lIdx < 0 || rIdx < 0 || lIdx >= rIdx || rIdx+2 >= len(data) {
return fmt.Errorf("failed to extract comm for pid %d from '%v'", pid, string(data))
}
self.Name = string(data[lIdx+1 : rIdx])
// Extract the rest of the fields that we are interested in.
fields := bytes.Fields(data[rIdx+2:])
if len(fields) <= 36 {
return fmt.Errorf("expected more stat fields for pid %d from '%v'", pid, string(data))
}
interests := bytes.Join([][]byte{
fields[0], // state
fields[1], // ppid
fields[2], // pgrp
fields[4], // tty_nr
fields[15], // priority
fields[16], // nice
fields[36], // processor (last processor executed on)
}, []byte(" "))
var state string
_, err = fmt.Fscan(bytes.NewBuffer(interests),
&state,
&self.Ppid,
&self.Pgid,
&self.Tty,
&self.Priority,
&self.Nice,
&self.Processor,
)
if err != nil {
return fmt.Errorf("failed to parse stat fields for pid %d from '%v': %v", pid, string(data), err)
}
self.State = RunState(state[0])
// Read /proc/[pid]/status to get the uid, then lookup uid to get username.
status, err := getProcStatus(pid)
if err != nil {
return fmt.Errorf("failed to read process status for pid %d: %v", pid, err)
}
uids, err := getUIDs(status)
if err != nil {
return fmt.Errorf("failed to read process status for pid %d: %v", pid, err)
}
user, err := user.LookupId(uids[0])
if err == nil {
self.Username = user.Username
} else {
self.Username = uids[0]
}
return nil
}