package ulimit // from go-ipfs import ( "fmt" "os" "strconv" "syscall" logging "github.com/ipfs/go-log" ) var log = logging.Logger("ulimit") var ( supportsFDManagement = false // getlimit returns the soft and hard limits of file descriptors counts getLimit func() (uint64, uint64, error) // set limit sets the soft and hard limits of file descriptors counts setLimit func(uint64, uint64) error ) // minimum file descriptor limit before we complain const minFds = 2048 // default max file descriptor limit. const maxFds = 16 << 10 // userMaxFDs returns the value of LOTUS_FD_MAX func userMaxFDs() uint64 { // check if the LOTUS_FD_MAX is set up and if it does // not have a valid fds number notify the user val := os.Getenv("LOTUS_FD_MAX") if val == "" { val = os.Getenv("IPFS_FD_MAX") } if val != "" { fds, err := strconv.ParseUint(val, 10, 64) if err != nil { log.Errorf("bad value for LOTUS_FD_MAX: %s", err) return 0 } return fds } return 0 } // ManageFdLimit raise the current max file descriptor count // of the process based on the LOTUS_FD_MAX value func ManageFdLimit() (changed bool, newLimit uint64, err error) { if !supportsFDManagement { return false, 0, nil } targetLimit := uint64(maxFds) userLimit := userMaxFDs() if userLimit > 0 { targetLimit = userLimit } soft, hard, err := getLimit() if err != nil { return false, 0, err } if targetLimit <= soft { return false, 0, nil } // the soft limit is the value that the kernel enforces for the // corresponding resource // the hard limit acts as a ceiling for the soft limit // an unprivileged process may only set it's soft limit to a // alue in the range from 0 up to the hard limit err = setLimit(targetLimit, targetLimit) switch err { case nil: newLimit = targetLimit case syscall.EPERM: // lower limit if necessary. if targetLimit > hard { targetLimit = hard } // the process does not have permission so we should only // set the soft value err = setLimit(targetLimit, hard) if err != nil { err = fmt.Errorf("error setting ulimit wihout hard limit: %s", err) break } newLimit = targetLimit // Warn on lowered limit. if newLimit < userLimit { err = fmt.Errorf( "failed to raise ulimit to LOTUS_FD_MAX (%d): set to %d", userLimit, newLimit, ) break } if userLimit == 0 && newLimit < minFds { err = fmt.Errorf( "failed to raise ulimit to minimum %d: set to %d", minFds, newLimit, ) break } default: err = fmt.Errorf("error setting: ulimit: %s", err) } return newLimit > 0, newLimit, err }