diff options
Diffstat (limited to 'vendor/src/github.com/coreos/go-systemd/journal/send.go')
-rw-r--r-- | vendor/src/github.com/coreos/go-systemd/journal/send.go | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/vendor/src/github.com/coreos/go-systemd/journal/send.go b/vendor/src/github.com/coreos/go-systemd/journal/send.go new file mode 100644 index 0000000000..a29bcbf0fa --- /dev/null +++ b/vendor/src/github.com/coreos/go-systemd/journal/send.go @@ -0,0 +1,168 @@ +/* +Copyright 2013 CoreOS Inc. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +// Package journal provides write bindings to the systemd journal +package journal + +import ( + "bytes" + "encoding/binary" + "errors" + "fmt" + "io" + "io/ioutil" + "net" + "os" + "strconv" + "strings" + "syscall" +) + +// Priority of a journal message +type Priority int + +const ( + PriEmerg Priority = iota + PriAlert + PriCrit + PriErr + PriWarning + PriNotice + PriInfo + PriDebug +) + +var conn net.Conn + +func init() { + var err error + conn, err = net.Dial("unixgram", "/run/systemd/journal/socket") + if err != nil { + conn = nil + } +} + +// Enabled returns true iff the systemd journal is available for logging +func Enabled() bool { + return conn != nil +} + +// Send a message to the systemd journal. vars is a map of journald fields to +// values. Fields must be composed of uppercase letters, numbers, and +// underscores, but must not start with an underscore. Within these +// restrictions, any arbitrary field name may be used. Some names have special +// significance: see the journalctl documentation +// (http://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html) +// for more details. vars may be nil. +func Send(message string, priority Priority, vars map[string]string) error { + if conn == nil { + return journalError("could not connect to journald socket") + } + + data := new(bytes.Buffer) + appendVariable(data, "PRIORITY", strconv.Itoa(int(priority))) + appendVariable(data, "MESSAGE", message) + for k, v := range vars { + appendVariable(data, k, v) + } + + _, err := io.Copy(conn, data) + if err != nil && isSocketSpaceError(err) { + file, err := tempFd() + if err != nil { + return journalError(err.Error()) + } + _, err = io.Copy(file, data) + if err != nil { + return journalError(err.Error()) + } + + rights := syscall.UnixRights(int(file.Fd())) + + /* this connection should always be a UnixConn, but better safe than sorry */ + unixConn, ok := conn.(*net.UnixConn) + if !ok { + return journalError("can't send file through non-Unix connection") + } + unixConn.WriteMsgUnix([]byte{}, rights, nil) + } else if err != nil { + return journalError(err.Error()) + } + return nil +} + +func appendVariable(w io.Writer, name, value string) { + if !validVarName(name) { + journalError("variable name contains invalid character, ignoring") + } + if strings.ContainsRune(value, '\n') { + /* When the value contains a newline, we write: + * - the variable name, followed by a newline + * - the size (in 64bit little endian format) + * - the data, followed by a newline + */ + fmt.Fprintln(w, name) + binary.Write(w, binary.LittleEndian, uint64(len(value))) + fmt.Fprintln(w, value) + } else { + /* just write the variable and value all on one line */ + fmt.Fprintln(w, "%s=%s", name, value) + } +} + +func validVarName(name string) bool { + /* The variable name must be in uppercase and consist only of characters, + * numbers and underscores, and may not begin with an underscore. (from the docs) + */ + + valid := name[0] != '_' + for _, c := range name { + valid = valid && ('A' <= c && c <= 'Z') || ('0' <= c && c <= '9') || c == '_' + } + return valid +} + +func isSocketSpaceError(err error) bool { + opErr, ok := err.(*net.OpError) + if !ok { + return false + } + + sysErr, ok := opErr.Err.(syscall.Errno) + if !ok { + return false + } + + return sysErr == syscall.EMSGSIZE || sysErr == syscall.ENOBUFS +} + +func tempFd() (*os.File, error) { + file, err := ioutil.TempFile("/dev/shm/", "journal.XXXXX") + if err != nil { + return nil, err + } + syscall.Unlink(file.Name()) + if err != nil { + return nil, err + } + return file, nil +} + +func journalError(s string) error { + s = "journal error: " + s + fmt.Fprintln(os.Stderr, s) + return errors.New(s) +} |