1 files changed, 138 insertions, 0 deletions
diff --git a/bin/posix-mq.rb b/bin/posix-mq.rb
new file mode 100755
index 0000000..fa44b94
--- /dev/null
+++ b/bin/posix-mq.rb
@@ -0,0 +1,138 @@
+#!/usr/bin/ruby
+# -*- encoding: binary -*-
+Encoding.default_external = Encoding::BINARY if defined?(Encoding)
+$stderr.sync = $stdout.sync = true
+
+require 'posix_mq'
+require 'optparse'
+
+commands = %w(create attr send receive wait unlink)
+usage = "Usage: MQUEUE=/name #{File.basename($0)} COMMAND " \
+        "[options] [<arguments>]\n" \
+        "COMMAND may be one of: #{commands.join(', ')}"
+
+mqueue = ENV["MQUEUE"] or abort usage
+command = ARGV.shift or abort usage
+commands.include?(command) or abort usage
+
+priority = nil
+timeout = nil
+mode = 0666
+oflags = IO::RDONLY
+mq_attr = nil
+nonblock = false
+command = command.to_sym
+
+ARGV.options do |x|
+  x.banner = usage.split(/\n/).first.gsub(/COMMAND/, command.to_s)
+  x.separator ''
+
+  case command
+  when :create
+    oflags |= IO::CREAT
+    x.on('-x', '--exclusive', "exclusive create") {
+      oflags |= IO::EXCL
+    }
+    x.on('-m', '--mode=MODE', "octal file mode") { |i|
+      mode = i.to_i(8)
+    }
+    x.on('-c', '--maxmsg=COUNT', Integer, "maximum number of messages") { |i|
+      mq_attr ||= POSIX_MQ::Attr.new
+      mq_attr.maxmsg = i
+    }
+    x.on('-s', '--msgsize=BYTES', Integer, "maximum size of message") { |i|
+      mq_attr ||= POSIX_MQ::Attr.new
+      mq_attr.msgsize = i
+    }
+  when :wait
+    x.on('-t', '--timeout=SECONDS', Float, "timeout in seconds") { |f|
+      timeout = f
+    }
+  when :send, :receive
+    conflict = "timeout and nonblock are exclusive"
+    x.on('-t', '--timeout=SECONDS', Float, "timeout in seconds") { |f|
+      abort conflict if nonblock
+      timeout = f
+    }
+    x.on('-n', '--nonblock', "nonblocking operation") {
+      abort conflict if timeout
+      nonblock = true
+      oflags |= IO::NONBLOCK
+    }
+    if command == :send
+      oflags = IO::WRONLY
+      x.on('-p', '--priority=PRIO', Integer, "priority of message") { |i|
+        priority = i
+      }
+    else
+      x.on('-p', '--priority', "output priority of message to stderr") {
+        priority = $stderr
+      }
+    end
+  end
+  x.on('-q', "quiet warnings and errors") { $stderr.reopen("/dev/null", "w") }
+  x.on('-h', '--help', 'Show this help message.') { puts x; exit }
+  x.parse!
+end
+
+trap(:INT) { exit 130 }
+
+unless command == :send || ARGV.empty?
+  abort "#{command} accepts no arguments"
+end
+
+begin
+  if command == :create && mq_attr
+    mq_attr.flags = mq_attr.curmsgs = 0
+    mq_attr.msgsize && ! mq_attr.maxmsg and
+      abort "--maxmsg must be set with --msgsize"
+    mq_attr.maxmsg && ! mq_attr.msgsize and
+      abort "--msgsize must be set with --maxmsg"
+  elsif command == :unlink
+    POSIX_MQ.unlink(mqueue)
+    exit
+  end
+
+  mq = POSIX_MQ.open(mqueue, oflags, mode, mq_attr)
+  case command
+  when :create
+    exit
+  when :receive
+    buf, prio = mq.receive("", timeout)
+    $stderr.syswrite("priority=#{prio}\n") if priority
+    $stdout.syswrite(buf)
+  when :send
+    ARGV << $stdin.read if ARGV.empty?
+    ARGV.each { |msg| mq.send(msg, priority, timeout) }
+  when :attr
+    mq_attr = mq.attr
+    $stdout.syswrite(
+      "flags=#{mq_attr.flags}\n" \
+      "maxmsg=#{mq_attr.maxmsg}\n" \
+      "msgsize=#{mq_attr.msgsize}\n" \
+      "curmsgs=#{mq_attr.curmsgs}\n")
+  when :wait
+    trap(:USR1) { exit }
+
+    # we wouldn't get a notification if there were already messages
+    exit if mq.attr.curmsgs > 0
+    mq.notify = :USR1
+    exit if mq.attr.curmsgs > 0 # avoid race condition
+
+    timeout.nil? ? sleep : sleep(timeout)
+    exit 2 # timed out
+  end
+rescue Errno::EEXIST
+  abort "Queue exists"
+rescue Errno::ENOENT
+  abort "Queue does not exist"
+rescue Errno::EMSGSIZE
+  abort "Message too long"
+rescue Errno::EAGAIN
+  abort(command == :send ? "Queue full" : "No messages available")
+rescue Errno::ETIMEDOUT
+  warn "Operation timed out"
+  exit 2
+rescue => e
+  abort e.message
+end