Detect virtualized OS from an application?

Have you heard about blue pill, red pill?. It's a technique used to see if you are running inside a virtual machine or not. The origin of the term stems from the matrix movie where Neo is offered a blue or a red pill (to stay inside the matrix = blue, or to enter the 'real' world = red).

The following is some code that will detect whether you are running inside 'the matrix' or not:
(code borrowed from this site which also contains some nice information about the topic at hand):

 int swallow_redpill () {
   unsigned char m[2+4], rpill[] = "\x0f\x01\x0d\x00\x00\x00\x00\xc3";
   *((unsigned*)&rpill[3]) = (unsigned)m;
   ((void(*)())&rpill)();
   return (m[5]>0xd0) ? 1 : 0;
 } 

The function will return 1 when you are running inside a virutal machine, and 0 otherwise.

Under Linux I used the command: dmidecode ( I have it both on CentOS and Ubuntu )

from the man:

dmidecode is a tool for dumping a computer's DMI (some say SMBIOS) table contents in a human-readable format.

So I searched the output and found out its probably Microsoft Hyper-V

Handle 0x0001, DMI type 1, 25 bytes
System Information
    Manufacturer: Microsoft Corporation
    Product Name: Virtual Machine
    Version: 5.0
    Serial Number: some-strings
    UUID: some-strings
    Wake-up Type: Power Switch


Handle 0x0002, DMI type 2, 8 bytes
Base Board Information
    Manufacturer: Microsoft Corporation
    Product Name: Virtual Machine
    Version: 5.0
    Serial Number: some-strings

Another way is to search to which manufacturer the MAC address of eth0 is related to: http://www.coffer.com/mac_find/

If it return Microsoft, vmware & etc.. then its probably a virtual server.