How to define CMake options

The most time, defining (and exporting) CFLAGS and CXXFLAGS options

Git - alias to cherry-pick with automatic message

While working with Git, there is situation where you will use git cherry-pick to carry over change from a version to another.
Even if you want to adapt cherry-picked commit messages, it can be done very quickly, if

Git - alias to get my last commits

While working with Git, there is lots of situation where it is interesting to give a quick list of

Migrate from SVN to Git

There is lots of article about migration from SVN to Git (a powerful distributed version control system), but I didn't find all needed information in only one.
This is the aim of this article.

Git, a powerful Distributed Version Control System (DVCS)

In last ten years, we've seen emergence of Distributed Version Control Systems (DVCS).
IMO, the noteworthy advantages of a Distributed Version Control System against a Centralized one are:

Fix Java Web Start UnsatisfiedLinkError

In some cases, mixing i386 and x86_64 architectures, Java Web Start can fall into such error:
Exception in thread "main" java.lang.UnsatisfiedLinkError: Can't load library: /usr/local/java/jdk/jdk1.5.0_14/jre/lib/amd64/libdeploy.so

Get Java Web Start Application error when console vanished

Java Web Start technology allows activating either "trace" or "log" system (or the two of them).

Compile VMwareTools on Linux kernel 2.6.22

To compile the vmhgfs VMwareTools on Linux kernel 2.6.22, it is needed to patch the source code, like explained there, from a tar.gz installation.
The same fix works from rpm installation, although the VMwareTools source code directory may be different (/usr/lib/vmware-tools/modules/source for me):
- move to /usr/lib/vmware-tools/modules/source/
- untar vmhgfs.tar and backup it
- then follow the same instructions:
"Now edit vmhgfs/driver.c and change lines 44 and 45 from
#define INODE_SET_II_P(inode, info) do { (inode)->u.generic_ip = (info); } while (0)
#define INODE_GET_II_P(inode) ((HgfsInodeInfo *)(inode)->u.generic_ip)
to
#define INODE_SET_II_P(inode, info) do { (inode)->i_private = (info); } while (0)
#define INODE_GET_II_P(inode) ((HgfsInodeInfo *)(inode)->i_private)

Also, remove line 763: inode->i_blksize = HGFS_BLOCKSIZE;
"
- create a new vmhgfs.tar with patched source code
- the compilation can now be fully performed -> launch /usr/bin/vmware-config-tools.pl again

Get the list of gcc defined macro after preprocessing

It various situation, it is very useful to get the list of all defined maco after gcc preprocessing.
Particularly when porting C/C++ source code to another OS/Architecture to know what macro to use to identify it.

A simple way is to use gcc with the following options:
-E to end after preprocessing step,
-dM to print all defined macros.

For instance to known the "default" macros, use those options with a simple source code file "test.c" defining a main function:
gcc -E -dM test.c

Remove network interface under Solaris

Under Solaris, it is very more easy to remove than to add. The network interface can be found thanks to the couple (name, inet address):
N.B.: All checks have been removed for better legibility, but it is very important to check returned code after each request.

// We consider the existence of the variables (unsigned char *) "networkInterfaceName", "inetAddress" which could be respectively "eth0" and "192.168.80.1" for instance.

int socketDescriptor;
struct sockaddr_in *addr;
struct lifreq lifr;

sd = socket(AF_INET, SOCK_DGRAM, 0);

memset(&lifr, 0, sizeof(lifr));
addr = (struct sockaddr_in *) &(lifr.lifr_addr);
strncpy(lifr.lifr_name, networkInterfaceName, sizeof(lifr.lifr_name));
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = inet_addr(inetAddress);
ioctl(socketDescriptor, SIOCLIFREMOVEIF, (caddr_t) &lifr)
close(socketDescriptor);

Remove network interface under GNU/Linux

It is enough to switch down the corresponding alias network interface:
N.B.: All checks have been removed for better legibility, but it is very important to check returned code after each request.

// We consider the existence of the variable (unsigned char *) "aliasInterfaceName" ("eth0:myAlias" for instance).
int sd;
struct ifreq ifr;

sd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));

memset(&ifr, 0, sizeof(struct ifreq));
strncpy(ifr.lifr_name, aliasInterfaceName, sizeof(ifr.ifr_name));
ifr.ifr_flags = ~IFF_UP;
ioctl(sd, SIOCSIFFLAGS, &ifr);
close(sd);

Add network interface under Solaris

Under Solairs, it is not trivial to add a network interface, there is no alias, and it seems to not be possible to specify the additional network interface name (so it must be got and kept).
N.B.: All checks have been removed for better legibility, but it is very important to check returned code after each request.

// We consider the existence of the variables (unsigned char *) "networkInterfaceName", "inetAddress", "broadcastAddress" and "netmaskAddress" which could be respectively "eth0", "192.168.80.1", "192.168.80.255" and "255.255.255.0" for instance.

int sd;
struct sockaddr_in *addr;
struct lifreq lifr, lifrBroadcast, lifrNetmask, lifrFlags;
const char *aliasName;

// Resets structure.
memset(&lifr, 0, sizeof(lifr));
strncpy(lifr.lifr_name, networkInterfaceName, sizeof(lifr.lifr_name));

sd = socket(AF_INET, SOCK_DGRAM, 0);
ioctl(sd, SIOCLIFADDIF, (caddr_t) &lifr);

// Very important to get the alias name to update network interface parameters.
aliasName = lifr.lifr_name;

// Manages broadcast.
memset(&lifrBroadcast, 0, sizeof(lifrBroadcast));
addr = (struct sockaddr_in *) &(lifrBroadcast.lifr_broadaddr);
strncpy(lifrBroadcast.lifr_name, aliasName, sizeof(lifrBroadcast.lifr_name));
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = inet_addr(broadcastAddress);
ioctl(sd, SIOCSLIFBRDADDR, (caddr_t) &lifrBroadcast);

// Manages netmask.
memset(&lifrNetmask, 0, sizeof(lifrNetmask));
addr = (struct sockaddr_in *) &(lifrNetmask.lifr_addr);
strncpy(lifrNetmask.lifr_name, aliasName, sizeof(lifrNetmask.lifr_name));
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = inet_addr(netmaskAddress);
ioctl(sd, SIOCSLIFNETMASK, (caddr_t) &lifrNetmask);

// Defines the address of the new interface.
addr = (struct sockaddr_in *) &(lifr.lifr_addr);
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = inet_addr(inetAddress);
ioctl(sd, SIOCSLIFADDR, (caddr_t) &lifr);

// Sets the new interface UP.
memset(&lifrFlags, 0, sizeof(lifrFlags));
strncpy(lifrFlags.lifr_name, aliasName, sizeof(lifrFlags.lifr_name));
ioctl(sd, SIOCGLIFFLAGS, (caddr_t) &lifrFlags)
lifrFlags.lifr_flags |= IFF_UP;
ioctl(sd, SIOCSLIFFLAGS, (caddr_t) &lifrFlags);
close(sd);

Add network interface under GNU/Linux

It is not so hard to perform it under GNU/Linux with alias.
The aim, is to add an alias to an existing network interface with the wished inet, broadcast and netmask addresses:
N.B.: All checks have been removed for better legibility, but it is very important to check returned code after each request.

// We consider the existence of the variables (unsigned char *) "aliasInterfaceName", "inetAddress", "broadcastAddress" and "netmaskAddress" which could be respectively "eth0:myAlias"; "192.168.80.1", "192.168.80.255" and "255.255.255.0" for instance.

int sd;
struct sockaddr_in *addr;
struct ifreq ifr, ifrBroadcast, ifrNetmask;

sd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));

// Add alias.
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.lifr_name, aliasInterfaceName, sizeof(ifr.ifr_name));
addr = (struct sockaddr_in *) &(ifr.ifr_addr);
addr->sin_family=AF_INET;
addr->sin_addr.s_addr=inet_addr(inetAddress);
ioctl(sd, SIOCSIFADDR, &ifr);

// Manages broadcast.
memset(&ifrBroadcast, 0, sizeof(ifrBroadcast));
strncpy(ifrBroadcast.lifr_name, aliasInterfaceName, sizeof(ifrBroadcast.ifr_name));
addr = (struct sockaddr_in *) &(ifrBroadcast.ifr_addr);
addr->sin_family=AF_INET;
addr->sin_addr.s_addr=inet_addr(broadcastAddress);
ioctl(sd, SIOCSIFBRDADDR, &ifrBroadcast)

// Manages netmask.
memset(&ifrNetmask, 0, sizeof(ifrNetmask));
strncpy(ifrNetmask.lifr_name, aliasInterfaceName, sizeof(ifrNetmask.ifr_name));
addr = (struct sockaddr_in *) &(ifrNetmask.ifr_addr);
addr->sin_family=AF_INET;
addr->sin_addr.s_addr=inet_addr(netmaskAddress);
ioctl(sd, SIOCSIFNETMASK, &ifrNetmask);

close(sd);

Get MAC address under GNU/Linux or Solaris

This is a way to get MAC address of a network interface in C language.
Under GNU/Linux it can be done thanks to a RAW socket:
N.B.: All checks have been removed for better legibility, but it is very important to check returned code after each request.

// Consider a variable "networkInterfaceName" of type char * is defined ("eth0" for instance).
int sd;
struct ifreq ifr;
const unsigned char *hardwareAddress;

sd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
memset(&ifr, 0, sizeof(ifr));
setNameInIfreq(&ifr, networkInterfaceName);
hardwareAddress = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
close(sd);

Under Solaris, it begins to be less easy, we need to use DLPI code:
// Consider a variable "devicePath" of type char * is defined ("/dev/eth0" for instance).
int sd;
dl_phys_addr_req_t dlpareq;
dl_phys_addr_ack_t *dlpaack;
struct strbuf msg;
char buf[128];
int flags = 0;
const unsigned char *hardwareAddress;

sd = open(devicePath, O_RDWR));
dlpareq.dl_primitive = DL_PHYS_ADDR_REQ;
dlpareq.dl_addr_type = DL_CURR_PHYS_ADDR;
msg.buf = (char *)&dlpareq;
msg.len = DL_PHYS_ADDR_REQ_SIZE;
putmsg(sd, &msg, NULL, 0);
dlpaack = (dl_phys_addr_ack_t *)buf;
msg.buf = (char *)buf;
msg.len = 0;
msg.maxlen = sizeof (buf);
getmsg(sd, &msg, NULL, &flags);
memcpy(hardwareAddress, &buf[dlpaack->dl_addr_offset], dlpaack->dl_addr_length);
close(sd);

How to choose a *nix shell

Today, there is very lots of shells like sh, bash, csh, tcsh, ksh, zsh, ash ...
For various reasons, it makes sens to choose one, a time for all, although it is not so easy.
Personally, I have first chosen tcsh for its functionalities and its legibility very near the C language. On the first hand, it was not a bad choice because thanks to it, I had done all I had needed, on the other hand I had faced two issues.
The first was the fact that function does not exists under tcsh, and that alias become dirty very quickly.
The second, the more important, is this is not installed by default on all *nix operating systems.

The wish to create something which can be used on lots of operating system, particularly on GNU/Linux, Solaris, and Cygwin which was my first shell multi-OS need, my second and definitive choice has been for GNU/Bash. It resolves the two points and it perfectly fits my needs.

To lead me on this choice, I have read lots of articles and Web Site, and I have concluded that GNU/Bash is now embedded as installation base on almost all operating systems. In the case it would not, it can be used as sh compatible.

It is why, I think it is the best choice in most cases. If you have not made your choice, you might make this one too, it will be a guarantee of perenity and should answer to all your needs.

Compile OpenVPN and TUN under Solaris

I've recently worked on Solaris and need to compile the source code of openVPN and TUN.
At first, it seemed easy but because of some compatibility issues, it was not.
You can follow those steps to get openvpn executable under Solaris:
- download the openVPN source code and uncompress it under [OPENVPN_DIRECTORY],
- download the TUN source code and uncompress it under [TUNE_DIRECTORY],
- copy the [TUNE_DIRECTORY]/solaris/if_tun.h file to [OPENVPN_DIRECTORY],
- edit the [OPENVPN_DIRECTORY]/tun.c file and add the #include "if_tun.h" line after the #include "tun.h" one,
- under [OPENVPN_DIRECTORY], execute ./configure --disable-lzo,
- ensure there is a make executable into your path, for instance create a symbolic link executing ln -s /usr/sfw/bin/gmake /usr/bin/make,
- then execute make under [OPENVPN_DIRECTORY],
- finally the openvpn executable is ready for Solaris.

Then, you can follow those steps to get the tun functionality under Solaris:
- create the subdirectory [TUNE_DIRECTORY] /solaris/sys,
- download the dditypes.h file and put it under [TUNE_DIRECTORY] /solaris/sys (it fixes an incompatibility issue),
- ensure there is a ld executable into your path, for instance create a symbolic link executing ln -s /usr/sfw/bin/gld /usr/bin/ld,
- execute make install under [TUNE_DIRECTORY],
- finally the tun functionality is ready for Solaris.

It is now possible to use openVPN and TUN under Solaris.