The Chhamanator

A 2-in-1 post

2009-03-21T14:45:00.003+05:30

Stop Telling sudo Your Password

If you get tired of typing your password for sudo, but you don't want (or don't have permissions) to put NOPASSWD in your sudoers file, you can use the following procedure to update the sudo password timestamp and avoid typing your password.

Step 1) Create $HOME/bin/sudo-hack.sh:

#!/bin/bash
while [ true ];
do
 sudo -u root /bin/true > /dev/null 2> /dev/null
 sleep 60
done

Step 2) Do an initial run of sudo to set its password timestamp:

$ sudo -u root /bin/true
Password: *******

Step 3) Start $HOME/bin/sudo-hack.sh in the background:

$ HOME/bin/sudo-hack.sh &

Now you can use sudo without getting a password prompt, regardless of how long it's been since the last time you ran sudo.

Note: there are most certainly security implications related to using this procedure; of course, that's also true of using NOPASSWD in the sudoers file.

from Linux Journal

Firefox Browser Goes Mobile

Mozilla late last night posted the first beta release of Fennec, its mobile version of the Firefox Web browser.

The Fennec 1.0 beta 1 release currently is only available for one mobile device, the Nokia N810 Internet Tablet, which runs Nokia's Maemo open source operating system. But beta versions have been released for Windows, Mac and Linux desktop PCs, to let users and developers experiment with the new application and start building the all-important Firefox plug-ins.

More at PC World

Linux Foundation has bought Linux.com

2009-03-04T04:15:00.001+05:30

The Linux Foundation has long wanted the Linux.com domain name for obvious reasons. For a long time SourceForge, formerly VA Linux Systems, kept the site, but the company has now sold Linux.com to the Foundation.

Sources close to the deal say that the deal was made because, -- an all too familiar story these days -- the company needed the money. SourceForge, had, in addition to its well-known open-source eponymous code Web site, been in the media business. In December 2008, however, the company laid off the bulk of its NewsForge editorial staff. NewsForge was hosted at Linux.com. The Linux.com site then became something of a placeholder site, which held only a discussion forum.

from Computerworld

Lenny's out

2009-02-16T15:22:00.007+05:30

On Valentine's Day, The Debian Project announced the release of Debian GNU/Linux version 5.0 (codenamed Lenny) after 22 months of constant development.

Debian GNU/Linux is a free operating system which supports a total of twelve processor architectures and includes the KDE, GNOME, Xfce, and LXDE desktop environments. It also features compatibility with the FHS v2.3 and software developed for version 3.2 of the LSB.

This release includes numerous updated software packages, such as the K Desktop Environment 3.5.10 (KDE), an updated version of the GNOME desktop environment 2.22.2, the Xfce 4.4.2 desktop environment, LXDE 0.3.2.1, the GNUstep desktop 7.3, X.Org 7.3, OpenOffice.org 2.4.1, GIMP 2.4.7, Iceweasel 3.0.6 (an unbranded version of Mozilla Firefox), Icedove 2.0.0.19 (an unbranded version of Mozilla Thunderbird), PostgreSQL 8.3.6, MySQL 5.0.51a, GNU Compiler Collection 4.3.2, Linux kernel version 2.6.26, Apache 2.2.9, Samba 3.2.5, Python 2.5.2 and 2.4.6, Perl 5.10.0, PHP 5.2.6, Asterisk 1.4.21.2, Emacs 22, Inkscape 0.46, Nagios 3.06, Xen Hypervisor 3.2.1 (dom0 as well as domU support), OpenJDK 6b11, and more than 23,000 other ready-to-use software packages (built from over 12,000 source packages).

Newly introduced packages allow the full support of NTFS filesystems and the use of most multimedia keys out of the box. Support for Adobe® Flash® format files is available via the swfdec or Gnash plugins. Overall improvements for notebooks have been introduced, such as out of the box support of CPU frequency scaling.

The availability and updates of OpenJDK, GNU Java compiler, GNU Java bytecode interpreter, Classpath and other free versions of Sun's Java technology, into Debian GNU/Linux 5.0 allow us to ship Java-based applications in Debian's main repository.

Debian GNU/Linux can be installed from various installation media such as DVDs, CDs, USB sticks and floppies, or from the network. GNOME is the default desktop environment and is contained on the first CD. Other desktop environments — KDE, Xfce, or LXDE — can be installed through two new alternative CD images. Again available with Debian GNU/Linux 5.0 are multi-arch CDs and DVDs supporting installation of multiple architectures from a single disc; and this release adds Blu-ray Discs, allowing the archive for an entire architecture to be shipped on a single BD.

In addition to the regular installation media, Debian GNU/Linux can now also be directly used without prior installation. The special images used, known as live images, are available for CDs, USB sticks, and netboot setups. Initially, these are provided for the amd64 and i386 architectures only.

Installation

The installation process for Debian GNU/Linux 5.0 has been improved in many ways: among many other improvements, support for installation from more than one CD or DVD has been restored, firmware required by some devices can be loaded by using removable media, and installations via Braille display are supported. The installer boot process has also received much attention: a graphical menu can be used to choose front-ends and desktop environments, and to select expert or rescue mode. The installation system for Debian GNU/Linux has now been translated to 63 languages.

Download

Debian GNU/Linux can be downloaded right now via bittorrent (the recommended way), jigdo or HTTP; see Debian GNU/Linux on CDs for further information. It will soon be available on DVD, CD-ROM and Blu-ray Disc from numerous vendors, too.

32 bit vs 64 bit Debian version

For almost all PCs select 32 bit version. For e.g., most machines with Intel/AMD/etc type processors.
Choose 64 bit version to take full advantage of computers based on the AMD64 or EM64T architecture (e.g., Athlon64, Opteron, EM64T Xeon, Core 2).

There are total 5 DVD images:

Visit mirror to download Debian ISO image 32 bit i386 DVD ISO (4.4 GB each)
Visit mirror to download Debian ISO images 64 bit DVD ISO (4.4 GB each)

CD Download

There are total 31 ISO images, I strongly suggest to get DVD images :

Debian 5 DVD ISO BitTorrent download

Download from BitTorrent i386 32 bit DVD (requires a BitTorrent client)
Download from BitTorrent 64 bit DVD (requires a BitTorrent client)

Debian Trivia

The code names of Debian releases are names of characters from the film Toy Story. The unstable, development distribution is nicknamed sid, after the emotionally unstable next-door neighbor boy who regularly destroyed toys.
Ubuntu, probably the most famous and popular Linux distro. is derived from Debian.
It is one of the few distros to follow the Free Software Foundation's convention of writing Linux as GNU/Linux.

And here's the real Lenny

Source:
Nixcraft
The Debian Project
The Free Software Foundation

Some C programming questions

2009-02-13T01:59:00.001+05:30

Here are some questions related to C which is asked in the mock campus technical test at MNNIT, Allahabad. How many can you answer:

1. What is the output of the following program?
main()
{
char *p="hai friends",*p1;
p1=p;
while(*p!='\0')++*p++;
printf("%s %s",p,p1);
}

2. What is the output of the following program?
main()
{
static char names[5][20]={"pascal","ada","cobol","fortran","perl"};
int i;
char *t;
t=names[3];
names[3]=names[4];
names[4]=t;
printf("%s",names[3][4]);
}

3. Choose the correct output of the following program?
char *gxxx()
{
static char xxx[1024];
return xxx;
}
main()
{
char *g="string";
strcpy(gxxx().g);
g=gxxx();
strcpy(g,"oldstring");
printf("The string is: %s",gxxx());
}
a. The string is : string
b. The string is : Oldstring
c. Runtime error/core dump
d. Syntax error during compilation
e. None of these

4. What do the following statements indicate? Explain
1. int (*p)[10]
2. int *f()
3. int (*pf)()
4. int *p[10]

5. What is the output of the following program?
int i;
main()
{
int t;
for(t=4;scanf("%d",&i)-t;printf("%d\n",i))
printf("%d--",t--);
}
//if the inputs are 0,1,2,3 find the output

6. Choose the correct output of the following program
void main()
{
unsigned i=1;signed j=-1;
if(i<j)
printf("less");
else if(i>j)
printf("greater");
else if(i==j)
printf("equal");
}
a. greater
b. less
c. equal
d. compile time error: type mismatch

7. What is wrong with the above code (assuming the call to malloc does not fail)?
char ptr1[]="Hello World";
char *ptr2[]=malloc(5);
ptr2=ptr1;
a. There will be a memory overwrite
b. There will be a memory leak
c. There will be a segmentation fault
d. Not enough space is allocated to the malloc
e. It will not compile

8. int read_long_string(const char ** const buf)
{
char *p=NULL;
const char *fwd=NULL;
size_t len =0;
assert(buf);do
{
p=realloc(p,len+=256);
if(!p)
return 0;
if(!fwd)
fwd=p;
else
fwd=strchr(p,'\0');
}
while(fgets(fwd,256,stdin));
*buf=p;
return 1;
}
The function read_long_string(), defined above, contains an error that may be particularly visible under heavy stress. Which one of the following describes it?
a. The write to *buf is blocked by the const qualifications applied to its type.
b. If the null pointer for char is not zero-valued on the host machine, the implicit comparisons to zero(0) may introduce undesired behavior. Moreover, even if successful, it introduces machine-dependent behavior and harms portability.
c. The symbol stdin may not be defined on some ANSI C compliant systems.
d. The else causes fwd to contain an errant address
e. If the call to realloc() fails during any iteration but the first, all memory prevously allocated by the loop is leaked

9. char *get_rightmost(const char *d)
{
char rightmost [MAXPATHLEN];
const char *p=d;
assert(d!=NULL;
while(*d!='\0')
{
if(*d=='/')
p=(*(d+1)!='\0')?d+1:p;
d++;
}
memset(rightmost,0,sizeof(rightmost));
memcpy(rightmost,p,strlen(p)+1);
return rightmost;
}
The function get_rightmost(), defined abouve, contains an error. Which one of the following describes it?
a. The calls to memset() and memcpy() illegally perform a pointer conversion on rightmost without an appropriate cast
b. The code does not correctly handle the situation where the directory separator '\' is the final character
c. The if condition contains an incorrectly terminated character literal
d. memcpy() cannot be used safely to copy string data
e. The return value of get_rightmost() will be invalid in the caller's context

10. Choose the correct output of the following program?
int func1(int,int)
typedef int(*f)(int,int);
int func2(f,int,int);
int main()
{
printf("%d",func2(func2,5,5);
return 0;
}
int func1(int x,int y)
{
return (x==y);
}
int func2(f p,int a,int b)
{
return ((*p)(a,b));
}
a. 6 b. 1 c. 0 d. -1

11. void main()
{
int arr[2][2][2]={10,2,3,4,5,6,7,8};
int *p,*q;
p=&arr[1][1][1];
*q=***arr;
printf("%d %d",*p,*q);
}
a.8 10 b.10 2 c.8 1 d. garbage values

12. What value will x contain in the sample code below?
int x=011|)x10;
a.3 b.25 c.19 d.none of these

13. What number will z in the sample code below contain?
int z,x=5,y=-10,a=4,b=2;
z=x++ --y * b /a;
a.5 b.6 c.10 d.11

14. Consider the array defined below. Which one of the following definitions and initializations of p is valid?
char **array[12][12][12];
a. char **(*p)[12][12]=array;
b. char *****p=array;
c. char *(*p)[12][12][12]=array;
d. const char **p[12][12][12]=array;
e. char (**p)[12][12]=array;

15. Choose the correct output of the following program?
int i=4;
switch(i)
{
default: ;
case 3:
i+=5;
if(i==8);
{
i++;if(i==9)break;
i*=2;
}
i-=4;
break;
case 8:
i+=5; break;
}
printf("i=%d\n",i);
a.8 b.9 c.5 d.18

16. Consider the following code
int m=-14;
int n=6;
int o;
o=m%++n;
n+=m++ -o;
m<<=(o^n)&3;
printf("%d %d %d",m,n,o);
What is the output?
a)-54 -4 -2 b) -52 -6 0 c) -26 -7 0 d) -26 -5 -2

17. Choose the correct output of the following program
int fun(int **ptr)
void main()
{
int i=10;
const int *ptr=&i;
fun(&ptr);
}
int fun(int **ptr)
{
int j=2;
int *temp=&j;
printf("%5x",*ptr);
const *ptr=temp;
printf("%5x",*ptr);
return 0;
}
a. address of i address of j b. 10 233 c. error d. none of these

18. void main()
{
unsigned int res;
res=(64>>(2+1-8)&(~(1<<2));
printf("%d",res);
}
a.32 b.64 c.0 d.none of these

19. Choose the correct output of the following program
#include
int mystery(unsigned int x)
{
static unsigned int mask[]={0x55555555,0x33333333,0x0F0F0F0F0F,0x00FF00FF00FF,0x0000FFFF};
int i;
int shift;/*Number of positions to shift to right*/
for(i=0;shift=1;i<5;i++,shift*=2)
x=(xmask[i])+((x>>shift)&mask[i]);
return x;
}

int main()
{
printf("%d %d %d %d",mystery(1299),mystery(128),mystery(283),mystery(10000));
return 0;
}
a. 5 1 0 0 b. compilation error c. 0 1 5 0 d. none of these

20. Choose the correct output or the following program
#include
#define PrintInt(expr) printf("%s: %d\n",#expr,(expr))
int main()
{
int y=100;
int *p;
p=malloc(sizeof(int));
*p=10;
y=y/*p; //dividing y by *p
PrintInt(y);
return 0;
}
a. Compilation error b. y:10 c. y:100 d. None of these

The System Administrator Song

2009-02-13T00:49:00.000+05:30

A song sung by someone called West

Visit his website for more stuff.

Syadmin Horror Stories

2007-05-31T13:16:00.000+05:30

Here are some Sysadmin horror stories to enjoy:

As a new system administrator of a Unix machine with limited space I
thought I was doing myself a favor by keeping things neat and clean. One
day as I was 'cleaning up' I removed a file called 'bzero'. Strange
things started to happen like vi didn't work then the compliants started
coming in. Mail didn't work. The compilers didn't work. About this time
the REAL system administrator poked his head in and asked what I had
done. Further examination showed that bzero is the zeroed memory without
which the OS had no operating space so anything using temporary memory
was non-functional. The repair? Well things are tough to do when most of
the utilities don't work. Eventually the REAL system administrator took
the system to single user and rebuilt the system including full
restores from a tape system. The Moral is don't be to anal about things
you don't understand. Take the time learn what those strange files are before
removeing them and screwing yourself.

And another one:

I used to work at Siemens R&D in Erlangen (33000 people out of 115000
population work at Siemens - 12000 in the R&D area). We were working
on a project porting an ISO FTAM implementation in Ada to C.

About 2 months into the project we received a new project leader who
decided there were too few people working on the project (sigh!).
Anyway we were promised that a "Spitzen Klasse" (Outstanding) SW guy
was being sent over from the next lab.

The fateful day turned up (had to be a monday) and there was our very
own 'Einstein'. We gave him a tour of the lab (ie. Coffee machine on
the left, laser on the right etc.) finally getting to out work area.
We had a couple of fast 386's (this happened in '89) running Xenix 386.
We told Einstein that I was the sysadmin for both machines and that if
*anything* was strange or not working to speak with me. OK so the first
morning went off without a hitch and we all went to get someting to eat
around midday. All except Einstein who said he wanted to check a few
things out (Code practices we thought etc. - turned out to be Page 3 of
that months playboy).

We came back from eating to find Einstein twiddling his thumbs and
saying that he could no longer log in on either machine. Ermmm...

I asked him if *anything* had happened while we were away. He thought
and thought and then said "Nothing really but the lights went out for
a few minutes". OK I thought "fsck the disks, remount them and away
we go" but then I stopped and asked him again "Anything else?". He
then really started looking around and found the palms of his hand
the most interesting thing he'd ever seen. He answered "Well I know
a little about Unix and fsck is the 'ajax' cleaning program of Unix
so when it started again after the lights came back on it started
fsck and asked me for a scratchpad file. I just took the one it
printed on the line above!" (ie. the name of the filesystem to clean).

Another comment he made was "Must be a fast machine as fsck ran quick".

Bad you might say until he told me he had done the same thing to our
backup machine.

Needless to say Einstein & our project leader exited stage left...

And we eventually got a backup tape from our data safe stored at
another lab. The SW guy is kind of a living legend around here :-)

You can read more stuff here.