Dear Experts,
I have Debian Lenny running in an AMD Geode processor and I need run administrative services with c++ for sample I need use the date function but I have problems because I need use "su" or "sudo" password , I dont know how I can use it
I use :
system ("su mypassword");
system ("date mydate");
but isn't work ...any idea?
thanks thanks
cheers,
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If you want a program to change the date, everytime the user password changes you have to pull it out of somewhere, or recompile the application. Therefore it is better to not do a sudo within the application if it can be helped and simply use the chmod +s approach to and change the ownership of the file to root with global executable, or executable within a group.
This way you are not tied in to password management, etc.
Wouldnt it be better if your program gets launched with sudo permissions rather than your program trying to get sudo permissions mid-execution. What if you need to spend some time in a loop and then execute another command?
sudo ./myprogram
This would launch your program with sufficient permissions to execute some privileged commands. I am not a fan chmod +s for obvious reasons but if system("su -c date datetime"); works then it would be a good alternative.
Thanks Sunnycoder and sweetfa2
the system("su -c date datetime"); not works ...
I Use
char myDate[50]=" sudo -c date 041223002008";
system(myDate) ;
and I have the msg : Uknown id: 041223002008
and the date hasn't any change ...
I want only change the date with my date automatically without the su or sudo password.
any idea ? thanks
my best regards
Dear Sunnycoder,
In my program Im using the serial ports and with the chmod +s my program not run fine .. I don't have connection with my equipment (a datalogger) ,
I send an instrucction to my datalogger and the answer is a date, with this date I want update my PC.
what can't I do?, I need update the date without the sudo or su and via c/++ code
thanks
Place the following in sudoers instead of whatever you have for username:
username ALL=(ALL) NOPASSWD: /bin/date
Then you can use sudo, and it won't prompt for a password while using the allowed command; full path is required both here, and when running the
command with sudo, for security reasons.
This is better than 'su' in that you are not having to give the program a blank check to do anything as root, and no passwords. Only the commands you list are available, although in this example any options may be given to the 'date' command, sudo also allows you to have some control over command line arguments.
Then use
char buffer[512];
char newdate[30] = "041223002008";
/* ^^^^^^^^^^^^^^^^^^^^^^ populate this with new date string */
sprintf(buffer, "sudo /bin/date +%.30s", newdate);
system(buffer);
* To use sudo in a scripted method on some Linux distributions, you may also need to comment out a line in sudoers that says
Defaults requiretty
By placing a '#' symbol in front of it.
*The line you are commenting out essentially prevents sudo from working if a TTY has not been allocated;
i.e. stops sudo from being used by non-interactive scripts.
The reason 'requiretty' has sometimes been added by default is to do with the fact sudo can't stop display of user password while you're typing it in on a non-TTY.
or add options using a user-specific defaults line such as
Defaults:username env_reset, stay_setuid, !requiretty, !authenticate, mail_no_perms, mailto=(EMAIL ADDRESS TO SEND TO IF permissions are violated)
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by: sweetfa2Posted on 2008-10-08 at 17:43:55ID: 22674721
As root user "chmod +s executable"