/etcpasswd & /etc/shadow 1

[Bangieff]

Hi all
I need my program to be abled to add users but I couldn't find how to do it so I use execve(useradd....) but it doesn't add the user's password in the /etc/shadow file. Then I found in man the setpwent() function but I just can't untherstand how to use it. the compiler doesn't like the code...
So would someone give me a short exapmle how to use it?
Or may be a better way to add users...

thanks in advance

 

[ranand]

Hi,

Here is what i did in Perl..It works perfect for me.See if it helps you.Try calling these Perl subroutines from your program.

-------------------------------------------------------

my $shadowFile = "/etc/shadow";
my $oldpasswdFile = "$passwdFile.old";

#write logintest11:ZCr0cYGXAmhI2:501:100:LoginUser:/home/logintest11:
sub writeToShadow {

$shParam1 = &getNumDays();
$shParam2 = 0;
$shParam3 = 99999;
$shParam4 = 7;
$shParam5 = -1;
$shParam6 = -1;
$shParam7 = 134537898;
$encryptedPasswd = &encryptmd5Passwd($password);

$tmpShadowFile = $shadowFile.".$$";
system("cp -f $shadowFile $tmpShadowFile"
open(SFH,$shadowFile);
open(TSFH,">>$tmpShadowFile"
flock(SFH,1);

if(&detectmd5()) {
$encryptedPasswd = &encryptmd5Passwd($password);
}
else {
$encryptedPasswd = &encryptedPasswd($password);
}

print TSFH "$userName:$encryptedPasswd:$shParam1:$shParam2:$shParam3:$shParam4:$shParam5:$shParam6:$shParam7\n";
close(TSFH);
close(SFH);
system("cp -f $tmpShadowFile $shadowFile"
system("rm -f $tmpShadowFile"

}

#encrypt a plain text passwd as an md5 passwd
sub encryptmd5Passwd {
local $password = $_[0];
local(@saltset)=('a'..'z','A'..'Z','0'..'9','.','/');
my $now = time;
srand ($now);
for($i=0;$i<8;$i++)
{
my $random = int(rand(65));
push(@randarr,$random);
}
for($i=0;$i<8;$i++)
{
$salt .= $saltset[$randarr[$i]];
}

return crypt($password,&quot;\$1\$$salt\$&quot;
}

#Detect if we have MD5 or not..
sub detectmd5 {
my($md5flag,$passwdFile);
$md5flag = 0;
if(-e &quot;/etc/shadow&quot {
$passwdFile =&quot;/etc/shadow&quot;;
}
else {
$passwdFile = &quot;/etc/passwd&quot;;
}
open(PFH,&quot;$passwdFile&quot;
flock(PFH,1);
while(<PFH>) {
if($_ =~ /\$/) {
$md5flag =1;
}
}
close(PFH);
return $md5flag;
}

 

[cibrran]

You can Add your User's ID and Passwd

first. &quot;#useradd your user'sID&quot;

lastly &quot;#passwd your user'sID&quot;

It's give you some nice pleasure!

 

[bitforbrains]

Here's what I did, maybe it'll be helpful
NOTE: this sets the password to x, so that it can be set later in the shadow file. if you're not using a shadow file, use the crypt() function, it has a man page, or reply and I can tell you how to use it.

int addUser(char* username, int uid, int gid, char* gecos, char* password, char* shell, char* home) {
struct passwd* entry;
FILE* tempfile;
FILE* passwdfile;
bool exists = false;
size_t newuid = 0;

/* Open temporary file */
tempfile = tmpfile();
if(ferror(tempfile)) {
cerr << &quot;Couldn't open temporary file. Exiting...\n&quot;;
return 1;
}

/* Loop through password file, change entry for username, then write to temp file */
entry = getpwent();
while(entry){
if(! strcmp(entry->pw_name,username)) {
exists = true;
}
if(! uid && entry->pw_uid > newuid)
newuid = entry->pw_uid;
entry = getpwent();
}
endpwent();

if(exists) {
cerr << &quot;User already exists.\n&quot;;
return 1;
}

/* Open pasword file for writing, test for errors */
passwdfile = fopen(&quot;/etc/passwd&quot;,&quot;a&quot;
if(ferror(passwdfile)) {
cerr << &quot;Couldn't open password file. Exiting...\n&quot;;
return 1;
}

if(! uid)
uid = newuid +1;

/* Create new passwd struct, fill with info, then write to passwd file */
entry = new struct passwd;
entry->pw_name = username;
entry->pw_passwd[0] = 'x';
entry->pw_passwd[1] = '\0';
entry->pw_uid = uid;
entry->pw_gid = gid;
entry->pw_gecos = gecos;
entry->pw_dir = home;
entry->pw_shell = shell;
putpwent(entry,passwdfile);

fclose(passwdfile);

cout << &quot;User Add Successful.\n&quot;;

return 0;
}

 

[Bangieff]

what happens if the server get restarted in the middle of tranzaction? That's what I'm afraid of.