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  • etc/etc.c

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Etc

The etc module provides access to information from the /etc/passwd and /etc/group files on Linux and Unix systems.

Documented by mathew <meta@pobox.com>.

Constants

Group
Passwd

Public Class Methods

endgrent() click to toggle source

Ends the process of scanning through the /etc/group file begun by getgrent, and closes the file.

 
               static VALUE
etc_endgrent(VALUE obj)
{
#ifdef HAVE_GETGRENT
    endgrent();
#endif
    return Qnil;
}
            
endpwent() click to toggle source

Ends the process of scanning through the /etc/passwd file begun with getpwent, and closes the file.

 
               static VALUE
etc_endpwent(VALUE obj)
{
#ifdef HAVE_GETPWENT
    endpwent();
#endif
    return Qnil;
}
            
getgrent() click to toggle source

Returns an entry from the /etc/group file. The first time it is called it opens the file and returns the first entry; each successive call returns the next entry, or nil if the end of the file has been reached.

To close the file when processing is complete, call endgrent.

Each entry is returned as a Struct::Group:

  • Group#name contains the name of the group as a String.

  • Group#passwd contains the encrypted password as a String. An ‘x’ is returned if password access to the group is not available; an empty string is returned if no password is needed to obtain membership of the group.

  • Group#gid contains the group’s numeric ID as an integer.

  • Group#mem is an Array of Strings containing the short login names of the members of the group.

 
               static VALUE
etc_getgrent(VALUE obj)
{
#ifdef HAVE_GETGRENT
    struct group *gr;

    if (gr = getgrent()) {
        return setup_group(gr);
    }
#endif
    return Qnil;
}
            
getgrgid(p1 = v1) click to toggle source

Returns information about the group with specified integer group id (gid), as found in /etc/group.

The information is returned as a Struct::Group; see getgrent above for details.

e.g. ::getgrgid -> #<struct Struct::Group name=“users”, passwd=“x”, gid=100, mem=[“meta”, “root”]>

 
               static VALUE
etc_getgrgid(int argc, VALUE *argv, VALUE obj)
{
#ifdef HAVE_GETGRENT
    VALUE id;
    gid_t gid;
    struct group *grp;

    rb_secure(4);
    if (rb_scan_args(argc, argv, "01", &id) == 1) {
        gid = NUM2GIDT(id);
    }
    else {
        gid = getgid();
    }
    grp = getgrgid(gid);
    if (grp == 0) rb_raise(rb_eArgError, "can't find group for %d", (int)gid);
    return setup_group(grp);
#else
    return Qnil;
#endif
}
            
getgrnam(p1) click to toggle source

Returns information about the group with specified String name, as found in /etc/group.

The information is returned as a Struct::Group; see getgrent above for details.

e.g. ::getgrnam(‘users’) -> #<struct Struct::Group name=“users”, passwd=“x”, gid=100, mem=[“meta”, “root”]>

 
               static VALUE
etc_getgrnam(VALUE obj, VALUE nam)
{
#ifdef HAVE_GETGRENT
    struct group *grp;

    rb_secure(4);
    SafeStringValue(nam);
    grp = getgrnam(RSTRING_PTR(nam));
    if (grp == 0) rb_raise(rb_eArgError, "can't find group for %s", RSTRING_PTR(nam));
    return setup_group(grp);
#else
    return Qnil;
#endif
}
            
getlogin() click to toggle source

Returns the short user name of the currently logged in user. Unfortunately, it is often rather easy to fool getlogin(). Avoid getlogin() for security-related purposes.

e.g.

Etc.getlogin -> 'guest'
 
               static VALUE
etc_getlogin(VALUE obj)
{
    char *login;

    rb_secure(4);
#ifdef HAVE_GETLOGIN
    login = getlogin();
    if (!login) login = getenv("USER");
#else
    login = getenv("USER");
#endif

    if (login)
        return rb_tainted_str_new2(login);
    return Qnil;
}
            
getpwent() click to toggle source

Returns an entry from the /etc/passwd file. The first time it is called it opens the file and returns the first entry; each successive call returns the next entry, or nil if the end of the file has been reached.

To close the file when processing is complete, call endpwent.

Each entry is returned as a Struct::Passwd:

  • Passwd#name contains the short login name of the user as a String.

  • Passwd#passwd contains the encrypted password of the user as a String. an ‘x’ is returned if shadow passwords are in use. An ‘*’ is returned if the user cannot log in using a password.

  • Passwd#uid contains the integer user ID (uid) of the user.

  • Passwd#gid contains the integer group ID (gid) of the user’s primary group.

  • Passwd#gecos contains a longer String description of the user, such as a full name. Some Unix systems provide structured information in the gecos field, but this is system-dependent.

  • Passwd#dir contains the path to the home directory of the user as a String.

  • Passwd#shell contains the path to the login shell of the user as a String.

 
               static VALUE
etc_getpwent(VALUE obj)
{
#ifdef HAVE_GETPWENT
    struct passwd *pw;

    if (pw = getpwent()) {
        return setup_passwd(pw);
    }
#endif
    return Qnil;
}
            
getpwnam(p1) click to toggle source

Returns the /etc/passwd information for the user with specified login name.

The information is returned as a Struct::Passwd; see getpwent above for details.

e.g. * ::getpwnam(‘root’) -> #<struct Struct::Passwd name=“root”, passwd=“x”, uid=0, gid=0, gecos=“root”,dir=“/root”, shell=“/bin/bash”>

 
               static VALUE
etc_getpwnam(VALUE obj, VALUE nam)
{
#ifdef HAVE_GETPWENT
    struct passwd *pwd;

    SafeStringValue(nam);
    pwd = getpwnam(RSTRING_PTR(nam));
    if (pwd == 0) rb_raise(rb_eArgError, "can't find user for %s", RSTRING_PTR(nam));
    return setup_passwd(pwd);
#else 
    return Qnil;
#endif
}
            
getpwuid(p1 = v1) click to toggle source

Returns the /etc/passwd information for the user with specified integer user id (uid).

The information is returned as a Struct::Passwd; see getpwent above for details.

e.g. * ::getpwuid -> #<struct Struct::Passwd name=“root”, passwd=“x”, uid=0, gid=0, gecos=“root”,dir=“/root”, shell=“/bin/bash”>

 
               static VALUE
etc_getpwuid(int argc, VALUE *argv, VALUE obj)
{
#if defined(HAVE_GETPWENT)
    VALUE id;
    uid_t uid;
    struct passwd *pwd;

    rb_secure(4);
    if (rb_scan_args(argc, argv, "01", &id) == 1) {
        uid = NUM2UIDT(id);
    }
    else {
        uid = getuid();
    }
    pwd = getpwuid(uid);
    if (pwd == 0) rb_raise(rb_eArgError, "can't find user for %d", (int)uid);
    return setup_passwd(pwd);
#else 
    return Qnil;
#endif
}
            
group() click to toggle source

Provides a convenient Ruby iterator which executes a block for each entry in the /etc/group file.

The code block is passed an Struct::Group struct; see getgrent above for details.

Example:

require 'etc'

Etc.group {|g|
  puts g.name + ": " + g.mem.join(', ')
}
 
               static VALUE
etc_group(VALUE obj)
{
#ifdef HAVE_GETGRENT
    struct group *grp;

    rb_secure(4);
    if (rb_block_given_p()) {
        if (group_blocking) {
            rb_raise(rb_eRuntimeError, "parallel group iteration");
        }
        group_blocking = Qtrue;
        rb_ensure(group_iterate, 0, group_ensure, 0);
    }
    if (grp = getgrent()) {
        return setup_group(grp);
    }
#endif
    return Qnil;
}
            
passwd() click to toggle source

Provides a convenient Ruby iterator which executes a block for each entry in the /etc/passwd file.

The code block is passed an Struct::Passwd struct; see getpwent above for details.

Example:

require 'etc'

Etc.passwd {|u|
  puts u.name + " = " + u.gecos
}
 
               static VALUE
etc_passwd(VALUE obj)
{
#ifdef HAVE_GETPWENT
    struct passwd *pw;

    rb_secure(4);
    if (rb_block_given_p()) {
        if (passwd_blocking) {
            rb_raise(rb_eRuntimeError, "parallel passwd iteration");
        }
        passwd_blocking = Qtrue;
        rb_ensure(passwd_iterate, 0, passwd_ensure, 0);
    }
    if (pw = getpwent()) {
        return setup_passwd(pw);
    }
#endif
    return Qnil;
}
            
setgrent() click to toggle source

Resets the process of reading the /etc/group file, so that the next call to getgrent will return the first entry again.

 
               static VALUE
etc_setgrent(VALUE obj)
{
#ifdef HAVE_GETGRENT
    setgrent();
#endif
    return Qnil;
}
            
setpwent() click to toggle source

Resets the process of reading the /etc/passwd file, so that the next call to getpwent will return the first entry again.

 
               static VALUE
etc_setpwent(VALUE obj)
{
#ifdef HAVE_GETPWENT
    setpwent();
#endif
    return Qnil;
}
            

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