Module: Process::UID

Defined in:

process.c

Overview

The Process::UID module contains a collection of module functions which can be used to portably get, set, and switch the current process's real, effective, and saved user IDs.

Class Method Summary

• .Process::UID.change_privilege(integer) ⇒ Fixnum

  Change the current process's real and effective user ID to that specified by integer.

• .eid ⇒ Object

  Returns the effective user ID for this process.

• .grant_privilege ⇒ Object

  Set the effective user ID, and if possible, the saved user ID of the process to the given integer.

• .Process::UID.re_exchange ⇒ Fixnum

  Exchange real and effective user IDs and return the new effective user ID.

• .Process::UID.re_exchangeable? ⇒ Boolean

  Returns true if the real and effective user IDs of a process may be exchanged on the current platform.

• .rid ⇒ Object

  Returns the (real) user ID of this process.

• .Process::UID.sid_available? ⇒ Boolean

  Returns true if the current platform has saved user ID functionality.

• .switch ⇒ Object

  Switch the effective and real user IDs of the current process.

Class Method Details

.Process::UID.change_privilege(integer) ⇒ Fixnum

Change the current process's real and effective user ID to that specified by integer. Returns the new user ID. Not available on all platforms.

[Process.uid, Process.euid]          #=> [0, 0]
Process::UID.change_privilege(31)    #=> 31
[Process.uid, Process.euid]          #=> [31, 31]

Returns:

• (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process::UID.change_privilege(integer)   -> fixnum
 *
 *  Change the current process's real and effective user ID to that
 *  specified by _integer_. Returns the new user ID. Not
 *  available on all platforms.
 *
 *     [Process.uid, Process.euid]          #=> [0, 0]
 *     Process::UID.change_privilege(31)    #=> 31
 *     [Process.uid, Process.euid]          #=> [31, 31]
 */

static VALUE
p_uid_change_privilege(VALUE obj, VALUE id)
{
    rb_uid_t uid;

    check_uid_switch();

    uid = NUM2UIDT(id);

    if (geteuid() == 0) { /* root-user */
#if defined(HAVE_SETRESUID)
    if (setresuid(uid, uid, uid) < 0) rb_sys_fail(0);
    SAVED_USER_ID = uid;
#elif defined(HAVE_SETUID)
    if (setuid(uid) < 0) rb_sys_fail(0);
    SAVED_USER_ID = uid;
#elif defined(HAVE_SETREUID) && !defined(OBSOLETE_SETREUID)
    if (getuid() == uid) {
        if (SAVED_USER_ID == uid) {
        if (setreuid(-1, uid) < 0) rb_sys_fail(0);
        } else {
        if (uid == 0) { /* (r,e,s) == (root, root, x) */
            if (setreuid(-1, SAVED_USER_ID) < 0) rb_sys_fail(0);
            if (setreuid(SAVED_USER_ID, 0) < 0) rb_sys_fail(0);
            SAVED_USER_ID = 0; /* (r,e,s) == (x, root, root) */
            if (setreuid(uid, uid) < 0) rb_sys_fail(0);
            SAVED_USER_ID = uid;
        } else {
            if (setreuid(0, -1) < 0) rb_sys_fail(0);
            SAVED_USER_ID = 0;
            if (setreuid(uid, uid) < 0) rb_sys_fail(0);
            SAVED_USER_ID = uid;
        }
        }
    } else {
        if (setreuid(uid, uid) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
    }
#elif defined(HAVE_SETRUID) && defined(HAVE_SETEUID)
    if (getuid() == uid) {
        if (SAVED_USER_ID == uid) {
        if (seteuid(uid) < 0) rb_sys_fail(0);
        } else {
        if (uid == 0) {
            if (setruid(SAVED_USER_ID) < 0) rb_sys_fail(0);
            SAVED_USER_ID = 0;
            if (setruid(0) < 0) rb_sys_fail(0);
        } else {
            if (setruid(0) < 0) rb_sys_fail(0);
            SAVED_USER_ID = 0;
            if (seteuid(uid) < 0) rb_sys_fail(0);
            if (setruid(uid) < 0) rb_sys_fail(0);
            SAVED_USER_ID = uid;
        }
        }
    } else {
        if (seteuid(uid) < 0) rb_sys_fail(0);
        if (setruid(uid) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
    }
#else
    rb_notimplement();
#endif
    } else { /* unprivileged user */
#if defined(HAVE_SETRESUID)
    if (setresuid((getuid() == uid)? -1: uid,
              (geteuid() == uid)? -1: uid,
              (SAVED_USER_ID == uid)? -1: uid) < 0) rb_sys_fail(0);
    SAVED_USER_ID = uid;
#elif defined(HAVE_SETREUID) && !defined(OBSOLETE_SETREUID)
    if (SAVED_USER_ID == uid) {
        if (setreuid((getuid() == uid)? -1: uid,
             (geteuid() == uid)? -1: uid) < 0) rb_sys_fail(0);
    } else if (getuid() != uid) {
        if (setreuid(uid, (geteuid() == uid)? -1: uid) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
    } else if (/* getuid() == uid && */ geteuid() != uid) {
        if (setreuid(geteuid(), uid) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
        if (setreuid(uid, -1) < 0) rb_sys_fail(0);
    } else { /* getuid() == uid && geteuid() == uid */
        if (setreuid(-1, SAVED_USER_ID) < 0) rb_sys_fail(0);
        if (setreuid(SAVED_USER_ID, uid) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
        if (setreuid(uid, -1) < 0) rb_sys_fail(0);
    }
#elif defined(HAVE_SETRUID) && defined(HAVE_SETEUID)
    if (SAVED_USER_ID == uid) {
        if (geteuid() != uid && seteuid(uid) < 0) rb_sys_fail(0);
        if (getuid() != uid && setruid(uid) < 0) rb_sys_fail(0);
    } else if (/* SAVED_USER_ID != uid && */ geteuid() == uid) {
        if (getuid() != uid) {
        if (setruid(uid) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
        } else {
        if (setruid(SAVED_USER_ID) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
        if (setruid(uid) < 0) rb_sys_fail(0);
        }
    } else if (/* geteuid() != uid && */ getuid() == uid) {
        if (seteuid(uid) < 0) rb_sys_fail(0);
        if (setruid(SAVED_USER_ID) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
        if (setruid(uid) < 0) rb_sys_fail(0);
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#elif defined HAVE_44BSD_SETUID
    if (getuid() == uid) {
        /* (r,e,s)==(uid,?,?) ==> (uid,uid,uid) */
        if (setuid(uid) < 0) rb_sys_fail(0);
        SAVED_USER_ID = uid;
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#elif defined HAVE_SETEUID
    if (getuid() == uid && SAVED_USER_ID == uid) {
        if (seteuid(uid) < 0) rb_sys_fail(0);
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#elif defined HAVE_SETUID
    if (getuid() == uid && SAVED_USER_ID == uid) {
        if (setuid(uid) < 0) rb_sys_fail(0);
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#else
    rb_notimplement();
#endif
    }
    return id;
}

.euid ⇒ Fixnum .Process::UID.eid ⇒ Fixnum .Process::Sys.geteuid ⇒ Fixnum

Returns the effective user ID for this process.

Process.euid   #=> 501

Overloads:

• .euid ⇒ Fixnum

  Returns:

  • (Fixnum)
• .Process::UID.eid ⇒ Fixnum

  Returns:

  • (Fixnum)
• .Process::Sys.geteuid ⇒ Fixnum

  Returns:

  • (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process.euid           -> fixnum
 *     Process::UID.eid       -> fixnum
 *     Process::Sys.geteuid   -> fixnum
 *
 *  Returns the effective user ID for this process.
 *
 *     Process.euid   #=> 501
 */

static VALUE
proc_geteuid(VALUE obj)
{
    rb_uid_t euid = geteuid();
    return UIDT2NUM(euid);
}

.Process::UID.grant_privilege(integer) ⇒ Fixnum .Process::UID.eid=(integer) ⇒ Fixnum

Set the effective user ID, and if possible, the saved user ID of the process to the given integer. Returns the new effective user ID. Not available on all platforms.

[Process.uid, Process.euid]          #=> [0, 0]
Process::UID.grant_privilege(31)     #=> 31
[Process.uid, Process.euid]          #=> [0, 31]

Overloads:

• .Process::UID.grant_privilege(integer) ⇒ Fixnum

  Returns:

  • (Fixnum)
• .Process::UID.eid=(integer) ⇒ Fixnum

  Returns:

  • (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process::UID.grant_privilege(integer)   -> fixnum
 *     Process::UID.eid= integer               -> fixnum
 *
 *  Set the effective user ID, and if possible, the saved user ID of
 *  the process to the given _integer_. Returns the new
 *  effective user ID. Not available on all platforms.
 *
 *     [Process.uid, Process.euid]          #=> [0, 0]
 *     Process::UID.grant_privilege(31)     #=> 31
 *     [Process.uid, Process.euid]          #=> [0, 31]
 */

static VALUE
p_uid_grant_privilege(VALUE obj, VALUE id)
{
    rb_seteuid_core(NUM2UIDT(id));
    return id;
}

.Process::UID.re_exchange ⇒ Fixnum

Exchange real and effective user IDs and return the new effective user ID. Not available on all platforms.

[Process.uid, Process.euid]   #=> [0, 31]
Process::UID.re_exchange      #=> 0
[Process.uid, Process.euid]   #=> [31, 0]

Returns:

• (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process::UID.re_exchange   -> fixnum
 *
 *  Exchange real and effective user IDs and return the new effective
 *  user ID. Not available on all platforms.
 *
 *     [Process.uid, Process.euid]   #=> [0, 31]
 *     Process::UID.re_exchange      #=> 0
 *     [Process.uid, Process.euid]   #=> [31, 0]
 */

static VALUE
p_uid_exchange(VALUE obj)
{
    rb_uid_t uid, euid;

    check_uid_switch();

    uid = getuid();
    euid = geteuid();

#if defined(HAVE_SETRESUID)
    if (setresuid(euid, uid, uid) < 0) rb_sys_fail(0);
    SAVED_USER_ID = uid;
#elif defined(HAVE_SETREUID) && !defined(OBSOLETE_SETREUID)
    if (setreuid(euid,uid) < 0) rb_sys_fail(0);
    SAVED_USER_ID = uid;
#else
    rb_notimplement();
#endif
    return UIDT2NUM(uid);
}

.Process::UID.re_exchangeable? ⇒ Boolean

Returns true if the real and effective user IDs of a process may be exchanged on the current platform.

Returns:

• (Boolean)

# File 'process.c'

/*
 *  call-seq:
 *     Process::UID.re_exchangeable?   -> true or false
 *
 *  Returns +true+ if the real and effective user IDs of a
 *  process may be exchanged on the current platform.
 *
 */

static VALUE
p_uid_exchangeable(void)
{
#if defined(HAVE_SETRESUID)
    return Qtrue;
#elif defined(HAVE_SETREUID) && !defined(OBSOLETE_SETREUID)
    return Qtrue;
#else
    return Qfalse;
#endif
}

.uid ⇒ Fixnum .Process::UID.rid ⇒ Fixnum .Process::Sys.getuid ⇒ Fixnum

Returns the (real) user ID of this process.

Process.uid   #=> 501

Overloads:

• .uid ⇒ Fixnum

  Returns:

  • (Fixnum)
• .Process::UID.rid ⇒ Fixnum

  Returns:

  • (Fixnum)
• .Process::Sys.getuid ⇒ Fixnum

  Returns:

  • (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process.uid           -> fixnum
 *     Process::UID.rid      -> fixnum
 *     Process::Sys.getuid   -> fixnum
 *
 *  Returns the (real) user ID of this process.
 *
 *     Process.uid   #=> 501
 */

static VALUE
proc_getuid(VALUE obj)
{
    rb_uid_t uid = getuid();
    return UIDT2NUM(uid);
}

.Process::UID.sid_available? ⇒ Boolean

Returns true if the current platform has saved user ID functionality.

Returns:

• (Boolean)

# File 'process.c'

/*
 *  call-seq:
 *     Process::UID.sid_available?   -> true or false
 *
 *  Returns +true+ if the current platform has saved user
 *  ID functionality.
 *
 */

static VALUE
p_uid_have_saved_id(void)
{
#if defined(HAVE_SETRESUID) || defined(HAVE_SETEUID) || defined(_POSIX_SAVED_IDS)
    return Qtrue;
#else
    return Qfalse;
#endif
}

.Process::UID.switch ⇒ Fixnum .Process::UID.switch { ... } ⇒ Object

Switch the effective and real user IDs of the current process. If a block is given, the user IDs will be switched back after the block is executed. Returns the new effective user ID if called without a block, and the return value of the block if one is given.

Overloads:

• .Process::UID.switch ⇒ Fixnum

  Returns:

  • (Fixnum)
• .Process::UID.switch { ... } ⇒ Object

  Yields:

  Returns:

  • (Object)

# File 'process.c'

/*
 *  call-seq:
 *     Process::UID.switch              -> fixnum
 *     Process::UID.switch {|| block}   -> object
 *
 *  Switch the effective and real user IDs of the current process. If
 *  a <em>block</em> is given, the user IDs will be switched back
 *  after the block is executed. Returns the new effective user ID if
 *  called without a block, and the return value of the block if one
 *  is given.
 *
 */

static VALUE
p_uid_switch(VALUE obj)
{
    rb_uid_t uid, euid;

    check_uid_switch();

    uid = getuid();
    euid = geteuid();

    if (uid != euid) {
    proc_seteuid(obj, UIDT2NUM(uid));
    if (rb_block_given_p()) {
        under_uid_switch = 1;
        return rb_ensure(rb_yield, Qnil, p_uid_sw_ensure, SAVED_USER_ID);
    } else {
        return UIDT2NUM(euid);
    }
    } else if (euid != SAVED_USER_ID) {
    proc_seteuid(obj, UIDT2NUM(SAVED_USER_ID));
    if (rb_block_given_p()) {
        under_uid_switch = 1;
        return rb_ensure(rb_yield, Qnil, p_uid_sw_ensure, euid);
    } else {
        return UIDT2NUM(uid);
    }
    } else {
    errno = EPERM;
    rb_sys_fail(0);
    }
}