Module: Process::GID

Defined in:

process.c

Overview

The Process::GID 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 group IDs.

Class Method Summary

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

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

• .eid ⇒ Object

  Returns the effective group ID for this process.

• .grant_privilege ⇒ Object

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

• .Process::GID.re_exchange ⇒ Fixnum

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

• .Process::GID.re_exchangeable? ⇒ Boolean

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

• .rid ⇒ Object

  Returns the (real) group ID for this process.

• .Process::GID.sid_available? ⇒ Boolean

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

• .switch ⇒ Object

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

Class Method Details

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

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

[Process.gid, Process.egid]          #=> [0, 0]
Process::GID.change_privilege(33)    #=> 33
[Process.gid, Process.egid]          #=> [33, 33]

Returns:

• (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process::GID.change_privilege(integer)   -> fixnum
 *
 *  Change the current process's real and effective group ID to that
 *  specified by _integer_. Returns the new group ID. Not
 *  available on all platforms.
 *
 *     [Process.gid, Process.egid]          #=> [0, 0]
 *     Process::GID.change_privilege(33)    #=> 33
 *     [Process.gid, Process.egid]          #=> [33, 33]
 */

static VALUE
p_gid_change_privilege(VALUE obj, VALUE id)
{
    rb_gid_t gid;

    check_gid_switch();

    gid = NUM2GIDT(id);

    if (geteuid() == 0) { /* root-user */
#if defined(HAVE_SETRESGID)
    if (setresgid(gid, gid, gid) < 0) rb_sys_fail(0);
    SAVED_GROUP_ID = gid;
#elif defined HAVE_SETGID
    if (setgid(gid) < 0) rb_sys_fail(0);
    SAVED_GROUP_ID = gid;
#elif defined(HAVE_SETREGID) && !defined(OBSOLETE_SETREGID)
    if (getgid() == gid) {
        if (SAVED_GROUP_ID == gid) {
        if (setregid(-1, gid) < 0) rb_sys_fail(0);
        } else {
        if (gid == 0) { /* (r,e,s) == (root, y, x) */
            if (setregid(-1, SAVED_GROUP_ID) < 0) rb_sys_fail(0);
            if (setregid(SAVED_GROUP_ID, 0) < 0) rb_sys_fail(0);
            SAVED_GROUP_ID = 0; /* (r,e,s) == (x, root, root) */
            if (setregid(gid, gid) < 0) rb_sys_fail(0);
            SAVED_GROUP_ID = gid;
        } else { /* (r,e,s) == (z, y, x) */
            if (setregid(0, 0) < 0) rb_sys_fail(0);
            SAVED_GROUP_ID = 0;
            if (setregid(gid, gid) < 0) rb_sys_fail(0);
            SAVED_GROUP_ID = gid;
        }
        }
    } else {
        if (setregid(gid, gid) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
    }
#elif defined(HAVE_SETRGID) && defined (HAVE_SETEGID)
    if (getgid() == gid) {
        if (SAVED_GROUP_ID == gid) {
        if (setegid(gid) < 0) rb_sys_fail(0);
        } else {
        if (gid == 0) {
            if (setegid(gid) < 0) rb_sys_fail(0);
            if (setrgid(SAVED_GROUP_ID) < 0) rb_sys_fail(0);
            SAVED_GROUP_ID = 0;
            if (setrgid(0) < 0) rb_sys_fail(0);
        } else {
            if (setrgid(0) < 0) rb_sys_fail(0);
            SAVED_GROUP_ID = 0;
            if (setegid(gid) < 0) rb_sys_fail(0);
            if (setrgid(gid) < 0) rb_sys_fail(0);
            SAVED_GROUP_ID = gid;
        }
        }
    } else {
        if (setegid(gid) < 0) rb_sys_fail(0);
        if (setrgid(gid) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
    }
#else
    rb_notimplement();
#endif
    } else { /* unprivileged user */
#if defined(HAVE_SETRESGID)
    if (setresgid((getgid() == gid)? -1: gid,
              (getegid() == gid)? -1: gid,
              (SAVED_GROUP_ID == gid)? -1: gid) < 0) rb_sys_fail(0);
    SAVED_GROUP_ID = gid;
#elif defined(HAVE_SETREGID) && !defined(OBSOLETE_SETREGID)
    if (SAVED_GROUP_ID == gid) {
        if (setregid((getgid() == gid)? -1: gid,
             (getegid() == gid)? -1: gid) < 0) rb_sys_fail(0);
    } else if (getgid() != gid) {
        if (setregid(gid, (getegid() == gid)? -1: gid) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
    } else if (/* getgid() == gid && */ getegid() != gid) {
        if (setregid(getegid(), gid) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
        if (setregid(gid, -1) < 0) rb_sys_fail(0);
    } else { /* getgid() == gid && getegid() == gid */
        if (setregid(-1, SAVED_GROUP_ID) < 0) rb_sys_fail(0);
        if (setregid(SAVED_GROUP_ID, gid) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
        if (setregid(gid, -1) < 0) rb_sys_fail(0);
    }
#elif defined(HAVE_SETRGID) && defined(HAVE_SETEGID)
    if (SAVED_GROUP_ID == gid) {
        if (getegid() != gid && setegid(gid) < 0) rb_sys_fail(0);
        if (getgid() != gid && setrgid(gid) < 0) rb_sys_fail(0);
    } else if (/* SAVED_GROUP_ID != gid && */ getegid() == gid) {
        if (getgid() != gid) {
        if (setrgid(gid) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
        } else {
        if (setrgid(SAVED_GROUP_ID) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
        if (setrgid(gid) < 0) rb_sys_fail(0);
    }
    } else if (/* getegid() != gid && */ getgid() == gid) {
        if (setegid(gid) < 0) rb_sys_fail(0);
        if (setrgid(SAVED_GROUP_ID) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
        if (setrgid(gid) < 0) rb_sys_fail(0);
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#elif defined HAVE_44BSD_SETGID
    if (getgid() == gid) {
        /* (r,e,s)==(gid,?,?) ==> (gid,gid,gid) */
        if (setgid(gid) < 0) rb_sys_fail(0);
        SAVED_GROUP_ID = gid;
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#elif defined HAVE_SETEGID
    if (getgid() == gid && SAVED_GROUP_ID == gid) {
        if (setegid(gid) < 0) rb_sys_fail(0);
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#elif defined HAVE_SETGID
    if (getgid() == gid && SAVED_GROUP_ID == gid) {
        if (setgid(gid) < 0) rb_sys_fail(0);
    } else {
        errno = EPERM;
        rb_sys_fail(0);
    }
#else
    rb_notimplement();
#endif
    }
    return id;
}

.egid ⇒ Fixnum .Process::GID.eid ⇒ Fixnum .Process::Sys.geteid ⇒ Fixnum

Returns the effective group ID for this process. Not available on all platforms.

Process.egid   #=> 500

Overloads:

• .egid ⇒ Fixnum

  Returns:

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

  Returns:

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

  Returns:

  • (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process.egid          -> fixnum
 *     Process::GID.eid      -> fixnum
 *     Process::Sys.geteid   -> fixnum
 *
 *  Returns the effective group ID for this process. Not available on
 *  all platforms.
 *
 *     Process.egid   #=> 500
 */

static VALUE
proc_getegid(VALUE obj)
{
    rb_gid_t egid = getegid();

    return GIDT2NUM(egid);
}

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

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

[Process.gid, Process.egid]          #=> [0, 0]
Process::GID.grant_privilege(31)     #=> 33
[Process.gid, Process.egid]          #=> [0, 33]

Overloads:

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

  Returns:

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

  Returns:

  • (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process::GID.grant_privilege(integer)    -> fixnum
 *     Process::GID.eid = integer               -> fixnum
 *
 *  Set the effective group ID, and if possible, the saved group ID of
 *  the process to the given _integer_. Returns the new
 *  effective group ID. Not available on all platforms.
 *
 *     [Process.gid, Process.egid]          #=> [0, 0]
 *     Process::GID.grant_privilege(31)     #=> 33
 *     [Process.gid, Process.egid]          #=> [0, 33]
 */

static VALUE
p_gid_grant_privilege(VALUE obj, VALUE id)
{
    rb_setegid_core(NUM2GIDT(id));
    return id;
}

.Process::GID.re_exchange ⇒ Fixnum

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

[Process.gid, Process.egid]   #=> [0, 33]
Process::GID.re_exchange      #=> 0
[Process.gid, Process.egid]   #=> [33, 0]

Returns:

• (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process::GID.re_exchange   -> fixnum
 *
 *  Exchange real and effective group IDs and return the new effective
 *  group ID. Not available on all platforms.
 *
 *     [Process.gid, Process.egid]   #=> [0, 33]
 *     Process::GID.re_exchange      #=> 0
 *     [Process.gid, Process.egid]   #=> [33, 0]
 */

static VALUE
p_gid_exchange(VALUE obj)
{
    rb_gid_t gid, egid;

    check_gid_switch();

    gid = getgid();
    egid = getegid();

#if defined(HAVE_SETRESGID)
    if (setresgid(egid, gid, gid) < 0) rb_sys_fail(0);
    SAVED_GROUP_ID = gid;
#elif defined(HAVE_SETREGID) && !defined(OBSOLETE_SETREGID)
    if (setregid(egid,gid) < 0) rb_sys_fail(0);
    SAVED_GROUP_ID = gid;
#else
    rb_notimplement();
#endif
    return GIDT2NUM(gid);
}

.Process::GID.re_exchangeable? ⇒ Boolean

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

Returns:

• (Boolean)

# File 'process.c'

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

static VALUE
p_gid_exchangeable(void)
{
#if defined(HAVE_SETRESGID)
    return Qtrue;
#elif defined(HAVE_SETREGID) && !defined(OBSOLETE_SETREGID)
    return Qtrue;
#else
    return Qfalse;
#endif
}

.gid ⇒ Fixnum .Process::GID.rid ⇒ Fixnum .Process::Sys.getgid ⇒ Fixnum

Returns the (real) group ID for this process.

Process.gid   #=> 500

Overloads:

• .gid ⇒ Fixnum

  Returns:

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

  Returns:

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

  Returns:

  • (Fixnum)

# File 'process.c'

/*
 *  call-seq:
 *     Process.gid           -> fixnum
 *     Process::GID.rid      -> fixnum
 *     Process::Sys.getgid   -> fixnum
 *
 *  Returns the (real) group ID for this process.
 *
 *     Process.gid   #=> 500
 */

static VALUE
proc_getgid(VALUE obj)
{
    rb_gid_t gid = getgid();
    return GIDT2NUM(gid);
}

.Process::GID.sid_available? ⇒ Boolean

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

Returns:

• (Boolean)

# File 'process.c'

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

static VALUE
p_gid_have_saved_id(void)
{
#if defined(HAVE_SETRESGID) || defined(HAVE_SETEGID) || defined(_POSIX_SAVED_IDS)
    return Qtrue;
#else
    return Qfalse;
#endif
}

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

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

Overloads:

• .Process::GID.switch ⇒ Fixnum

  Returns:

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

  Yields:

  Returns:

  • (Object)

# File 'process.c'

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

static VALUE
p_gid_switch(VALUE obj)
{
    rb_gid_t gid, egid;

    check_gid_switch();

    gid = getgid();
    egid = getegid();

    if (gid != egid) {
    proc_setegid(obj, GIDT2NUM(gid));
    if (rb_block_given_p()) {
        under_gid_switch = 1;
        return rb_ensure(rb_yield, Qnil, p_gid_sw_ensure, SAVED_GROUP_ID);
    } else {
        return GIDT2NUM(egid);
    }
    }
    else if (egid != SAVED_GROUP_ID) {
    proc_setegid(obj, GIDT2NUM(SAVED_GROUP_ID));
    if (rb_block_given_p()) {
        under_gid_switch = 1;
        return rb_ensure(rb_yield, Qnil, p_gid_sw_ensure, egid);
    } else {
        return GIDT2NUM(gid);
    }
    }
    else {
    errno = EPERM;
    rb_sys_fail(0);
    }
}