Module: Process::GID

Relationships & Source Files
Defined in:	process.c

Overview

The 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 Attribute Summary

.re_exchangeable? ⇒ Boolean readonly mod_func

Returns true if the real and effective group IDs of a process may be exchanged on the current platform.
.rid ⇒ Integer readonly mod_func

Alias for gid.
.sid_available? ⇒ Boolean readonly mod_func

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

Class Method Summary

.change_privilege(group) ⇒ Integer mod_func

Change the current process’s real and effective group ID to that specified by group.
.eid ⇒ Integer mod_func

Alias for egid.
.from_name(name) ⇒ GID mod_func

Get the group ID by the name.
.grant_privilege(group) ⇒ Integer mod_func

Set the effective group ID, and if possible, the saved group ID of the process to the given group.
.re_exchange ⇒ Integer mod_func

Exchange real and effective group IDs and return the new effective group ID.
.switch ⇒ Integer mod_func

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

Class Attribute Details

.re_exchangeable? ⇒ `Boolean` (readonly, mod_func)

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

[ GitHub ]

# File 'process.c', line 7569


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

.rid ⇒ Integer (readonly, mod_func)

Alias for Process.gid.

.sid_available? ⇒ `Boolean` (readonly, mod_func)

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

[ GitHub ]

# File 'process.c', line 7747


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

Class Method Details

.change_privilege(group) ⇒ Integer (mod_func)

Change the current process’s real and effective group ID to that specified by group. 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]

[ GitHub ]

# File 'process.c', line 7089


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

    check_gid_switch();

    gid = OBJ2GID(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)? (rb_gid_t)-1: gid,
		      (getegid() == gid)? (rb_gid_t)-1: gid,
		      (SAVED_GROUP_ID == gid)? (rb_gid_t)-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)? (rb_uid_t)-1: gid,
			 (getegid() == gid)? (rb_uid_t)-1: gid) < 0)
		rb_sys_fail(0);
	}
	else if (getgid() != gid) {
	    if (setregid(gid, (getegid() == gid)? (rb_uid_t)-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 {
	    rb_syserr_fail(EPERM, 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 {
	    rb_syserr_fail(EPERM, 0);
	}
#elif defined HAVE_SETEGID
	if (getgid() == gid && SAVED_GROUP_ID == gid) {
	    if (setegid(gid) < 0) rb_sys_fail(0);
	}
	else {
	    rb_syserr_fail(EPERM, 0);
	}
#elif defined HAVE_SETGID
	if (getgid() == gid && SAVED_GROUP_ID == gid) {
	    if (setgid(gid) < 0) rb_sys_fail(0);
	}
	else {
	    rb_syserr_fail(EPERM, 0);
	}
#else
	(void)gid;
	rb_notimplement();
#endif
    }
    return id;
}

.eid ⇒ Integer (mod_func)

Alias for Process.egid.

.from_name(name) ⇒ `GID` (mod_func)

Get the group ID by the name. If the group is not found, ::ArgumentError will be raised.

Process::GID.from_name("wheel") #=> 0
Process::GID.from_name("nosuchgroup") #=> can't find group for nosuchgroup (ArgumentError)

[ GitHub ]

# File 'process.c', line 6143


static VALUE
p_gid_from_name(VALUE self, VALUE id)
{
    return GIDT2NUM(OBJ2GID(id));
}

.grant_privilege(group) ⇒ Integer (mod_func) .eid=(group) ⇒ Integer

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

[ GitHub ]

# File 'process.c', line 7490


static VALUE
p_gid_grant_privilege(VALUE obj, VALUE id)
{
    rb_setegid_core(OBJ2GID(id));
    return id;
}

.re_exchange ⇒ Integer (mod_func)

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]

[ GitHub ]

# File 'process.c', line 7594


static VALUE
p_gid_exchange(VALUE obj)
{
    rb_gid_t gid;
#if defined(HAVE_SETRESGID) || (defined(HAVE_SETREGID) && !defined(OBSOLETE_SETREGID))
    rb_gid_t egid;
#endif

    check_gid_switch();

    gid = getgid();
#if defined(HAVE_SETRESGID) || (defined(HAVE_SETREGID) && !defined(OBSOLETE_SETREGID))
    egid = getegid();
#endif

#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);
}

.switch ⇒ Integer (mod_func) .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.

[ GitHub ]

# File 'process.c', line 7781


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 {
	rb_syserr_fail(EPERM, 0);
    }

    UNREACHABLE_RETURN(Qnil);
}

Module: Process::GID

Overview

Class Attribute Summary

Class Method Summary

Class Attribute Details

.re_exchangeable? ⇒ Boolean (readonly, mod_func)

.rid ⇒ Integer (readonly, mod_func)

.sid_available? ⇒ Boolean (readonly, mod_func)

Class Method Details

.change_privilege(group) ⇒ Integer (mod_func)

.eid ⇒ Integer (mod_func)

.from_name(name) ⇒ GID (mod_func)

.grant_privilege(group) ⇒ Integer (mod_func) .eid=(group) ⇒ Integer

.re_exchange ⇒ Integer (mod_func)

.switch ⇒ Integer (mod_func) .switch ⇒ Object

.re_exchangeable? ⇒ `Boolean` (readonly, mod_func)

.sid_available? ⇒ `Boolean` (readonly, mod_func)

.from_name(name) ⇒ `GID` (mod_func)