Module
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 Methods
process.c
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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;
}
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]
process.c
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static VALUE
proc_getegid(VALUE obj)
{
rb_gid_t egid = getegid();
return GIDT2NUM(egid);
}
Returns the effective group ID for the current process:
Process.egid # => 500
Not available on all platforms.
process.c
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static VALUE
p_gid_from_name(VALUE self, VALUE id)
{
return GIDT2NUM(OBJ2GID(id));
}
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)
process.c
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static VALUE
p_gid_grant_privilege(VALUE obj, VALUE id)
{
rb_setegid_core(OBJ2GID(id));
return id;
}
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]
process.c
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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);
}
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]
process.c
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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
}
Returns true if the real and effective group IDs of a process may be exchanged on the current platform.
process.c
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static VALUE
proc_getgid(VALUE obj)
{
rb_gid_t gid = getgid();
return GIDT2NUM(gid);
}
Returns the (real) group ID for the current process:
Process.gid # => 1000
process.c
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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
}
Returns true if the current platform has saved group ID functionality.
process.c
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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);
}
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.