+ log(LOG_ERR, "pid %ld (%s), uid (%u): corename is too long\n",
+ (long)pid, name, (uint32_t)uid);
+ return (1);
+}
+
+#if CONFIG_LCTX
+
+static void
+lctxinit(void)
+{
+ LIST_INIT(&alllctx);
+ alllctx_cnt = 0;
+
+ /* allocate lctx lock group attribute and group */
+ lctx_lck_grp_attr = lck_grp_attr_alloc_init();
+ lck_grp_attr_setstat(lctx_lck_grp_attr);
+
+ lctx_lck_grp = lck_grp_alloc_init("lctx", lctx_lck_grp_attr);
+ /* Allocate lctx lock attribute */
+ lctx_lck_attr = lck_attr_alloc_init();
+
+ lck_mtx_init(&alllctx_lock, lctx_lck_grp, lctx_lck_attr);
+}
+
+/*
+ * Locate login context by number.
+ */
+struct lctx *
+lcfind(pid_t lcid)
+{
+ struct lctx *l;
+
+ ALLLCTX_LOCK;
+ LIST_FOREACH(l, &alllctx, lc_list) {
+ if (l->lc_id == lcid) {
+ LCTX_LOCK(l);
+ break;
+ }
+ }
+ ALLLCTX_UNLOCK;
+ return (l);
+}
+
+#define LCID_INC \
+ do { \
+ lastlcid++; \
+ if (lastlcid > maxlcid) \
+ lastlcid = 1; \
+ } while (0) \
+
+struct lctx *
+lccreate(void)
+{
+ struct lctx *l;
+ pid_t newlcid;
+
+ /* Not very efficient but this isn't a common operation. */
+ while ((l = lcfind(lastlcid)) != NULL) {
+ LCTX_UNLOCK(l);
+ LCID_INC;
+ }
+ newlcid = lastlcid;
+ LCID_INC;
+
+ MALLOC(l, struct lctx *, sizeof(struct lctx), M_LCTX, M_WAITOK|M_ZERO);
+ l->lc_id = newlcid;
+ LIST_INIT(&l->lc_members);
+ lck_mtx_init(&l->lc_mtx, lctx_lck_grp, lctx_lck_attr);
+#if CONFIG_MACF
+ l->lc_label = mac_lctx_label_alloc();
+#endif
+ ALLLCTX_LOCK;
+ LIST_INSERT_HEAD(&alllctx, l, lc_list);
+ alllctx_cnt++;
+ ALLLCTX_UNLOCK;
+
+ return (l);
+}
+
+/*
+ * Call with proc protected (either by being invisible
+ * or by having the all-login-context lock held) and
+ * the lctx locked.
+ *
+ * Will unlock lctx on return.
+ */
+void
+enterlctx (proc_t p, struct lctx *l, __unused int create)
+{
+ if (l == NULL)
+ return;
+
+ p->p_lctx = l;
+ LIST_INSERT_HEAD(&l->lc_members, p, p_lclist);
+ l->lc_mc++;
+
+#if CONFIG_MACF
+ if (create)
+ mac_lctx_notify_create(p, l);
+ else
+ mac_lctx_notify_join(p, l);
+#endif
+ LCTX_UNLOCK(l);
+
+ return;
+}
+
+/*
+ * Remove process from login context (if any). Called with p protected by
+ * the alllctx lock.
+ */
+void
+leavelctx (proc_t p)
+{
+ struct lctx *l;
+
+ if (p->p_lctx == NULL) {
+ return;
+ }
+
+ LCTX_LOCK(p->p_lctx);
+ l = p->p_lctx;
+ p->p_lctx = NULL;
+ LIST_REMOVE(p, p_lclist);
+ l->lc_mc--;
+#if CONFIG_MACF
+ mac_lctx_notify_leave(p, l);
+#endif
+ if (LIST_EMPTY(&l->lc_members)) {
+ LIST_REMOVE(l, lc_list);
+ alllctx_cnt--;
+ LCTX_UNLOCK(l);
+ lck_mtx_destroy(&l->lc_mtx, lctx_lck_grp);
+#if CONFIG_MACF
+ mac_lctx_label_free(l->lc_label);
+ l->lc_label = NULL;
+#endif
+ FREE(l, M_LCTX);
+ } else {
+ LCTX_UNLOCK(l);
+ }
+ return;
+}
+
+static int
+sysctl_kern_lctx SYSCTL_HANDLER_ARGS
+{
+ int *name = (int*) arg1;
+ u_int namelen = arg2;
+ struct kinfo_lctx kil;
+ struct lctx *l;
+ int error;
+
+ error = 0;
+
+ switch (oidp->oid_number) {
+ case KERN_LCTX_ALL:
+ ALLLCTX_LOCK;
+ /* Request for size. */
+ if (!req->oldptr) {
+ error = SYSCTL_OUT(req, 0,
+ sizeof(struct kinfo_lctx) * (alllctx_cnt + 1));
+ goto out;
+ }
+ break;
+
+ case KERN_LCTX_LCID:
+ /* No space */
+ if (req->oldlen < sizeof(struct kinfo_lctx))
+ return (ENOMEM);
+ /* No argument */
+ if (namelen != 1)
+ return (EINVAL);
+ /* No login context */
+ l = lcfind((pid_t)name[0]);
+ if (l == NULL)
+ return (ENOENT);
+ kil.id = l->lc_id;
+ kil.mc = l->lc_mc;
+ LCTX_UNLOCK(l);
+ return (SYSCTL_OUT(req, (caddr_t)&kil, sizeof(kil)));
+
+ default:
+ return (EINVAL);
+ }
+
+ /* Provided buffer is too small. */
+ if (req->oldlen < (sizeof(struct kinfo_lctx) * alllctx_cnt)) {
+ error = ENOMEM;
+ goto out;
+ }
+
+ LIST_FOREACH(l, &alllctx, lc_list) {
+ LCTX_LOCK(l);
+ kil.id = l->lc_id;
+ kil.mc = l->lc_mc;
+ LCTX_UNLOCK(l);
+ error = SYSCTL_OUT(req, (caddr_t)&kil, sizeof(kil));
+ if (error)
+ break;
+ }
+out:
+ ALLLCTX_UNLOCK;
+
+ return (error);
+}
+
+SYSCTL_NODE(_kern, KERN_LCTX, lctx, CTLFLAG_RW|CTLFLAG_LOCKED, 0, "Login Context");
+
+SYSCTL_PROC(_kern_lctx, KERN_LCTX_ALL, all, CTLFLAG_RD|CTLTYPE_STRUCT | CTLFLAG_LOCKED,
+ 0, 0, sysctl_kern_lctx, "S,lctx",
+ "Return entire login context table");
+SYSCTL_NODE(_kern_lctx, KERN_LCTX_LCID, lcid, CTLFLAG_RD | CTLFLAG_LOCKED,
+ sysctl_kern_lctx, "Login Context Table");
+SYSCTL_INT(_kern_lctx, OID_AUTO, last, CTLFLAG_RD | CTLFLAG_LOCKED, &lastlcid, 0, "");
+SYSCTL_INT(_kern_lctx, OID_AUTO, count, CTLFLAG_RD | CTLFLAG_LOCKED, &alllctx_cnt, 0, "");
+SYSCTL_INT(_kern_lctx, OID_AUTO, max, CTLFLAG_RW | CTLFLAG_LOCKED, &maxlcid, 0, "");
+
+#endif /* LCTX */
+
+/* Code Signing related routines */
+
+int
+csops(__unused proc_t p, struct csops_args *uap, __unused int32_t *retval)
+{
+ return(csops_internal(uap->pid, uap->ops, uap->useraddr,
+ uap->usersize, USER_ADDR_NULL));
+}
+
+int
+csops_audittoken(__unused proc_t p, struct csops_audittoken_args *uap, __unused int32_t *retval)
+{
+ if (uap->uaudittoken == USER_ADDR_NULL)
+ return(EINVAL);
+ switch (uap->ops) {
+ case CS_OPS_PIDPATH:
+ case CS_OPS_ENTITLEMENTS_BLOB:
+ break;
+ default:
+ return(EINVAL);
+ };
+
+ return(csops_internal(uap->pid, uap->ops, uap->useraddr,
+ uap->usersize, uap->uaudittoken));
+}
+
+static int
+csops_internal(pid_t pid, int ops, user_addr_t uaddr, user_size_t usersize, user_addr_t uaudittoken)
+{
+ size_t usize = (size_t)CAST_DOWN(size_t, usersize);
+ proc_t pt;
+ uint32_t retflags;
+ int vid, forself;
+ int error;
+ vnode_t tvp;
+ off_t toff;
+ char * buf;
+ unsigned char cdhash[SHA1_RESULTLEN];
+ audit_token_t token;
+ unsigned int upid=0, uidversion = 0;
+
+ forself = error = 0;
+
+ if (pid == 0)
+ pid = proc_selfpid();
+ if (pid == proc_selfpid())
+ forself = 1;
+
+
+ /* Pre flight checks for CS_OPS_PIDPATH */
+ if (ops == CS_OPS_PIDPATH) {
+ /* usize is unsigned.. */
+ if (usize > 4 * PATH_MAX)
+ return(EOVERFLOW);
+ if (kauth_cred_issuser(kauth_cred_get()) != TRUE)
+ return(EPERM);
+ } else {
+ switch (ops) {
+ case CS_OPS_STATUS:
+ case CS_OPS_CDHASH:
+ case CS_OPS_PIDOFFSET:
+ case CS_OPS_ENTITLEMENTS_BLOB:
+ break; /* unrestricted */
+ default:
+ if (forself == 0 && kauth_cred_issuser(kauth_cred_get()) != TRUE)
+ return(EPERM);
+ break;
+ }
+ }
+
+ pt = proc_find(pid);
+ if (pt == PROC_NULL)
+ return(ESRCH);
+
+ upid = pt->p_pid;
+ uidversion = pt->p_idversion;
+ if (uaudittoken != USER_ADDR_NULL) {
+
+ error = copyin(uaudittoken, &token, sizeof(audit_token_t));
+ if (error != 0)
+ goto out;
+ /* verify the audit token pid/idversion matches with proc */
+ if ((token.val[5] != upid) || (token.val[7] != uidversion)) {
+ error = ESRCH;
+ goto out;
+ }
+ }
+
+ switch (ops) {
+
+ case CS_OPS_STATUS:
+ retflags = pt->p_csflags;
+ if (uaddr != USER_ADDR_NULL)
+ error = copyout(&retflags, uaddr, sizeof(uint32_t));
+ break;
+
+ case CS_OPS_MARKINVALID:
+ proc_lock(pt);
+ if ((pt->p_csflags & CS_VALID) == CS_VALID) { /* is currently valid */
+ pt->p_csflags &= ~CS_VALID; /* set invalid */
+ if ((pt->p_csflags & CS_KILL) == CS_KILL) {
+ pt->p_csflags |= CS_KILLED;
+ proc_unlock(pt);
+ if (cs_debug) {
+ printf("CODE SIGNING: marked invalid by pid %d: "
+ "p=%d[%s] honoring CS_KILL, final status 0x%x\n",
+ proc_selfpid(), pt->p_pid, pt->p_comm, pt->p_csflags);
+ }
+ psignal(pt, SIGKILL);
+ } else
+ proc_unlock(pt);
+ } else
+ proc_unlock(pt);
+
+ break;
+
+ case CS_OPS_MARKHARD:
+ proc_lock(pt);
+ pt->p_csflags |= CS_HARD;
+ if ((pt->p_csflags & CS_VALID) == 0) {
+ /* @@@ allow? reject? kill? @@@ */
+ proc_unlock(pt);
+ error = EINVAL;
+ goto out;
+ } else
+ proc_unlock(pt);
+ break;
+
+ case CS_OPS_MARKKILL:
+ proc_lock(pt);
+ pt->p_csflags |= CS_KILL;
+ if ((pt->p_csflags & CS_VALID) == 0) {
+ proc_unlock(pt);
+ psignal(pt, SIGKILL);
+ } else
+ proc_unlock(pt);
+ break;
+
+ case CS_OPS_PIDPATH:
+ tvp = pt->p_textvp;
+ vid = vnode_vid(tvp);
+
+ if (tvp == NULLVP) {
+ proc_rele(pt);
+ return(EINVAL);
+ }
+
+ buf = (char *)kalloc(usize);
+ if (buf == NULL) {
+ proc_rele(pt);
+ return(ENOMEM);
+ }
+ bzero(buf, usize);
+
+ error = vnode_getwithvid(tvp, vid);
+ if (error == 0) {
+ int len;
+ len = usize;
+ error = vn_getpath(tvp, buf, &len);
+ vnode_put(tvp);
+ if (error == 0) {
+ error = copyout(buf, uaddr, usize);
+ }
+ kfree(buf, usize);
+ }
+
+ proc_rele(pt);
+
+ return(error);
+
+ case CS_OPS_PIDOFFSET:
+ toff = pt->p_textoff;
+ proc_rele(pt);
+ error = copyout(&toff, uaddr, sizeof(toff));
+ return(error);
+
+ case CS_OPS_CDHASH:
+
+ /* pt already holds a reference on its p_textvp */
+ tvp = pt->p_textvp;
+ toff = pt->p_textoff;
+
+ if (tvp == NULLVP || usize != SHA1_RESULTLEN) {
+ proc_rele(pt);
+ return EINVAL;
+ }
+
+ error = vn_getcdhash(tvp, toff, cdhash);
+ proc_rele(pt);
+
+ if (error == 0) {
+ error = copyout(cdhash, uaddr, sizeof (cdhash));
+ }
+
+ return error;
+
+ case CS_OPS_ENTITLEMENTS_BLOB: {
+ char fakeheader[8] = { 0 };
+ void *start;
+ size_t length;
+
+ if ((pt->p_csflags & CS_VALID) == 0) {
+ error = EINVAL;
+ break;
+ }
+ if (usize < sizeof(fakeheader)) {
+ error = ERANGE;
+ break;
+ }
+ if (0 != (error = cs_entitlements_blob_get(pt,
+ &start, &length)))
+ break;
+ /* if no entitlement, fill in zero header */
+ if (NULL == start) {
+ start = fakeheader;
+ length = sizeof(fakeheader);
+ } else if (usize < length) {
+ /* ... if input too short, copy out length of entitlement */
+ uint32_t length32 = htonl((uint32_t)length);
+ memcpy(&fakeheader[4], &length32, sizeof(length32));
+
+ error = copyout(fakeheader, uaddr, sizeof(fakeheader));
+ if (error == 0)
+ error = ERANGE; /* input buffer to short, ERANGE signals that */
+ break;
+ }
+ error = copyout(start, uaddr, length);
+ break;
+ }
+
+ case CS_OPS_MARKRESTRICT:
+ proc_lock(pt);
+ pt->p_csflags |= CS_RESTRICT;
+ proc_unlock(pt);
+ break;
+
+ default:
+ error = EINVAL;
+ break;
+ }
+out:
+ proc_rele(pt);
+ return(error);
+}
+
+int
+proc_iterate(flags, callout, arg, filterfn, filterarg)
+ int flags;
+ int (*callout)(proc_t, void *);
+ void * arg;
+ int (*filterfn)(proc_t, void *);
+ void * filterarg;
+{
+ proc_t p;
+ pid_t * pid_list;
+ int count, pidcount, alloc_count, i, retval;
+
+ count = nprocs+ 10;
+ if (count > hard_maxproc)
+ count = hard_maxproc;
+ alloc_count = count * sizeof(pid_t);
+ pid_list = (pid_t *)kalloc(alloc_count);
+ bzero(pid_list, alloc_count);
+
+
+ proc_list_lock();
+
+
+ pidcount = 0;
+ if (flags & PROC_ALLPROCLIST) {
+ for (p = allproc.lh_first; (p != 0); p = p->p_list.le_next) {
+ if (p->p_stat == SIDL)
+ continue;
+ if ( (filterfn == 0 ) || (filterfn(p, filterarg) != 0)) {
+ pid_list[pidcount] = p->p_pid;
+ pidcount++;
+ if (pidcount >= count)
+ break;
+ }
+ }
+ }
+ if ((pidcount < count ) && (flags & PROC_ZOMBPROCLIST)) {
+ for (p = zombproc.lh_first; p != 0; p = p->p_list.le_next) {
+ if ( (filterfn == 0 ) || (filterfn(p, filterarg) != 0)) {
+ pid_list[pidcount] = p->p_pid;
+ pidcount++;
+ if (pidcount >= count)
+ break;
+ }
+ }
+ }
+
+
+ proc_list_unlock();
+
+
+ for (i = 0; i< pidcount; i++) {
+ p = proc_find(pid_list[i]);
+ if (p) {
+ if ((flags & PROC_NOWAITTRANS) == 0)
+ proc_transwait(p, 0);
+ retval = callout(p, arg);
+
+ switch (retval) {
+ case PROC_RETURNED:
+ case PROC_RETURNED_DONE:
+ proc_rele(p);
+ if (retval == PROC_RETURNED_DONE) {
+ goto out;
+ }
+ break;
+
+ case PROC_CLAIMED_DONE:
+ goto out;
+ case PROC_CLAIMED:
+ default:
+ break;
+ }
+ } else if (flags & PROC_ZOMBPROCLIST) {
+ p = proc_find_zombref(pid_list[i]);
+ if (p != PROC_NULL) {
+ retval = callout(p, arg);
+
+ switch (retval) {
+ case PROC_RETURNED:
+ case PROC_RETURNED_DONE:
+ proc_drop_zombref(p);
+ if (retval == PROC_RETURNED_DONE) {
+ goto out;
+ }
+ break;
+
+ case PROC_CLAIMED_DONE:
+ goto out;
+ case PROC_CLAIMED:
+ default:
+ break;
+ }
+ }
+ }
+ }
+
+out:
+ kfree(pid_list, alloc_count);
+ return(0);
+
+}
+
+
+#if 0
+/* This is for iteration in case of trivial non blocking callouts */
+int
+proc_scanall(flags, callout, arg)
+ int flags;
+ int (*callout)(proc_t, void *);
+ void * arg;
+{
+ proc_t p;
+ int retval;
+
+
+ proc_list_lock();
+
+
+ if (flags & PROC_ALLPROCLIST) {
+ for (p = allproc.lh_first; (p != 0); p = p->p_list.le_next) {
+ retval = callout(p, arg);
+ if (retval == PROC_RETURNED_DONE)
+ goto out;
+ }
+ }
+ if (flags & PROC_ZOMBPROCLIST) {
+ for (p = zombproc.lh_first; p != 0; p = p->p_list.le_next) {
+ retval = callout(p, arg);
+ if (retval == PROC_RETURNED_DONE)
+ goto out;
+ }
+ }
+out:
+
+ proc_list_unlock();
+
+ return(0);
+}
+#endif
+
+
+int
+proc_rebootscan(callout, arg, filterfn, filterarg)
+ int (*callout)(proc_t, void *);
+ void * arg;
+ int (*filterfn)(proc_t, void *);
+ void * filterarg;
+{
+ proc_t p;
+ int lockheld = 0, retval;
+
+ proc_shutdown_exitcount = 0;
+
+ps_allprocscan:
+
+ proc_list_lock();
+
+ lockheld = 1;
+
+ for (p = allproc.lh_first; (p != 0); p = p->p_list.le_next) {
+ if ( (filterfn == 0 ) || (filterfn(p, filterarg) != 0)) {
+ p = proc_ref_locked(p);
+
+ proc_list_unlock();
+ lockheld = 0;
+
+ if (p) {
+ proc_transwait(p, 0);
+ retval = callout(p, arg);
+ proc_rele(p);
+
+ switch (retval) {
+ case PROC_RETURNED_DONE:
+ case PROC_CLAIMED_DONE:
+ goto out;
+ }
+ }
+ goto ps_allprocscan;
+ } /* filter pass */
+ } /* allproc walk thru */
+
+ if (lockheld == 1) {
+ proc_list_unlock();
+ lockheld = 0;
+ }
+
+out:
+ return(0);
+
+}
+
+
+int
+proc_childrenwalk(parent, callout, arg)
+ struct proc * parent;
+ int (*callout)(proc_t, void *);
+ void * arg;
+{
+ register struct proc *p;
+ pid_t * pid_list;
+ int count, pidcount, alloc_count, i, retval;
+
+ count = nprocs+ 10;
+ if (count > hard_maxproc)
+ count = hard_maxproc;
+ alloc_count = count * sizeof(pid_t);
+ pid_list = (pid_t *)kalloc(alloc_count);
+ bzero(pid_list, alloc_count);
+
+
+ proc_list_lock();
+
+
+ pidcount = 0;
+ for (p = parent->p_children.lh_first; (p != 0); p = p->p_sibling.le_next) {
+ if (p->p_stat == SIDL)
+ continue;
+ pid_list[pidcount] = p->p_pid;
+ pidcount++;
+ if (pidcount >= count)
+ break;
+ }
+ proc_list_unlock();
+
+
+ for (i = 0; i< pidcount; i++) {
+ p = proc_find(pid_list[i]);
+ if (p) {
+ proc_transwait(p, 0);
+ retval = callout(p, arg);
+
+ switch (retval) {
+ case PROC_RETURNED:
+ case PROC_RETURNED_DONE:
+ proc_rele(p);
+ if (retval == PROC_RETURNED_DONE) {
+ goto out;
+ }
+ break;
+
+ case PROC_CLAIMED_DONE:
+ goto out;
+ case PROC_CLAIMED:
+ default:
+ break;
+ }
+ }
+ }
+
+out:
+ kfree(pid_list, alloc_count);
+ return(0);
+
+}
+
+/*
+ */
+/* PGRP_BLOCKITERATE is not implemented yet */
+int
+pgrp_iterate(pgrp, flags, callout, arg, filterfn, filterarg)
+ struct pgrp *pgrp;
+ int flags;
+ int (*callout)(proc_t, void *);
+ void * arg;
+ int (*filterfn)(proc_t, void *);
+ void * filterarg;
+{
+ proc_t p;
+ pid_t * pid_list;
+ int count, pidcount, i, alloc_count;
+ int retval;
+ pid_t pgid;
+ int dropref = flags & PGRP_DROPREF;
+#if 0
+ int serialize = flags & PGRP_BLOCKITERATE;
+#else
+ int serialize = 0;
+#endif
+
+ if (pgrp == 0)
+ return(0);
+ count = pgrp->pg_membercnt + 10;
+ if (count > hard_maxproc)
+ count = hard_maxproc;
+ alloc_count = count * sizeof(pid_t);
+ pid_list = (pid_t *)kalloc(alloc_count);
+ bzero(pid_list, alloc_count);
+
+ pgrp_lock(pgrp);
+ if (serialize != 0) {
+ while ((pgrp->pg_listflags & PGRP_FLAG_ITERABEGIN) == PGRP_FLAG_ITERABEGIN) {
+ pgrp->pg_listflags |= PGRP_FLAG_ITERWAIT;
+ msleep(&pgrp->pg_listflags, &pgrp->pg_mlock, 0, "pgrp_iterate", 0);
+ }
+ pgrp->pg_listflags |= PGRP_FLAG_ITERABEGIN;
+ }
+
+ pgid = pgrp->pg_id;
+
+ pidcount = 0;
+ for (p = pgrp->pg_members.lh_first; p != 0;
+ p = p->p_pglist.le_next) {
+ if ( (filterfn == 0 ) || (filterfn(p, filterarg) != 0)) {
+ pid_list[pidcount] = p->p_pid;
+ pidcount++;
+ if (pidcount >= count)
+ break;
+ }
+ }
+
+
+ pgrp_unlock(pgrp);
+ if ((serialize == 0) && (dropref != 0))
+ pg_rele(pgrp);
+
+
+ for (i = 0; i< pidcount; i++) {
+ /* No handling or proc0 */
+ if (pid_list[i] == 0)
+ continue;
+ p = proc_find(pid_list[i]);
+ if (p) {
+ if (p->p_pgrpid != pgid) {
+ proc_rele(p);
+ continue;
+ }
+ proc_transwait(p, 0);
+ retval = callout(p, arg);
+
+ switch (retval) {
+ case PROC_RETURNED:
+ case PROC_RETURNED_DONE:
+ proc_rele(p);
+ if (retval == PROC_RETURNED_DONE) {
+ goto out;
+ }
+ break;
+
+ case PROC_CLAIMED_DONE:
+ goto out;
+ case PROC_CLAIMED:
+ default:
+ break;
+ }
+ }
+ }
+out:
+ if (serialize != 0) {
+ pgrp_lock(pgrp);
+ pgrp->pg_listflags &= ~PGRP_FLAG_ITERABEGIN;
+ if ((pgrp->pg_listflags & PGRP_FLAG_ITERWAIT) == PGRP_FLAG_ITERWAIT) {
+ pgrp->pg_listflags &= ~PGRP_FLAG_ITERWAIT;
+ wakeup(&pgrp->pg_listflags);
+ }
+ pgrp_unlock(pgrp);
+ if (dropref != 0)
+ pg_rele(pgrp);
+ }
+ kfree(pid_list, alloc_count);
+ return(0);
+}
+
+static void
+pgrp_add(struct pgrp * pgrp, struct proc * parent, struct proc * child)
+{
+ proc_list_lock();
+ child->p_pgrp = pgrp;
+ child->p_pgrpid = pgrp->pg_id;
+ child->p_listflag |= P_LIST_INPGRP;
+ /*
+ * When pgrp is being freed , a process can still
+ * request addition using setpgid from bash when
+ * login is terminated (login cycler) return ESRCH
+ * Safe to hold lock due to refcount on pgrp
+ */
+ if ((pgrp->pg_listflags & (PGRP_FLAG_TERMINATE | PGRP_FLAG_DEAD)) == PGRP_FLAG_TERMINATE) {
+ pgrp->pg_listflags &= ~PGRP_FLAG_TERMINATE;
+ }
+
+ if ((pgrp->pg_listflags & PGRP_FLAG_DEAD) == PGRP_FLAG_DEAD)
+ panic("pgrp_add : pgrp is dead adding process");
+ proc_list_unlock();
+
+ pgrp_lock(pgrp);
+ pgrp->pg_membercnt++;
+ if ( parent != PROC_NULL) {
+ LIST_INSERT_AFTER(parent, child, p_pglist);
+ }else {
+ LIST_INSERT_HEAD(&pgrp->pg_members, child, p_pglist);
+ }
+ pgrp_unlock(pgrp);
+
+ proc_list_lock();
+ if (((pgrp->pg_listflags & (PGRP_FLAG_TERMINATE | PGRP_FLAG_DEAD)) == PGRP_FLAG_TERMINATE) && (pgrp->pg_membercnt != 0)) {
+ pgrp->pg_listflags &= ~PGRP_FLAG_TERMINATE;
+ }
+ proc_list_unlock();
+}
+
+static void
+pgrp_remove(struct proc * p)
+{
+ struct pgrp * pg;
+
+ pg = proc_pgrp(p);
+
+ proc_list_lock();
+#if __PROC_INTERNAL_DEBUG
+ if ((p->p_listflag & P_LIST_INPGRP) == 0)
+ panic("removing from pglist but no named ref\n");
+#endif
+ p->p_pgrpid = PGRPID_DEAD;
+ p->p_listflag &= ~P_LIST_INPGRP;
+ p->p_pgrp = NULL;
+ proc_list_unlock();
+
+ if (pg == PGRP_NULL)
+ panic("pgrp_remove: pg is NULL");
+ pgrp_lock(pg);
+ pg->pg_membercnt--;
+
+ if (pg->pg_membercnt < 0)
+ panic("pgprp: -ve membercnt pgprp:%p p:%p\n",pg, p);
+
+ LIST_REMOVE(p, p_pglist);
+ if (pg->pg_members.lh_first == 0) {
+ pgrp_unlock(pg);
+ pgdelete_dropref(pg);
+ } else {
+ pgrp_unlock(pg);
+ pg_rele(pg);
+ }
+}
+
+
+/* cannot use proc_pgrp as it maybe stalled */
+static void
+pgrp_replace(struct proc * p, struct pgrp * newpg)
+{
+ struct pgrp * oldpg;
+
+
+
+ proc_list_lock();
+
+ while ((p->p_listflag & P_LIST_PGRPTRANS) == P_LIST_PGRPTRANS) {
+ p->p_listflag |= P_LIST_PGRPTRWAIT;
+ (void)msleep(&p->p_pgrpid, proc_list_mlock, 0, "proc_pgrp", 0);
+ }
+
+ p->p_listflag |= P_LIST_PGRPTRANS;
+
+ oldpg = p->p_pgrp;
+ if (oldpg == PGRP_NULL)
+ panic("pgrp_replace: oldpg NULL");
+ oldpg->pg_refcount++;
+#if __PROC_INTERNAL_DEBUG
+ if ((p->p_listflag & P_LIST_INPGRP) == 0)
+ panic("removing from pglist but no named ref\n");
+#endif
+ p->p_pgrpid = PGRPID_DEAD;
+ p->p_listflag &= ~P_LIST_INPGRP;
+ p->p_pgrp = NULL;
+
+ proc_list_unlock();
+
+ pgrp_lock(oldpg);
+ oldpg->pg_membercnt--;
+ if (oldpg->pg_membercnt < 0)
+ panic("pgprp: -ve membercnt pgprp:%p p:%p\n",oldpg, p);
+ LIST_REMOVE(p, p_pglist);
+ if (oldpg->pg_members.lh_first == 0) {
+ pgrp_unlock(oldpg);
+ pgdelete_dropref(oldpg);
+ } else {
+ pgrp_unlock(oldpg);
+ pg_rele(oldpg);
+ }
+
+ proc_list_lock();
+ p->p_pgrp = newpg;
+ p->p_pgrpid = newpg->pg_id;
+ p->p_listflag |= P_LIST_INPGRP;
+ /*
+ * When pgrp is being freed , a process can still
+ * request addition using setpgid from bash when
+ * login is terminated (login cycler) return ESRCH
+ * Safe to hold lock due to refcount on pgrp
+ */
+ if ((newpg->pg_listflags & (PGRP_FLAG_TERMINATE | PGRP_FLAG_DEAD)) == PGRP_FLAG_TERMINATE) {
+ newpg->pg_listflags &= ~PGRP_FLAG_TERMINATE;
+ }
+
+ if ((newpg->pg_listflags & PGRP_FLAG_DEAD) == PGRP_FLAG_DEAD)
+ panic("pgrp_add : pgrp is dead adding process");
+ proc_list_unlock();
+
+ pgrp_lock(newpg);
+ newpg->pg_membercnt++;
+ LIST_INSERT_HEAD(&newpg->pg_members, p, p_pglist);
+ pgrp_unlock(newpg);
+
+ proc_list_lock();
+ if (((newpg->pg_listflags & (PGRP_FLAG_TERMINATE | PGRP_FLAG_DEAD)) == PGRP_FLAG_TERMINATE) && (newpg->pg_membercnt != 0)) {
+ newpg->pg_listflags &= ~PGRP_FLAG_TERMINATE;
+ }
+
+ p->p_listflag &= ~P_LIST_PGRPTRANS;
+ if ((p->p_listflag & P_LIST_PGRPTRWAIT) == P_LIST_PGRPTRWAIT) {
+ p->p_listflag &= ~P_LIST_PGRPTRWAIT;
+ wakeup(&p->p_pgrpid);
+
+ }
+ proc_list_unlock();
+}
+
+void
+pgrp_lock(struct pgrp * pgrp)
+{
+ lck_mtx_lock(&pgrp->pg_mlock);
+}
+
+void
+pgrp_unlock(struct pgrp * pgrp)
+{
+ lck_mtx_unlock(&pgrp->pg_mlock);
+}
+
+void
+session_lock(struct session * sess)
+{
+ lck_mtx_lock(&sess->s_mlock);
+}
+
+
+void
+session_unlock(struct session * sess)
+{
+ lck_mtx_unlock(&sess->s_mlock);
+}
+
+struct pgrp *
+proc_pgrp(proc_t p)
+{
+ struct pgrp * pgrp;
+
+ if (p == PROC_NULL)
+ return(PGRP_NULL);
+ proc_list_lock();
+
+ while ((p->p_listflag & P_LIST_PGRPTRANS) == P_LIST_PGRPTRANS) {
+ p->p_listflag |= P_LIST_PGRPTRWAIT;
+ (void)msleep(&p->p_pgrpid, proc_list_mlock, 0, "proc_pgrp", 0);
+ }
+
+ pgrp = p->p_pgrp;
+
+ assert(pgrp != NULL);
+
+ if (pgrp != PGRP_NULL) {
+ pgrp->pg_refcount++;
+ if ((pgrp->pg_listflags & (PGRP_FLAG_TERMINATE | PGRP_FLAG_DEAD)) != 0)
+ panic("proc_pgrp: ref being povided for dead pgrp");
+ }
+
+ proc_list_unlock();
+
+ return(pgrp);
+}
+
+struct pgrp *
+tty_pgrp(struct tty * tp)
+{
+ struct pgrp * pg = PGRP_NULL;
+
+ proc_list_lock();
+ pg = tp->t_pgrp;
+
+ if (pg != PGRP_NULL) {
+ if ((pg->pg_listflags & PGRP_FLAG_DEAD) != 0)
+ panic("tty_pgrp: ref being povided for dead pgrp");
+ pg->pg_refcount++;
+ }
+ proc_list_unlock();
+
+ return(pg);
+}
+
+struct session *
+proc_session(proc_t p)
+{
+ struct session * sess = SESSION_NULL;
+
+ if (p == PROC_NULL)
+ return(SESSION_NULL);
+
+ proc_list_lock();
+
+ /* wait during transitions */
+ while ((p->p_listflag & P_LIST_PGRPTRANS) == P_LIST_PGRPTRANS) {
+ p->p_listflag |= P_LIST_PGRPTRWAIT;
+ (void)msleep(&p->p_pgrpid, proc_list_mlock, 0, "proc_pgrp", 0);
+ }
+
+ if ((p->p_pgrp != PGRP_NULL) && ((sess = p->p_pgrp->pg_session) != SESSION_NULL)) {
+ if ((sess->s_listflags & (S_LIST_TERM | S_LIST_DEAD)) != 0)
+ panic("proc_session:returning sesssion ref on terminating session");
+ sess->s_count++;
+ }
+ proc_list_unlock();
+ return(sess);
+}
+
+void
+session_rele(struct session *sess)
+{
+ proc_list_lock();
+ if (--sess->s_count == 0) {
+ if ((sess->s_listflags & (S_LIST_TERM | S_LIST_DEAD)) != 0)
+ panic("session_rele: terminating already terminated session");
+ sess->s_listflags |= S_LIST_TERM;
+ LIST_REMOVE(sess, s_hash);
+ sess->s_listflags |= S_LIST_DEAD;
+ if (sess->s_count != 0)
+ panic("session_rele: freeing session in use");
+ proc_list_unlock();
+#if CONFIG_FINE_LOCK_GROUPS
+ lck_mtx_destroy(&sess->s_mlock, proc_mlock_grp);
+#else
+ lck_mtx_destroy(&sess->s_mlock, proc_lck_grp);
+#endif
+ FREE_ZONE(sess, sizeof(struct session), M_SESSION);
+ } else
+ proc_list_unlock();
+}
+
+int
+proc_transstart(proc_t p, int locked)
+{
+ if (locked == 0)
+ proc_lock(p);
+ while ((p->p_lflag & P_LINTRANSIT) == P_LINTRANSIT) {
+ if ((p->p_lflag & P_LTRANSCOMMIT) == P_LTRANSCOMMIT) {
+ if (locked == 0)
+ proc_unlock(p);
+ return EDEADLK;
+ }
+ p->p_lflag |= P_LTRANSWAIT;
+ msleep(&p->p_lflag, &p->p_mlock, 0, "proc_signstart", NULL);
+ }
+ p->p_lflag |= P_LINTRANSIT;
+ p->p_transholder = current_thread();
+ if (locked == 0)
+ proc_unlock(p);
+ return 0;
+}
+
+void
+proc_transcommit(proc_t p, int locked)
+{
+ if (locked == 0)
+ proc_lock(p);
+
+ assert ((p->p_lflag & P_LINTRANSIT) == P_LINTRANSIT);
+ assert (p->p_transholder == current_thread());
+ p->p_lflag |= P_LTRANSCOMMIT;
+
+ if ((p->p_lflag & P_LTRANSWAIT) == P_LTRANSWAIT) {
+ p->p_lflag &= ~P_LTRANSWAIT;
+ wakeup(&p->p_lflag);
+ }
+ if (locked == 0)
+ proc_unlock(p);
+}
+
+void
+proc_transend(proc_t p, int locked)
+{
+ if (locked == 0)
+ proc_lock(p);
+
+ p->p_lflag &= ~( P_LINTRANSIT | P_LTRANSCOMMIT);
+ p->p_transholder = NULL;
+
+ if ((p->p_lflag & P_LTRANSWAIT) == P_LTRANSWAIT) {
+ p->p_lflag &= ~P_LTRANSWAIT;
+ wakeup(&p->p_lflag);
+ }
+ if (locked == 0)
+ proc_unlock(p);
+}
+
+int
+proc_transwait(proc_t p, int locked)
+{
+ if (locked == 0)
+ proc_lock(p);
+ while ((p->p_lflag & P_LINTRANSIT) == P_LINTRANSIT) {
+ if ((p->p_lflag & P_LTRANSCOMMIT) == P_LTRANSCOMMIT && current_proc() == p) {
+ if (locked == 0)
+ proc_unlock(p);
+ return EDEADLK;
+ }
+ p->p_lflag |= P_LTRANSWAIT;
+ msleep(&p->p_lflag, &p->p_mlock, 0, "proc_signstart", NULL);
+ }
+ if (locked == 0)
+ proc_unlock(p);
+ return 0;
+}
+
+void
+proc_klist_lock(void)
+{
+ lck_mtx_lock(proc_klist_mlock);
+}
+
+void
+proc_klist_unlock(void)
+{
+ lck_mtx_unlock(proc_klist_mlock);
+}
+
+void
+proc_knote(struct proc * p, long hint)
+{
+ proc_klist_lock();
+ KNOTE(&p->p_klist, hint);
+ proc_klist_unlock();
+}
+
+void
+proc_knote_drain(struct proc *p)
+{
+ struct knote *kn = NULL;
+
+ /*
+ * Clear the proc's klist to avoid references after the proc is reaped.
+ */
+ proc_klist_lock();
+ while ((kn = SLIST_FIRST(&p->p_klist))) {
+ kn->kn_ptr.p_proc = PROC_NULL;
+ KNOTE_DETACH(&p->p_klist, kn);
+ }
+ proc_klist_unlock();
+}
+
+unsigned long cs_procs_killed = 0;
+unsigned long cs_procs_invalidated = 0;
+int cs_force_kill = 0;
+int cs_force_hard = 0;
+int cs_debug = 0;
+SYSCTL_INT(_vm, OID_AUTO, cs_force_kill, CTLFLAG_RW | CTLFLAG_LOCKED, &cs_force_kill, 0, "");
+SYSCTL_INT(_vm, OID_AUTO, cs_force_hard, CTLFLAG_RW | CTLFLAG_LOCKED, &cs_force_hard, 0, "");
+SYSCTL_INT(_vm, OID_AUTO, cs_debug, CTLFLAG_RW | CTLFLAG_LOCKED, &cs_debug, 0, "");
+
+int
+cs_allow_invalid(struct proc *p)
+{
+#if MACH_ASSERT
+ lck_mtx_assert(&p->p_mlock, LCK_MTX_ASSERT_NOTOWNED);
+#endif
+#if CONFIG_MACF && CONFIG_ENFORCE_SIGNED_CODE
+ /* There needs to be a MAC policy to implement this hook, or else the
+ * kill bits will be cleared here every time. If we have
+ * CONFIG_ENFORCE_SIGNED_CODE, we can assume there is a policy
+ * implementing the hook.
+ */
+ if( 0 != mac_proc_check_run_cs_invalid(p)) {
+ if(cs_debug) printf("CODE SIGNING: cs_allow_invalid() "
+ "not allowed: pid %d\n",
+ p->p_pid);
+ return 0;
+ }
+ if(cs_debug) printf("CODE SIGNING: cs_allow_invalid() "
+ "allowed: pid %d\n",
+ p->p_pid);
+ proc_lock(p);
+ p->p_csflags &= ~(CS_KILL | CS_HARD | CS_VALID);
+ proc_unlock(p);
+ vm_map_switch_protect(get_task_map(p->task), FALSE);
+#endif
+ return (p->p_csflags & (CS_KILL | CS_HARD)) == 0;
+}
+
+int
+cs_invalid_page(
+ addr64_t vaddr)
+{
+ struct proc *p;
+ int retval;
+
+ p = current_proc();
+
+ /*
+ * XXX revisit locking when proc is no longer protected
+ * by the kernel funnel...
+ */
+
+ /* XXX for testing */
+ proc_lock(p);
+ if (cs_force_kill)
+ p->p_csflags |= CS_KILL;
+ if (cs_force_hard)
+ p->p_csflags |= CS_HARD;
+
+ /* CS_KILL triggers us to send a kill signal. Nothing else. */
+ if (p->p_csflags & CS_KILL) {
+ p->p_csflags |= CS_KILLED;
+ proc_unlock(p);
+ if (cs_debug) {
+ printf("CODE SIGNING: cs_invalid_page(0x%llx): "
+ "p=%d[%s] honoring CS_KILL, final status 0x%x\n",
+ vaddr, p->p_pid, p->p_comm, p->p_csflags);
+ }
+ cs_procs_killed++;
+ psignal(p, SIGKILL);
+ proc_lock(p);
+ }
+
+ /* CS_HARD means fail the mapping operation so the process stays valid. */
+ if (p->p_csflags & CS_HARD) {
+ proc_unlock(p);
+ if (cs_debug) {
+ printf("CODE SIGNING: cs_invalid_page(0x%llx): "
+ "p=%d[%s] honoring CS_HARD\n",
+ vaddr, p->p_pid, p->p_comm);
+ }
+ retval = 1;
+ } else {
+ if (p->p_csflags & CS_VALID) {
+ p->p_csflags &= ~CS_VALID;
+
+ proc_unlock(p);
+ cs_procs_invalidated++;
+ printf("CODE SIGNING: cs_invalid_page(0x%llx): "
+ "p=%d[%s] clearing CS_VALID\n",
+ vaddr, p->p_pid, p->p_comm);
+ } else {
+ proc_unlock(p);
+ }
+
+ retval = 0;
+ }
+
+ return retval;
+}
+
+void
+proc_setregister(proc_t p)
+{
+ proc_lock(p);
+ p->p_lflag |= P_LREGISTER;
+ proc_unlock(p);
+}
+
+void
+proc_resetregister(proc_t p)
+{
+ proc_lock(p);
+ p->p_lflag &= ~P_LREGISTER;
+ proc_unlock(p);
+}
+
+pid_t
+proc_pgrpid(proc_t p)
+{
+ return p->p_pgrpid;
+}
+
+pid_t
+proc_selfpgrpid()
+{
+ return current_proc()->p_pgrpid;
+}
+
+
+/* return control and action states */
+int
+proc_getpcontrol(int pid, int * pcontrolp)
+{
+ proc_t p;
+
+ p = proc_find(pid);
+ if (p == PROC_NULL)
+ return(ESRCH);
+ if (pcontrolp != NULL)
+ *pcontrolp = p->p_pcaction;
+
+ proc_rele(p);
+ return(0);
+}
+
+int
+proc_dopcontrol(proc_t p, void *num_found)
+{
+ int pcontrol;
+
+ proc_lock(p);
+
+ pcontrol = PROC_CONTROL_STATE(p);
+
+ if (PROC_ACTION_STATE(p) ==0) {
+ switch(pcontrol) {
+ case P_PCTHROTTLE:
+ PROC_SETACTION_STATE(p);
+ proc_unlock(p);
+ printf("low swap: throttling pid %d (%s)\n", p->p_pid, p->p_comm);
+ (*(int *)num_found)++;
+ break;
+
+ case P_PCSUSP:
+ PROC_SETACTION_STATE(p);
+ proc_unlock(p);
+ printf("low swap: suspending pid %d (%s)\n", p->p_pid, p->p_comm);
+ task_suspend(p->task);
+ (*(int *)num_found)++;
+ break;
+
+ case P_PCKILL:
+ PROC_SETACTION_STATE(p);
+ proc_unlock(p);
+ printf("low swap: killing pid %d (%s)\n", p->p_pid, p->p_comm);
+ psignal(p, SIGKILL);
+ (*(int *)num_found)++;
+ break;
+
+ default:
+ proc_unlock(p);
+ }
+
+ } else
+ proc_unlock(p);
+
+ return(PROC_RETURNED);
+}
+
+
+/*
+ * Resume a throttled or suspended process. This is an internal interface that's only
+ * used by the user level code that presents the GUI when we run out of swap space and
+ * hence is restricted to processes with superuser privileges.
+ */
+
+int
+proc_resetpcontrol(int pid)
+{
+ proc_t p;
+ int pcontrol;
+ int error;
+ proc_t self = current_proc();
+
+ /* if the process has been validated to handle resource control or root is valid one */
+ if (((self->p_lflag & P_LVMRSRCOWNER) == 0) && (error = suser(kauth_cred_get(), 0)))
+ return error;
+
+ p = proc_find(pid);
+ if (p == PROC_NULL)
+ return(ESRCH);
+
+ proc_lock(p);
+
+ pcontrol = PROC_CONTROL_STATE(p);
+
+ if(PROC_ACTION_STATE(p) !=0) {
+ switch(pcontrol) {
+ case P_PCTHROTTLE:
+ PROC_RESETACTION_STATE(p);
+ proc_unlock(p);
+ printf("low swap: unthrottling pid %d (%s)\n", p->p_pid, p->p_comm);
+ break;
+
+ case P_PCSUSP:
+ PROC_RESETACTION_STATE(p);
+ proc_unlock(p);
+ printf("low swap: resuming pid %d (%s)\n", p->p_pid, p->p_comm);
+ task_resume(p->task);
+ break;
+
+ case P_PCKILL:
+ /* Huh? */
+ PROC_SETACTION_STATE(p);
+ proc_unlock(p);
+ printf("low swap: attempt to unkill pid %d (%s) ignored\n", p->p_pid, p->p_comm);
+ break;
+
+ default:
+ proc_unlock(p);
+ }
+
+ } else
+ proc_unlock(p);
+
+ proc_rele(p);
+ return(0);
+}
+
+
+/*
+ * Return true if the specified process has an action state specified for it and it isn't
+ * already in an action state and it's using more physical memory than the specified threshold.
+ * Note: the memory_threshold argument is specified in bytes and is of type uint64_t.
+ */
+
+static int
+proc_pcontrol_filter(proc_t p, void *memory_thresholdp)
+{
+
+ return PROC_CONTROL_STATE(p) && /* if there's an action state specified... */
+ (PROC_ACTION_STATE(p) == 0) && /* and we're not in the action state yet... */
+ (get_task_resident_size(p->task) > *((uint64_t *)memory_thresholdp)); /* and this proc is over the mem threshold, */
+ /* then return true to take action on this proc */
+}
+
+
+
+/*
+ * Deal with the out of swap space condition. This routine gets called when
+ * we want to swap something out but there's no more space left. Since this
+ * creates a memory deadlock situtation, we need to take action to free up
+ * some memory resources in order to prevent the system from hanging completely.
+ * The action we take is based on what the system processes running at user level
+ * have specified. Processes are marked in one of four categories: ones that
+ * can be killed immediately, ones that should be suspended, ones that should
+ * be throttled, and all the rest which are basically none of the above. Which
+ * processes are marked as being in which category is a user level policy decision;
+ * we just take action based on those decisions here.
+ */
+
+#define STARTING_PERCENTAGE 50 /* memory threshold expressed as a percentage */
+ /* of physical memory */
+
+struct timeval last_no_space_action = {0, 0};
+
+void
+no_paging_space_action(void)
+{
+
+ uint64_t memory_threshold;
+ int num_found;
+ struct timeval now;
+
+ /*
+ * Throttle how often we come through here. Once every 20 seconds should be plenty.
+ */
+
+ microtime(&now);
+
+ if (now.tv_sec <= last_no_space_action.tv_sec + 20)
+ return;
+
+ last_no_space_action = now;
+
+ /*
+ * Examine all processes and find those that have been marked to have some action
+ * taken when swap space runs out. Of those processes, select one or more and
+ * apply the specified action to them. The idea is to only take action against
+ * a few processes rather than hitting too many at once. If the low swap condition
+ * persists, this routine will get called again and we'll take action against more
+ * processes.
+ *
+ * Of the processes that have been marked, we choose which ones to take action
+ * against according to how much physical memory they're presently using. We
+ * start with the STARTING_THRESHOLD and any processes using more physical memory
+ * than the percentage threshold will have action taken against it. If there
+ * are no processes over the threshold, then the threshold is cut in half and we
+ * look again for processes using more than this threshold. We continue in
+ * this fashion until we find at least one process to take action against. This
+ * iterative approach is less than ideally efficient, however we only get here
+ * when the system is almost in a memory deadlock and is pretty much just
+ * thrashing if it's doing anything at all. Therefore, the cpu overhead of
+ * potentially multiple passes here probably isn't revelant.
+ */
+
+ memory_threshold = (sane_size * STARTING_PERCENTAGE) / 100; /* resident threshold in bytes */
+
+ for (num_found = 0; num_found == 0; memory_threshold = memory_threshold / 2) {
+ proc_iterate(PROC_ALLPROCLIST, proc_dopcontrol, (void *)&num_found, proc_pcontrol_filter, (void *)&memory_threshold);
+
+ /*
+ * If we just looked with memory_threshold == 0, then there's no need to iterate any further since
+ * we won't find any eligible processes at this point.
+ */
+
+ if (memory_threshold == 0) {
+ if (num_found == 0) /* log that we couldn't do anything in this case */
+ printf("low swap: unable to find any eligible processes to take action on\n");
+
+ break;
+ }
+ }