1/* Iterate over a process's threads.
2 Copyright (C) 1999-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include "thread_dbP.h"
21
22
23static td_err_e
24iterate_thread_list (td_thragent_t *ta, td_thr_iter_f *callback,
25 void *cbdata_p, td_thr_state_e state, int ti_pri,
26 psaddr_t head, bool fake_empty)
27{
28 td_err_e err;
29 psaddr_t next, ofs;
30 void *copy;
31
32 /* Test the state.
33 XXX This is incomplete. Normally this test should be in the loop. */
34 if (state != TD_THR_ANY_STATE)
35 return TD_OK;
36
37 err = DB_GET_FIELD (next, ta, head, list_t, next, 0);
38 if (err != TD_OK)
39 return err;
40
41 if (next == 0 && fake_empty)
42 {
43 /* __pthread_initialize_minimal has not run. There is just the main
44 thread to return. We cannot rely on its thread register. They
45 sometimes contain garbage that would confuse us, left by the
46 kernel at exec. So if it looks like initialization is incomplete,
47 we only fake a special descriptor for the initial thread. */
48 td_thrhandle_t th = { ta, 0 };
49 return callback (&th, cbdata_p) != 0 ? TD_DBERR : TD_OK;
50 }
51
52 /* Cache the offset from struct pthread to its list_t member. */
53 err = DB_GET_FIELD_ADDRESS (ofs, ta, 0, pthread, list, 0);
54 if (err != TD_OK)
55 return err;
56
57 if (ta->ta_sizeof_pthread == 0)
58 {
59 err = _td_check_sizeof (ta, &ta->ta_sizeof_pthread, SYM_SIZEOF_pthread);
60 if (err != TD_OK)
61 return err;
62 }
63 copy = __alloca (ta->ta_sizeof_pthread);
64
65 while (next != head)
66 {
67 psaddr_t addr, schedpolicy, schedprio;
68
69 addr = next - (ofs - (psaddr_t) 0);
70 if (next == 0 || addr == 0) /* Sanity check. */
71 return TD_DBERR;
72
73 /* Copy the whole descriptor in once so we can access the several
74 fields locally. Excess copying in one go is much better than
75 multiple ps_pdread calls. */
76 if (ps_pdread (ta->ph, addr, copy, ta->ta_sizeof_pthread) != PS_OK)
77 return TD_ERR;
78
79 err = DB_GET_FIELD_LOCAL (schedpolicy, ta, copy, pthread,
80 schedpolicy, 0);
81 if (err != TD_OK)
82 break;
83 err = DB_GET_FIELD_LOCAL (schedprio, ta, copy, pthread,
84 schedparam_sched_priority, 0);
85 if (err != TD_OK)
86 break;
87
88 /* Now test whether this thread matches the specified conditions. */
89
90 /* Only if the priority level is as high or higher. */
91 int descr_pri = ((uintptr_t) schedpolicy == SCHED_OTHER
92 ? 0 : (uintptr_t) schedprio);
93 if (descr_pri >= ti_pri)
94 {
95 /* Yep, it matches. Call the callback function. */
96 td_thrhandle_t th;
97 th.th_ta_p = (td_thragent_t *) ta;
98 th.th_unique = addr;
99 if (callback (&th, cbdata_p) != 0)
100 return TD_DBERR;
101 }
102
103 /* Get the pointer to the next element. */
104 err = DB_GET_FIELD_LOCAL (next, ta, copy + (ofs - (psaddr_t) 0), list_t,
105 next, 0);
106 if (err != TD_OK)
107 break;
108 }
109
110 return err;
111}
112
113
114td_err_e
115td_ta_thr_iter (const td_thragent_t *ta_arg, td_thr_iter_f *callback,
116 void *cbdata_p, td_thr_state_e state, int ti_pri,
117 sigset_t *ti_sigmask_p, unsigned int ti_user_flags)
118{
119 td_thragent_t *const ta = (td_thragent_t *) ta_arg;
120 td_err_e err;
121 psaddr_t list = 0;
122
123 LOG ("td_ta_thr_iter");
124
125 /* Test whether the TA parameter is ok. */
126 if (! ta_ok (ta))
127 return TD_BADTA;
128
129 /* The thread library keeps two lists for the running threads. One
130 list contains the thread which are using user-provided stacks
131 (this includes the main thread) and the other includes the
132 threads for which the thread library allocated the stacks. We
133 have to iterate over both lists separately. We start with the
134 list of threads with user-defined stacks. */
135
136 err = __td_ta_stack_user (ta, &list);
137 if (err == TD_OK)
138 err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
139 list, true);
140
141 /* And the threads with stacks allocated by the implementation. */
142 if (err == TD_OK)
143 err = __td_ta_stack_used (ta, &list);
144 if (err == TD_OK)
145 err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
146 list, false);
147
148 return err;
149}
150