1 /*
2 *
3 * Copyright (c) International Business Machines Corp., 2009
4 * Copyright (c) 2014 Oracle and/or its affiliates. All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program 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
14 * the GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include <ctype.h>
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <limits.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <sys/types.h>
28 #include <unistd.h>
29 #include "test.h"
30 #include "tst_pid.h"
31 #include "old_safe_file_ops.h"
32 #include "tst_safe_macros.h"
33 #include "lapi/syscalls.h"
34
35 #define PID_MAX_PATH "/proc/sys/kernel/pid_max"
36 #define THREADS_MAX_PATH "/proc/sys/kernel/threads-max"
37 #define CGROUPS_V1_SLICE_FMT "/sys/fs/cgroup/pids/user.slice/user-%d.slice/pids.max"
38 #define CGROUPS_V2_SLICE_FMT "/sys/fs/cgroup/user.slice/user-%d.slice/pids.max"
39 /* Leave some available processes for the OS */
40 #define PIDS_RESERVE 50
41
tst_get_unused_pid_(void (* cleanup_fn)(void))42 pid_t tst_get_unused_pid_(void (*cleanup_fn) (void))
43 {
44 pid_t pid;
45
46 SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &pid);
47
48 return pid;
49 }
50
51 /*
52 * Get the effective session UID - either one invoking current test via sudo
53 * or the real UID.
54 */
get_session_uid(void)55 static unsigned int get_session_uid(void)
56 {
57 const char *sudo_uid;
58
59 sudo_uid = getenv("SUDO_UID");
60 if (sudo_uid) {
61 unsigned int real_uid;
62 int ret;
63
64 ret = sscanf(sudo_uid, "%u", &real_uid);
65 if (ret == 1)
66 return real_uid;
67 }
68
69 return getuid();
70 }
71
read_session_pids_limit(const char * path_fmt,int uid,void (* cleanup_fn)(void))72 static int read_session_pids_limit(const char *path_fmt, int uid,
73 void (*cleanup_fn) (void))
74 {
75 int max_pids, ret;
76 char max_pid_value[100];
77 char path[PATH_MAX];
78
79 ret = snprintf(path, sizeof(path), path_fmt, uid);
80 if (ret < 0 || (size_t)ret >= sizeof(path))
81 return -1;
82
83 if (access(path, R_OK) != 0) {
84 tst_resm(TINFO, "Cannot read session user limits from '%s'", path);
85 return -1;
86 }
87
88 SAFE_FILE_SCANF(cleanup_fn, path, "%s", max_pid_value);
89 if (!strcmp(max_pid_value, "max")) {
90 SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids);
91 tst_resm(TINFO, "Found limit of processes %d (from %s=max)", max_pids, path);
92 } else {
93 max_pids = SAFE_STRTOL(max_pid_value, 0, INT_MAX);
94 tst_resm(TINFO, "Found limit of processes %d (from %s)", max_pids, path);
95 }
96
97 return max_pids;
98 }
99
get_session_pids_limit(void (* cleanup_fn)(void))100 static int get_session_pids_limit(void (*cleanup_fn) (void))
101 {
102 int max_pids, uid;
103
104 uid = get_session_uid();
105 max_pids = read_session_pids_limit(CGROUPS_V2_SLICE_FMT, uid, cleanup_fn);
106 if (max_pids < 0)
107 max_pids = read_session_pids_limit(CGROUPS_V1_SLICE_FMT, uid,
108 cleanup_fn);
109
110 if (max_pids < 0)
111 return -1;
112
113 return max_pids;
114 }
115
get_used_pids(void (* cleanup_fn)(void))116 static int get_used_pids(void (*cleanup_fn) (void))
117 {
118 DIR *dir_proc;
119 struct dirent *ent;
120 char status_path[PATH_MAX];
121 int used_threads, used_pids = 0;
122
123 dir_proc = SAFE_OPENDIR("/proc");
124
125 while ((ent = SAFE_READDIR(dir_proc))) {
126 if (isdigit(ent->d_name[0])) {
127 snprintf(status_path, sizeof(status_path), "/proc/%s/status", ent->d_name);
128 if (!FILE_LINES_SCANF(cleanup_fn, status_path, "Threads: %d", &used_threads))
129 used_pids += used_threads;
130 }
131 }
132
133 SAFE_CLOSEDIR(dir_proc);
134
135 return used_pids;
136 }
137
tst_get_free_pids_(void (* cleanup_fn)(void))138 int tst_get_free_pids_(void (*cleanup_fn) (void))
139 {
140 int max_pids, max_session_pids, max_threads, used_pids = get_used_pids(cleanup_fn);
141
142 SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids);
143 SAFE_FILE_SCANF(cleanup_fn, THREADS_MAX_PATH, "%d", &max_threads);
144 max_pids = MIN(max_pids, max_threads);
145
146 max_session_pids = get_session_pids_limit(cleanup_fn);
147 if ((max_session_pids > 0) && (max_session_pids < max_pids))
148 max_pids = max_session_pids;
149
150 if (max_pids > PIDS_RESERVE)
151 max_pids -= PIDS_RESERVE;
152 else
153 max_pids = 0;
154
155 /* max_pids contains the maximum PID + 1,
156 * used_pids contains used PIDs + 1,
157 * so this additional '1' is eliminated by the substraction */
158 if (used_pids >= max_pids) {
159 tst_brkm(TBROK, cleanup_fn, "No free pids");
160 return 0;
161 }
162 return max_pids - used_pids;
163 }
164
tst_getpid(void)165 pid_t tst_getpid(void)
166 {
167 return syscall(SYS_getpid);
168 }
169