1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Helper functions for handling target threads/cpus
4 *
5 * Copyright (C) 2012, LG Electronics, Namhyung Kim <namhyung.kim@lge.com>
6 */
7
8#include "target.h"
9
10#include <pwd.h>
11#include <stdio.h>
12#include <stdlib.h>
13#include <string.h>
14#include <linux/kernel.h>
15#include <linux/string.h>
16
17enum target_errno target__validate(struct target *target)
18{
19	enum target_errno ret = TARGET_ERRNO__SUCCESS;
20
21	if (target->pid)
22		target->tid = target->pid;
23
24	/* CPU and PID are mutually exclusive */
25	if (target->tid && target->cpu_list) {
26		target->cpu_list = NULL;
27		if (ret == TARGET_ERRNO__SUCCESS)
28			ret = TARGET_ERRNO__PID_OVERRIDE_CPU;
29	}
30
31	/* UID and PID are mutually exclusive */
32	if (target->tid && target->uid_str) {
33		target->uid_str = NULL;
34		if (ret == TARGET_ERRNO__SUCCESS)
35			ret = TARGET_ERRNO__PID_OVERRIDE_UID;
36	}
37
38	/* UID and CPU are mutually exclusive */
39	if (target->uid_str && target->cpu_list) {
40		target->cpu_list = NULL;
41		if (ret == TARGET_ERRNO__SUCCESS)
42			ret = TARGET_ERRNO__UID_OVERRIDE_CPU;
43	}
44
45	/* PID and SYSTEM are mutually exclusive */
46	if (target->tid && target->system_wide) {
47		target->system_wide = false;
48		if (ret == TARGET_ERRNO__SUCCESS)
49			ret = TARGET_ERRNO__PID_OVERRIDE_SYSTEM;
50	}
51
52	/* UID and SYSTEM are mutually exclusive */
53	if (target->uid_str && target->system_wide) {
54		target->system_wide = false;
55		if (ret == TARGET_ERRNO__SUCCESS)
56			ret = TARGET_ERRNO__UID_OVERRIDE_SYSTEM;
57	}
58
59	/* BPF and CPU are mutually exclusive */
60	if (target->bpf_str && target->cpu_list) {
61		target->cpu_list = NULL;
62		if (ret == TARGET_ERRNO__SUCCESS)
63			ret = TARGET_ERRNO__BPF_OVERRIDE_CPU;
64	}
65
66	/* BPF and PID/TID are mutually exclusive */
67	if (target->bpf_str && target->tid) {
68		target->tid = NULL;
69		if (ret == TARGET_ERRNO__SUCCESS)
70			ret = TARGET_ERRNO__BPF_OVERRIDE_PID;
71	}
72
73	/* BPF and UID are mutually exclusive */
74	if (target->bpf_str && target->uid_str) {
75		target->uid_str = NULL;
76		if (ret == TARGET_ERRNO__SUCCESS)
77			ret = TARGET_ERRNO__BPF_OVERRIDE_UID;
78	}
79
80	/* BPF and THREADS are mutually exclusive */
81	if (target->bpf_str && target->per_thread) {
82		target->per_thread = false;
83		if (ret == TARGET_ERRNO__SUCCESS)
84			ret = TARGET_ERRNO__BPF_OVERRIDE_THREAD;
85	}
86
87	/* THREAD and SYSTEM/CPU are mutually exclusive */
88	if (target->per_thread && (target->system_wide || target->cpu_list)) {
89		target->per_thread = false;
90		if (ret == TARGET_ERRNO__SUCCESS)
91			ret = TARGET_ERRNO__SYSTEM_OVERRIDE_THREAD;
92	}
93
94	return ret;
95}
96
97enum target_errno target__parse_uid(struct target *target)
98{
99	struct passwd pwd, *result;
100	char buf[1024];
101	const char *str = target->uid_str;
102
103	target->uid = UINT_MAX;
104	if (str == NULL)
105		return TARGET_ERRNO__SUCCESS;
106
107	/* Try user name first */
108	getpwnam_r(str, &pwd, buf, sizeof(buf), &result);
109
110	if (result == NULL) {
111		/*
112		 * The user name not found. Maybe it's a UID number.
113		 */
114		char *endptr;
115		int uid = strtol(str, &endptr, 10);
116
117		if (*endptr != '\0')
118			return TARGET_ERRNO__INVALID_UID;
119
120		getpwuid_r(uid, &pwd, buf, sizeof(buf), &result);
121
122		if (result == NULL)
123			return TARGET_ERRNO__USER_NOT_FOUND;
124	}
125
126	target->uid = result->pw_uid;
127	return TARGET_ERRNO__SUCCESS;
128}
129
130/*
131 * This must have a same ordering as the enum target_errno.
132 */
133static const char *target__error_str[] = {
134	"PID/TID switch overriding CPU",
135	"PID/TID switch overriding UID",
136	"UID switch overriding CPU",
137	"PID/TID switch overriding SYSTEM",
138	"UID switch overriding SYSTEM",
139	"SYSTEM/CPU switch overriding PER-THREAD",
140	"BPF switch overriding CPU",
141	"BPF switch overriding PID/TID",
142	"BPF switch overriding UID",
143	"BPF switch overriding THREAD",
144	"Invalid User: %s",
145	"Problems obtaining information for user %s",
146};
147
148int target__strerror(struct target *target, int errnum,
149			  char *buf, size_t buflen)
150{
151	int idx;
152	const char *msg;
153
154	BUG_ON(buflen == 0);
155
156	if (errnum >= 0) {
157		str_error_r(errnum, buf, buflen);
158		return 0;
159	}
160
161	if (errnum <  __TARGET_ERRNO__START || errnum >= __TARGET_ERRNO__END)
162		return -1;
163
164	idx = errnum - __TARGET_ERRNO__START;
165	msg = target__error_str[idx];
166
167	switch (errnum) {
168	case TARGET_ERRNO__PID_OVERRIDE_CPU ...
169	     TARGET_ERRNO__BPF_OVERRIDE_THREAD:
170		snprintf(buf, buflen, "%s", msg);
171		break;
172
173	case TARGET_ERRNO__INVALID_UID:
174	case TARGET_ERRNO__USER_NOT_FOUND:
175		snprintf(buf, buflen, msg, target->uid_str);
176		break;
177
178	default:
179		/* cannot reach here */
180		break;
181	}
182
183	return 0;
184}
185