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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2012 Linux Test Project.  All Rights Reserved.
4  * Ngie Cooper, April 2012
5  *
6  * DESCRIPTION
7  *     verify that IN_DELETE_SELF functions as expected
8  *
9  * ALGORITHM
10  *     This testcase creates a temporary directory, then add watches to a
11  *     predefined file and subdirectory, and delete the file and directory to
12  *     ensure that the IN_DELETE_SELF event is captured properly.
13  *
14  *     Because of how the inotify(7) API is designed, we also need to catch the
15  *     IN_ATTRIB and IN_IGNORED events.
16  */
17 
18 #include "config.h"
19 
20 #if defined(HAVE_SYS_INOTIFY_H)
21 # include <sys/inotify.h>
22 #endif
23 #include <errno.h>
24 #include <string.h>
25 #include "tst_test.h"
26 #include "inotify.h"
27 
28 #if defined(HAVE_SYS_INOTIFY_H)
29 
30 #define EVENT_MAX 1024
31 /* size of the event structure, not counting name */
32 #define EVENT_SIZE  (sizeof(struct inotify_event))
33 /* reasonable guess as to size of 1024 events */
34 #define EVENT_BUF_LEN        (EVENT_MAX * (EVENT_SIZE + 16))
35 
36 
37 #define BUF_SIZE 256
38 
39 struct event_t {
40 	char name[BUF_SIZE];
41 	unsigned int mask;
42 };
43 
44 #define	TEST_DIR	"test_dir"
45 #define	TEST_FILE	"test_file"
46 
47 struct event_t event_set[EVENT_MAX];
48 
49 char event_buf[EVENT_BUF_LEN];
50 
51 int fd_notify, reap_wd_file, reap_wd_dir, wd_dir, wd_file;
52 
53 static struct tst_kern_exv kvers[] = {
54 	{ "RHEL5", "2.6.18-132" },
55 	{ NULL, NULL },
56 };
57 
cleanup(void)58 static void cleanup(void)
59 {
60 	if (reap_wd_dir && myinotify_rm_watch(fd_notify, wd_dir) == -1)
61 		tst_res(TWARN,
62 			"inotify_rm_watch(%d, %d) [1] failed", fd_notify,
63 			wd_dir);
64 
65 	if (reap_wd_file && myinotify_rm_watch(fd_notify, wd_file) == -1)
66 		tst_res(TWARN,
67 			"inotify_rm_watch(%d, %d) [2] failed", fd_notify,
68 			wd_file);
69 
70 	if (fd_notify > 0)
71 		SAFE_CLOSE(fd_notify);
72 }
73 
setup(void)74 static void setup(void)
75 {
76 	fd_notify = SAFE_MYINOTIFY_INIT();
77 }
78 
verify_inotify(void)79 void verify_inotify(void)
80 {
81 	int i = 0, test_num = 0, len;
82 	int test_cnt = 0;
83 
84 	SAFE_MKDIR(TEST_DIR, 00700);
85 	close(SAFE_CREAT(TEST_FILE, 00600));
86 
87 	wd_dir = SAFE_MYINOTIFY_ADD_WATCH(fd_notify, TEST_DIR, IN_ALL_EVENTS);
88 	reap_wd_dir = 1;
89 
90 	wd_file = SAFE_MYINOTIFY_ADD_WATCH(fd_notify, TEST_FILE, IN_ALL_EVENTS);
91 	reap_wd_file = 1;
92 
93 	SAFE_RMDIR(TEST_DIR);
94 	reap_wd_dir = 0;
95 
96 	event_set[test_cnt].mask = IN_DELETE_SELF;
97 	strcpy(event_set[test_cnt].name, "");
98 	test_cnt++;
99 	event_set[test_cnt].mask = IN_IGNORED;
100 	strcpy(event_set[test_cnt].name, "");
101 	test_cnt++;
102 
103 	SAFE_UNLINK(TEST_FILE);
104 	reap_wd_file = 0;
105 
106 	/*
107 	 * When a file is unlinked, the link count is reduced by 1, and when it
108 	 * hits 0 the file is removed.
109 	 *
110 	 * This isn't well documented in inotify(7), but it's intuitive if you
111 	 * understand how Unix works.
112 	 */
113 	if (tst_kvercmp2(2, 6, 25, kvers) >= 0) {
114 		event_set[test_cnt].mask = IN_ATTRIB;
115 		strcpy(event_set[test_cnt].name, "");
116 		test_cnt++;
117 	}
118 
119 	event_set[test_cnt].mask = IN_DELETE_SELF;
120 	strcpy(event_set[test_cnt].name, TEST_FILE);
121 	test_cnt++;
122 	event_set[test_cnt].mask = IN_IGNORED;
123 	strcpy(event_set[test_cnt].name, "");
124 	test_cnt++;
125 
126 	len = read(fd_notify, event_buf, EVENT_BUF_LEN);
127 	if (len == -1)
128 		tst_brk(TBROK | TERRNO, "read failed");
129 
130 	while (i < len) {
131 		struct inotify_event *event;
132 		event = (struct inotify_event *)&event_buf[i];
133 		if (test_num >= test_cnt) {
134 			if (tst_kvercmp(2, 6, 25) < 0
135 			    && event_set[test_cnt - 1].mask == event->mask)
136 				tst_res(TWARN,
137 					"This may be kernel bug. "
138 					"Before kernel 2.6.25, a kernel bug "
139 					"meant that the kernel code that was "
140 					"intended to coalesce successive identical "
141 					"events (i.e., the two most recent "
142 					"events could potentially be coalesced "
143 					"if the older had not yet been read) "
144 					"instead checked if the most recent event "
145 					"could be coalesced with the oldest "
146 					"unread event. This has been fixed by commit"
147 					"1c17d18e3775485bf1e0ce79575eb637a94494a2.");
148 			tst_res(TFAIL,
149 				"got unnecessary event: "
150 				"wd=%d mask=%04x cookie=%u len=%u "
151 				"name=\"%.*s\"", event->wd, event->mask,
152 				event->cookie, event->len, event->len, event->name);
153 
154 		} else if ((event_set[test_num].mask == event->mask)
155 			   &&
156 			   (!strncmp
157 			    (event_set[test_num].name, event->name,
158 			     event->len))) {
159 			tst_res(TPASS,
160 				"got event: wd=%d mask=%04x "
161 				"cookie=%u len=%u name=\"%.*s\"",
162 				event->wd, event->mask, event->cookie,
163 				event->len, event->len, event->name);
164 
165 		} else {
166 			tst_res(TFAIL, "got event: wd=%d mask=%04x "
167 				"(expected %x) cookie=%u len=%u "
168 				"name=\"%.*s\" (expected \"%s\") %d",
169 				event->wd, event->mask,
170 				event_set[test_num].mask,
171 				event->cookie, event->len,
172 				event->len, event->name,
173 				event_set[test_num].name,
174 				strncmp(event_set[test_num].name, event->name, event->len));
175 		}
176 		test_num++;
177 		i += EVENT_SIZE + event->len;
178 	}
179 
180 	for (; test_num < test_cnt; test_num++) {
181 		tst_res(TFAIL, "didn't get event: mask=%04x ",
182 			event_set[test_num].mask);
183 	}
184 
185 }
186 
187 static struct tst_test test = {
188 	.needs_tmpdir = 1,
189 	.setup = setup,
190 	.cleanup = cleanup,
191 	.test_all = verify_inotify,
192 };
193 
194 #else
195 	TST_TEST_TCONF("system doesn't have required inotify support");
196 #endif /* defined(HAVE_SYS_INOTIFY_H) */
197