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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <stdio.h>
7#include <stdlib.h>
8#include <dirent.h>
9#include <errno.h>
10#include <fcntl.h>
11#include <signal.h>
12#include <string.h>
13#include <unistd.h>
14#include <sys/stat.h>
15#include <init.h>
16#include <os.h>
17
18#define UML_DIR "~/.uml/"
19
20#define UMID_LEN 64
21
22/* Changed by set_umid, which is run early in boot */
23static char umid[UMID_LEN] = { 0 };
24
25/* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
26static char *uml_dir = UML_DIR;
27
28static int __init make_uml_dir(void)
29{
30 char dir[512] = { '\0' };
31 int len, err;
32
33 if (*uml_dir == '~') {
34 char *home = getenv("HOME");
35
36 err = -ENOENT;
37 if (home == NULL) {
38 printk(UM_KERN_ERR
39 "%s: no value in environment for $HOME\n",
40 __func__);
41 goto err;
42 }
43 strlcpy(dir, home, sizeof(dir));
44 uml_dir++;
45 }
46 strlcat(dir, uml_dir, sizeof(dir));
47 len = strlen(dir);
48 if (len > 0 && dir[len - 1] != '/')
49 strlcat(dir, "/", sizeof(dir));
50
51 err = -ENOMEM;
52 uml_dir = malloc(strlen(dir) + 1);
53 if (uml_dir == NULL) {
54 printk(UM_KERN_ERR "%s : malloc failed, errno = %d\n",
55 __func__, errno);
56 goto err;
57 }
58 strcpy(uml_dir, dir);
59
60 if ((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)) {
61 printk(UM_KERN_ERR "Failed to mkdir '%s': %s\n",
62 uml_dir, strerror(errno));
63 err = -errno;
64 goto err_free;
65 }
66 return 0;
67
68err_free:
69 free(uml_dir);
70err:
71 uml_dir = NULL;
72 return err;
73}
74
75/*
76 * Unlinks the files contained in @dir and then removes @dir.
77 * Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
78 * ignore ENOENT errors for anything (they happen, strangely enough - possibly
79 * due to races between multiple dying UML threads).
80 */
81static int remove_files_and_dir(char *dir)
82{
83 DIR *directory;
84 struct dirent *ent;
85 int len;
86 char file[256];
87 int ret;
88
89 directory = opendir(dir);
90 if (directory == NULL) {
91 if (errno != ENOENT)
92 return -errno;
93 else
94 return 0;
95 }
96
97 while ((ent = readdir(directory)) != NULL) {
98 if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
99 continue;
100 len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
101 if (len > sizeof(file)) {
102 ret = -E2BIG;
103 goto out;
104 }
105
106 sprintf(file, "%s/%s", dir, ent->d_name);
107 if (unlink(file) < 0 && errno != ENOENT) {
108 ret = -errno;
109 goto out;
110 }
111 }
112
113 if (rmdir(dir) < 0 && errno != ENOENT) {
114 ret = -errno;
115 goto out;
116 }
117
118 ret = 0;
119out:
120 closedir(directory);
121 return ret;
122}
123
124/*
125 * This says that there isn't already a user of the specified directory even if
126 * there are errors during the checking. This is because if these errors
127 * happen, the directory is unusable by the pre-existing UML, so we might as
128 * well take it over. This could happen either by
129 * the existing UML somehow corrupting its umid directory
130 * something other than UML sticking stuff in the directory
131 * this boot racing with a shutdown of the other UML
132 * In any of these cases, the directory isn't useful for anything else.
133 *
134 * Boolean return: 1 if in use, 0 otherwise.
135 */
136static inline int is_umdir_used(char *dir)
137{
138 char pid[sizeof("nnnnn\0")], *end, *file;
139 int dead, fd, p, n, err;
140 size_t filelen;
141
142 err = asprintf(&file, "%s/pid", dir);
143 if (err < 0)
144 return 0;
145
146 filelen = strlen(file);
147
148 n = snprintf(file, filelen, "%s/pid", dir);
149 if (n >= filelen) {
150 printk(UM_KERN_ERR "is_umdir_used - pid filename too long\n");
151 err = -E2BIG;
152 goto out;
153 }
154
155 dead = 0;
156 fd = open(file, O_RDONLY);
157 if (fd < 0) {
158 fd = -errno;
159 if (fd != -ENOENT) {
160 printk(UM_KERN_ERR "is_umdir_used : couldn't open pid "
161 "file '%s', err = %d\n", file, -fd);
162 }
163 goto out;
164 }
165
166 err = 0;
167 n = read(fd, pid, sizeof(pid));
168 if (n < 0) {
169 printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
170 "'%s', err = %d\n", file, errno);
171 goto out_close;
172 } else if (n == 0) {
173 printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
174 "'%s', 0-byte read\n", file);
175 goto out_close;
176 }
177
178 p = strtoul(pid, &end, 0);
179 if (end == pid) {
180 printk(UM_KERN_ERR "is_umdir_used : couldn't parse pid file "
181 "'%s', errno = %d\n", file, errno);
182 goto out_close;
183 }
184
185 if ((kill(p, 0) == 0) || (errno != ESRCH)) {
186 printk(UM_KERN_ERR "umid \"%s\" is already in use by pid %d\n",
187 umid, p);
188 return 1;
189 }
190
191out_close:
192 close(fd);
193out:
194 free(file);
195 return 0;
196}
197
198/*
199 * Try to remove the directory @dir unless it's in use.
200 * Precondition: @dir exists.
201 * Returns 0 for success, < 0 for failure in removal or if the directory is in
202 * use.
203 */
204static int umdir_take_if_dead(char *dir)
205{
206 int ret;
207 if (is_umdir_used(dir))
208 return -EEXIST;
209
210 ret = remove_files_and_dir(dir);
211 if (ret) {
212 printk(UM_KERN_ERR "is_umdir_used - remove_files_and_dir "
213 "failed with err = %d\n", ret);
214 }
215 return ret;
216}
217
218static void __init create_pid_file(void)
219{
220 char pid[sizeof("nnnnn\0")], *file;
221 int fd, n;
222
223 file = malloc(strlen(uml_dir) + UMID_LEN + sizeof("/pid\0"));
224 if (!file)
225 return;
226
227 if (umid_file_name("pid", file, sizeof(file)))
228 goto out;
229
230 fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0644);
231 if (fd < 0) {
232 printk(UM_KERN_ERR "Open of machine pid file \"%s\" failed: "
233 "%s\n", file, strerror(errno));
234 goto out;
235 }
236
237 snprintf(pid, sizeof(pid), "%d\n", getpid());
238 n = write(fd, pid, strlen(pid));
239 if (n != strlen(pid))
240 printk(UM_KERN_ERR "Write of pid file failed - err = %d\n",
241 errno);
242
243 close(fd);
244out:
245 free(file);
246}
247
248int __init set_umid(char *name)
249{
250 if (strlen(name) > UMID_LEN - 1)
251 return -E2BIG;
252
253 strlcpy(umid, name, sizeof(umid));
254
255 return 0;
256}
257
258/* Changed in make_umid, which is called during early boot */
259static int umid_setup = 0;
260
261static int __init make_umid(void)
262{
263 int fd, err;
264 char tmp[256];
265
266 if (umid_setup)
267 return 0;
268
269 make_uml_dir();
270
271 if (*umid == '\0') {
272 strlcpy(tmp, uml_dir, sizeof(tmp));
273 strlcat(tmp, "XXXXXX", sizeof(tmp));
274 fd = mkstemp(tmp);
275 if (fd < 0) {
276 printk(UM_KERN_ERR "make_umid - mkstemp(%s) failed: "
277 "%s\n", tmp, strerror(errno));
278 err = -errno;
279 goto err;
280 }
281
282 close(fd);
283
284 set_umid(&tmp[strlen(uml_dir)]);
285
286 /*
287 * There's a nice tiny little race between this unlink and
288 * the mkdir below. It'd be nice if there were a mkstemp
289 * for directories.
290 */
291 if (unlink(tmp)) {
292 err = -errno;
293 goto err;
294 }
295 }
296
297 snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
298 err = mkdir(tmp, 0777);
299 if (err < 0) {
300 err = -errno;
301 if (err != -EEXIST)
302 goto err;
303
304 if (umdir_take_if_dead(tmp) < 0)
305 goto err;
306
307 err = mkdir(tmp, 0777);
308 }
309 if (err) {
310 err = -errno;
311 printk(UM_KERN_ERR "Failed to create '%s' - err = %d\n", umid,
312 errno);
313 goto err;
314 }
315
316 umid_setup = 1;
317
318 create_pid_file();
319
320 err = 0;
321 err:
322 return err;
323}
324
325static int __init make_umid_init(void)
326{
327 if (!make_umid())
328 return 0;
329
330 /*
331 * If initializing with the given umid failed, then try again with
332 * a random one.
333 */
334 printk(UM_KERN_ERR "Failed to initialize umid \"%s\", trying with a "
335 "random umid\n", umid);
336 *umid = '\0';
337 make_umid();
338
339 return 0;
340}
341
342__initcall(make_umid_init);
343
344int __init umid_file_name(char *name, char *buf, int len)
345{
346 int n, err;
347
348 err = make_umid();
349 if (err)
350 return err;
351
352 n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
353 if (n >= len) {
354 printk(UM_KERN_ERR "umid_file_name : buffer too short\n");
355 return -E2BIG;
356 }
357
358 return 0;
359}
360
361char *get_umid(void)
362{
363 return umid;
364}
365
366static int __init set_uml_dir(char *name, int *add)
367{
368 if (*name == '\0') {
369 os_warn("uml_dir can't be an empty string\n");
370 return 0;
371 }
372
373 if (name[strlen(name) - 1] == '/') {
374 uml_dir = name;
375 return 0;
376 }
377
378 uml_dir = malloc(strlen(name) + 2);
379 if (uml_dir == NULL) {
380 os_warn("Failed to malloc uml_dir - error = %d\n", errno);
381
382 /*
383 * Return 0 here because do_initcalls doesn't look at
384 * the return value.
385 */
386 return 0;
387 }
388 sprintf(uml_dir, "%s/", name);
389
390 return 0;
391}
392
393__uml_setup("uml_dir=", set_uml_dir,
394"uml_dir=<directory>\n"
395" The location to place the pid and umid files.\n\n"
396);
397
398static void remove_umid_dir(void)
399{
400 char *dir, err;
401
402 dir = malloc(strlen(uml_dir) + UMID_LEN + 1);
403 if (!dir)
404 return;
405
406 sprintf(dir, "%s%s", uml_dir, umid);
407 err = remove_files_and_dir(dir);
408 if (err)
409 os_warn("%s - remove_files_and_dir failed with err = %d\n",
410 __func__, err);
411
412 free(dir);
413}
414
415__uml_exitcall(remove_umid_dir);
1/*
2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <stdio.h>
7#include <stdlib.h>
8#include <dirent.h>
9#include <errno.h>
10#include <fcntl.h>
11#include <signal.h>
12#include <string.h>
13#include <unistd.h>
14#include <sys/stat.h>
15#include <init.h>
16#include <os.h>
17
18#define UML_DIR "~/.uml/"
19
20#define UMID_LEN 64
21
22/* Changed by set_umid, which is run early in boot */
23static char umid[UMID_LEN] = { 0 };
24
25/* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
26static char *uml_dir = UML_DIR;
27
28static int __init make_uml_dir(void)
29{
30 char dir[512] = { '\0' };
31 int len, err;
32
33 if (*uml_dir == '~') {
34 char *home = getenv("HOME");
35
36 err = -ENOENT;
37 if (home == NULL) {
38 printk(UM_KERN_ERR
39 "%s: no value in environment for $HOME\n",
40 __func__);
41 goto err;
42 }
43 strlcpy(dir, home, sizeof(dir));
44 uml_dir++;
45 }
46 strlcat(dir, uml_dir, sizeof(dir));
47 len = strlen(dir);
48 if (len > 0 && dir[len - 1] != '/')
49 strlcat(dir, "/", sizeof(dir));
50
51 err = -ENOMEM;
52 uml_dir = malloc(strlen(dir) + 1);
53 if (uml_dir == NULL) {
54 printk(UM_KERN_ERR "%s : malloc failed, errno = %d\n",
55 __func__, errno);
56 goto err;
57 }
58 strcpy(uml_dir, dir);
59
60 if ((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)) {
61 printk(UM_KERN_ERR "Failed to mkdir '%s': %s\n",
62 uml_dir, strerror(errno));
63 err = -errno;
64 goto err_free;
65 }
66 return 0;
67
68err_free:
69 free(uml_dir);
70err:
71 uml_dir = NULL;
72 return err;
73}
74
75/*
76 * Unlinks the files contained in @dir and then removes @dir.
77 * Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
78 * ignore ENOENT errors for anything (they happen, strangely enough - possibly
79 * due to races between multiple dying UML threads).
80 */
81static int remove_files_and_dir(char *dir)
82{
83 DIR *directory;
84 struct dirent *ent;
85 int len;
86 char file[256];
87 int ret;
88
89 directory = opendir(dir);
90 if (directory == NULL) {
91 if (errno != ENOENT)
92 return -errno;
93 else
94 return 0;
95 }
96
97 while ((ent = readdir(directory)) != NULL) {
98 if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
99 continue;
100 len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
101 if (len > sizeof(file)) {
102 ret = -E2BIG;
103 goto out;
104 }
105
106 sprintf(file, "%s/%s", dir, ent->d_name);
107 if (unlink(file) < 0 && errno != ENOENT) {
108 ret = -errno;
109 goto out;
110 }
111 }
112
113 if (rmdir(dir) < 0 && errno != ENOENT) {
114 ret = -errno;
115 goto out;
116 }
117
118 ret = 0;
119out:
120 closedir(directory);
121 return ret;
122}
123
124/*
125 * This says that there isn't already a user of the specified directory even if
126 * there are errors during the checking. This is because if these errors
127 * happen, the directory is unusable by the pre-existing UML, so we might as
128 * well take it over. This could happen either by
129 * the existing UML somehow corrupting its umid directory
130 * something other than UML sticking stuff in the directory
131 * this boot racing with a shutdown of the other UML
132 * In any of these cases, the directory isn't useful for anything else.
133 *
134 * Boolean return: 1 if in use, 0 otherwise.
135 */
136static inline int is_umdir_used(char *dir)
137{
138 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
139 char pid[sizeof("nnnnn\0")], *end;
140 int dead, fd, p, n, err;
141
142 n = snprintf(file, sizeof(file), "%s/pid", dir);
143 if (n >= sizeof(file)) {
144 printk(UM_KERN_ERR "is_umdir_used - pid filename too long\n");
145 err = -E2BIG;
146 goto out;
147 }
148
149 dead = 0;
150 fd = open(file, O_RDONLY);
151 if (fd < 0) {
152 fd = -errno;
153 if (fd != -ENOENT) {
154 printk(UM_KERN_ERR "is_umdir_used : couldn't open pid "
155 "file '%s', err = %d\n", file, -fd);
156 }
157 goto out;
158 }
159
160 err = 0;
161 n = read(fd, pid, sizeof(pid));
162 if (n < 0) {
163 printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
164 "'%s', err = %d\n", file, errno);
165 goto out_close;
166 } else if (n == 0) {
167 printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
168 "'%s', 0-byte read\n", file);
169 goto out_close;
170 }
171
172 p = strtoul(pid, &end, 0);
173 if (end == pid) {
174 printk(UM_KERN_ERR "is_umdir_used : couldn't parse pid file "
175 "'%s', errno = %d\n", file, errno);
176 goto out_close;
177 }
178
179 if ((kill(p, 0) == 0) || (errno != ESRCH)) {
180 printk(UM_KERN_ERR "umid \"%s\" is already in use by pid %d\n",
181 umid, p);
182 return 1;
183 }
184
185out_close:
186 close(fd);
187out:
188 return 0;
189}
190
191/*
192 * Try to remove the directory @dir unless it's in use.
193 * Precondition: @dir exists.
194 * Returns 0 for success, < 0 for failure in removal or if the directory is in
195 * use.
196 */
197static int umdir_take_if_dead(char *dir)
198{
199 int ret;
200 if (is_umdir_used(dir))
201 return -EEXIST;
202
203 ret = remove_files_and_dir(dir);
204 if (ret) {
205 printk(UM_KERN_ERR "is_umdir_used - remove_files_and_dir "
206 "failed with err = %d\n", ret);
207 }
208 return ret;
209}
210
211static void __init create_pid_file(void)
212{
213 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
214 char pid[sizeof("nnnnn\0")];
215 int fd, n;
216
217 if (umid_file_name("pid", file, sizeof(file)))
218 return;
219
220 fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0644);
221 if (fd < 0) {
222 printk(UM_KERN_ERR "Open of machine pid file \"%s\" failed: "
223 "%s\n", file, strerror(errno));
224 return;
225 }
226
227 snprintf(pid, sizeof(pid), "%d\n", getpid());
228 n = write(fd, pid, strlen(pid));
229 if (n != strlen(pid))
230 printk(UM_KERN_ERR "Write of pid file failed - err = %d\n",
231 errno);
232
233 close(fd);
234}
235
236int __init set_umid(char *name)
237{
238 if (strlen(name) > UMID_LEN - 1)
239 return -E2BIG;
240
241 strlcpy(umid, name, sizeof(umid));
242
243 return 0;
244}
245
246/* Changed in make_umid, which is called during early boot */
247static int umid_setup = 0;
248
249static int __init make_umid(void)
250{
251 int fd, err;
252 char tmp[256];
253
254 if (umid_setup)
255 return 0;
256
257 make_uml_dir();
258
259 if (*umid == '\0') {
260 strlcpy(tmp, uml_dir, sizeof(tmp));
261 strlcat(tmp, "XXXXXX", sizeof(tmp));
262 fd = mkstemp(tmp);
263 if (fd < 0) {
264 printk(UM_KERN_ERR "make_umid - mkstemp(%s) failed: "
265 "%s\n", tmp, strerror(errno));
266 err = -errno;
267 goto err;
268 }
269
270 close(fd);
271
272 set_umid(&tmp[strlen(uml_dir)]);
273
274 /*
275 * There's a nice tiny little race between this unlink and
276 * the mkdir below. It'd be nice if there were a mkstemp
277 * for directories.
278 */
279 if (unlink(tmp)) {
280 err = -errno;
281 goto err;
282 }
283 }
284
285 snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
286 err = mkdir(tmp, 0777);
287 if (err < 0) {
288 err = -errno;
289 if (err != -EEXIST)
290 goto err;
291
292 if (umdir_take_if_dead(tmp) < 0)
293 goto err;
294
295 err = mkdir(tmp, 0777);
296 }
297 if (err) {
298 err = -errno;
299 printk(UM_KERN_ERR "Failed to create '%s' - err = %d\n", umid,
300 errno);
301 goto err;
302 }
303
304 umid_setup = 1;
305
306 create_pid_file();
307
308 err = 0;
309 err:
310 return err;
311}
312
313static int __init make_umid_init(void)
314{
315 if (!make_umid())
316 return 0;
317
318 /*
319 * If initializing with the given umid failed, then try again with
320 * a random one.
321 */
322 printk(UM_KERN_ERR "Failed to initialize umid \"%s\", trying with a "
323 "random umid\n", umid);
324 *umid = '\0';
325 make_umid();
326
327 return 0;
328}
329
330__initcall(make_umid_init);
331
332int __init umid_file_name(char *name, char *buf, int len)
333{
334 int n, err;
335
336 err = make_umid();
337 if (err)
338 return err;
339
340 n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
341 if (n >= len) {
342 printk(UM_KERN_ERR "umid_file_name : buffer too short\n");
343 return -E2BIG;
344 }
345
346 return 0;
347}
348
349char *get_umid(void)
350{
351 return umid;
352}
353
354static int __init set_uml_dir(char *name, int *add)
355{
356 if (*name == '\0') {
357 os_warn("uml_dir can't be an empty string\n");
358 return 0;
359 }
360
361 if (name[strlen(name) - 1] == '/') {
362 uml_dir = name;
363 return 0;
364 }
365
366 uml_dir = malloc(strlen(name) + 2);
367 if (uml_dir == NULL) {
368 os_warn("Failed to malloc uml_dir - error = %d\n", errno);
369
370 /*
371 * Return 0 here because do_initcalls doesn't look at
372 * the return value.
373 */
374 return 0;
375 }
376 sprintf(uml_dir, "%s/", name);
377
378 return 0;
379}
380
381__uml_setup("uml_dir=", set_uml_dir,
382"uml_dir=<directory>\n"
383" The location to place the pid and umid files.\n\n"
384);
385
386static void remove_umid_dir(void)
387{
388 char dir[strlen(uml_dir) + UMID_LEN + 1], err;
389
390 sprintf(dir, "%s%s", uml_dir, umid);
391 err = remove_files_and_dir(dir);
392 if (err)
393 os_warn("%s - remove_files_and_dir failed with err = %d\n",
394 __func__, err);
395}
396
397__uml_exitcall(remove_umid_dir);