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1/*
2 * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <stdio.h>
7#include <stddef.h>
8#include <stdlib.h>
9#include <unistd.h>
10#include <errno.h>
11#include <fcntl.h>
12#include <string.h>
13#include <sys/stat.h>
14#include <sys/mman.h>
15#include <sys/param.h>
16#include "init.h"
17#include "os.h"
18
19/* Modified by which_tmpdir, which is called during early boot */
20static char *default_tmpdir = "/tmp";
21
22/*
23 * Modified when creating the physical memory file and when checking
24 * the tmp filesystem for usability, both happening during early boot.
25 */
26static char *tempdir = NULL;
27
28static void __init find_tempdir(void)
29{
30 const char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL };
31 int i;
32 char *dir = NULL;
33
34 if (tempdir != NULL)
35 /* We've already been called */
36 return;
37 for (i = 0; dirs[i]; i++) {
38 dir = getenv(dirs[i]);
39 if ((dir != NULL) && (*dir != '\0'))
40 break;
41 }
42 if ((dir == NULL) || (*dir == '\0'))
43 dir = default_tmpdir;
44
45 tempdir = malloc(strlen(dir) + 2);
46 if (tempdir == NULL) {
47 fprintf(stderr, "Failed to malloc tempdir, "
48 "errno = %d\n", errno);
49 return;
50 }
51 strcpy(tempdir, dir);
52 strcat(tempdir, "/");
53}
54
55/*
56 * This will return 1, with the first character in buf being the
57 * character following the next instance of c in the file. This will
58 * read the file as needed. If there's an error, -errno is returned;
59 * if the end of the file is reached, 0 is returned.
60 */
61static int next(int fd, char *buf, size_t size, char c)
62{
63 ssize_t n;
64 size_t len;
65 char *ptr;
66
67 while ((ptr = strchr(buf, c)) == NULL) {
68 n = read(fd, buf, size - 1);
69 if (n == 0)
70 return 0;
71 else if (n < 0)
72 return -errno;
73
74 buf[n] = '\0';
75 }
76
77 ptr++;
78 len = strlen(ptr);
79 memmove(buf, ptr, len + 1);
80
81 /*
82 * Refill the buffer so that if there's a partial string that we care
83 * about, it will be completed, and we can recognize it.
84 */
85 n = read(fd, &buf[len], size - len - 1);
86 if (n < 0)
87 return -errno;
88
89 buf[len + n] = '\0';
90 return 1;
91}
92
93/* which_tmpdir is called only during early boot */
94static int checked_tmpdir = 0;
95
96/*
97 * Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner
98 * way to do this than to parse /proc/mounts. statfs will return the
99 * same filesystem magic number and fs id for both /dev and /dev/shm
100 * when they are both tmpfs, so you can't tell if they are different
101 * filesystems. Also, there seems to be no other way of finding the
102 * mount point of a filesystem from within it.
103 *
104 * If a /dev/shm tmpfs entry is found, then we switch to using it.
105 * Otherwise, we stay with the default /tmp.
106 */
107static void which_tmpdir(void)
108{
109 int fd, found;
110 char buf[128] = { '\0' };
111
112 if (checked_tmpdir)
113 return;
114
115 checked_tmpdir = 1;
116
117 printf("Checking for tmpfs mount on /dev/shm...");
118
119 fd = open("/proc/mounts", O_RDONLY);
120 if (fd < 0) {
121 printf("failed to open /proc/mounts, errno = %d\n", errno);
122 return;
123 }
124
125 while (1) {
126 found = next(fd, buf, ARRAY_SIZE(buf), ' ');
127 if (found != 1)
128 break;
129
130 if (!strncmp(buf, "/dev/shm", strlen("/dev/shm")))
131 goto found;
132
133 found = next(fd, buf, ARRAY_SIZE(buf), '\n');
134 if (found != 1)
135 break;
136 }
137
138err:
139 if (found == 0)
140 printf("nothing mounted on /dev/shm\n");
141 else if (found < 0)
142 printf("read returned errno %d\n", -found);
143
144out:
145 close(fd);
146
147 return;
148
149found:
150 found = next(fd, buf, ARRAY_SIZE(buf), ' ');
151 if (found != 1)
152 goto err;
153
154 if (strncmp(buf, "tmpfs", strlen("tmpfs"))) {
155 printf("not tmpfs\n");
156 goto out;
157 }
158
159 printf("OK\n");
160 default_tmpdir = "/dev/shm";
161 goto out;
162}
163
164static int __init make_tempfile(const char *template, char **out_tempname,
165 int do_unlink)
166{
167 char *tempname;
168 int fd;
169
170 which_tmpdir();
171 tempname = malloc(MAXPATHLEN);
172 if (tempname == NULL)
173 return -1;
174
175 find_tempdir();
176 if ((tempdir == NULL) || (strlen(tempdir) >= MAXPATHLEN))
177 goto out;
178
179 if (template[0] != '/')
180 strcpy(tempname, tempdir);
181 else
182 tempname[0] = '\0';
183 strncat(tempname, template, MAXPATHLEN-1-strlen(tempname));
184 fd = mkstemp(tempname);
185 if (fd < 0) {
186 fprintf(stderr, "open - cannot create %s: %s\n", tempname,
187 strerror(errno));
188 goto out;
189 }
190 if (do_unlink && (unlink(tempname) < 0)) {
191 perror("unlink");
192 goto close;
193 }
194 if (out_tempname) {
195 *out_tempname = tempname;
196 } else
197 free(tempname);
198 return fd;
199close:
200 close(fd);
201out:
202 free(tempname);
203 return -1;
204}
205
206#define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
207
208static int __init create_tmp_file(unsigned long long len)
209{
210 int fd, err;
211 char zero;
212
213 fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1);
214 if (fd < 0)
215 exit(1);
216
217 err = fchmod(fd, 0777);
218 if (err < 0) {
219 perror("fchmod");
220 exit(1);
221 }
222
223 /*
224 * Seek to len - 1 because writing a character there will
225 * increase the file size by one byte, to the desired length.
226 */
227 if (lseek64(fd, len - 1, SEEK_SET) < 0) {
228 perror("lseek64");
229 exit(1);
230 }
231
232 zero = 0;
233
234 err = write(fd, &zero, 1);
235 if (err != 1) {
236 perror("write");
237 exit(1);
238 }
239
240 return fd;
241}
242
243int __init create_mem_file(unsigned long long len)
244{
245 int err, fd;
246
247 fd = create_tmp_file(len);
248
249 err = os_set_exec_close(fd);
250 if (err < 0) {
251 errno = -err;
252 perror("exec_close");
253 }
254 return fd;
255}
256
257
258void __init check_tmpexec(void)
259{
260 void *addr;
261 int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
262
263 addr = mmap(NULL, UM_KERN_PAGE_SIZE,
264 PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
265 printf("Checking PROT_EXEC mmap in %s...",tempdir);
266 fflush(stdout);
267 if (addr == MAP_FAILED) {
268 err = errno;
269 perror("failed");
270 close(fd);
271 if (err == EPERM)
272 printf("%s must be not mounted noexec\n",tempdir);
273 exit(1);
274 }
275 printf("OK\n");
276 munmap(addr, UM_KERN_PAGE_SIZE);
277
278 close(fd);
279}
1/*
2 * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <stdio.h>
7#include <stddef.h>
8#include <stdlib.h>
9#include <unistd.h>
10#include <errno.h>
11#include <fcntl.h>
12#include <string.h>
13#include <sys/stat.h>
14#include <sys/mman.h>
15#include <sys/param.h>
16#include "init.h"
17#include "kern_constants.h"
18#include "os.h"
19#include "user.h"
20
21/* Modified by which_tmpdir, which is called during early boot */
22static char *default_tmpdir = "/tmp";
23
24/*
25 * Modified when creating the physical memory file and when checking
26 * the tmp filesystem for usability, both happening during early boot.
27 */
28static char *tempdir = NULL;
29
30static void __init find_tempdir(void)
31{
32 const char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL };
33 int i;
34 char *dir = NULL;
35
36 if (tempdir != NULL)
37 /* We've already been called */
38 return;
39 for (i = 0; dirs[i]; i++) {
40 dir = getenv(dirs[i]);
41 if ((dir != NULL) && (*dir != '\0'))
42 break;
43 }
44 if ((dir == NULL) || (*dir == '\0'))
45 dir = default_tmpdir;
46
47 tempdir = malloc(strlen(dir) + 2);
48 if (tempdir == NULL) {
49 fprintf(stderr, "Failed to malloc tempdir, "
50 "errno = %d\n", errno);
51 return;
52 }
53 strcpy(tempdir, dir);
54 strcat(tempdir, "/");
55}
56
57/*
58 * This will return 1, with the first character in buf being the
59 * character following the next instance of c in the file. This will
60 * read the file as needed. If there's an error, -errno is returned;
61 * if the end of the file is reached, 0 is returned.
62 */
63static int next(int fd, char *buf, size_t size, char c)
64{
65 ssize_t n;
66 size_t len;
67 char *ptr;
68
69 while ((ptr = strchr(buf, c)) == NULL) {
70 n = read(fd, buf, size - 1);
71 if (n == 0)
72 return 0;
73 else if (n < 0)
74 return -errno;
75
76 buf[n] = '\0';
77 }
78
79 ptr++;
80 len = strlen(ptr);
81 memmove(buf, ptr, len + 1);
82
83 /*
84 * Refill the buffer so that if there's a partial string that we care
85 * about, it will be completed, and we can recognize it.
86 */
87 n = read(fd, &buf[len], size - len - 1);
88 if (n < 0)
89 return -errno;
90
91 buf[len + n] = '\0';
92 return 1;
93}
94
95/* which_tmpdir is called only during early boot */
96static int checked_tmpdir = 0;
97
98/*
99 * Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner
100 * way to do this than to parse /proc/mounts. statfs will return the
101 * same filesystem magic number and fs id for both /dev and /dev/shm
102 * when they are both tmpfs, so you can't tell if they are different
103 * filesystems. Also, there seems to be no other way of finding the
104 * mount point of a filesystem from within it.
105 *
106 * If a /dev/shm tmpfs entry is found, then we switch to using it.
107 * Otherwise, we stay with the default /tmp.
108 */
109static void which_tmpdir(void)
110{
111 int fd, found;
112 char buf[128] = { '\0' };
113
114 if (checked_tmpdir)
115 return;
116
117 checked_tmpdir = 1;
118
119 printf("Checking for tmpfs mount on /dev/shm...");
120
121 fd = open("/proc/mounts", O_RDONLY);
122 if (fd < 0) {
123 printf("failed to open /proc/mounts, errno = %d\n", errno);
124 return;
125 }
126
127 while (1) {
128 found = next(fd, buf, ARRAY_SIZE(buf), ' ');
129 if (found != 1)
130 break;
131
132 if (!strncmp(buf, "/dev/shm", strlen("/dev/shm")))
133 goto found;
134
135 found = next(fd, buf, ARRAY_SIZE(buf), '\n');
136 if (found != 1)
137 break;
138 }
139
140err:
141 if (found == 0)
142 printf("nothing mounted on /dev/shm\n");
143 else if (found < 0)
144 printf("read returned errno %d\n", -found);
145
146out:
147 close(fd);
148
149 return;
150
151found:
152 found = next(fd, buf, ARRAY_SIZE(buf), ' ');
153 if (found != 1)
154 goto err;
155
156 if (strncmp(buf, "tmpfs", strlen("tmpfs"))) {
157 printf("not tmpfs\n");
158 goto out;
159 }
160
161 printf("OK\n");
162 default_tmpdir = "/dev/shm";
163 goto out;
164}
165
166static int __init make_tempfile(const char *template, char **out_tempname,
167 int do_unlink)
168{
169 char *tempname;
170 int fd;
171
172 which_tmpdir();
173 tempname = malloc(MAXPATHLEN);
174 if (tempname == NULL)
175 return -1;
176
177 find_tempdir();
178 if ((tempdir == NULL) || (strlen(tempdir) >= MAXPATHLEN))
179 goto out;
180
181 if (template[0] != '/')
182 strcpy(tempname, tempdir);
183 else
184 tempname[0] = '\0';
185 strncat(tempname, template, MAXPATHLEN-1-strlen(tempname));
186 fd = mkstemp(tempname);
187 if (fd < 0) {
188 fprintf(stderr, "open - cannot create %s: %s\n", tempname,
189 strerror(errno));
190 goto out;
191 }
192 if (do_unlink && (unlink(tempname) < 0)) {
193 perror("unlink");
194 goto close;
195 }
196 if (out_tempname) {
197 *out_tempname = tempname;
198 } else
199 free(tempname);
200 return fd;
201close:
202 close(fd);
203out:
204 free(tempname);
205 return -1;
206}
207
208#define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
209
210static int __init create_tmp_file(unsigned long long len)
211{
212 int fd, err;
213 char zero;
214
215 fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1);
216 if (fd < 0)
217 exit(1);
218
219 err = fchmod(fd, 0777);
220 if (err < 0) {
221 perror("fchmod");
222 exit(1);
223 }
224
225 /*
226 * Seek to len - 1 because writing a character there will
227 * increase the file size by one byte, to the desired length.
228 */
229 if (lseek64(fd, len - 1, SEEK_SET) < 0) {
230 perror("lseek64");
231 exit(1);
232 }
233
234 zero = 0;
235
236 err = write(fd, &zero, 1);
237 if (err != 1) {
238 perror("write");
239 exit(1);
240 }
241
242 return fd;
243}
244
245int __init create_mem_file(unsigned long long len)
246{
247 int err, fd;
248
249 fd = create_tmp_file(len);
250
251 err = os_set_exec_close(fd);
252 if (err < 0) {
253 errno = -err;
254 perror("exec_close");
255 }
256 return fd;
257}
258
259
260void __init check_tmpexec(void)
261{
262 void *addr;
263 int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
264
265 addr = mmap(NULL, UM_KERN_PAGE_SIZE,
266 PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
267 printf("Checking PROT_EXEC mmap in %s...",tempdir);
268 fflush(stdout);
269 if (addr == MAP_FAILED) {
270 err = errno;
271 perror("failed");
272 close(fd);
273 if (err == EPERM)
274 printf("%s must be not mounted noexec\n",tempdir);
275 exit(1);
276 }
277 printf("OK\n");
278 munmap(addr, UM_KERN_PAGE_SIZE);
279
280 close(fd);
281}