Commit | Line | Data |
---|---|---|
5134d8fe JD |
1 | /* |
2 | * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) | |
3 | * Licensed under the GPL | |
4 | */ | |
5 | ||
0f80bc85 | 6 | #include <stdio.h> |
0f80bc85 | 7 | #include <stddef.h> |
5134d8fe | 8 | #include <stdlib.h> |
0f80bc85 JD |
9 | #include <unistd.h> |
10 | #include <errno.h> | |
0f80bc85 | 11 | #include <fcntl.h> |
5134d8fe | 12 | #include <string.h> |
fb967ecc | 13 | #include <sys/stat.h> |
0f80bc85 | 14 | #include <sys/mman.h> |
5134d8fe | 15 | #include <sys/param.h> |
0f80bc85 | 16 | #include "init.h" |
5134d8fe | 17 | #include "os.h" |
0f80bc85 | 18 | |
6bf79482 | 19 | /* Modified by which_tmpdir, which is called during early boot */ |
966a082f | 20 | static char *default_tmpdir = "/tmp"; |
6bf79482 JD |
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 | */ | |
0f80bc85 JD |
26 | static char *tempdir = NULL; |
27 | ||
28 | static void __init find_tempdir(void) | |
29 | { | |
c0a9290e | 30 | const char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL }; |
0f80bc85 JD |
31 | int i; |
32 | char *dir = NULL; | |
33 | ||
5134d8fe JD |
34 | if (tempdir != NULL) |
35 | /* We've already been called */ | |
81999a01 | 36 | return; |
5134d8fe | 37 | for (i = 0; dirs[i]; i++) { |
0f80bc85 | 38 | dir = getenv(dirs[i]); |
5134d8fe | 39 | if ((dir != NULL) && (*dir != '\0')) |
0f80bc85 JD |
40 | break; |
41 | } | |
5134d8fe | 42 | if ((dir == NULL) || (*dir == '\0')) |
966a082f | 43 | dir = default_tmpdir; |
0f80bc85 JD |
44 | |
45 | tempdir = malloc(strlen(dir) + 2); | |
5134d8fe | 46 | if (tempdir == NULL) { |
0f80bc85 JD |
47 | fprintf(stderr, "Failed to malloc tempdir, " |
48 | "errno = %d\n", errno); | |
49 | return; | |
50 | } | |
51 | strcpy(tempdir, dir); | |
52 | strcat(tempdir, "/"); | |
53 | } | |
54 | ||
5134d8fe JD |
55 | /* |
56 | * This will return 1, with the first character in buf being the | |
966a082f RL |
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 | */ | |
c0a9290e | 61 | static int next(int fd, char *buf, size_t size, char c) |
966a082f | 62 | { |
c0a9290e WC |
63 | ssize_t n; |
64 | size_t len; | |
966a082f RL |
65 | char *ptr; |
66 | ||
5134d8fe | 67 | while ((ptr = strchr(buf, c)) == NULL) { |
966a082f | 68 | n = read(fd, buf, size - 1); |
5134d8fe | 69 | if (n == 0) |
966a082f | 70 | return 0; |
5134d8fe | 71 | else if (n < 0) |
966a082f RL |
72 | return -errno; |
73 | ||
74 | buf[n] = '\0'; | |
75 | } | |
76 | ||
77 | ptr++; | |
c2b7a4bb JD |
78 | len = strlen(ptr); |
79 | memmove(buf, ptr, len + 1); | |
80 | ||
5134d8fe JD |
81 | /* |
82 | * Refill the buffer so that if there's a partial string that we care | |
c2b7a4bb JD |
83 | * about, it will be completed, and we can recognize it. |
84 | */ | |
85 | n = read(fd, &buf[len], size - len - 1); | |
5134d8fe | 86 | if (n < 0) |
c2b7a4bb JD |
87 | return -errno; |
88 | ||
89 | buf[len + n] = '\0'; | |
966a082f RL |
90 | return 1; |
91 | } | |
92 | ||
6bf79482 | 93 | /* which_tmpdir is called only during early boot */ |
966a082f RL |
94 | static int checked_tmpdir = 0; |
95 | ||
5134d8fe JD |
96 | /* |
97 | * Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner | |
966a082f RL |
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 | */ | |
107 | static void which_tmpdir(void) | |
108 | { | |
109 | int fd, found; | |
110 | char buf[128] = { '\0' }; | |
111 | ||
5134d8fe | 112 | if (checked_tmpdir) |
966a082f RL |
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); | |
5134d8fe | 120 | if (fd < 0) { |
966a082f RL |
121 | printf("failed to open /proc/mounts, errno = %d\n", errno); |
122 | return; | |
123 | } | |
124 | ||
5134d8fe | 125 | while (1) { |
91b165c0 | 126 | found = next(fd, buf, ARRAY_SIZE(buf), ' '); |
5134d8fe | 127 | if (found != 1) |
966a082f RL |
128 | break; |
129 | ||
5134d8fe | 130 | if (!strncmp(buf, "/dev/shm", strlen("/dev/shm"))) |
966a082f RL |
131 | goto found; |
132 | ||
91b165c0 | 133 | found = next(fd, buf, ARRAY_SIZE(buf), '\n'); |
5134d8fe | 134 | if (found != 1) |
966a082f RL |
135 | break; |
136 | } | |
137 | ||
138 | err: | |
5134d8fe | 139 | if (found == 0) |
966a082f | 140 | printf("nothing mounted on /dev/shm\n"); |
5134d8fe | 141 | else if (found < 0) |
966a082f RL |
142 | printf("read returned errno %d\n", -found); |
143 | ||
80c13749 JD |
144 | out: |
145 | close(fd); | |
146 | ||
966a082f RL |
147 | return; |
148 | ||
149 | found: | |
91b165c0 | 150 | found = next(fd, buf, ARRAY_SIZE(buf), ' '); |
5134d8fe | 151 | if (found != 1) |
966a082f RL |
152 | goto err; |
153 | ||
5134d8fe | 154 | if (strncmp(buf, "tmpfs", strlen("tmpfs"))) { |
966a082f | 155 | printf("not tmpfs\n"); |
80c13749 | 156 | goto out; |
966a082f RL |
157 | } |
158 | ||
159 | printf("OK\n"); | |
160 | default_tmpdir = "/dev/shm"; | |
80c13749 | 161 | goto out; |
966a082f RL |
162 | } |
163 | ||
5134d8fe JD |
164 | static int __init make_tempfile(const char *template, char **out_tempname, |
165 | int do_unlink) | |
0f80bc85 | 166 | { |
87276f72 | 167 | char *tempname; |
0f80bc85 JD |
168 | int fd; |
169 | ||
966a082f | 170 | which_tmpdir(); |
87276f72 | 171 | tempname = malloc(MAXPATHLEN); |
11a7ac23 JM |
172 | if (tempname == NULL) |
173 | return -1; | |
87276f72 | 174 | |
0f80bc85 | 175 | find_tempdir(); |
11a7ac23 | 176 | if ((tempdir == NULL) || (strlen(tempdir) >= MAXPATHLEN)) |
2a6d0ac1 | 177 | goto out; |
11a7ac23 | 178 | |
87276f72 | 179 | if (template[0] != '/') |
0f80bc85 JD |
180 | strcpy(tempname, tempdir); |
181 | else | |
87276f72 | 182 | tempname[0] = '\0'; |
c9a3072d | 183 | strncat(tempname, template, MAXPATHLEN-1-strlen(tempname)); |
0f80bc85 | 184 | fd = mkstemp(tempname); |
5134d8fe | 185 | if (fd < 0) { |
0f80bc85 JD |
186 | fprintf(stderr, "open - cannot create %s: %s\n", tempname, |
187 | strerror(errno)); | |
87276f72 | 188 | goto out; |
0f80bc85 | 189 | } |
5134d8fe | 190 | if (do_unlink && (unlink(tempname) < 0)) { |
0f80bc85 | 191 | perror("unlink"); |
2a6d0ac1 | 192 | goto close; |
0f80bc85 | 193 | } |
5134d8fe | 194 | if (out_tempname) { |
87276f72 | 195 | *out_tempname = tempname; |
11a7ac23 | 196 | } else |
87276f72 | 197 | free(tempname); |
81999a01 | 198 | return fd; |
2a6d0ac1 DB |
199 | close: |
200 | close(fd); | |
87276f72 PBG |
201 | out: |
202 | free(tempname); | |
203 | return -1; | |
0f80bc85 JD |
204 | } |
205 | ||
206 | #define TEMPNAME_TEMPLATE "vm_file-XXXXXX" | |
207 | ||
5134d8fe | 208 | static int __init create_tmp_file(unsigned long long len) |
0f80bc85 JD |
209 | { |
210 | int fd, err; | |
211 | char zero; | |
212 | ||
213 | fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1); | |
5134d8fe | 214 | if (fd < 0) |
0f80bc85 | 215 | exit(1); |
0f80bc85 JD |
216 | |
217 | err = fchmod(fd, 0777); | |
5134d8fe | 218 | if (err < 0) { |
512b6fb1 | 219 | perror("fchmod"); |
0f80bc85 JD |
220 | exit(1); |
221 | } | |
222 | ||
5134d8fe JD |
223 | /* |
224 | * Seek to len - 1 because writing a character there will | |
190f4939 JD |
225 | * increase the file size by one byte, to the desired length. |
226 | */ | |
227 | if (lseek64(fd, len - 1, SEEK_SET) < 0) { | |
512b6fb1 | 228 | perror("lseek64"); |
0f80bc85 JD |
229 | exit(1); |
230 | } | |
231 | ||
232 | zero = 0; | |
233 | ||
a61f334f | 234 | err = write(fd, &zero, 1); |
5134d8fe | 235 | if (err != 1) { |
a61f334f | 236 | perror("write"); |
0f80bc85 JD |
237 | exit(1); |
238 | } | |
239 | ||
81999a01 | 240 | return fd; |
0f80bc85 JD |
241 | } |
242 | ||
36e45463 | 243 | int __init create_mem_file(unsigned long long len) |
0f80bc85 JD |
244 | { |
245 | int err, fd; | |
246 | ||
02dea087 | 247 | fd = create_tmp_file(len); |
0f80bc85 | 248 | |
512b6fb1 | 249 | err = os_set_exec_close(fd); |
5134d8fe | 250 | if (err < 0) { |
0f80bc85 JD |
251 | errno = -err; |
252 | perror("exec_close"); | |
253 | } | |
81999a01 | 254 | return fd; |
0f80bc85 | 255 | } |
966a082f RL |
256 | |
257 | ||
36e45463 | 258 | void __init check_tmpexec(void) |
966a082f RL |
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); | |
5134d8fe | 267 | if (addr == MAP_FAILED) { |
966a082f RL |
268 | err = errno; |
269 | perror("failed"); | |
c9a3072d | 270 | close(fd); |
5134d8fe | 271 | if (err == EPERM) |
966a082f RL |
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 | } |