Commit | Line | Data |
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0f80bc85 JD |
1 | #include <stdio.h> |
2 | #include <stdlib.h> | |
3 | #include <stddef.h> | |
4 | #include <stdarg.h> | |
5 | #include <unistd.h> | |
6 | #include <errno.h> | |
7 | #include <string.h> | |
8 | #include <fcntl.h> | |
9 | #include <sys/types.h> | |
10 | #include <sys/mman.h> | |
966a082f | 11 | #include <sys/statfs.h> |
0f80bc85 JD |
12 | #include "kern_util.h" |
13 | #include "user.h" | |
0f80bc85 JD |
14 | #include "mem_user.h" |
15 | #include "init.h" | |
16 | #include "os.h" | |
17 | #include "tempfile.h" | |
18 | #include "kern_constants.h" | |
19 | ||
20 | #include <sys/param.h> | |
21 | ||
6bf79482 | 22 | /* Modified by which_tmpdir, which is called during early boot */ |
966a082f | 23 | static char *default_tmpdir = "/tmp"; |
6bf79482 JD |
24 | |
25 | /* | |
26 | * Modified when creating the physical memory file and when checking | |
27 | * the tmp filesystem for usability, both happening during early boot. | |
28 | */ | |
0f80bc85 JD |
29 | static char *tempdir = NULL; |
30 | ||
31 | static void __init find_tempdir(void) | |
32 | { | |
33 | char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL }; | |
34 | int i; | |
35 | char *dir = NULL; | |
36 | ||
81999a01 JD |
37 | if(tempdir != NULL) /* We've already been called */ |
38 | return; | |
0f80bc85 JD |
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')) | |
966a082f | 45 | dir = default_tmpdir; |
0f80bc85 JD |
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 | ||
966a082f RL |
57 | /* This will return 1, with the first character in buf being the |
58 | * character following the next instance of c in the file. This will | |
59 | * read the file as needed. If there's an error, -errno is returned; | |
60 | * if the end of the file is reached, 0 is returned. | |
61 | */ | |
62 | static int next(int fd, char *buf, int size, char c) | |
63 | { | |
c2b7a4bb | 64 | int n, len; |
966a082f RL |
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++; | |
c2b7a4bb JD |
78 | len = strlen(ptr); |
79 | memmove(buf, ptr, len + 1); | |
80 | ||
81 | /* Refill the buffer so that if there's a partial string that we care | |
82 | * about, it will be completed, and we can recognize it. | |
83 | */ | |
84 | n = read(fd, &buf[len], size - len - 1); | |
85 | if(n < 0) | |
86 | return -errno; | |
87 | ||
88 | buf[len + n] = '\0'; | |
966a082f RL |
89 | return 1; |
90 | } | |
91 | ||
6bf79482 | 92 | /* which_tmpdir is called only during early boot */ |
966a082f RL |
93 | static int checked_tmpdir = 0; |
94 | ||
95 | /* Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner | |
96 | * way to do this than to parse /proc/mounts. statfs will return the | |
97 | * same filesystem magic number and fs id for both /dev and /dev/shm | |
98 | * when they are both tmpfs, so you can't tell if they are different | |
99 | * filesystems. Also, there seems to be no other way of finding the | |
100 | * mount point of a filesystem from within it. | |
101 | * | |
102 | * If a /dev/shm tmpfs entry is found, then we switch to using it. | |
103 | * Otherwise, we stay with the default /tmp. | |
104 | */ | |
105 | static void which_tmpdir(void) | |
106 | { | |
107 | int fd, found; | |
108 | char buf[128] = { '\0' }; | |
109 | ||
110 | if(checked_tmpdir) | |
111 | return; | |
112 | ||
113 | checked_tmpdir = 1; | |
114 | ||
115 | printf("Checking for tmpfs mount on /dev/shm..."); | |
116 | ||
117 | fd = open("/proc/mounts", O_RDONLY); | |
118 | if(fd < 0){ | |
119 | printf("failed to open /proc/mounts, errno = %d\n", errno); | |
120 | return; | |
121 | } | |
122 | ||
123 | while(1){ | |
91b165c0 | 124 | found = next(fd, buf, ARRAY_SIZE(buf), ' '); |
966a082f RL |
125 | if(found != 1) |
126 | break; | |
127 | ||
128 | if(!strncmp(buf, "/dev/shm", strlen("/dev/shm"))) | |
129 | goto found; | |
130 | ||
91b165c0 | 131 | found = next(fd, buf, ARRAY_SIZE(buf), '\n'); |
966a082f RL |
132 | if(found != 1) |
133 | break; | |
134 | } | |
135 | ||
136 | err: | |
137 | if(found == 0) | |
138 | printf("nothing mounted on /dev/shm\n"); | |
139 | else if(found < 0) | |
140 | printf("read returned errno %d\n", -found); | |
141 | ||
80c13749 JD |
142 | out: |
143 | close(fd); | |
144 | ||
966a082f RL |
145 | return; |
146 | ||
147 | found: | |
91b165c0 | 148 | found = next(fd, buf, ARRAY_SIZE(buf), ' '); |
966a082f RL |
149 | if(found != 1) |
150 | goto err; | |
151 | ||
152 | if(strncmp(buf, "tmpfs", strlen("tmpfs"))){ | |
153 | printf("not tmpfs\n"); | |
80c13749 | 154 | goto out; |
966a082f RL |
155 | } |
156 | ||
157 | printf("OK\n"); | |
158 | default_tmpdir = "/dev/shm"; | |
80c13749 | 159 | goto out; |
966a082f RL |
160 | } |
161 | ||
0f80bc85 JD |
162 | /* |
163 | * This proc still used in tt-mode | |
164 | * (file: kernel/tt/ptproxy/proxy.c, proc: start_debugger). | |
165 | * So it isn't 'static' yet. | |
166 | */ | |
36e45463 JD |
167 | int __init make_tempfile(const char *template, char **out_tempname, |
168 | int do_unlink) | |
0f80bc85 | 169 | { |
87276f72 | 170 | char *tempname; |
0f80bc85 JD |
171 | int fd; |
172 | ||
966a082f | 173 | which_tmpdir(); |
87276f72 | 174 | tempname = malloc(MAXPATHLEN); |
c9a3072d WC |
175 | if (!tempname) |
176 | goto out; | |
87276f72 | 177 | |
0f80bc85 | 178 | find_tempdir(); |
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 JD |
184 | fd = mkstemp(tempname); |
185 | if(fd < 0){ | |
186 | fprintf(stderr, "open - cannot create %s: %s\n", tempname, | |
187 | strerror(errno)); | |
87276f72 | 188 | goto out; |
0f80bc85 JD |
189 | } |
190 | if(do_unlink && (unlink(tempname) < 0)){ | |
191 | perror("unlink"); | |
87276f72 | 192 | goto out; |
0f80bc85 JD |
193 | } |
194 | if(out_tempname){ | |
87276f72 PBG |
195 | *out_tempname = tempname; |
196 | } else { | |
197 | free(tempname); | |
0f80bc85 | 198 | } |
81999a01 | 199 | return fd; |
87276f72 PBG |
200 | out: |
201 | free(tempname); | |
202 | return -1; | |
0f80bc85 JD |
203 | } |
204 | ||
205 | #define TEMPNAME_TEMPLATE "vm_file-XXXXXX" | |
206 | ||
207 | /* | |
208 | * This proc is used in start_up.c | |
209 | * So it isn't 'static'. | |
210 | */ | |
36e45463 | 211 | int __init create_tmp_file(unsigned long long len) |
0f80bc85 JD |
212 | { |
213 | int fd, err; | |
214 | char zero; | |
215 | ||
216 | fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1); | |
217 | if(fd < 0) { | |
218 | exit(1); | |
219 | } | |
220 | ||
221 | err = fchmod(fd, 0777); | |
222 | if(err < 0){ | |
512b6fb1 | 223 | perror("fchmod"); |
0f80bc85 JD |
224 | exit(1); |
225 | } | |
226 | ||
190f4939 JD |
227 | /* Seek to len - 1 because writing a character there will |
228 | * increase the file size by one byte, to the desired length. | |
229 | */ | |
230 | if (lseek64(fd, len - 1, SEEK_SET) < 0) { | |
512b6fb1 | 231 | perror("lseek64"); |
0f80bc85 JD |
232 | exit(1); |
233 | } | |
234 | ||
235 | zero = 0; | |
236 | ||
a61f334f | 237 | err = write(fd, &zero, 1); |
0f80bc85 | 238 | if(err != 1){ |
a61f334f | 239 | perror("write"); |
0f80bc85 JD |
240 | exit(1); |
241 | } | |
242 | ||
81999a01 | 243 | return fd; |
0f80bc85 JD |
244 | } |
245 | ||
36e45463 | 246 | int __init create_mem_file(unsigned long long len) |
0f80bc85 JD |
247 | { |
248 | int err, fd; | |
249 | ||
02dea087 | 250 | fd = create_tmp_file(len); |
0f80bc85 | 251 | |
512b6fb1 | 252 | err = os_set_exec_close(fd); |
0f80bc85 JD |
253 | if(err < 0){ |
254 | errno = -err; | |
255 | perror("exec_close"); | |
256 | } | |
81999a01 | 257 | return fd; |
0f80bc85 | 258 | } |
966a082f RL |
259 | |
260 | ||
36e45463 | 261 | void __init check_tmpexec(void) |
966a082f RL |
262 | { |
263 | void *addr; | |
264 | int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE); | |
265 | ||
266 | addr = mmap(NULL, UM_KERN_PAGE_SIZE, | |
267 | PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0); | |
268 | printf("Checking PROT_EXEC mmap in %s...",tempdir); | |
269 | fflush(stdout); | |
270 | if(addr == MAP_FAILED){ | |
271 | err = errno; | |
272 | perror("failed"); | |
c9a3072d | 273 | close(fd); |
966a082f RL |
274 | if(err == EPERM) |
275 | printf("%s must be not mounted noexec\n",tempdir); | |
276 | exit(1); | |
277 | } | |
278 | printf("OK\n"); | |
279 | munmap(addr, UM_KERN_PAGE_SIZE); | |
280 | ||
281 | close(fd); | |
282 | } |