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> |
0d71832e TS |
15 | #include <sys/vfs.h> |
16 | #include <linux/magic.h> | |
37185b33 AV |
17 | #include <init.h> |
18 | #include <os.h> | |
0f80bc85 | 19 | |
0d71832e | 20 | /* Set by make_tempfile() during early boot. */ |
0f80bc85 JD |
21 | static char *tempdir = NULL; |
22 | ||
0d71832e TS |
23 | /* Check if dir is on tmpfs. Return 0 if yes, -1 if no or error. */ |
24 | static int __init check_tmpfs(const char *dir) | |
0f80bc85 | 25 | { |
0d71832e | 26 | struct statfs st; |
0f80bc85 | 27 | |
0d71832e TS |
28 | printf("Checking if %s is on tmpfs...", dir); |
29 | if (statfs(dir, &st) < 0) { | |
30 | printf("%s\n", strerror(errno)); | |
31 | } else if (st.f_type != TMPFS_MAGIC) { | |
32 | printf("no\n"); | |
33 | } else { | |
34 | printf("OK\n"); | |
35 | return 0; | |
966a082f | 36 | } |
0d71832e | 37 | return -1; |
74735341 TS |
38 | } |
39 | ||
40 | /* | |
0d71832e TS |
41 | * Choose the tempdir to use. We want something on tmpfs so that our memory is |
42 | * not subject to the host's vm.dirty_ratio. If a tempdir is specified in the | |
43 | * environment, we use that even if it's not on tmpfs, but we warn the user. | |
44 | * Otherwise, we try common tmpfs locations, and if no tmpfs directory is found | |
45 | * then we fall back to /tmp. | |
74735341 | 46 | */ |
0d71832e | 47 | static char * __init choose_tempdir(void) |
74735341 | 48 | { |
0d71832e TS |
49 | static const char * const vars[] = { |
50 | "TMPDIR", | |
51 | "TMP", | |
52 | "TEMP", | |
53 | NULL | |
54 | }; | |
55 | static const char fallback_dir[] = "/tmp"; | |
56 | static const char * const tmpfs_dirs[] = { | |
57 | "/dev/shm", | |
58 | fallback_dir, | |
59 | NULL | |
60 | }; | |
74735341 | 61 | int i; |
0d71832e TS |
62 | const char *dir; |
63 | ||
64 | printf("Checking environment variables for a tempdir..."); | |
65 | for (i = 0; vars[i]; i++) { | |
66 | dir = getenv(vars[i]); | |
67 | if ((dir != NULL) && (*dir != '\0')) { | |
68 | printf("%s\n", dir); | |
69 | if (check_tmpfs(dir) >= 0) | |
70 | goto done; | |
71 | else | |
72 | goto warn; | |
74735341 TS |
73 | } |
74 | } | |
0d71832e | 75 | printf("none found\n"); |
74735341 | 76 | |
0d71832e TS |
77 | for (i = 0; tmpfs_dirs[i]; i++) { |
78 | dir = tmpfs_dirs[i]; | |
79 | if (check_tmpfs(dir) >= 0) | |
80 | goto done; | |
74735341 TS |
81 | } |
82 | ||
0d71832e TS |
83 | dir = fallback_dir; |
84 | warn: | |
85 | printf("Warning: tempdir %s is not on tmpfs\n", dir); | |
86 | done: | |
87 | /* Make a copy since getenv results may not remain valid forever. */ | |
88 | return strdup(dir); | |
966a082f RL |
89 | } |
90 | ||
5134d8fe | 91 | /* |
0d71832e TS |
92 | * Create an unlinked tempfile in a suitable tempdir. template must be the |
93 | * basename part of the template with a leading '/'. | |
966a082f | 94 | */ |
0d71832e | 95 | static int __init make_tempfile(const char *template) |
966a082f | 96 | { |
0d71832e | 97 | char *tempname; |
74735341 | 98 | int fd; |
966a082f | 99 | |
0d71832e TS |
100 | if (tempdir == NULL) { |
101 | tempdir = choose_tempdir(); | |
102 | if (tempdir == NULL) { | |
103 | fprintf(stderr, "Failed to choose tempdir: %s\n", | |
104 | strerror(errno)); | |
105 | return -1; | |
74735341 | 106 | } |
966a082f RL |
107 | } |
108 | ||
0d71832e | 109 | tempname = malloc(strlen(tempdir) + strlen(template) + 1); |
11a7ac23 JM |
110 | if (tempname == NULL) |
111 | return -1; | |
87276f72 | 112 | |
0d71832e TS |
113 | strcpy(tempname, tempdir); |
114 | strcat(tempname, template); | |
0f80bc85 | 115 | fd = mkstemp(tempname); |
5134d8fe | 116 | if (fd < 0) { |
0f80bc85 JD |
117 | fprintf(stderr, "open - cannot create %s: %s\n", tempname, |
118 | strerror(errno)); | |
87276f72 | 119 | goto out; |
0f80bc85 | 120 | } |
0d71832e | 121 | if (unlink(tempname) < 0) { |
0f80bc85 | 122 | perror("unlink"); |
2a6d0ac1 | 123 | goto close; |
0f80bc85 | 124 | } |
0d71832e | 125 | free(tempname); |
81999a01 | 126 | return fd; |
2a6d0ac1 DB |
127 | close: |
128 | close(fd); | |
87276f72 PBG |
129 | out: |
130 | free(tempname); | |
131 | return -1; | |
0f80bc85 JD |
132 | } |
133 | ||
0d71832e | 134 | #define TEMPNAME_TEMPLATE "/vm_file-XXXXXX" |
0f80bc85 | 135 | |
5134d8fe | 136 | static int __init create_tmp_file(unsigned long long len) |
0f80bc85 JD |
137 | { |
138 | int fd, err; | |
139 | char zero; | |
140 | ||
0d71832e | 141 | fd = make_tempfile(TEMPNAME_TEMPLATE); |
5134d8fe | 142 | if (fd < 0) |
0f80bc85 | 143 | exit(1); |
0f80bc85 JD |
144 | |
145 | err = fchmod(fd, 0777); | |
5134d8fe | 146 | if (err < 0) { |
512b6fb1 | 147 | perror("fchmod"); |
0f80bc85 JD |
148 | exit(1); |
149 | } | |
150 | ||
5134d8fe JD |
151 | /* |
152 | * Seek to len - 1 because writing a character there will | |
190f4939 JD |
153 | * increase the file size by one byte, to the desired length. |
154 | */ | |
155 | if (lseek64(fd, len - 1, SEEK_SET) < 0) { | |
512b6fb1 | 156 | perror("lseek64"); |
0f80bc85 JD |
157 | exit(1); |
158 | } | |
159 | ||
160 | zero = 0; | |
161 | ||
a61f334f | 162 | err = write(fd, &zero, 1); |
5134d8fe | 163 | if (err != 1) { |
a61f334f | 164 | perror("write"); |
0f80bc85 JD |
165 | exit(1); |
166 | } | |
167 | ||
81999a01 | 168 | return fd; |
0f80bc85 JD |
169 | } |
170 | ||
36e45463 | 171 | int __init create_mem_file(unsigned long long len) |
0f80bc85 JD |
172 | { |
173 | int err, fd; | |
174 | ||
02dea087 | 175 | fd = create_tmp_file(len); |
0f80bc85 | 176 | |
512b6fb1 | 177 | err = os_set_exec_close(fd); |
5134d8fe | 178 | if (err < 0) { |
0f80bc85 JD |
179 | errno = -err; |
180 | perror("exec_close"); | |
181 | } | |
81999a01 | 182 | return fd; |
0f80bc85 | 183 | } |
966a082f | 184 | |
36e45463 | 185 | void __init check_tmpexec(void) |
966a082f RL |
186 | { |
187 | void *addr; | |
188 | int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE); | |
189 | ||
190 | addr = mmap(NULL, UM_KERN_PAGE_SIZE, | |
191 | PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0); | |
0d71832e | 192 | printf("Checking PROT_EXEC mmap in %s...", tempdir); |
5134d8fe | 193 | if (addr == MAP_FAILED) { |
966a082f | 194 | err = errno; |
0d71832e | 195 | printf("%s\n", strerror(err)); |
c9a3072d | 196 | close(fd); |
5134d8fe | 197 | if (err == EPERM) |
0d71832e | 198 | printf("%s must be not mounted noexec\n", tempdir); |
966a082f RL |
199 | exit(1); |
200 | } | |
201 | printf("OK\n"); | |
202 | munmap(addr, UM_KERN_PAGE_SIZE); | |
203 | ||
204 | close(fd); | |
205 | } |