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| 2 | * Copyright (c) 2019 Alexey Dobriyan <[email protected]>
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| 3 | *
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| 4 | * Permission to use, copy, modify, and distribute this software for any
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| 5 | * purpose with or without fee is hereby granted, provided that the above
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| 6 | * copyright notice and this permission notice appear in all copies.
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| 7 | *
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| 8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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| 9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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| 10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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| 11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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| 12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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| 13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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| 14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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| 15 |
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| 16 |
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| 17 | #include <errno.h>
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| 18 | #include <sched.h>
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| 19 | #include <stdio.h>
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| 20 | #include <string.h>
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| 21 | #include <sys/types.h>
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| 22 | #include <sys/stat.h>
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| 23 | #include <fcntl.h>
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| 24 | #include <sys/mount.h>
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| 25 | #include <unistd.h>
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| 26 |
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| 27 | int main(void)
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| 28 | {
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| 29 | if (unshare(CLONE_NEWNS) == -1) {
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| 30 | if (errno == ENOSYS || errno == EPERM) {
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| 31 | fprintf(stderr, "error: unshare, errno %d\n", errno);
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| 32 | return 4;
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| 33 | }
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| 34 | fprintf(stderr, "error: unshare, errno %d\n", errno);
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| 35 | return 1;
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| 36 | }
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| 37 | if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
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| 38 | fprintf(stderr, "error: mount '/', errno %d\n", errno);
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| 39 | return 1;
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| 40 | }
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| 41 |
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| 42 | if (mount(NULL, "/tmp", "ramfs", 0, NULL) == -1) {
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| 43 | fprintf(stderr, "error: mount ramfs, errno %d\n", errno);
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| 44 | return 1;
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| 45 | }
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| 46 |
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| 47 | #define FILENAME "/tmp/1"
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| 48 |
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| 49 | int fd = creat(FILENAME, 0700);
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| 50 | if (fd == -1) {
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| 51 | fprintf(stderr, "error: creat, errno %d\n", errno);
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| 52 | return 1;
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| 53 | }
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| 54 | #define S "#!" FILENAME "\n"
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| 55 | if (write(fd, S, strlen(S)) != strlen(S)) {
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| 56 | fprintf(stderr, "error: write, errno %d\n", errno);
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| 57 | return 1;
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| 58 | }
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| 59 | close(fd);
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| 60 |
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| 61 | int rv = execve(FILENAME, NULL, NULL);
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| 62 | if (rv == -1 && errno == ELOOP) {
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| 63 | return 0;
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| 64 | }
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| 65 | fprintf(stderr, "error: execve, rv %d, errno %d\n", rv, errno);
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| 66 | return 1;
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| 67 | }
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