| 1 | |
| 2 |
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| 3 | #define _GNU_SOURCE
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| 4 | #include <errno.h>
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| 5 | #include <fcntl.h>
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| 6 | #include <sched.h>
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| 7 | #include <stdio.h>
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| 8 | #include <stdlib.h>
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| 9 | #include <string.h>
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| 10 | #include <sys/ioctl.h>
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| 11 | #include <sys/mount.h>
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| 12 | #include <sys/stat.h>
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| 13 | #include <sys/types.h>
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| 14 | #include <unistd.h>
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| 15 | #include <linux/android/binder.h>
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| 16 | #include <linux/android/binderfs.h>
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| 17 |
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| 18 | int main(int argc, char *argv[])
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| 19 | {
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| 20 | int fd, ret, saved_errno;
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| 21 | struct binderfs_device device = { 0 };
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| 22 |
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| 23 | ret = unshare(CLONE_NEWNS);
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| 24 | if (ret < 0) {
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| 25 | fprintf(stderr, "%s - Failed to unshare mount namespace\n",
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| 26 | strerror(errno));
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| 27 | exit(EXIT_FAILURE);
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| 28 | }
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| 29 |
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| 30 | ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
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| 31 | if (ret < 0) {
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| 32 | fprintf(stderr, "%s - Failed to mount / as private\n",
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| 33 | strerror(errno));
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| 34 | exit(EXIT_FAILURE);
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| 35 | }
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| 36 |
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| 37 | ret = mkdir("/dev/binderfs", 0755);
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| 38 | if (ret < 0 && errno != EEXIST) {
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| 39 | fprintf(stderr, "%s - Failed to create binderfs mountpoint\n",
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| 40 | strerror(errno));
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| 41 | exit(EXIT_FAILURE);
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| 42 | }
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| 43 |
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| 44 | ret = mount(NULL, "/dev/binderfs", "binder", 0, 0);
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| 45 | if (ret < 0) {
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| 46 | fprintf(stderr, "%s - Failed to mount binderfs\n",
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| 47 | strerror(errno));
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| 48 | exit(EXIT_FAILURE);
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| 49 | }
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| 50 |
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| 51 | memcpy(device.name, "my-binder", strlen("my-binder"));
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| 52 |
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| 53 | fd = open("/dev/binderfs/binder-control", O_RDONLY | O_CLOEXEC);
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| 54 | if (fd < 0) {
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| 55 | fprintf(stderr, "%s - Failed to open binder-control device\n",
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| 56 | strerror(errno));
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| 57 | exit(EXIT_FAILURE);
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| 58 | }
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| 59 |
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| 60 | ret = ioctl(fd, BINDER_CTL_ADD, &device);
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| 61 | saved_errno = errno;
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| 62 | close(fd);
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| 63 | errno = saved_errno;
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| 64 | if (ret < 0) {
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| 65 | fprintf(stderr, "%s - Failed to allocate new binder device\n",
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| 66 | strerror(errno));
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| 67 | exit(EXIT_FAILURE);
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| 68 | }
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| 69 |
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| 70 | printf("Allocated new binder device with major %d, minor %d, and name %s\n",
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| 71 | device.major, device.minor, device.name);
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| 72 |
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| 73 | ret = unlink("/dev/binderfs/my-binder");
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| 74 | if (ret < 0) {
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| 75 | fprintf(stderr, "%s - Failed to delete binder device\n",
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| 76 | strerror(errno));
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| 77 | exit(EXIT_FAILURE);
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| 78 | }
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| 79 |
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| 80 |
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| 81 | exit(EXIT_SUCCESS);
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| 82 | }
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