59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
#define _GNU_SOURCE
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#include <linux/limits.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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/* from /usr/include/bits/fcntl-linux.h in newer glibc */
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#ifndef __O_TMPFILE
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#pragma message "__O_TMPFILE is not defined!"
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# define __O_TMPFILE (020000000 | __O_DIRECTORY)
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//# define O_TMPFILE __O_TMPFILE /* Atomically create nameless file. */
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#endif
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int main()
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{
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int fd, kfd;
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char path[PATH_MAX], tmp[PATH_MAX];
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struct stat statbuf;
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kfd = syscall(SYS_openat, AT_FDCWD, ".", __O_TMPFILE | O_RDWR, 0600);
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if (kfd == -1) {
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if (errno == EISDIR || errno == ENOTSUP) {
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printf("__O_TMPFILE not supported by kernel, next checks dont make sense!\n");
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exit(10);
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}
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}
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fd = openat(AT_FDCWD, ".", __O_TMPFILE | O_RDWR, 0600);
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if (fd == -1) {
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if (errno == EISDIR || errno == ENOTSUP) {
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printf("__O_TMPFILE not supported by glibc\n");
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exit(EXIT_FAILURE);
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}
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}
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snprintf(path, PATH_MAX, "/proc/self/fd/%d", fd);
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readlink(path, tmp, PATH_MAX);
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printf("%s -> %s file created with __O_TMPFILE\n", path, tmp);
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if (stat(path, &statbuf) == -1) {
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perror("stat");
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exit(EXIT_FAILURE);
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}
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printf("%s has mode 0%o\n", path, statbuf.st_mode & ~S_IFMT);
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if ((statbuf.st_mode & ~S_IFMT) != 0600) {
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printf("FAIL: mode is not 0600\n");
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exit(EXIT_FAILURE);
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}
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return 0;
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}
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