Attachment 18556 Details for Bug 15805 – Test program

Test program

test2.c (text/x-csrc), 3.23 KB, created by Samuel Cabrero on 2025-02-13 15:45:02 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Samuel Cabrero

Created: 2025-02-13 15:45:02 UTC

Size: 3.23 KB

patch

obsolete

>#define _GNU_SOURCE
>
>#include <fcntl.h>
>#include <linux/openat2.h>
>#include <sys/syscall.h>
>#include <stdio.h>
>#include <unistd.h>
>#include <errno.h>
>#include <string.h>
>#include <sys/statfs.h>
>#include <linux/magic.h>
>#include <dirent.h>
>
>struct linux_dirent {
>	unsigned long  d_ino;     /* Inode number */
>	unsigned long  d_off;     /* Offset to next linux_dirent */
>	unsigned short d_reclen;  /* Length of this linux_dirent */
>	char           d_name[];  /* Filename (null-terminated) */
>	/*
>	char           pad;       // Zero padding byte
>	char           d_type;    // File type (only since Linux
>	                              // 2.6.4); offset is (d_reclen - 1)
>	*                                                                                       */
>};
>
>
>int main(int argc, char **argv)
>{
>	const char *target = NULL;
>	int data_pathref_fd = -1;
>	int d1_pathref_fd = -1;
>	int proc_fd = -1;
>	int rc = -1;
>	int i;
>	char proc_path[256];
>	struct open_how linux_how = {
>		.flags = O_RDONLY | O_DIRECTORY,
>		.mode = 0,
>		.resolve = RESOLVE_NO_XDEV,
>	};
>	char dentbuf[1024*1024];
>
>	if (argc < 2) {
>		printf("Usage: %s <target>\n", argv[0]);
>		return 1;
>	}
>	target = argv[1];
>
>	printf("Target is %s\n", target);
>
>	rc = chdir(target);
>	printf("chddir(%s) -> %d\n", target, rc);
>	if (rc == -1) {
>		perror("chdir");
>		return 1;
>	}
>
>	data_pathref_fd = openat(AT_FDCWD,
>				 "data",
>				 O_RDONLY | O_NOFOLLOW | O_PATH);
>	printf("openat(AT_FDCWD, data, O_RDONLY | O_NOFOLLOW | O_PATH) -> %d\n", data_pathref_fd);
>	if (data_pathref_fd == -1) {
>		perror("openat");
>		return 1;
>	}
>
>	d1_pathref_fd = openat(data_pathref_fd,
>			       "d1",
>			       O_RDONLY | O_NOFOLLOW | O_PATH);
>	printf("openat(%d, d1, O_RDONLY | O_NOFOLLOW | O_PATH) -> %d\n", data_pathref_fd, d1_pathref_fd);
>	if (d1_pathref_fd == -1) {
>		perror("openat");
>		return 1;
>	}
>
>	snprintf(proc_path,
>		 sizeof(proc_path),
>		 "/proc/self/fd/%d",
>		 d1_pathref_fd);
>again:
>	proc_fd = syscall(SYS_openat2, AT_FDCWD, proc_path, &linux_how, sizeof(linux_how));
>	printf("openat2(AT_FDCWD, %s, ) -> %d %s\n", proc_path, proc_fd, proc_fd == -1 ? strerror(errno) : "");
>	//printf("Press key to continue (pid=%d)...\n", getpid());
>	//getchar();
>	if (proc_fd == -1) {
>		struct statfs sbuf = { 0 };
>		rc = fstatfs(d1_pathref_fd, &sbuf);
>		if (rc == -1) {
>			perror("statfs");
>			return 1;
>		}
>
>		printf("sbuf.f_type=0x%X\n", sbuf.f_type);
>		if (sbuf.f_type == AUTOFS_SUPER_MAGIC) {
>			printf("It is autofs, fallback to name-based\n");
>			proc_fd = openat(data_pathref_fd,
>			       "d1",
>			       O_RDONLY | O_NOFOLLOW);
>			printf("openat(%d, d1, O_RDONLY | O_NOFOLLOW) -> %d\n", data_pathref_fd, proc_fd);
>			if (proc_fd == -1) {
>				perror("fallback");
>				return -1;
>			}
>			goto list;
>		} else {
>			linux_how.resolve &= ~RESOLVE_NO_XDEV;
>			printf("It is not autofs, retry without RESOLVE_NO_XDEV\n");
>			goto again;
>		}
>		return 1;
>	}
>list:
>	rc = syscall(SYS_getdents, proc_fd, dentbuf, sizeof(dentbuf));
>	printf("getdents(%d) -> %d\n", proc_fd);
>	if (rc == -1) {
>		perror("getdents");
>		return 1;
>	}
>	for (i = 0; i < rc;) {
>		struct linux_dirent *d = NULL;
>		char d_type;
>		d = (struct linux_dirent *) (dentbuf + i);
>			printf("%s\n", (char *)d->d_name );
>		i += d->d_reclen;
>	}
>
>	close(proc_fd);
>	close(d1_pathref_fd);
>	close(data_pathref_fd);
>	return 0;
>}

Actions: View

Attachments on bug 15805: 18556 | 18573