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From: Reiner Herrmann <reiner@reiner-h.de>
Newsgroups: gmane.linux.lib.musl.general
Subject: realpath after chroot
Date: Tue, 8 Oct 2019 19:24:02 +0200
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Hi,

I noticed that realpath is no longer working after chroot is called.
With the example from below I get the following output with musl 1.1.23:

# ./a.out
/
No such file or directory

With glibc it is working as I would expect:

# ./a.out
/
/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <unistd.h>
#include <errno.h>

int main() {
	char *p = realpath("/", NULL);
	if (!p) {
		printf("%s\n", strerror(errno));
	} else {
		printf("%s\n", p);
		free(p);
	}

	if (chroot("/tmp") == -1)
		printf("chroot failed\n");

	p = realpath("/", NULL);
	if (!p) {
		printf("%s\n", strerror(errno));
	} else {
		printf("%s\n", p);
		free(p);
	}

	return 0;
}


Kind regards,
  Reiner

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