glibc/support/xreadlink.c

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/* Error-checking, allocating wrapper for readlink.
Copyright (C) 2017-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <scratch_buffer.h>
#include <support/check.h>
#include <support/support.h>
#include <xunistd.h>
char *
xreadlink (const char *path)
{
struct scratch_buffer buf;
scratch_buffer_init (&buf);
while (true)
{
ssize_t count = readlink (path, buf.data, buf.length);
if (count < 0)
FAIL_EXIT1 ("readlink (\"%s\"): %m", path);
if (count < buf.length)
{
char *result = xstrndup (buf.data, count);
scratch_buffer_free (&buf);
return result;
}
if (!scratch_buffer_grow (&buf))
FAIL_EXIT1 ("scratch_buffer_grow in xreadlink");
}
}