glibc/pwd/fgetpwent.c
Adhemerval Zanella Netto 88677348b4 Move libc_freeres_ptrs and libc_subfreeres to hidden/weak functions
They are both used by __libc_freeres to free all library malloc
allocated resources to help tooling like mtrace or valgrind with
memory leak tracking.

The current scheme uses assembly markers and linker script entries
to consolidate the free routine function pointers in the RELRO segment
and to be freed buffers in BSS.

This patch changes it to use specific free functions for
libc_freeres_ptrs buffers and call the function pointer array directly
with call_function_static_weak.

It allows the removal of both the internal macros and the linker
script sections.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-03-27 13:57:55 -03:00

88 lines
2.2 KiB
C

/* Copyright (C) 1991-2023 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
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <libc-lock.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <set-freeres.h>
/* We need to protect the dynamic buffer handling. */
__libc_lock_define_initialized (static, lock);
static char *buffer;
/* Read one entry from the given stream. */
struct passwd *
fgetpwent (FILE *stream)
{
static size_t buffer_size;
static struct passwd resbuf;
fpos_t pos;
struct passwd *result;
int save;
if (fgetpos (stream, &pos) != 0)
return NULL;
/* Get lock. */
__libc_lock_lock (lock);
/* Allocate buffer if not yet available. */
if (buffer == NULL)
{
buffer_size = NSS_BUFLEN_PASSWD;
buffer = malloc (buffer_size);
}
while (buffer != NULL
&& (__fgetpwent_r (stream, &resbuf, buffer, buffer_size, &result)
== ERANGE))
{
char *new_buf;
buffer_size += NSS_BUFLEN_PASSWD;
new_buf = realloc (buffer, buffer_size);
if (new_buf == NULL)
{
/* We are out of memory. Free the current buffer so that the
process gets a chance for a normal termination. */
save = errno;
free (buffer);
__set_errno (save);
}
buffer = new_buf;
/* Reset the stream. */
if (fsetpos (stream, &pos) != 0)
buffer = NULL;
}
if (buffer == NULL)
result = NULL;
/* Release lock. Preserve error value. */
save = errno;
__libc_lock_unlock (lock);
__set_errno (save);
return result;
}
weak_alias (buffer, __libc_fgetpwent_freemem_ptr)