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Avoid alloca in setenv for long strings.

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This commit is contained in:
Ulrich Drepper 2010-02-02 09:55:55 -08:00
parent b34e12e22c
commit c63bfa7994
2 changed files with 70 additions and 30 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
2010-02-02 Ulrich Drepper <drepper@redhat.com>
* stdlib/setenv.c (__add_to_environ): Don't use alloca if
__libc_use_alloca tells us not to. Fix memory leak in an error
situation. Based partially on patch by Jim Meyering.
2010-01-26 Samuel Thibault <samuel.thibault@ens-lyon.org>
* sysdeps/mach/getsysstats.c (get_nprocs_conf, get_nprocs,

94
stdlib/setenv.c
View file

@ -1,4 +1,4 @@
/* Copyright (C) 1992,1995-2001,2004, 2008 Free Software Foundation, Inc.
/* Copyright (C) 1992,1995-2001,2004, 2008, 2010 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
@ -136,6 +136,7 @@ __add_to_environ (name, value, combined, replace)
if (ep == NULL || __builtin_expect (*ep == NULL, 1))
{
const size_t varlen = namelen + 1 + vallen;
char **new_environ;
/* We allocated this space; we can extend it. */
@ -156,11 +157,21 @@ __add_to_environ (name, value, combined, replace)
{
/* See whether the value is already known. */
#ifdef USE_TSEARCH
# ifdef __GNUC__
char new_value[namelen + 1 + vallen];
# else
char *new_value = (char *) alloca (namelen + 1 + vallen);
# endif
char *new_value;
int use_alloca = __libc_use_alloca (varlen);
if (__builtin_expect (use_alloca, 1))
new_value = (char *) alloca (varlen);
else
{
new_value = malloc (varlen);
if (new_value == NULL)
{
UNLOCK;
if (last_environ == NULL)
free (new_environ);
return -1;
}
}
# ifdef _LIBC
__mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
value, vallen);
@ -174,21 +185,28 @@ __add_to_environ (name, value, combined, replace)
if (__builtin_expect (new_environ[size] == NULL, 1))
#endif
{
new_environ[size] = (char *) malloc (namelen + 1 + vallen);
if (__builtin_expect (new_environ[size] == NULL, 0))
#ifdef USE_TSEARCH
if (__builtin_expect (! use_alloca, 0))
new_environ[size] = new_value;
else
#endif
{
__set_errno (ENOMEM);
UNLOCK;
return -1;
}
new_environ[size] = (char *) malloc (varlen);
if (__builtin_expect (new_environ[size] == NULL, 0))
{
UNLOCK;
return -1;
}
#ifdef USE_TSEARCH
memcpy (new_environ[size], new_value, namelen + 1 + vallen);
memcpy (new_environ[size], new_value, varlen);
#else
memcpy (new_environ[size], name, namelen);
new_environ[size][namelen] = '=';
memcpy (&new_environ[size][namelen + 1], value, vallen);
memcpy (new_environ[size], name, namelen);
new_environ[size][namelen] = '=';
memcpy (&new_environ[size][namelen + 1], value, vallen);
#endif
}
/* And save the value now. We cannot do this when we remove
the string since then we cannot decide whether it is a
user string or not. */
@ -213,12 +231,21 @@ __add_to_environ (name, value, combined, replace)
np = (char *) combined;
else
{
const size_t varlen = namelen + 1 + vallen;
#ifdef USE_TSEARCH
# ifdef __GNUC__
char new_value[namelen + 1 + vallen];
# else
char *new_value = (char *) alloca (namelen + 1 + vallen);
# endif
char *new_value;
int use_alloca = __libc_use_alloca (varlen);
if (__builtin_expect (use_alloca, 1))
new_value = (char *) alloca (varlen);
else
{
new_value = malloc (varlen);
if (new_value == NULL)
{
UNLOCK;
return -1;
}
}
# ifdef _LIBC
__mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
value, vallen);
@ -232,20 +259,27 @@ __add_to_environ (name, value, combined, replace)
if (__builtin_expect (np == NULL, 1))
#endif
{
np = malloc (namelen + 1 + vallen);
if (__builtin_expect (np == NULL, 0))
#ifdef USE_TSEARCH
if (__builtin_expect (! use_alloca, 0))
np = new_value;
else
#endif
{
UNLOCK;
return -1;
}
np = malloc (varlen);
if (__builtin_expect (np == NULL, 0))
{
UNLOCK;
return -1;
}
#ifdef USE_TSEARCH
memcpy (np, new_value, namelen + 1 + vallen);
memcpy (np, new_value, varlen);
#else
memcpy (np, name, namelen);
np[namelen] = '=';
memcpy (&np[namelen + 1], value, vallen);
memcpy (np, name, namelen);
np[namelen] = '=';
memcpy (&np[namelen + 1], value, vallen);
#endif
}
/* And remember the value. */
STORE_VALUE (np);
}