/****************************************************************************
* sched/env_setenv.c
*
* Copyright (C) 2007, 2009, 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifndef CONFIG_DISABLE_ENVIRON
#include <stdio.h>
#include <stdlib.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#include <nuttx/kmalloc.h>
#include "os_internal.h"
#include "env_internal.h"
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: setenv
*
* Description:
* The setenv() function adds the variable name to the environment with the
* specified 'value' if the varialbe 'name" does not exist. If the 'name'
* does exist in the environment, then its value is changed to 'value' if
* 'overwrite' is non-zero; if 'overwrite' is zero, then the value of name
* unaltered.
*
* Parameters:
* name - The name of the variable to change
* value - The new value of the variable
* overwrite - Replace any existing value if non-zero.
*
* Return Value:
* Zero on success
*
* Assumptions:
* Not called from an interrupt handler
*
****************************************************************************/
int setenv(const char *name, const char *value, int overwrite)
{
FAR _TCB *rtcb;
FAR environ_t *envp;
FAR char *pvar;
int varlen;
int ret = OK;
/* Verify input parameter */
if (!name)
{
ret = EINVAL;
goto errout;
}
/* if no value is provided, then this is the same as unsetenv (unless
* overwrite is false)
*/
if (!value || *value == '\0')
{
/* If overwite is set then this is the same as unsetenv */
if (overwrite)
{
return unsetenv(name);
}
else
{
/* Otherwise, it is a request to remove a variable without altering it? */
return OK;
}
}
/* Get a reference to the thread-private environ in the TCB.*/
sched_lock();
rtcb = (FAR _TCB*)g_readytorun.head;
envp = rtcb->envp;
/* Check if the variable alreay exists */
if ( envp && (pvar = env_findvar(envp, name)) != NULL)
{
/* It does! Do we have permission to overwrite the existing value? */
if (!overwrite)
{
/* No.. then just return success */
sched_unlock();
return OK;
}
/* Yes.. just remove the name=value pair from the environment. It will
* be added again below. Note that we are responsible for reallocating
* the environment buffer; this will happen below.
*/
(void)env_removevar(envp, pvar);
}
/* Get the size of the new name=value string. The +2 is for the '=' and for
* null terminator
*/
varlen = strlen(name) + strlen(value) + 2;
/* Then allocate or reallocate the environment buffer */
if (envp)
{
int alloc = envp->ev_alloc;
environ_t *tmp = (environ_t*)krealloc(envp, SIZEOF_ENVIRON_T(alloc + varlen));
if (!tmp)
{
ret = ENOMEM;
goto errout_with_lock;
}
envp = tmp;
envp->ev_alloc = alloc + varlen;
pvar = &envp->ev_env[alloc];
}
else
{
envp = (environ_t*)kmalloc(SIZEOF_ENVIRON_T(varlen));
if (!envp)
{
ret = ENOMEM;
goto errout_with_lock;
}
envp->ev_crefs = 1;
envp->ev_alloc = varlen;
pvar = envp->ev_env;
}
/* Now, put the new name=value string into the environment buffer */
sprintf(pvar, "%s=%s", name, value);
/* Save the new environment pointer (it might have changed due to allocation or
* reallocation.
*/
rtcb->envp = envp;
sched_unlock();
return OK;
errout_with_lock:
sched_unlock();
errout:
errno = ret;
return ERROR;
}
#endif /* CONFIG_DISABLE_ENVIRON */
