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author | px4dev <px4@purgatory.org> | 2012-08-04 15:12:36 -0700 |
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committer | px4dev <px4@purgatory.org> | 2012-08-04 15:12:36 -0700 |
commit | 8a365179eafdf3aea98e60ab9f5882b200d4c759 (patch) | |
tree | 4f38d6d4cd80bd0b6e22e2bb534c3f117ce44e56 /nuttx/sched/env_release.c | |
download | px4-firmware-8a365179eafdf3aea98e60ab9f5882b200d4c759.tar.gz px4-firmware-8a365179eafdf3aea98e60ab9f5882b200d4c759.tar.bz2 px4-firmware-8a365179eafdf3aea98e60ab9f5882b200d4c759.zip |
Fresh import of the PX4 firmware sources.
Diffstat (limited to 'nuttx/sched/env_release.c')
-rw-r--r-- | nuttx/sched/env_release.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/nuttx/sched/env_release.c b/nuttx/sched/env_release.c new file mode 100644 index 000000000..83e65dbb5 --- /dev/null +++ b/nuttx/sched/env_release.c @@ -0,0 +1,125 @@ +/**************************************************************************** + * sched/env_clearenv.c + * + * Copyright (C) 2007, 2009 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 <sched.h> +#include <errno.h> +#include "os_internal.h" +#include "env_internal.h" + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: env_release + * + * Description: + * The env_release() function clears the environment of all name-value + * pairs and sets the value of the external variable environ to NULL. + * + * Parameters: + * ptcb Identifies the TCB containing the environment structure + * + * Return Value: + * zero on success + * + * Assumptions: + * Not called from an interrupt handler + * + ****************************************************************************/ + +int env_release(FAR _TCB *ptcb) +{ + int ret = OK; + + if (!ptcb) + { + ret = -EINVAL; + } + else + { + FAR environ_t *envp; + + /* Examine the environ data in the TCB. Preemption is disabled because the + * the environment could be shared among threads. + */ + + sched_lock(); + envp = ptcb->envp; + if (ptcb->envp) + { + /* Check the reference count on the environment structure */ + + if ( envp->ev_crefs <= 1) + { + /* Decrementing the reference count will destroy the environment */ + + sched_free( envp ); /* plain free() should be fine here */ + } + else + { + /* The environment will persist after decrementing the reference + * count */ + + envp->ev_crefs--; + } + + /* In any case, the environment is no longer accessible on this thread */ + + ptcb->envp = NULL; + } + + sched_unlock(); + } + + return ret; +} + +#endif /* CONFIG_DISABLE_ENVIRON */ + + + |