Add environment variable function

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@294 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 118 insertions, 0 deletions

diff --git a/nuttx/sched/env_removevar.c b/nuttx/sched/env_removevar.c
new file mode 100644
index 000000000..990e9659a
--- /dev/null
+++ b/nuttx/sched/env_removevar.c
@@ -0,0 +1,118 @@
+/****************************************************************************
+ * env_removevar.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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 <string.h>
+#include <sched.h>
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  env_removevar
+ *
+ * Description:
+ *   Remove the referenced name=value pair from the environment
+ *
+ * Parameters:
+ *   envp The environment containing the name=value pair
+ *   pvar A pointer to the name=value pair in the restroom
+ *
+ * Return Value:
+ *   Zero on success
+ *
+ * Assumptions:
+ *   - Not called from an interrupt handler
+ *   - Caller has pre-emptions disabled
+ *   - Caller will reallocate the environment structure to the correct size
+ *
+ ****************************************************************************/
+
+int env_removevar(environ_t *envp, char *pvar)
+{
+  int ret = ERROR;
+  if (envp && pvar)
+    {
+      /* Verify that the pointer lies within the environment region */
+
+      int   alloc = envp->ev_alloc;       /* Size of the allocated environment */
+      char *end   = &envp->ev_env[alloc]; /* Pointer to the end+1 of the environment */
+
+      if (pvar >= envp->ev_env && pvar < end)
+        {
+          /* Set up for the removal */
+
+          int   len  = strlen(pvar) + 1;  /* Length of name=value string to remove */
+          char *src  = &pvar[len];        /* Address of name=value string after */
+          char *dest = pvar;              /* Location to move the next string */
+          int   count = end - src;         /* Number of bytes to move (might be zero) */
+
+          /* Move all of the environment strings after the removed one 'down.'
+           * this is inefficient, but robably not high duty.
+           */
+
+          while (count-- > 0)
+            {
+              *dest++ = *src++;
+            }
+
+          /* Then set to the new allocation size.  The caller is expected to
+           * call realloc at some point but we don't do that here because the
+           * caller may add more stuff to the environment.
+           */
+
+          envp->ev_alloc -= len;
+          ret = OK;
+        }
+    }
+  return ret;
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+