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[PATCH 2/5] Cygwin: Allow the environment pointer to be NULL
- From: Ken Brown <kbrown at cornell dot edu>
- To: cygwin-patches at cygwin dot com
- Date: Mon, 4 Jun 2018 15:36:04 -0400
- Subject: [PATCH 2/5] Cygwin: Allow the environment pointer to be NULL
- References: <20180604193607.17088-1-kbrown@cornell.edu>
Following glibc, interpret this as meaning the environment is empty.
---
winsup/cygwin/environ.cc | 29 ++++++++++++++++++-----------
1 file changed, 18 insertions(+), 11 deletions(-)
diff --git a/winsup/cygwin/environ.cc b/winsup/cygwin/environ.cc
index b452d21a5..8e6bbe561 100644
--- a/winsup/cygwin/environ.cc
+++ b/winsup/cygwin/environ.cc
@@ -483,6 +483,9 @@ my_findenv (const char *name, int *offset)
register char **p;
const char *c;
+ if (cur_environ () == NULL)
+ return NULL;
+
c = name;
len = 0;
while (*c && *c != '=')
@@ -545,14 +548,18 @@ _getenv_r (struct _reent *, const char *name)
return findenv_func (name, &offset);
}
-/* Return size of environment block, including terminating NULL. */
+/* Return number of environment entries, including terminating NULL. */
static int __stdcall
envsize (const char * const *in_envp)
{
const char * const *envp;
+
+ if (in_envp == NULL)
+ return 0;
+
for (envp = in_envp; *envp; envp++)
continue;
- return (1 + envp - in_envp) * sizeof (const char *);
+ return 1 + envp - in_envp;
}
/* Takes similar arguments to setenv except that overwrite is
@@ -584,23 +591,23 @@ _addenv (const char *name, const char *value, int overwrite)
{ /* Create new slot. */
int sz = envsize (cur_environ ());
- /* Allocate space for two new slots even though only one is needed.
- According to the commit message for commit ebd645e
- (2001-10-03), this is done to "work around problems with some
- buggy applications." */
- int allocsz = sz + (2 * sizeof (char *));
+ /* If sz == 0, we need two new slots, one for the terminating NULL.
+ But we add two slots in all cases, as has been done since
+ 2001-10-03 (commit ebd645e) to "work around problems with
+ some buggy applications." */
+ int allocsz = (sz + 2) * sizeof (char *);
- offset = (sz - 1) / sizeof (char *);
+ offset = sz == 0 ? 0 : sz - 1;
/* Allocate space for additional element. */
if (cur_environ () == lastenviron)
lastenviron = __cygwin_environ = (char **) realloc (cur_environ (),
allocsz);
else if ((lastenviron = (char **) malloc (allocsz)) != NULL)
- __cygwin_environ = (char **) memcpy ((char **) lastenviron,
- __cygwin_environ, sz);
+ __cygwin_environ = (char **) memcpy (lastenviron, __cygwin_environ,
+ sz * sizeof (char *));
- if (!__cygwin_environ)
+ if (!lastenviron)
{
#ifdef DEBUGGING
try_to_debug ();
--
2.17.0