Com: avoid intentional memory leak in epicsEnvSet

Switch default impl. to setenv/unsetenv
Switch WIN32 to use _putenv_s
On vxWorks putenv() is documented to make a copy.

log error, but never halt, if env (un)set not possible.

RTEMS <4.10 compat where unsetenv() returns void.

modules/libcom/src/osi/os/WIN32/osdEnv.c

@@ -21,38 +21,28 @@
 
 #include "epicsStdio.h"
 #include "errlog.h"
-#include "cantProceed.h"
 #include "envDefs.h"
 #include "osiUnistd.h"
 #include "epicsFindSymbol.h"
 #include "iocsh.h"
 
+static
+void setEnv(const char *name, const char *value)
+{
+    errno_t err = _putenv_s(name, value);
+    if(err)
+        errlogPrintf("Can't set environment %s=\"%s\" : %d\n", name, value, (int)err);
+}
+
 /*
  * Set the value of an environment variable
  * Leaks memory, but the assumption is that this routine won't be
  * called often enough for the leak to be a problem.
  */
 LIBCOM_API void epicsStdCall epicsEnvSet (const char *name, const char *value)
 {
-    char *cp;
-
     iocshEnvClear(name);
-
-    cp = mallocMustSucceed (strlen (name) + strlen (value) + 2, "epicsEnvSet");
-    strcpy (cp, name);
-    strcat (cp, "=");
-    strcat (cp, value);
-    if (putenv (cp) < 0) {
-        errPrintf(
-                -1L,
-                __FILE__,
-                __LINE__,
-                "Failed to set environment parameter \"%s\" to \"%s\": %s\n",
-                name,
-                value,
-                strerror (errno));
-        free (cp);
-    }
+    setEnv(name, value);
 }
 
 /*
@@ -63,8 +53,7 @@ LIBCOM_API void epicsStdCall epicsEnvSet (const char *name, const char *value)
 LIBCOM_API void epicsStdCall epicsEnvUnset (const char *name)
 {
     iocshEnvClear(name);
-    if (getenv(name) != NULL)
-        epicsEnvSet((char*)name, "");
+    setEnv(name, "");
 }
 
 /*

modules/libcom/src/osi/os/default/osdEnv.c

@@ -20,40 +20,35 @@
 #include <errno.h>
 
 #include "epicsStdio.h"
+#include "epicsVersion.h"
 #include "errlog.h"
-#include "cantProceed.h"
 #include "envDefs.h"
 #include "osiUnistd.h"
 #include "epicsFindSymbol.h"
 #include "iocsh.h"
 
+#ifdef __rtems__
+#  include <rtems.h>
+#  define RTEMS_VERSION_INT VERSION_INT(__RTEMS_MAJOR__, __RTEMS_MINOR__, 0, 0)
+#endif
+
+#if defined(__RTEMS_MAJOR__) && RTEMS_VERSION_INT<VERSION_INT(4,10,0,0)
+   /* newlib w/ RTEMS <=4.9 returns void */
+#  define unSetEnv(name) ({unsetenv(name); 0;})
+#else
+#  define unSetEnv(name) unsetenv(name)
+#endif
+
 /*
  * Set the value of an environment variable
  * Leaks memory, but the assumption is that this routine won't be
  * called often enough for the leak to be a problem.
  */
 LIBCOM_API void epicsStdCall epicsEnvSet (const char *name, const char *value)
 {
-    char *cp;
-
-    if (!name) return;
     iocshEnvClear(name);
-
-    cp = mallocMustSucceed (strlen (name) + strlen (value) + 2, "epicsEnvSet");
-    strcpy (cp, name);
-    strcat (cp, "=");
-    strcat (cp, value);
-    if (putenv (cp) < 0) {
-        errPrintf(
-                -1L,
-                __FILE__,
-                __LINE__,
-                "Failed to set environment parameter \"%s\" to \"%s\": %s\n",
-                name,
-                value,
-                strerror (errno));
-        free (cp);
-    }
+    if(setenv(name, value, 1))
+        errlogPrintf("setenv(\"%s\", \"%s\") -> %d\n", name, value, errno);
 }
 
 /*
@@ -64,8 +59,8 @@ LIBCOM_API void epicsStdCall epicsEnvSet (const char *name, const char *value)
 LIBCOM_API void epicsStdCall epicsEnvUnset (const char *name)
 {
     iocshEnvClear(name);
-    if (getenv(name) != NULL)
-        putenv((char*)name);
+    if(unSetEnv(name))
+        errlogPrintf("unsetenv(\"%s\") -> %d\n", name, errno);
 }
 
 /*