Allow adding or removing individual environment variables.

Specifying an environment string as +KEY=VALUE will append KEY=VALUE to
the existing block, or create a new one if none was previously
configured.  If KEY is already present, +KEY=VALUE will override it in
place.

Specifying -KEY=VALUE will remove KEY=VALUE from the existing block.

Specifying -KEY will remove KEY regardless of its value.

Removing the last key will delete the whole block.

Specifying :KEY=VALUE is equivalent to KEY=VALUE, ie it creates a new
block with only KEY=VALUE present.  Its main purpose is to make scripts
easier to read.

    nssm set <servicename> AppEnvironment :FIRST=one
    nssm set <servicename> AppEnvironment +SECOND=two
    nssm set <servicename> AppEnvironment +THIRD=two

diff --git a/README.txt b/README.txt
index 2158741..12a8393 100644 (file)
--- a/README.txt
+++ b/README.txt
@@ -638,9 +638,10 @@ would have the same effect.
 \r
 Non-standard parameters\r
 -----------------------\r
-The AppEnvironment and AppEnvironmentExtra parameters recognise an\r
-additional argument when querying the environment.  The following syntax\r
-will print all extra environment variables configured for a service\r
+The AppEnvironment, AppEnvironmentExtra and Environment parameters\r
+recognise an additional argument when querying the environment.  The\r
+following syntax will print all extra environment variables configured\r
+for a service\r
 \r
     nssm get <servicename> AppEnvironmentExtra\r
 \r
@@ -655,6 +656,39 @@ KEY=VALUE pair in separate command line arguments.  For example:
 \r
     nssm set <servicename> AppEnvironment CLASSPATH=C:\Classes TEMP=C:\Temp\r
 \r
+Alternatively the KEY can be prefixed with a + or - symbol to respectively\r
+add or remove a pair from the block.\r
+\r
+The following two lines set CLASSPATH and TEMP:\r
+\r
+    nssm set <servicename> AppEnvironment CLASSPATH=C:\Classes\r
+    nssm set <servicename> AppEnvironment +TEMP=C:\Temp\r
+\r
+If the key is already present, specifying +KEY will override the value\r
+while preserving the order of keys:\r
+\r
+    nssm set <servicename> AppEnvironment +CLASSPATH=C:\NewClasses\r
+\r
+The following syntax removes a single variable from the block while\r
+leaving any other variables in place.\r
+\r
+    nssm set <servicename> AppEnvironment -TEMP\r
+\r
+Specifying -KEY=VALUE will remove the variable only if the existing\r
+value matches.\r
+\r
+The following syntax would not remove TEMP=C:\Temp\r
+\r
+    nssm set <servicename> AppEnvironment -TEMP=C:\Work\Temporary\r
+\r
+The + and - symbols are valid characters in environment variables.\r
+The syntax :KEY=VALUE is equivalent to KEY=VALUE and can be used to\r
+set variables which start with +/- or to explicitly reset the block in\r
+a script:\r
+\r
+    nssm set <servicename> AppEnvironment :CLASSPATH=C:\Classes\r
+    nssm set <servicename> AppEnvironment +TEMP=C:\Temp\r
+\r
 \r
 The AppExit parameter requires an additional argument specifying the exit\r
 code to get or set.  The default action can be specified with the string\r

diff --git a/settings.cpp b/settings.cpp
index f50dcc4..3ed5ec4 100644 (file)
--- a/settings.cpp
+++ b/settings.cpp
@@ -339,17 +339,54 @@ static int setting_set_environment(const TCHAR *service_name, void *param, const
   HKEY key = (HKEY) param;\r
   if (! param) return -1;\r
 \r
-  if (! value || ! value->string || ! value->string[0]) {\r
+  TCHAR *string = 0;\r
+  TCHAR *unformatted = 0;\r
+  unsigned long envlen;\r
+  unsigned long newlen = 0;\r
+  int op = 0;\r
+  if (value && value->string && value->string[0]) {\r
+    string = value->string;\r
+    switch (string[0]) {\r
+      case _T('+'): op = 1; break;\r
+      case _T('-'): op = -1; break;\r
+      case _T(':'): string++; break;\r
+    }\r
+  }\r
+\r
+  if (op) {\r
+    string++;\r
+    TCHAR *env = 0;\r
+    if (get_environment((TCHAR *) service_name, key, (TCHAR *) name, &env, &envlen)) return -1;\r
+    if (env) {\r
+      int ret;\r
+      if (op > 0) ret = append_to_environment_block(env, envlen, string, &unformatted, &newlen);\r
+      else ret = remove_from_environment_block(env, envlen, string, &unformatted, &newlen);\r
+      if (envlen) HeapFree(GetProcessHeap(), 0, env);\r
+      if (ret) return -1;\r
+\r
+      string = unformatted;\r
+    }\r
+    else {\r
+      /*\r
+        No existing environment.\r
+        We can't remove from an empty environment so just treat an add\r
+        operation as setting a new string.\r
+      */\r
+      if (op < 0) return 0;\r
+      op = 0;\r
+    }\r
+  }\r
+\r
+  if (! string || ! string[0]) {\r
     long error = RegDeleteValue(key, name);\r
     if (error == ERROR_SUCCESS || error == ERROR_FILE_NOT_FOUND) return 0;\r
     print_message(stderr, NSSM_MESSAGE_REGDELETEVALUE_FAILED, name, service_name, error_string(error));\r
     return -1;\r
   }\r
 \r
-  unsigned long envlen = (unsigned long) _tcslen(value->string) + 1;\r
-  TCHAR *unformatted = 0;\r
-  unsigned long newlen;\r
-  if (unformat_double_null(value->string, envlen, &unformatted, &newlen)) return -1;\r
+  if (! op) {\r
+    if (unformat_double_null(string, (unsigned long) _tcslen(string), &unformatted, &newlen)) return -1;\r
+  }\r
 \r
   if (test_environment(unformatted)) {\r
     HeapFree(GetProcessHeap(), 0, unformatted);\r