Re: [RFA/mingw32] environment variables are case-insensitive on win32

[Jerome Guitton <guitton at adacore dot com>]

Eli Zaretskii (eliz@gnu.org):

> Configure-time test is not good enough, as the binary could then be
> run in a different environment.
> 
> How about making it case-insensitive for Cygwin as well?

I ended up implementing Pedro's suggestion (a run-time test) but it
does not work in the case of Cygwin; getenv/setenv acts as if we add a
case-sensitive environment, but we use CreateProcess to create the
inferior, so we end up with a case-insensitive environment for the
inferior. So making it case-insensitive is indeed what makes sense.

Last versions of the patch in attachment, along with the testcase.
Fully tested on x86_64-linux; partially tested on Cygwin (e.g. without
gdb.threads) amd mingw32 (testenv.exp only).

Any comments?

commit b67dcf26ae8f9ae0390c229518fe34456b4dfe20
Author: Jerome Guitton <guitton@adacore.com>
Date:   Wed Dec 5 15:48:29 2012 +0100

    Add test for case sensitivity in env vars
    
    gdb/testsuite/ChangeLog:
    
    	* gdb.base/testenv.exp: Check consistent case sensitivity of
    	env variables.

diff --git a/gdb/testsuite/gdb.base/testenv.exp b/gdb/testsuite/gdb.base/testenv.exp
index 55e3088..4b681a5 100644
--- a/gdb/testsuite/gdb.base/testenv.exp
+++ b/gdb/testsuite/gdb.base/testenv.exp
@@ -123,3 +123,40 @@ gdb_exit
 # Clear environment in case we're doing multiple runs
 unset env(TEST_GDB_GLOBAL)
 
+# Check consistent case sensitivity of env variables
+# for GDB and the inferior
+
+clean_restart $binfile
+
+set upper_case_value "VAR1"
+set mixed_case_value "Var1"
+gdb_test_no_output "set env TEST_GDB_VAR1 $upper_case_value" \
+  "Set TEST_GDB_VAR1"
+
+gdb_test_no_output "set env TEST_GDB_Var1 $mixed_case_value" \
+  "Set TEST_GDB_Var1"
+
+set test "Case sensitivity for env vars in GDB"
+set var1_value $upper_case_value
+set nb_vars 2
+gdb_test_multiple "show env TEST_GDB_VAR1" $test {
+    -re ".*TEST_GDB_VAR1 = $upper_case_value.*$gdb_prompt $" {
+	set nb_vars 2
+	pass $test
+    }
+    -re ".*TEST_GDB_VAR1 = $mixed_case_value.*$gdb_prompt $" {
+	set nb_vars 1
+	pass $test
+    }
+}
+
+# make sure $pc is sane, in case we're talking to a board.
+if { ![runto_main] } {
+    gdb_suppress_tests;
+}
+
+gdb_breakpoint  $bp_line
+gdb_test "continue" \
+    ".*Program found ${nb_vars} variables starting with TEST_GDB.*" \
+	"Case sensitivity for env vars in inferior"
+gdb_exit

commit df61bd719e348f530419215ce71f344198231d7f
Author: Jerome Guitton <guitton@adacore.com>
Date:   Thu May 24 18:19:23 2012 +0200

    environment variables are case-insensitive on win32
    
    gdb/ChangeLog:
    
    	* environ.c (host_has_case_sensitive_env_vars)
    	(env_var_name_ncmp): New functions.
    	(get_in_environ, set_in_environ, unset_in_environ): Use
    	env_var_name_ncmp instead of strncmp.

diff --git a/gdb/environ.c b/gdb/environ.c
index 33426eb..e4cc30c 100644
--- a/gdb/environ.c
+++ b/gdb/environ.c
@@ -96,6 +96,57 @@ environ_vector (struct gdb_environ *e)
   return e->vector;
 }
 
+
+/* Return 1 if the names of environ variables are case sensitive
+   on host.  */
+
+static int
+host_has_case_sensitive_env_vars()
+{
+  static int result = -1;
+  char *value;
+
+  if (result != -1)
+    return result;
+
+  /* On Cygwin, setenv/getenv supports case-sensitive environment
+     variables; so the run-time check would return 1. However, GDB
+     uses the windows API to create the inferior, which is case
+     insensitive.  So override the check.  */
+
+#if defined (__CYGWIN__)
+  result = 0;
+  return result;
+
+#elif defined(_WIN32) && !defined(__CYGWIN__)
+  putenv ("__GDB_TEST_CASE_SENSITIVITY=set");
+
+#else
+  setenv ("__GDB_TEST_CASE_SENSITIVITY", "set", 1);
+#endif
+
+  value = getenv ("__GDB_test_CASE_Sensitivity");
+
+  if (value && (strcmp (value, "set") == 0))
+    result = 0;
+  else
+    result = 1;
+
+  return result;
+}
+
+/* Compare the first LENGTH characters of the names of two
+   environment variable A and B.  */
+
+static int
+env_var_name_ncmp(const char *a, const char *b, int length)
+{
+  if (host_has_case_sensitive_env_vars())
+    return strncmp(a, b, length);
+  else
+    return strncasecmp (a, b, length);
+}
+
 /* Return the value in environment E of variable VAR.  */
 
 char *
@@ -106,7 +157,7 @@ get_in_environ (const struct gdb_environ *e, const char *var)
   char *s;
 
   for (; (s = *vector) != NULL; vector++)
-    if (strncmp (s, var, len) == 0 && s[len] == '=')
+    if (env_var_name_ncmp (s, var, len) == 0 && s[len] == '=')
       return &s[len + 1];
 
   return 0;
@@ -123,7 +174,7 @@ set_in_environ (struct gdb_environ *e, const char *var, const char *value)
   char *s;
 
   for (i = 0; (s = vector[i]) != NULL; i++)
-    if (strncmp (s, var, len) == 0 && s[len] == '=')
+    if (env_var_name_ncmp (s, var, len) == 0 && s[len] == '=')
       break;
 
   if (s == 0)
@@ -170,7 +221,7 @@ unset_in_environ (struct gdb_environ *e, char *var)
 
   for (; (s = *vector) != NULL; vector++)
     {
-      if (strncmp (s, var, len) == 0 && s[len] == '=')
+      if (env_var_name_ncmp (s, var, len) == 0 && s[len] == '=')
 	{
 	  xfree (s);
 	  /* Walk through the vector, shuffling args down by one, including