Re-implement env functionality in minipal.

Author: lateralusX

src/coreclr/nativeaot/Runtime/unix/PalUnix.cpp

@@ -41,6 +41,7 @@
 #include <cstdarg>
 #include <signal.h>
 #include <minipal/thread.h>
+#include <minipal/env.h>
 
 #ifdef TARGET_LINUX
 #include <sys/syscall.h>
@@ -981,21 +982,25 @@ UInt32_BOOL PalResetEvent(HANDLE event)
 
 uint32_t PalGetEnvironmentVariable(const char * name, char * buffer, uint32_t size)
 {
-    const char* value = getenv(name);
-    if (value == NULL)
+    size_t valueLen = 0;
+    if (!minipal_env_get_s(&valueLen, buffer, size, name, false))
     {
         return 0;
     }
 
-    size_t valueLen = strlen(value);
+    // minipal_env_get_s returns the length of the value including the null terminator.
+    if (valueLen > 0)
+    {
+        valueLen--;
+    }
+
     if (valueLen < size)
     {
-        strcpy(buffer, value);
-        return valueLen;
+        return (uint32_t)valueLen;
     }
 
     // return required size including the null character or 0 if the size doesn't fit into uint32_t
-    return (valueLen < UINT32_MAX) ? (valueLen + 1) : 0;
+    return valueLen < UINT32_MAX ? (uint32_t)(valueLen + 1) : 0;
 }
 
 uint16_t PalCaptureStackBackTrace(uint32_t arg1, uint32_t arg2, void* arg3, uint32_t* arg4)

src/coreclr/pal/src/config.h.in

@@ -99,7 +99,6 @@
 #define PAL_THREAD_PRIORITY_MIN 0
 #define PAL_THREAD_PRIORITY_MAX 0
 
-#cmakedefine01 HAVE__NSGETENVIRON
 #cmakedefine01 DEADLOCK_WHEN_THREAD_IS_SUSPENDED_WHILE_BLOCKED_ON_MUTEX
 #cmakedefine PAL_PTRACE(cmd, pid, addr, data) @PAL_PTRACE@
 #cmakedefine01 SYNCHMGR_SUSPENSION_SAFE_CONDITION_SIGNALING

src/coreclr/pal/src/configure.cmake

@@ -890,7 +890,6 @@ if(NOT CLR_CMAKE_HOST_ARCH_ARM AND NOT CLR_CMAKE_HOST_ARCH_ARM64)
 endif()
 
 if(CLR_CMAKE_TARGET_APPLE)
-  set(HAVE__NSGETENVIRON 1)
   set(DEADLOCK_WHEN_THREAD_IS_SUSPENDED_WHILE_BLOCKED_ON_MUTEX 1)
   set(PAL_PTRACE "ptrace((cmd), (pid), (caddr_t)(addr), (data))")
   set(HAVE_SCHED_OTHER_ASSIGNABLE 1)

src/coreclr/pal/src/debug/debug.cpp

@@ -160,11 +160,8 @@ OutputDebugStringA(
           lpOutputString ? lpOutputString : "NULL");
 
     // As we don't support debug events, we are going to output the debug string
-    // to stderr instead of generating OUT_DEBUG_STRING_EVENT. It's safe to tell
-    // EnvironGetenv not to make a copy of the value here since we only want to
-    // check whether it exists, not actually use it.
-    if ((lpOutputString != NULL) &&
-        (NULL != EnvironGetenv(PAL_OUTPUTDEBUGSTRING, /* copyValue */ FALSE)))
+    // to stderr instead of generating OUT_DEBUG_STRING_EVENT.
+    if ((lpOutputString != NULL) && (EnvironCheckenv(PAL_OUTPUTDEBUGSTRING)))
     {
         fprintf(stderr, "%s", lpOutputString);
     }

src/coreclr/pal/src/exception/machmessage.h

@@ -50,7 +50,7 @@ using namespace CorUnix;
 
 #ifdef _DEBUG
 
-#define NONPAL_TRACE_ENABLED EnvironGetenv("NONPAL_TRACING", /* copyValue */ false)
+#define NONPAL_TRACE_ENABLED EnvironCheckenv("NONPAL_TRACING")
 
 #define NONPAL_ASSERT(_msg, ...) NONPAL_RETAIL_ASSERT(_msg, __VA_ARGS__)
 

src/coreclr/pal/src/include/pal/environ.h

@@ -26,32 +26,41 @@ extern "C"
 #endif // __cplusplus
 
 /*++
-Variables :
 
-    palEnvironment: a global variable equivalent to environ on systems on
-                    which that exists, and a pointer to an array of environment
-                    strings on systems without environ.
-    gcsEnvironment: critical section to synchronize access to palEnvironment
+Function:
+  EnvironInitialize
+
+Initialization function for the PAL environment code.
 --*/
-extern char **palEnvironment;
-extern minipal_mutex gcsEnvironment;
+BOOL EnvironInitialize();
 
 /*++
+Function:
+  EnvironGetUnsafe
 
+Get the current environment. This is similar accessing
+global environ variable and is not thread safe. This function
+should only be called from code that guarantees environment won't
+change while using returned pointer.
+--*/
+char **EnvironGetUnsafe();
+
+/*++
 Function:
-  EnvironInitialize
+  EnvironCheckenv
 
-Initialization function for the PAL environment code.
+Check if environment variable with the given name exists in environment.
 --*/
-BOOL EnvironInitialize();
+BOOL EnvironCheckenv(const char *name);
 
 /*++
 Function:
   EnvironGetenv
 
 Get the value of environment variable with the given name.
+Caller should free the returned string if it is not NULL.
 --*/
-char *EnvironGetenv(const char *name, BOOL copyValue = TRUE);
+char *EnvironGetenv(const char *name);
 
 /*++
 Function:

src/coreclr/pal/src/misc/dbgmsg.cpp

@@ -705,24 +705,11 @@ bool DBG_ShouldCheckStackAlignment()
 
     if (caMode == CheckAlignment_Uninitialized)
     {
-        char* checkAlignmentSettings;
-        bool shouldFreeCheckAlignmentSettings = false;
-        if (palEnvironment == nullptr)
-        {
-            // This function might be called before the PAL environment is initialized.
-            // In this case, use the system getenv instead.
-            checkAlignmentSettings = ::getenv(PAL_CHECK_ALIGNMENT_MODE);
-        }
-        else
-        {
-            checkAlignmentSettings = EnvironGetenv(PAL_CHECK_ALIGNMENT_MODE);
-            shouldFreeCheckAlignmentSettings = true;
-        }
-
+        char* checkAlignmentSettings = EnvironGetenv(PAL_CHECK_ALIGNMENT_MODE);
         caMode = checkAlignmentSettings ?
             (CheckAlignmentMode)atoi(checkAlignmentSettings) : CheckAlignment_Default;
 
-        if (checkAlignmentSettings && shouldFreeCheckAlignmentSettings)
+        if (checkAlignmentSettings)
         {
             free(checkAlignmentSettings);
         }