add c primitives, move getenv into primitives

src/prim/prim-unix.c

@@ -589,3 +589,69 @@ void _mi_prim_process_info(mi_msecs_t* utime, mi_msecs_t* stime, size_t* current
 
 #endif
 
+
+//----------------------------------------------------------------
+// Output
+//----------------------------------------------------------------
+
+void _mi_prim_out_stderr( const char* msg ) {
+  fputs(msg,stderr);
+}
+
+
+//----------------------------------------------------------------
+// Environment
+//----------------------------------------------------------------
+
+#if !defined(MI_USE_ENVIRON) || (MI_USE_ENVIRON!=0)
+// On Posix systemsr use `environ` to acces environment variables
+// even before the C runtime is initialized.
+#if defined(__APPLE__) && defined(__has_include) && __has_include(<crt_externs.h>)
+#include <crt_externs.h>
+static char** mi_get_environ(void) {
+  return (*_NSGetEnviron());
+}
+#else
+extern char** environ;
+static char** mi_get_environ(void) {
+  return environ;
+}
+#endif
+bool _mi_prim_getenv(const char* name, char* result, size_t result_size) {
+  if (name==NULL) return false;
+  const size_t len = _mi_strlen(name);
+  if (len == 0) return false;
+  char** env = mi_get_environ();
+  if (env == NULL) return false;
+  // compare up to 256 entries
+  for (int i = 0; i < 256 && env[i] != NULL; i++) {
+    const char* s = env[i];
+    if (_mi_strnicmp(name, s, len) == 0 && s[len] == '=') { // case insensitive
+      // found it
+      _mi_strlcpy(result, s + len + 1, result_size);
+      return true;
+    }
+  }
+  return false;
+}
+#else
+// fallback: use standard C `getenv` but this cannot be used while initializing the C runtime
+bool _mi_prim_getenv(const char* name, char* result, size_t result_size) {
+  // cannot call getenv() when still initializing the C runtime.
+  if (_mi_preloading()) return false;
+  const char* s = getenv(name);
+  if (s == NULL) {
+    // we check the upper case name too.
+    char buf[64+1];
+    size_t len = _mi_strnlen(name,sizeof(buf)-1);
+    for (size_t i = 0; i < len; i++) {
+      buf[i] = _mi_toupper(name[i]);
+    }
+    buf[len] = 0;
+    s = getenv(buf);
+  }
+  if (s == NULL || _mi_strnlen(s,result_size) >= result_size)  return false;
+  _mi_strlcpy(result, s, result_size);
+  return true;
+}
+#endif  // !MI_USE_ENVIRON

src/prim/prim-wasi.c

@@ -197,4 +197,34 @@ void _mi_prim_process_info(mi_msecs_t* utime, mi_msecs_t* stime, size_t* current
   *stime = 0;
 }
 
+//----------------------------------------------------------------
+// Output
+//----------------------------------------------------------------
 
+void _mi_prim_out_stderr( const char* msg ) {
+  fputs(msg,stderr);
+}
+
+
+//----------------------------------------------------------------
+// Environment
+//----------------------------------------------------------------
+
+bool _mi_prim_getenv(const char* name, char* result, size_t result_size) {
+  // cannot call getenv() when still initializing the C runtime.
+  if (_mi_preloading()) return false;
+  const char* s = getenv(name);
+  if (s == NULL) {
+    // we check the upper case name too.
+    char buf[64+1];
+    size_t len = _mi_strnlen(name,sizeof(buf)-1);
+    for (size_t i = 0; i < len; i++) {
+      buf[i] = _mi_toupper(name[i]);
+    }
+    buf[len] = 0;
+    s = getenv(buf);
+  }
+  if (s == NULL || _mi_strnlen(s,result_size) >= result_size)  return false;
+  _mi_strlcpy(result, s, result_size);
+  return true;
+}

src/prim/prim-windows.c

@@ -10,6 +10,7 @@ terms of the MIT license. A copy of the license can be found in the file
 #include "mimalloc-atomic.h"
 #include "prim.h"
 #include <string.h>  // strerror
+#include <stdio.h>   // fputs, stderr
 
 #ifdef _MSC_VER
 #pragma warning(disable:4996)  // strerror
@@ -407,10 +408,6 @@ mi_msecs_t _mi_prim_clock_now(void) {
 }
 
 
-//----------------------------------------------------------------
-// Process info
-//----------------------------------------------------------------
-
 #include <windows.h>
 #include <psapi.h>
 
@@ -455,3 +452,53 @@ void _mi_prim_process_info(mi_msecs_t* utime, mi_msecs_t* stime, size_t* current
   *peak_commit    = (size_t)info.PeakPagefileUsage;
   *page_faults    = (size_t)info.PageFaultCount;
 }
+
+//----------------------------------------------------------------
+// Output
+//----------------------------------------------------------------
+
+void _mi_prim_out_stderr( const char* msg ) 
+{
+  // on windows with redirection, the C runtime cannot handle locale dependent output
+  // after the main thread closes so we use direct console output.
+  if (!_mi_preloading()) {
+    // _cputs(msg);  // _cputs cannot be used at is aborts if it fails to lock the console
+    static HANDLE hcon = INVALID_HANDLE_VALUE;
+    static bool hconIsConsole;
+    if (hcon == INVALID_HANDLE_VALUE) {
+      CONSOLE_SCREEN_BUFFER_INFO sbi;
+      hcon = GetStdHandle(STD_ERROR_HANDLE);
+      hconIsConsole = ((hcon != INVALID_HANDLE_VALUE) && GetConsoleScreenBufferInfo(hcon, &sbi));
+    }
+    const size_t len = strlen(msg);
+    if (len > 0 && len < UINT32_MAX) {
+      DWORD written = 0;
+      if (hconIsConsole) {
+        WriteConsoleA(hcon, msg, (DWORD)len, &written, NULL);
+      }
+      else if (hcon != INVALID_HANDLE_VALUE) {
+        // use direct write if stderr was redirected
+        WriteFile(hcon, msg, (DWORD)len, &written, NULL);
+      }
+      else {
+        // finally fall back to fputs after all
+        fputs(msg, stderr);
+      }
+    }
+  }
+}
+
+
+//----------------------------------------------------------------
+// Environment
+//----------------------------------------------------------------
+
+// On Windows use GetEnvironmentVariable instead of getenv to work
+// reliably even when this is invoked before the C runtime is initialized.
+// i.e. when `_mi_preloading() == true`.
+// Note: on windows, environment names are not case sensitive.
+bool _mi_prim_getenv(const char* name, char* result, size_t result_size) {
+  result[0] = 0;
+  size_t len = GetEnvironmentVariableA(name, result, (DWORD)result_size);
+  return (len > 0 && len < result_size);
+}

src/prim/prim.h

@@ -66,6 +66,13 @@ void  _mi_prim_process_info(mi_msecs_t* utime, mi_msecs_t* stime,
                              size_t* current_rss, size_t* peak_rss, 
                              size_t* current_commit, size_t* peak_commit, size_t* page_faults);
 
+// Default stderr output. 
+// msg != NULL && strlen(msg) > 0
+void  _mi_prim_out_stderr( const char* msg );
+
+// Get an environment variable.
+// name != NULL, result != NULL, result_size >= 64
+bool _mi_prim_getenv(const char* name, char* result, size_t result_size);
 
 
 #endif  // MIMALLOC_PRIM_H