Improved version of mkdtemp() that support ebcdic (#40)

* add mkdtemp()

* ignore build.cache

* add test case and make stdlib.h work for ebcdic too

* getenv replacement is for ascii only

* remove zos-mkdtemp.cc

* fix a bug & add comments

.gitignore

@@ -18,4 +18,8 @@ test/cctest_a
 # Build artifacts
 *.a
 install/
+build.cache
+build/
+zoslib.xml
+zoslib_a.xml
 

include/stdlib.h

@@ -12,11 +12,14 @@
 #define __XPLAT 1
 #include "zos-macros.h"
 
+
 #if defined(__cplusplus)
 extern "C" {
 #endif
 __Z_EXPORT char *__realpath_extended(const char * __restrict__, char * __restrict__);
+#ifdef __NATIVE_ASCII_F
 __Z_EXPORT int __mkstemp_ascii(char*);
+#endif
 #if defined(__cplusplus)
 }
 #endif
@@ -29,16 +32,15 @@ __Z_EXPORT int __mkstemp_ascii(char*);
 #define mkstemp __mkstemp_replaced
 #endif
 
-#if defined(ZOSLIB_OVERRIDE_CLIB_GETENV)
+#if defined(ZOSLIB_OVERRIDE_CLIB_GETENV) && defined(__NATIVE_ASCII_F)
 #undef getenv
 #define getenv __getenv_replaced
 #endif
 
+
 #include_next <stdlib.h>
 
 #if defined(ZOSLIB_OVERRIDE_CLIB) || defined(ZOSLIB_OVERRIDE_CLIB_STDLIB)
-#undef mkstemp
-#undef realpath
 
 #if defined(__cplusplus)
 extern "C" {
@@ -47,17 +49,23 @@ extern "C" {
 /**
  * Same as original realpath, but this allocates a buffer if second parm is NULL as defined in Posix.1-2008
  */
+#undef realpath
 __Z_EXPORT char *realpath(const char * __restrict__, char * __restrict__) __asm("__realpath_extended");
+
+#ifdef __NATIVE_ASCII_F
 /**
  * Same as C mkstemp but tags fd as ASCII (819)
  */
+#undef mkstemp
 __Z_EXPORT int mkstemp(char*) __asm("__mkstemp_ascii");
+#endif /* __NATIVE_ASCII_F */
+
 #if defined(__cplusplus)
 }
 #endif
-#endif
+#endif /* defined(ZOSLIB_OVERRIDE_CLIB) || defined(ZOSLIB_OVERRIDE_CLIB_STDLIB) */
 
-#if defined(ZOSLIB_OVERRIDE_CLIB_GETENV)
+#if defined(ZOSLIB_OVERRIDE_CLIB_GETENV) && defined(__NATIVE_ASCII_F)
 #undef getenv
 
 #if defined(__cplusplus)
@@ -80,11 +88,29 @@ extern "C" {
 /**
  * C Lib functions that do not conflict with z/OS LE
  */
-__Z_EXPORT char *mkdtemp(char *templ);
 __Z_EXPORT int getloadavg(double loadavg[], int nelem);
 __Z_EXPORT const char * getprogname(void);
 #if defined(__cplusplus)
 }
 #endif
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+__Z_EXPORT char *mkdtemp(char *);
+#ifdef __NATIVE_ASCII_F
+  __Z_EXPORT char *mkdtemp(char *) asm("__mkdtemp_a");
+#ifdef __AE_BIMODAL_F
+  __Z_EXPORT char *__mkdtemp_a(char *);
+  __Z_EXPORT char *__mkdtemp_e(char *);
+#endif
+#else
+  __Z_EXPORT char *mkdtemp(char *)  asm("__mkdtemp_e");
+#endif
+
+#if defined(__cplusplus)
+}
+#endif
+
 #endif

src/CMakeLists.txt

@@ -18,6 +18,7 @@ set(libsrc
   zos-tls.cc
   zos.cc
   zos-mount.c
+  zos-mkdtemp.c
 )
 set(zoslib-help zoslib-help.cc)
 

src/zos-io.cc

@@ -930,37 +930,6 @@ int __mkstemp_ascii(char * tmpl) {
   return ret;
 }
 
-char *mkdtemp(char *templ) {
-  size_t len = strlen(templ);
-  int retries = 10;  // Number of retries to generate a unique directory name
-
-  // Check that the templ ends with "XXXXXX" as required
-  if (len < 6 || strcmp(templ + len - 6, "XXXXXX") != 0) {
-    errno = EINVAL;
-    return NULL;
-  }
-
-  while (retries--) {
-    // Generate a random string to replace "XXXXXX" in the templ
-    for (size_t i = len - 6; i < len; i++) {
-      templ[i] = 'a' + rand() % 26;
-    }
-
-    // Attempt to create the directory
-    if (mkdir(templ, 0700) == 0) {
-      return templ;
-    }
-
-    // If mkdir failed, check if it was due to a collision with an existing directory
-    if (errno != EEXIST) {
-      return NULL;
-    }
-  }
-
-  // If all retries fail, return NULL
-  return NULL;
-}
-
 int __close(int fd) {
   int ret = __close_orig(fd);
   if (ret < 0)

src/zos-mkdtemp.c

@@ -0,0 +1,110 @@
+//////////////////////////////////////////////////////////////////////////////
+//// Licensed Materials - Property of IBM
+//// ZOSLIB
+//// (C) Copyright IBM Corp. 2020. All Rights Reserved.
+//// US Government Users Restricted Rights - Use, duplication
+//// or disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
+/////////////////////////////////////////////////////////////////////////////////
+
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+typedef enum {
+  cp_ebcdic,
+  cp_ascii
+} CodePage;
+
+#define XXXXXX "XXXXXX"
+#define ValidChars "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_.,-"
+typedef struct CodePage {
+  char xes[sizeof(XXXXXX)];
+  char validChars[sizeof(ValidChars)];
+}  CodePage_t;
+
+#pragma convert("IBM-1047")
+static const CodePage_t CharTraitsEbcdic = {
+   XXXXXX,
+   ValidChars
+};
+#pragma convert(pop)
+
+#pragma convert("ISO8859-1")
+static const CodePage_t CharTraitsAscii = {
+   XXXXXX,
+   ValidChars
+};
+#pragma convert(pop)
+
+enum {
+  TempLen = sizeof(XXXXXX)-1
+};
+
+char *real_mkdtemp(CodePage_t cp, char *templ) {
+  if (!templ) {
+    errno=EINVAL;
+    return NULL;
+  }
+  int len = strlen(templ);
+
+  if (len <TempLen || strncmp(templ+len-TempLen,cp.xes ,TempLen)!=0) {
+    errno=EINVAL;
+    return NULL;
+  }
+#define validChars cp.validChars
+  srand(time(NULL));
+#define RANDOM_INT(max) (1 + rand()/((RAND_MAX + 1u) / (max) ))
+#define UPDATE_CHAR(n) templ[len-TempLen+n-1] = validChars[(s##n+c##n)%(sizeof validChars)]
+
+  // Pick the first random letter for each X
+  int s1 = RANDOM_INT(sizeof validChars);
+  int s2 = RANDOM_INT(sizeof validChars);
+  int s3 = RANDOM_INT(sizeof validChars);
+  int s4 = RANDOM_INT(sizeof validChars);
+  int s5 = RANDOM_INT(sizeof validChars);
+  int s6 = RANDOM_INT(sizeof validChars);
+  // Loop over all of the possible combinations until we find
+  // a name that doesn't exist.  For example: start with 
+  // dir-aaaaaa, if that doesn't exist try dir-aaaaab.
+  // Of course the try is something more random than dir-aaaaaa.
+  for (int c1=0; c1<sizeof validChars; ++c1) {
+    UPDATE_CHAR(1); // dir-aXXXXX
+    for (int c2=0; c2<sizeof validChars; ++c2) {
+      UPDATE_CHAR(2); // dir-aaXXXX
+      for (int c3=0; c3<sizeof validChars; ++c3) {
+        UPDATE_CHAR(3); // dir-aaaXXX
+        for (int c4=0; c4<sizeof validChars; ++c4) {
+          UPDATE_CHAR(4); // dir-aaaaXX
+          for (int c5=0; c5<sizeof validChars; ++c5) {
+            UPDATE_CHAR(5); // dir-aaaaaX
+            for (int c6=0; c6<sizeof validChars; ++c6) {
+              UPDATE_CHAR(6); // dir-aaaaaa
+              int rc = mkdir(templ, 0700);
+              if (rc==0)
+                return templ;
+              if (errno!=EEXIST) {
+                // restore the X's in the template
+                strncpy(templ+len-TempLen,cp.xes ,TempLen);
+                return NULL;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  // restore the X's in the template
+  strncpy(templ+len-TempLen,cp.xes,TempLen);
+  return NULL;
+}
+
+__Z_EXPORT char *__mkdtemp_a(char *templ) {
+  return real_mkdtemp(CharTraitsAscii, templ);
+}
+
+__Z_EXPORT char *__mkdtemp_e(char *templ) {
+  return real_mkdtemp(CharTraitsEbcdic, templ);
+}

test/test-mkdtemp.cc

@@ -0,0 +1,21 @@
+#include "test-args.h"
+#include "zos.h"
+#include "gtest/gtest.h"
+#include <sys/stat.h>
+#include <unistd.h>
+
+namespace {
+
+TEST(MkdtempTest, MkdtempCC) {
+  char templ[] = "/tmp/dirXXXXXX";
+  char * dirname = mkdtemp(templ);
+  EXPECT_NE(dirname, nullptr);
+
+  struct stat stats;
+  int rc = stat(dirname, &stats);
+  rmdir(dirname);
+  EXPECT_EQ(rc, 0);
+  EXPECT_TRUE(S_ISDIR(stats.st_mode));
+}
+
+}