5 files changed, 51 insertions, 16 deletions
diff --git a/src/core/support/env_posix.c b/src/core/support/env_posix.c
index 4af5aea9b0..79b8fcd7d7 100644
--- a/src/core/support/env_posix.c
+++ b/src/core/support/env_posix.c
@@ -54,7 +54,8 @@ char *gpr_getenv(const char *name) {
 }
 
 void gpr_setenv(const char *name, const char *value) {
-  GPR_ASSERT(setenv(name, value, 1) == 0);
+  int res = setenv(name, value, 1);
+  GPR_ASSERT(res == 0);
 }
 
 #endif /* GPR_POSIX_ENV */
diff --git a/src/core/support/env_win32.c b/src/core/support/env_win32.c
index 7964409364..a31fa79d68 100644
--- a/src/core/support/env_win32.c
+++ b/src/core/support/env_win32.c
@@ -53,7 +53,8 @@ char *gpr_getenv(const char *name) {
 }
 
 void gpr_setenv(const char *name, const char *value) {
-  GPR_ASSERT(_putenv_s(name, value) == 0);
+  errno_t res = _putenv_s(name, value);
+  GPR_ASSERT(res == 0);
 }
 
 #endif /* GPR_WIN32 */
diff --git a/src/core/support/file.h b/src/core/support/file.h
index a9d81498e5..92f420e7ce 100644
--- a/src/core/support/file.h
+++ b/src/core/support/file.h
@@ -48,11 +48,11 @@ extern "C" {
    will be set to 1 in case of success and 0 in case of failure. */
 gpr_slice gpr_load_file(const char *filename, int *success);
 
-/* Creates a temporary file from a template.
-   The last six characters of template must be "XXXXXX" and these are replaced
-   with a string that makes the filename unique.  Since it will be modified,
-   template must not be a string constant. */
-FILE *gpr_tmpfile(char *template);
+/* Creates a temporary file from a prefix.
+   If tmp_filename is not NULL, *tmp_filename is assigned the name of the
+   created file and it is the responsibility of the caller to gpr_free it
+   unless an error occurs in which case it will be set to NULL. */
+FILE *gpr_tmpfile(const char *prefix, char **tmp_filename);
 
 #ifdef __cplusplus
 }
diff --git a/src/core/support/file_posix.c b/src/core/support/file_posix.c
index a156e7703c..a763fbcda2 100644
--- a/src/core/support/file_posix.c
+++ b/src/core/support/file_posix.c
@@ -54,15 +54,26 @@
 #include <string.h>
 #include <unistd.h>
 
+#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
-FILE *gpr_tmpfile(char *template) {
+#include "src/core/support/string.h"
+
+FILE *gpr_tmpfile(const char *prefix, char **tmp_filename) {
   FILE *result = NULL;
-  int fd = mkstemp(template);
+  char *template;
+  int fd;
+
+  if (tmp_filename != NULL) *tmp_filename = NULL;
+
+  gpr_asprintf(&template, "%s_XXXXXX", prefix);
+  GPR_ASSERT(template != NULL);
+
+  fd = mkstemp(template);
   if (fd == -1) {
     gpr_log(GPR_ERROR, "mkstemp failed for template %s with error %s.",
             template, strerror(errno));
-    return NULL;
+    goto end;
   }
   result = fdopen(fd, "w+");
   if (result == NULL) {
@@ -70,6 +81,14 @@ FILE *gpr_tmpfile(char *template) {
             template, fd, strerror(errno));
     unlink(template);
     close(fd);
+    goto end;
+  }
+
+end:
+  if (result != NULL && tmp_filename != NULL) {
+    *tmp_filename = template;
+  } else {
+    gpr_free(template);
   }
   return result;
 }
diff --git a/src/core/support/file_win32.c b/src/core/support/file_win32.c
index b85422c372..d415281e0d 100644
--- a/src/core/support/file_win32.c
+++ b/src/core/support/file_win32.c
@@ -41,24 +41,38 @@
 #include <stdio.h>
 #include <string.h>
 
+#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
-FILE *gpr_tmpfile(char *template) {
+FILE *gpr_tmpfile(const char *prefix, char **tmp_filename) {
   FILE *result = NULL;
+  char *template;
+
+  if (tmp_filename != NULL) *tmp_filename = NULL;
+
+  gpr_asprintf(&template, "%s_XXXXXX", prefix);
+  GPR_ASSERT(template != NULL);
 
   /* _mktemp_s can only create a maximum of 26 file names for any combination of
      base and template values which is kind of sad... We may revisit this
      function later to have something better... */
   if (_mktemp_s(template, strlen(template) + 1) != 0) {
     gpr_log(LOG_ERROR, "Could not create tmp file.");
-    return NULL;
+    goto end;
   }
-  if (fopen_s(&result, template, "wb+") == 0) {
-    return result;
-  } else {
+  if (fopen_s(&result, template, "wb+") != 0) {
     gpr_log(GPR_ERROR, "Could not open file %s", template);
-    return NULL;
+    result = NULL;
+    goto end;
+  }
+
+end:
+  if (result != NULL && tmp_filename != NULL) {
+    *tmp_filename = template;
+  } else {
+    gpr_free(template);
   }
+  return result;
 }
 
 #endif /* GPR_WIN32 */