base: Convert doGzipLoad to use std::string instead of *char

Change-Id: I28c9bf7853267686402b43be00f857914770f7a7

src/base/loader/image_file_data.cc

@@ -64,13 +64,10 @@ doGzipLoad(int fd)
         return -1;
     }
 
-    size_t tmp_len = strlen(P_tmpdir);
-    char *tmpnam = (char*) malloc(tmp_len + 20);
-    strcpy(tmpnam, P_tmpdir);
-    strcat(tmpnam, "/gem5-gz-obj-XXXXXX"); // concat 19 chars
+    std::string tmpnam_str = std::string(P_tmpdir) + "/gem5-gz-obj-XXXXXX";
+    char *tmpnam = const_cast<char*>(tmpnam_str.c_str());
     fd = mkstemp(tmpnam); // repurposing fd variable for output
     if (fd < 0) {
-        free(tmpnam);
         gzclose(fdz);
         return fd;
     }
@@ -78,8 +75,6 @@ doGzipLoad(int fd)
     if (unlink(tmpnam) != 0)
         warn("couldn't remove temporary file %s\n", tmpnam);
 
-    free(tmpnam);
-
     auto buf = new uint8_t[blk_sz];
     int r; // size of (r)emaining uncopied data in (buf)fer
     while ((r = gzread(fdz, buf, blk_sz)) > 0) {