Fix #435, Changes for string ops warnings

Resize buffers and tweak string copies to avoid truncation warnings
in GCC 9.  Note the code was generally OK (handled truncation) but
the new compiler still generates warnings even with correct usage
of certain functions.

In the UT_os_printf macro, be sure to "use" the return value
of the snprintf() call, which avoids warnings about truncation.

src/os/shared/inc/os-shared-filesys.h

@@ -96,8 +96,8 @@ typedef struct
 typedef struct
 {
     char device_name[OS_MAX_API_NAME];      /**< The name of the underlying block device, if applicable */
-    char volume_name[OS_MAX_API_NAME];
-    char system_mountpt[OS_MAX_PATH_LEN];   /**< The name/prefix where the contents are accessible in the host operating system */
+    char volume_name[OS_FS_VOL_NAME_LEN];
+    char system_mountpt[OS_MAX_LOCAL_PATH_LEN]; /**< The name/prefix where the contents are accessible in the host operating system */
     char virtual_mountpt[OS_MAX_PATH_LEN];  /**< The name/prefix in the OSAL Virtual File system exposed to applications */
     char *address;
     uint32 blocksize;

src/os/shared/src/osapi-filesys.c

@@ -116,18 +116,21 @@ int32 OS_FileSys_InitLocalFromVolTable(OS_filesys_internal_record_t *local, cons
             strcmp(Vol->DeviceName,"unused") != 0)
     {
         strncpy(local->volume_name, Vol->VolumeName, sizeof(local->volume_name)-1);
+        local->volume_name[sizeof(local->volume_name)-1] = 0;
     }
 
     if (isgraph((int)Vol->PhysDevName[0]) &&
             strcmp(Vol->PhysDevName,"unused") != 0)
     {
         strncpy(local->system_mountpt, Vol->PhysDevName, sizeof(local->system_mountpt)-1);
+        local->system_mountpt[sizeof(local->system_mountpt)-1] = 0;
     }
 
     if (isgraph((int)Vol->MountPoint[0]) &&
             strcmp(Vol->MountPoint,"unused") != 0)
     {
         strncpy(local->virtual_mountpt, Vol->MountPoint, sizeof(local->virtual_mountpt)-1);
+        local->virtual_mountpt[sizeof(local->virtual_mountpt)-1] = 0;
     }
 
     /*
@@ -471,10 +474,10 @@ int32 OS_FileSysAddFixedMap(uint32 *filesys_id, const char *phys_path, const cha
 
         memset(local, 0, sizeof(*local));
         global->name_entry = local->device_name;
-        strcpy(local->device_name, dev_name);
-        strcpy(local->volume_name, dev_name);
-        strcpy(local->system_mountpt, phys_path);
-        strcpy(local->virtual_mountpt, virt_path);
+        strncpy(local->device_name, dev_name, sizeof(local->device_name)-1);
+        strncpy(local->volume_name, dev_name, sizeof(local->volume_name)-1);
+        strncpy(local->system_mountpt, phys_path, sizeof(local->system_mountpt)-1);
+        strncpy(local->virtual_mountpt, virt_path, sizeof(local->virtual_mountpt)-1);
 
         /*
          * mark the entry that it is a fixed disk

src/unit-tests/inc/ut_os_support.h

@@ -79,7 +79,7 @@ static inline bool UtOsalImplemented(int32 Fn, const char *File, uint32 Line)
 /*--------------------------------------------------------------------------------*/
 
 #define UT_os_sprintf(buf,...)  \
-    snprintf(buf,sizeof(buf),__VA_ARGS__)
+    do { int x = snprintf(buf,sizeof(buf),__VA_ARGS__); if (x > 0) buf[x] = 0; } while (0)
 
 /*--------------------------------------------------------------------------------*/