Re: [libvirt] [PATCH 1/6] util: file: introduce VIR_AUTOCLOSE macro to close fd of the file automatically

By making use of GNU C's cleanup attribute handled by the VIR_AUTOCLOSE macro, many of the VIR_FORCE_CLOSE calls can be dropped, which in turn leads to getting rid of many of our cleanup sections. Signed-off-by: Shi Lei <shi_lei(a)massclouds.com&gt; --- src/util/virfile.h | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/src/util/virfile.h b/src/util/virfile.h index b30a1d3..70e7203 100644 --- a/src/util/virfile.h +++ b/src/util/virfile.h @@ -54,6 +54,11 @@ int virFileClose(int *fdptr, virFileCloseFlags flags) int virFileFclose(FILE **file, bool preserve_errno) ATTRIBUTE_RETURN_CHECK; FILE *virFileFdopen(int *fdptr, const char *mode) ATTRIBUTE_RETURN_CHECK; +static inline void virForceCloseHelper(int *_fd)

+{ + ignore_value(virFileClose(_fd, VIR_FILE_CLOSE_PRESERVE_ERRNO)); +} + /* For use on normal paths; caller must check return value, and failure sets errno per close. */ # define VIR_CLOSE(FD) virFileClose(&(FD), 0) @@ -64,8 +69,7 @@ FILE *virFileFdopen(int *fdptr, const char *mode) ATTRIBUTE_RETURN_CHECK; /* For use on cleanup paths; errno is unaffected by close, and no return value to worry about. */ -# define VIR_FORCE_CLOSE(FD) \ - ignore_value(virFileClose(&(FD), VIR_FILE_CLOSE_PRESERVE_ERRNO)) +# define VIR_FORCE_CLOSE(FD) virForceCloseHelper(&(FD)) # define VIR_FORCE_FCLOSE(FILE) ignore_value(virFileFclose(&(FILE), true)) /* Similar VIR_FORCE_CLOSE() but ignores EBADF errors since they are expected @@ -80,6 +84,18 @@ FILE *virFileFdopen(int *fdptr, const char *mode) ATTRIBUTE_RETURN_CHECK; VIR_FILE_CLOSE_PRESERVE_ERRNO | \ VIR_FILE_CLOSE_DONT_LOG)) +/** + * VIR_AUTOCLOSE: + * @fd: fd of the file to be closed automatically + * + * Macro to automatically force close the fd by calling virForceCloseHelper + * when the fd goes out of scope. It's used to eliminate VIR_FORCE_CLOSE + * in cleanup sections. + */ +# define VIR_AUTOCLOSE(fd) \ + __attribute__((cleanup(virForceCloseHelper))) int fd = -1

+ + /* Opaque type for managing a wrapper around a fd. */ struct _virFileWrapperFd;