src/common/ref.h

/*****************************************************************************\
 *  ref.h - Static strings reference
 *****************************************************************************
 *  Copyright (C) SchedMD LLC.
 *
 *  This file is part of Slurm, a resource management program.
 *  For details, see <https://slurm.schedmd.com/>.
 *  Please also read the included file: DISCLAIMER.
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\*****************************************************************************/

#ifndef _COMMON_REF_H_
#define _COMMON_REF_H_

/*
 * Static data embedded with objcopy always has 3 symbols defined
 * (start, end, size).
 *
 * See also the "-I binary" discussion in objcopy(1).
 *
 * Warning: Do *NOT* use the symbol names directly.
 * Warning: _size is an absolute symbol -- its address is the size,
 *          not its contents. Use static_ref_size() instead.
 *
 * objcopy replaces any non-alphanumeric character (such as '.') with '_'.
 */
#define decl_static_data(name) \
	extern const void *_binary_##name##_start __attribute__((aligned(1))); \
	extern const void *_binary_##name##_end __attribute__((aligned(1))); \
	extern const void *_binary_##name##_size;

/*
 * Macros to retrieve the values of static data blob
 * Warning: blob may not be NULL terminated!
 */
#define static_ref_start(name) ((const char *) &_binary_##name##_start)
#define static_ref_end(name) ((const char *) &_binary_##name##_end)
#define static_ref_size(name) \
	((const size_t) (static_ref_end(name) - static_ref_start(name)))

/* Copy and convert static data to a string that needs to be xfreed() */
#define static_ref_to_cstring(src, name)                             \
	do {                                                         \
		const size_t data_size = static_ref_size(name);      \
		unsigned char *data_ptr = xmalloc(data_size + 1);    \
		xassert(data_size < UINT32_MAX);                     \
		memcpy(data_ptr, static_ref_start(name), data_size); \
		data_ptr[data_size] = '\0';                          \
		src = (void *) data_ptr;                             \
	} while (0)

#endif /* _COMMON_REF_H_ */