core-lightning/common/utils.h
Rusty Russell 26dda57cc0 utils: make tal_arr_expand safer.
Christian and I both unwittingly used it in form:

	*tal_arr_expand(&x) = tal(x, ...)

Since '=' isn't a sequence point, the compiler can (and does!) cache
the value of x, handing it to tal *after* tal_arr_expand() moves it
due to tal_resize().

The new version is somewhat less convenient to use, but doesn't have
this problem, since the assignment is always evaluated after the
resize.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2019-01-15 12:01:38 +01:00

58 lines
1.6 KiB
C

#ifndef LIGHTNING_COMMON_UTILS_H
#define LIGHTNING_COMMON_UTILS_H
#include "config.h"
#include <ccan/crypto/ripemd160/ripemd160.h>
#include <ccan/crypto/sha256/sha256.h>
#include <ccan/short_types/short_types.h>
#include <ccan/structeq/structeq.h>
#include <ccan/tal/tal.h>
#include <secp256k1.h>
extern secp256k1_context *secp256k1_ctx;
/* Allocate and fill in a hex-encoded string of this data. */
char *tal_hexstr(const tal_t *ctx, const void *data, size_t len);
/* Allocate and fill a hex-encoding of this tal pointer. */
char *tal_hex(const tal_t *ctx, const tal_t *data);
/* Allocate and fill a buffer with the data of this hex string. */
u8 *tal_hexdata(const tal_t *ctx, const void *str, size_t len);
/* Note: p is never a complex expression, otherwise this multi-evaluates! */
#define tal_arr_expand(p, s) \
do { \
size_t n = tal_count(*(p)); \
tal_resize((p), n+1); \
(*(p))[n] = (s); \
} while(0)
/**
* Remove an element from an array
*
* This will shift the elements past the removed element, changing
* their position in memory, so only use this for arrays of pointers.
*/
#define tal_arr_remove(p, n) tal_arr_remove_((p), sizeof(**p), (n))
void tal_arr_remove_(void *p, size_t elemsize, size_t n);
/* Use the POSIX C locale. */
void setup_locale(void);
/* Global temporary convenience context: children freed in io loop core. */
extern const tal_t *tmpctx;
/* Initial creation of tmpctx. */
void setup_tmpctx(void);
/* Free any children of tmpctx. */
void clean_tmpctx(void);
/* Define sha256_eq. */
STRUCTEQ_DEF(sha256, 0, u);
/* Define ripemd160_eq. */
STRUCTEQ_DEF(ripemd160, 0, u);
#endif /* LIGHTNING_COMMON_UTILS_H */