Function append_to_file

lightningd/configs.c:340–380

}

static size_t append_to_file(struct lightningd *ld,
			     const char *fname,
			     const char *str,
			     bool must_exist)
{
	int fd;
	const char *buffer;

	fd = open(fname, O_RDWR|O_APPEND);
	if (fd < 0) {
		if (errno != ENOENT || must_exist)
			fatal("Could not write to config %s: %s",
			      fname, strerror(errno));
		fd = open(fname, O_RDWR|O_APPEND|O_CREAT, 0644);
		if (fd < 0)
			fatal("Could not create config file %s: %s",
			      fname, strerror(errno));
	}

	/* Note: always nul terminates */
	buffer = grab_fd_str(tmpctx, fd);
	if (!buffer)
		fatal("Error reading %s: %s", fname, strerror(errno));

	/* If there's a last character and it's not \n, add one */
	if (tal_bytelen(buffer) > 1
	    && buffer[tal_bytelen(buffer)-2] != '\n')
		str = tal_strcat(tmpctx, "\n", str);

	/* Always append a \n ourselves */
	str = tal_strcat(tmpctx, str, "\n");
	if (write(fd, str, strlen(str)) != strlen(str))
		fatal("Could not write to config file %s: %s",
		      fname, strerror(errno));
	if (fsync(fd) != 0)
		fatal("Syncing %s: %s", fname, strerror(errno));
	close(fd);

	/* 1-based counter of where new stuff appeared */
	return strcount(buffer, "\n") + 1;
}

static const char *grab_and_check(const tal_t *ctx,
				  const char *fname,