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Commit 2fd5b09c authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

kconfig: add 'shell' built-in function 



This accepts a single command to execute.  It returns the standard
output from it.

[Example code]

  config HELLO
          string
          default "$(shell,echo hello world)"

  config Y
          def_bool $(shell,echo y)

[Result]

  $ make -s alldefconfig && tail -n 2 .config
  CONFIG_HELLO="hello world"
  CONFIG_Y=y

Caveat:
Like environments, functions are expanded in the lexer.  You cannot
pass symbols to function arguments.  This is a limitation to simplify
the implementation.  I want to avoid the dynamic function evaluation,
which would introduce much more complexity.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
parent e298f3b4

scripts/kconfig/preprocess.c

+41 −0
Original line number Diff line number Diff line
@@ -106,8 +106,49 @@ struct function { 
	char *(*func)(int argc, char *argv[]);

};



static char *do_shell(int argc, char *argv[])

{

	FILE *p;

	char buf[256];

	char *cmd;

	size_t nread;

	int i;



	cmd = argv[0];



	p = popen(cmd, "r");

	if (!p) {

		perror(cmd);

		exit(1);

	}



	nread = fread(buf, 1, sizeof(buf), p);

	if (nread == sizeof(buf))

		nread--;



	/* remove trailing new lines */

	while (buf[nread - 1] == '\n')

		nread--;



	buf[nread] = 0;



	/* replace a new line with a space */

	for (i = 0; i < nread; i++) {

		if (buf[i] == '\n')

			buf[i] = ' ';

	}



	if (pclose(p) == -1) {

		perror(cmd);

		exit(1);

	}



	return xstrdup(buf);

}



static const struct function function_table[] = {

	/* Name		MIN	MAX	Function */

	{ "shell",	1,	1,	do_shell },

};



#define FUNCTION_MAX_ARGS		16