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

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
......@@ -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
......
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