This is the second built-in function, which retrieves the first line
of stdout from the given shell command.
Example code:
config CC_IS_GCC
bool
default $(shell $CC --version | grep -q gcc)
config GCC_VERSION
int
default $(shell-stdout $srctree/scripts/gcc-version.sh $CC | sed
's/^0*//') if CC_IS_GCC
default 0
Result:
$ make -s alldefconfig && tail -n 2 .config
CONFIG_CC_IS_GCC=y
CONFIG_GCC_VERSION=504
$ make CC=clang -s alldefconfig && tail -n 2 .config
# CONFIG_CC_IS_GCC is not set
CONFIG_GCC_VERSION=0
By the way, function calls can be nested, so the following works.
Example code:
config FOO
bool
default $(shell $(shell-stdout echo $COMMAND_IN_CAPITAL | tr [A-Z]
[a-z]))
Result:
$ make -s COMMAND=TRUE alldefconfig && tail -n 1 .config
CONFIG_FOO=y
$ make -s COMMAND=FALSE alldefconfig && tail -n 1 .config
# CONFIG_FOO is not set
Signed-off-by: Masahiro Yamada <yamada.masah...@socionext.com>
---
scripts/kconfig/function.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/scripts/kconfig/function.c b/scripts/kconfig/function.c
index f7f154d..266f4ec 100644
--- a/scripts/kconfig/function.c
+++ b/scripts/kconfig/function.c
@@ -189,10 +189,56 @@ static char *do_shell(struct function *f, int argc, char
*argv[])
return xstrdup(ret == 0 ? "y" : "n");
}
+static char *do_shell_stdout(struct function *f, int argc, char *argv[])
+{
+ static const char *pre = "(";
+ static const char *post = ") 2>/dev/null";
+ FILE *p;
+ char buf[256];
+ char *cmd;
+ int ret;
+
+ if (argc != 2)
+ return NULL;
+
+ /*
+ * Surround the command with ( ) in case it is piped commands.
+ * Also, redirect stderr to /dev/null.
+ */
+ cmd = xmalloc(strlen(pre) + strlen(argv[1]) + strlen(post) + 1);
+ strcpy(cmd, pre);
+ strcat(cmd, argv[1]);
+ strcat(cmd, post);
+
+ p = popen(cmd, "r");
+ if (!p) {
+ perror(cmd);
+ goto free;
+ }
+ if (fgets(buf, sizeof(buf), p)) {
+ size_t len = strlen(buf);
+
+ if (buf[len - 1] == '\n')
+ buf[len - 1] = '\0';
+ } else {
+ buf[0] = '\0';
+ }
+
+ ret = pclose(p);
+ if (ret == -1)
+ perror(cmd);
+
+free:
+ free(cmd);
+
+ return xstrdup(buf);
+}
+
void func_init(void)
{
/* register built-in functions */
func_add("shell", do_shell, NULL);
+ func_add("shell-stdout", do_shell_stdout, NULL);
}
void func_exit(void)
--
2.7.4
