From 2344a769a43b21f2a45a0397cc6d518b7cea7e33 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 28 May 2018 18:21:46 +0900 Subject: [PATCH] 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: Masahiro Yamada Signed-off-by: Christian Lamparter --- config/preprocess.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/config/preprocess.c b/config/preprocess.c index f32a496..528be59 100644 --- a/config/preprocess.c +++ b/config/preprocess.c @@ -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 -- 2.31.1