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msh_function.patch: picked it up in the wild.
Fixed allocation bugs (it was allocating one too small vectors) but it still is very buggy, thus not applied.
This commit is contained in:
Denis Vlasenko
parent
ed9d621cf4
commit
2d0529c9bc
350
shell/msh_function.patch
Normal file
350
shell/msh_function.patch
Normal file
@ -0,0 +1,350 @@
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This is a "function" patch for msh which is in use by some busybox
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users. Unfortunately it is far too buggy to be applied, but maybe
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it's a useful starting point for future work.
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Function-related code is delimited by comments of the form
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//funccode:start
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...
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//funccode:end
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for ease of grepping
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An example of buggy behavior:
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#f() {
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# echo foo
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# echo test`echo bar >&2`
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# echo END f
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#}
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function g {
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# echo 2 foo
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# echo 2 test`echo 2 bar >&2`
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# f
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echo END g
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# echo "1:'$1' 2:'$2'"
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}
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# Even this first block fails - it does not even call functions!
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# (replacing "echo END g" above with "echo END" makes it run ok)
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echo DRY RUN
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echo 2 foo
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echo 2 test`echo 2 bar >&2`
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echo END g
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echo "1:'$1' 2:'$2'"
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echo foo
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echo test`echo bar >&2`
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echo END f
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echo END DRY RUN
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exit
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# This would fail too
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g "$1-one" "two$2"
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echo DONE
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diff -d -urpN busybox.7/shell/msh.c busybox.8/shell/msh.c
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--- busybox.7/shell/msh.c 2008-06-09 09:34:45.000000000 +0200
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+++ busybox.8/shell/msh.c 2008-06-09 09:38:17.000000000 +0200
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@@ -89,6 +89,14 @@ static char *itoa(int n)
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//#define MSHDEBUG 4
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+/* Used only in "function" support code */
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+#ifdef KSDBG //funccode:start
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+ #define KSDBG_PRINT_FUNCNAME fprintf(stderr, "in %s\n", __FUNCTION__)
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+#else
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+ #define KSDBG_PRINT_FUNCNAME ((void)0)
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+#endif
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+//funccode:end
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+
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#ifdef MSHDEBUG
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static int mshdbg = MSHDEBUG;
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@@ -220,6 +228,9 @@ struct op {
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#define TASYNC 16 /* c & */
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/* Added to support "." file expansion */
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#define TDOT 17
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+#define TFUNC 18 //funccode:start
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+#define TRETURN 19
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+ //funccode:end
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/* Strings for names to make debug easier */
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#ifdef MSHDEBUG
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@@ -319,6 +330,27 @@ struct region {
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int area;
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};
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+static int func_finished; //funccode:start
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+struct func {
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+ char* name;
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+ int begin_addr; /* pos in buffer of function */
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+ int end_addr;
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+};
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+#define MAX_FUNCS 100
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+
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+static struct func funcs[MAX_FUNCS];
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+
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+/* the max DEPTH of function call */
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+#define MAX_DEPTH 100
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+static struct _frame_s {
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+ int argc;
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+ char **argv;
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+ int saved_return_addr;
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+} frame[MAX_DEPTH];
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+
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+static void register_func(int begin, int end);
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+static struct func* find_func(char* name);
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+static void exec_func(struct func* f); //funccode:end
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/* -------- grammar stuff -------- */
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typedef union {
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@@ -347,6 +379,8 @@ typedef union {
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#define IN 272
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/* Added for "." file expansion */
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#define DOT 273
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+#define FUNC 274 //funccode:start
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+#define RETURN 275 //funccode:end
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#define YYERRCODE 300
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@@ -1722,6 +1756,40 @@ static struct op *simple(void)
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(void) synio(0);
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break;
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+ case FUNC: { //funccode:start
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+ int stop_flag;
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+ int number_brace;
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+ int func_begin;
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+ int func_end;
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+ int c;
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+ while ((c = my_getc(0)) == ' ' || c == '\t'|| c == '\n') /* skip whitespace */
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+ continue;
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+ stop_flag = 1;
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+ number_brace = 0;
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+ func_begin = global_env.iobase->argp->afpos;
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+ while (stop_flag) {
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+ if (c == '{')
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+ number_brace++;
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+ if (c == '}')
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+ number_brace--;
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+ if (!number_brace) /* if we reach the brace of most outsite */
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+ stop_flag = 0;
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+ c = my_getc(0);
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+ }
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+ unget(c);
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+ unget(c);
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+ func_end = global_env.iobase->argp->afpos;
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+ register_func(func_begin, func_end);
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+ peeksym = 0;
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+ t = NULL;
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+ return t;
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+ }
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+ case RETURN:
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+ func_finished = 1;
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+ peeksym = 0;
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+ t = NULL;
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+ return t; //funccode:end
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+
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case WORD:
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if (t == NULL) {
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t = newtp();
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@@ -2265,6 +2333,13 @@ static int yylex(int cf)
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case ')':
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startl = 1;
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return c;
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+ case '{': //funccode:start
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+ c = collect(c, '}');
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+ if (c != '\0')
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+ return c;
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+ break;
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+ case '}':
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+ return RETURN; //funccode:end
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}
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unget(c);
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@@ -2293,9 +2368,172 @@ static int yylex(int cf)
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}
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yylval.cp = strsave(line, areanum);
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+ /* To identify a subroutine */ //funccode:start
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+ c = my_getc(0);
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+ if (c && any(c, "(")) {
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+ c = my_getc(0);
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+ if (c && any(c, ")"))
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+ return FUNC;
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+ zzerr();
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+ } else
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+ unget(c);
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+ /* read the first char */
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+ /* To identify a function */
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+ if (strcmp(yylval.cp, "function") == 0) {
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+ int ret = yylex(0);
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+ /* read the function name after "function" */
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+ if (ret == WORD)
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+ return (FUNC);
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+ zzerr();
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+ }
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+ {
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+ struct func* f = find_func(yylval.cp);
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+ if (f != NULL) {
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+ exec_func(f);
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+ return RETURN;
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+ }
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+ }
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+ if (yylval.cp != NULL && strcmp(yylval.cp, "return") == 0) {
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+ return RETURN;
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+ } //funccode:end
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return WORD;
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}
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+static void register_func(int begin, int end) //funccode:start
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+{
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+ struct func *p;
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+ int i;
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+ for (i = 0; i < MAX_FUNCS; i++) {
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+ if (funcs[i].name == NULL) {
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+ p = &funcs[i];
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+ break;
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+ }
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+ }
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+ if (i == MAX_FUNCS) {
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+ fprintf(stderr, "Too much functions beyond limit\n");
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+ leave();
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+ }
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+ p->name = xstrdup(yylval.cp);
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+ //fprintf(stderr, "register function,%d,%d,%s\n", begin, end, p->name);
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+ KSDBG_PRINT_FUNCNAME;
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+ /* io stream */
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+ p->begin_addr = begin;
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+ p->end_addr = end;
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+}
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+
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+static struct func* find_func(char* name)
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+{
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+ int i;
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+ for (i = 0; i < MAX_FUNCS; i++) {
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+ if (funcs[i].name == NULL)
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+ continue;
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+ if (!strcmp(funcs[i].name, name))
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+ return &funcs[i];
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+ }
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+ KSDBG_PRINT_FUNCNAME;
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+ //fprintf(stderr, "not found the function %s\n", name);
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+ return NULL;
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+ //zzerr();
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+}
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+
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+/* Begin to execute the function */
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+static int cur_frame = 0;
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+
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+static void exec_func(struct func* f)
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+{
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+ int c;
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+ int temp_argc;
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+ char** temp_argv;
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+ struct iobuf *bp;
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+
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+ /* create a new frame, save the argument and return address to this frame */
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+ frame[cur_frame].argc = dolc;
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+ frame[cur_frame].argv = dolv;
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+
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+ cur_frame++;
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+ /* do some argment parse and set arguments */
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+ temp_argv = xmalloc(sizeof(char *));
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+ temp_argv[0] = xstrdup(f->name);
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+ temp_argc = 0;
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+ global_env.iop->argp->afpos--;
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+ global_env.iop->argp->afbuf->bufp--;
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+// unget(c);
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+ while (((c = yylex(0)) != '\n') && (yylval.cp != NULL)) {
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+ temp_argc++;
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+ temp_argv = xrealloc(temp_argv, sizeof(char *) * (temp_argc+1));
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+ /* parse $ var if passed argument is a variable */
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+ if (yylval.cp[0] == '$') {
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+ struct var *arg = lookup(&yylval.cp[1]);
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+ temp_argv[temp_argc] = xstrdup(arg->value);
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+ //fprintf(stderr, "arg->value=%s\n", arg->value);
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+ } else {
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+ temp_argv[temp_argc] = xstrdup(yylval.cp);
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+ //fprintf(stderr, "ARG:%s\n", yylval.cp);
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+ }
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+ }
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+ /*
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+ global_env.iop->argp->afpos--;
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+ global_env.iop->argp->afbuf->bufp--;
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+ */
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+ dolc = temp_argc;
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+ dolv = temp_argv;
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+ //unget(c);
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+ //while ((c = my_getc(0)) == ' ' || c == '\t') /* Skip whitespace */
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+ // continue;
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+ //unget(c);
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+ frame[cur_frame].saved_return_addr = global_env.iop->argp->afpos;
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+
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+ /* get function begin address and execute this function */
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+
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+ bp = global_env.iop->argp->afbuf;
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+ bp->bufp = &(bp->buf[f->begin_addr]);
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+ global_env.iop->argp->afpos = f->begin_addr;
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+
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+ /* func_finished=0 means we are in a function and func_finished=1 means we are executing a function */
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+ func_finished = 0;
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+
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+ //fprintf(stderr, "exec function %s\n", f->name);
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+ KSDBG_PRINT_FUNCNAME;
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+ for (;;) {
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+ //fprintf(stderr, "afpos=%d,%s\n", global_env.iop->argp->afpos, yylval.cp);
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+ if (global_env.iop->argp->afpos == f->end_addr)
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+ break;
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+ onecommand();
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+ /* we return from a function, when func_finished = 1 */
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+ if (func_finished)
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+ break;
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+ }
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+
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+ {
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+ //fprintf(stderr, "%s is finished @%d!\n", f->name, global_env.iop->argp->afpos);
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+ int ret = frame[cur_frame].saved_return_addr;
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+ /* workaround code for \n */
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+ if (dolc)
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+ ret--;
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+ /* get return address from current frame and jump to */
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+ global_env.iop->argp->afpos = ret;
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+ global_env.iop->argp->afbuf->bufp = &(global_env.iop->argp->afbuf->buf[ret]);
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+ }
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+ /*
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+ fprintf(stderr, "******** after execution ********************\n");
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+ fprintf(stderr, " %s \n############# %d\n", global_env.iop->argp->afbuf->bufp, ret);
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+ fprintf(stderr, "*******************************\n");
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+ */
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+ /* we return to previous frame */
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+ cur_frame--;
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+ /* free some space occupied by argument */
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+ while (dolc--)
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+ free(dolv[dolc]);
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+ free(dolv);
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+
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+ /* recover argument for last function */
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+ dolv = frame[cur_frame].argv;
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+ dolc = frame[cur_frame].argc;
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+ /* If we are not in the outest frame, we should set
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+ * func_finished to 0 that means we still in some function */
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+ if (cur_frame != 0)
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+ func_finished = 0;
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+} //funccode:end
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static int collect(int c, int c1)
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{
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@@ -2601,6 +2839,10 @@ static int execute(struct op *t, int *pi
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execute(t->right->right, pin, pout, /* no_fork: */ 0);
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}
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break;
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+ case TFUNC: //funccode:start
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+ break;
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+ case TRETURN:
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+ break; //funccode:end
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case TCASE:
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cp = evalstr(t->str, DOSUB | DOTRIM);
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