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bcb25537d

Denis Vlasenko
Denis Vlasenko
2008-07-28
FAILED Duration: 27s

Subject

hush: implement break and continue

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

shell/hush.c +98 -73shell/hush_doc.txt +9 -4
shell/hush.c+98 -73
@@ -54,7 +54,7 @@
* to-do:
* port selected bugfixes from post-0.49 busybox lash - done?
* change { and } from special chars to reserved words
- * builtins: break, continue, eval, return, set, trap, ulimit
+ * builtins: return, trap, ulimit
* test magic exec
* check setting of global_argc and global_argv
* follow IFS rules more precisely, including update semantics
@@ -74,6 +74,7 @@
#include <fnmatch.h>
#endif
+#define HUSH_VER_STR "0.9"
#if !BB_MMU && ENABLE_HUSH_TICK
//#undef ENABLE_HUSH_TICK
@@ -230,7 +231,7 @@ void xxfree(void *ptr)
#define SPECIAL_VAR_SYMBOL 3
#define PARSEFLAG_EXIT_FROM_LOOP 1
-typedef enum {
+typedef enum redir_type {
REDIRECT_INPUT = 1,
REDIRECT_OVERWRITE = 2,
REDIRECT_APPEND = 3,
@@ -253,14 +254,14 @@ static const struct {
{ O_RDWR, 1, "<>" }
};
-typedef enum {
+typedef enum pipe_style {
PIPE_SEQ = 1,
PIPE_AND = 2,
PIPE_OR = 3,
PIPE_BG = 4,
} pipe_style;
-typedef enum {
+typedef enum reserved_style {
RES_NONE = 0,
#if ENABLE_HUSH_IF
RES_IF ,
@@ -358,7 +359,7 @@ struct variable {
smallint flg_read_only;
};
-typedef struct {
+typedef struct o_string {
char *data;
int length; /* position where data is appended */
int maxlen;
@@ -378,9 +379,9 @@ enum {
/* Used for initialization: o_string foo = NULL_O_STRING; */
#define NULL_O_STRING { NULL }
-/* I can almost use ordinary FILE *. Is open_memstream() universally
+/* I can almost use ordinary FILE*. Is open_memstream() universally
* available? Where is it documented? */
-struct in_str {
+typedef struct in_str {
const char *p;
/* eof_flag=1: last char in ->p is really an EOF */
char eof_flag; /* meaningless if ->p == NULL */
@@ -392,7 +393,7 @@ struct in_str {
FILE *file;
int (*get) (struct in_str *);
int (*peek) (struct in_str *);
-};
+} in_str;
#define i_getch(input) ((input)->get(input))
#define i_peek(input) ((input)->peek(input))
@@ -403,7 +404,11 @@ enum {
CHAR_SPECIAL = 3, /* example: $ */
};
-#define HUSH_VER_STR "0.02"
+enum {
+ BC_BREAK = 1,
+ BC_CONTINUE = 2,
+};
+
/* "Globals" within this file */
@@ -429,6 +434,7 @@ struct globals {
struct pipe *toplevel_list;
smallint ctrl_z_flag;
#endif
+ smallint flag_break_continue;
smallint fake_mode;
/* these three support $?, $#, and $1 */
smalluint last_return_code;
@@ -481,6 +487,7 @@ enum { run_list_level = 0 };
#define global_argc (G.global_argc )
#define last_return_code (G.last_return_code)
#define ifs (G.ifs )
+#define flag_break_continue (G.flag_break_continue)
#define fake_mode (G.fake_mode )
#define cwd (G.cwd )
#define last_bg_pid (G.last_bg_pid )
@@ -713,6 +720,8 @@ static int builtin_shift(char **argv);
static int builtin_source(char **argv);
static int builtin_umask(char **argv);
static int builtin_unset(char **argv);
+static int builtin_break(char **argv);
+static int builtin_continue(char **argv);
//static int builtin_not_written(char **argv);
/* Table of built-in functions. They can be forked or not, depending on
@@ -742,10 +751,10 @@ static const struct built_in_command bltins[] = {
#if ENABLE_HUSH_JOB
BLTIN("bg" , builtin_fg_bg, "Resume a job in the background"),
#endif
-// BLTIN("break" , builtin_not_written, "Exit for, while or until loop"),
+ BLTIN("break" , builtin_break, "Exit from a loop"),
BLTIN("cd" , builtin_cd, "Change directory"),
-// BLTIN("continue", builtin_not_written, "Continue for, while or until loop"),
- BLTIN("echo" , builtin_echo, "Write strings to stdout"),
+ BLTIN("continue", builtin_continue, "Start new loop iteration"),
+ BLTIN("echo" , builtin_echo, "Write to stdout"),
BLTIN("eval" , builtin_eval, "Construct and run shell command"),
BLTIN("exec" , builtin_exec, "Execute command, don't return to shell"),
BLTIN("exit" , builtin_exit, "Exit"),
@@ -2016,29 +2025,25 @@ static int run_list(struct pipe *pi)
char *case_word = NULL;
#endif
#if ENABLE_HUSH_LOOPS
- struct pipe *loop_top = loop_top; /* just for compiler */
+ struct pipe *loop_top = NULL;
char *for_varname = NULL;
char **for_lcur = NULL;
char **for_list = NULL;
- smallint flag_run_loop = 0;
- smallint flag_goto_looptop = 0;
#endif
smallint flag_skip = 1;
smalluint rcode = 0; /* probably just for compiler */
#if ENABLE_HUSH_IF
smalluint cond_code = 0;
-///experimentally off: last_cond_code seems to be bogus
- ///smalluint last_cond_code = 0; /* need double-buffer to handle "elif" */
#else
- enum { cond_code = 0, /* ///last_cond_code = 0 */ };
+ enum { cond_code = 0, };
#endif
- /*reserved_style*/ smallint rword IF_HAS_NO_KEYWORDS(= RES_NONE);
- /*reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
+ /*enum reserved_style*/ smallint rword = RES_NONE;
+ /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
debug_printf_exec("run_list start lvl %d\n", run_list_level + 1);
#if ENABLE_HUSH_LOOPS
- /* check syntax for "for" */
+ /* Check syntax for "for" */
for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
continue;
@@ -2108,20 +2113,16 @@ static int run_list(struct pipe *pi)
}
#endif /* JOB */
- /* Go through list of pipes, (maybe) executing them */
- for (; pi; pi = USE_HUSH_LOOPS( flag_goto_looptop ? loop_top : ) pi->next) {
+ /* Go through list of pipes, (maybe) executing them. */
+ for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
IF_HAS_KEYWORDS(rword = pi->res_word;)
IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
- debug_printf_exec(": rword=%d cond_code=%d last_cond_code=%d skip_more=%d flag_run_loop=%d\n",
- rword, cond_code, last_cond_code, skip_more_for_this_rword, flag_run_loop);
+ debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
+ rword, cond_code, skip_more_for_this_rword);
#if ENABLE_HUSH_LOOPS
if (rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) {
- /* start of a loop: remember it */
- flag_goto_looptop = 0; /* not yet reached final "done" */
-// if (!loop_top) { /* hmm why this check is needed? */
-// flag_run_loop = 0; /* suppose loop condition is false (for now) */
- loop_top = pi; /* remember where loop starts */
-// }
+ /* start of a loop: remember where loop starts */
+ loop_top = pi;
}
#endif
if (rword == skip_more_for_this_rword && flag_skip) {
@@ -2134,18 +2135,21 @@ static int run_list(struct pipe *pi)
flag_skip = 1;
skip_more_for_this_rword = RES_XXXX;
#if ENABLE_HUSH_IF
-/// if (rword == RES_THEN) // || rword == RES_ELSE)
-/// cond_code = last_cond_code;
- if (rword == RES_THEN && cond_code)
- continue; /* "if <false> THEN cmd": skip cmd */
- if (rword == RES_ELSE && !cond_code)
- //continue; /* "if <true> then ... ELSE cmd": skip cmd */
- break; //TEST
- if (rword == RES_ELIF && !cond_code)
- break; /* "if <true> then ... ELIF cmd": skip cmd and all following ones */
+ if (cond_code) {
+ if (rword == RES_THEN) {
+ /* "if <false> THEN cmd": skip cmd */
+ continue;
+ }
+ } else {
+ if (rword == RES_ELSE || rword == RES_ELIF) {
+ /* "if <true> then ... ELSE/ELIF cmd":
+ * skip cmd and all following ones */
+ break;
+ }
+ }
#endif
#if ENABLE_HUSH_LOOPS
- if (rword == RES_FOR && pi->num_progs) { /* hmm why "&& pi->num_progs"? */
+ if (rword == RES_FOR) { /* && pi->num_progs - always == 1 */
if (!for_lcur) {
/* first loop through for */
@@ -2161,7 +2165,7 @@ static int run_list(struct pipe *pi)
if (pi->next->res_word == RES_IN) {
/* if no variable values after "in" we skip "for" */
if (!pi->next->progs->argv)
- continue;
+ break;
vals = pi->next->progs->argv;
} /* else: "for var; do..." -> assume "$@" list */
/* create list of variable values */
@@ -2171,7 +2175,6 @@ static int run_list(struct pipe *pi)
debug_print_strings("for_list", for_list);
for_varname = pi->progs->argv[0];
pi->progs->argv[0] = NULL;
- flag_run_loop = 1; /* "for" has no loop condition, loop... */
}
free(pi->progs->argv[0]);
if (!*for_lcur) {
@@ -2179,33 +2182,22 @@ static int run_list(struct pipe *pi)
free(for_list);
for_list = NULL;
for_lcur = NULL;
- flag_run_loop = 0; /* ... until end of value list */
pi->progs->argv[0] = for_varname;
- continue;
+ break;
}
/* insert next value from for_lcur */
//TODO: does it need escaping?
pi->progs->argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
}
- if (rword == RES_IN) /* "for v IN list; do ..." - no pipe to execute here */
+ if (rword == RES_IN) /* "for v IN list;..." - "in" has no cmds anyway */
continue;
- if (rword == RES_DO) { /* "...; DO cmd; cmd" - this pipe is in loop body */
- if (!flag_run_loop)
- continue; /* we are skipping this iteration */
- }
- if (rword == RES_DONE) { /* end of loop? */
- if (flag_run_loop) {
- flag_goto_looptop = 1;
-// } else {
-// loop_top = NULL;
- }
- continue; //TEST /* "done" has no cmd anyway */
+ if (rword == RES_DONE) {
+ continue; /* "done" has no cmds too */
}
#endif
#if ENABLE_HUSH_CASE
if (rword == RES_CASE) {
case_word = expand_strvec_to_string(pi->progs->argv);
- //bb_error_msg("case: arg:'%s' case_word:'%s'", pi->progs->argv[0], case_word);
continue;
}
if (rword == RES_MATCH) {
@@ -2215,35 +2207,53 @@ static int run_list(struct pipe *pi)
/* all prev words didn't match, does this one match? */
pattern = expand_strvec_to_string(pi->progs->argv);
/* TODO: which FNM_xxx flags to use? */
- /* ///last_ */ cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
- //bb_error_msg("fnmatch('%s','%s'):%d", pattern, case_word, cond_code);
+ cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
free(pattern);
- if (/* ///last_ */ cond_code == 0) { /* match! we will execute this branch */
+ if (cond_code == 0) { /* match! we will execute this branch */
free(case_word); /* make future "word)" stop */
case_word = NULL;
}
continue;
}
if (rword == RES_CASEI) { /* inside of a case branch */
- if (/* ///last_ */ cond_code != 0)
+ if (cond_code != 0)
continue; /* not matched yet, skip this pipe */
}
#endif
if (pi->num_progs == 0)
continue;
- /* After analyzing all keywrds and conditions, we decided
- * to execute this pipe */
+ /* After analyzing all keywords and conditions, we decided
+ * to execute this pipe. NB: has to do checkjobs(NULL)
+ * after run_pipe() to collect any background children,
+ * even if list execution is to be stopped. */
debug_printf_exec(": run_pipe with %d members\n", pi->num_progs);
{
int r;
+ flag_break_continue = 0;
rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
if (r != -1) {
- /* We only ran a builtin: rcode was set by the return value
- * of run_pipe(), and we don't need to wait for anything. */
+ /* we only ran a builtin: rcode is already known
+ * and we don't need to wait for anything. */
+ /* was it "break" or "continue"? */
+ if (flag_break_continue) {
+ smallint fbc = flag_break_continue;
+ /* we might fall into outer *loop*,
+ * don't want to break it too */
+ flag_break_continue = 0;
+ if (loop_top) {
+ if (fbc == BC_BREAK)
+ goto check_jobs_and_break;
+ /* "continue": simulate end of loop */
+ rword = RES_DONE;
+ continue;
+ }
+ bb_error_msg("break/continue: only meaningful in a loop");
+ /* bash compat: exit code is still 0 */
+ }
} else if (pi->followup == PIPE_BG) {
- /* What does bash do with attempts to background builtins? */
- /* Even bash 3.2 doesn't do that well with nested bg:
+ /* what does bash do with attempts to background builtins? */
+ /* even bash 3.2 doesn't do that well with nested bg:
* try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
* I'm NOT treating inner &'s as jobs */
#if ENABLE_HUSH_JOB
@@ -2271,16 +2281,19 @@ static int run_list(struct pipe *pi)
/* Analyze how result affects subsequent commands */
#if ENABLE_HUSH_IF
if (rword == RES_IF || rword == RES_ELIF)
- /* ///last_cond_code = */ cond_code = rcode;
+ cond_code = rcode;
#endif
#if ENABLE_HUSH_LOOPS
if (rword == RES_WHILE) {
- flag_run_loop = !rcode;
- debug_printf_exec(": setting flag_run_loop=%d\n", flag_run_loop);
+ if (rcode)
+ goto check_jobs_and_break;
}
if (rword == RES_UNTIL) {
- flag_run_loop = rcode;
- debug_printf_exec(": setting flag_run_loop=%d\n", flag_run_loop);
+ if (!rcode) {
+ check_jobs_and_break:
+ checkjobs(NULL);
+ break;
+ }
}
#endif
if ((rcode == 0 && pi->followup == PIPE_OR)
@@ -4498,3 +4511,15 @@ static int builtin_unset(char **argv)
unset_local_var(argv[1]);
return EXIT_SUCCESS;
}
+
+static int builtin_break(char **argv UNUSED_PARAM)
+{
+ flag_break_continue = BC_BREAK;
+ return EXIT_SUCCESS;
+}
+
+static int builtin_continue(char **argv UNUSED_PARAM)
+{
+ flag_break_continue = BC_CONTINUE;
+ return EXIT_SUCCESS;
+}
shell/hush_doc.txt+9 -4
@@ -2,9 +2,10 @@
Command parsing
-Command parsing results in "pipe" structures. "Pipe" structure
-does not always correspond to what sh language calls "pipe",
-it also controls execution of if, while, etc statements.
+Command parsing results in a list of "pipe" structures.
+This list correspond not only to usual "pipe1 || pipe2 && pipe3"
+lists, but it also controls execution of if, while, etc statements.
+Every such statement is a list for hush. List consists of pipes.
struct pipe fields:
smallint res_word - "none" for normal commands,
@@ -18,7 +19,7 @@ Blocks of commands { pipe; pipe; } and (pipe; pipe) are represented
as one pipe struct with one progs[0] element which is a "group" -
struct child_prog can contain a list of pipes. Sometimes these
"groups" are created implicitly, e.g. every control
-statement (if, while, etc) sits inside its own "pipe" struct).
+statement (if, while, etc) sits inside its own group.
res_word controls statement execution. Examples:
@@ -41,6 +42,10 @@ res_word=NONE followup=SEQ
pipe 4 res_word=NONE followup=(null)
pipe 1 res_word=NONE followup=SEQ
+Above you see that if is a list, and it sits in a {} group
+implicitly created by hush. Also note two THEN res_word's -
+it is explained below.
+
"if true; then { echo Hello; true; }; fi" -
pipe 0 res_word=NONE followup=SEQ
prog 0 group {}: