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hush: implement break and continue
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function                                             old     new   delta
bltins                                               252     276     +24
builtin_continue                                       -      12     +12
builtin_break                                          -      12     +12
static.version_str                                    18      17      -1
run_list                                            1984    1948     -36
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 1/2 up/down: 48/-27)             Total: 11 bytes
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Denis Vlasenko committed Jul 28, 2008
1 parent cf22c89 commit bcb2553
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Showing 2 changed files with 107 additions and 77 deletions.
171 changes: 98 additions & 73 deletions shell/hush.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -74,6 +74,7 @@
#include <fnmatch.h>
#endif

#define HUSH_VER_STR "0.9"

#if !BB_MMU && ENABLE_HUSH_TICK
//#undef ENABLE_HUSH_TICK
Expand Down Expand Up @@ -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,
Expand All @@ -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 ,
Expand Down Expand Up @@ -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;
Expand All @@ -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 */
Expand All @@ -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))

Expand All @@ -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 */

Expand All @@ -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;
Expand Down Expand Up @@ -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 )
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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"),
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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) {
Expand All @@ -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 */

Expand All @@ -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 */
Expand All @@ -2171,41 +2175,29 @@ 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) {
/* "for" loop is over, clean up */
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) {
Expand All @@ -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
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
}
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