hush: implement break and continue
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
This commit is contained in:
Denis Vlasenko
parent
cf22c89f9a
commit
bcb25537d0
169
shell/hush.c
169
shell/hush.c
@ -54,7 +54,7 @@
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* to-do:
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* port selected bugfixes from post-0.49 busybox lash - done?
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* change { and } from special chars to reserved words
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* builtins: break, continue, eval, return, set, trap, ulimit
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* builtins: return, trap, ulimit
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* test magic exec
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* check setting of global_argc and global_argv
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* follow IFS rules more precisely, including update semantics
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@ -74,6 +74,7 @@
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#include <fnmatch.h>
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#endif
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#define HUSH_VER_STR "0.9"
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#if !BB_MMU && ENABLE_HUSH_TICK
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//#undef ENABLE_HUSH_TICK
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@ -230,7 +231,7 @@ void xxfree(void *ptr)
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#define SPECIAL_VAR_SYMBOL 3
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#define PARSEFLAG_EXIT_FROM_LOOP 1
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typedef enum {
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typedef enum redir_type {
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REDIRECT_INPUT = 1,
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REDIRECT_OVERWRITE = 2,
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REDIRECT_APPEND = 3,
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@ -253,14 +254,14 @@ static const struct {
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{ O_RDWR, 1, "<>" }
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};
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typedef enum {
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typedef enum pipe_style {
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PIPE_SEQ = 1,
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PIPE_AND = 2,
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PIPE_OR = 3,
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PIPE_BG = 4,
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} pipe_style;
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typedef enum {
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typedef enum reserved_style {
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RES_NONE = 0,
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#if ENABLE_HUSH_IF
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RES_IF ,
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@ -358,7 +359,7 @@ struct variable {
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smallint flg_read_only;
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};
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typedef struct {
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typedef struct o_string {
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char *data;
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int length; /* position where data is appended */
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int maxlen;
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@ -380,7 +381,7 @@ enum {
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/* I can almost use ordinary FILE*. Is open_memstream() universally
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* available? Where is it documented? */
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struct in_str {
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typedef struct in_str {
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const char *p;
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/* eof_flag=1: last char in ->p is really an EOF */
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char eof_flag; /* meaningless if ->p == NULL */
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@ -392,7 +393,7 @@ struct in_str {
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FILE *file;
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int (*get) (struct in_str *);
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int (*peek) (struct in_str *);
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};
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} in_str;
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#define i_getch(input) ((input)->get(input))
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#define i_peek(input) ((input)->peek(input))
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@ -403,7 +404,11 @@ enum {
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CHAR_SPECIAL = 3, /* example: $ */
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};
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#define HUSH_VER_STR "0.02"
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enum {
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BC_BREAK = 1,
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BC_CONTINUE = 2,
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};
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/* "Globals" within this file */
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@ -429,6 +434,7 @@ struct globals {
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struct pipe *toplevel_list;
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smallint ctrl_z_flag;
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#endif
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smallint flag_break_continue;
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smallint fake_mode;
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/* these three support $?, $#, and $1 */
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smalluint last_return_code;
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@ -481,6 +487,7 @@ enum { run_list_level = 0 };
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#define global_argc (G.global_argc )
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#define last_return_code (G.last_return_code)
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#define ifs (G.ifs )
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#define flag_break_continue (G.flag_break_continue)
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#define fake_mode (G.fake_mode )
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#define cwd (G.cwd )
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#define last_bg_pid (G.last_bg_pid )
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@ -713,6 +720,8 @@ static int builtin_shift(char **argv);
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static int builtin_source(char **argv);
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static int builtin_umask(char **argv);
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static int builtin_unset(char **argv);
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static int builtin_break(char **argv);
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static int builtin_continue(char **argv);
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//static int builtin_not_written(char **argv);
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/* Table of built-in functions. They can be forked or not, depending on
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@ -742,10 +751,10 @@ static const struct built_in_command bltins[] = {
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#if ENABLE_HUSH_JOB
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BLTIN("bg" , builtin_fg_bg, "Resume a job in the background"),
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#endif
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// BLTIN("break" , builtin_not_written, "Exit for, while or until loop"),
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BLTIN("break" , builtin_break, "Exit from a loop"),
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BLTIN("cd" , builtin_cd, "Change directory"),
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// BLTIN("continue", builtin_not_written, "Continue for, while or until loop"),
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BLTIN("echo" , builtin_echo, "Write strings to stdout"),
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BLTIN("continue", builtin_continue, "Start new loop iteration"),
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BLTIN("echo" , builtin_echo, "Write to stdout"),
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BLTIN("eval" , builtin_eval, "Construct and run shell command"),
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BLTIN("exec" , builtin_exec, "Execute command, don't return to shell"),
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BLTIN("exit" , builtin_exit, "Exit"),
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@ -2016,29 +2025,25 @@ static int run_list(struct pipe *pi)
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char *case_word = NULL;
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#endif
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#if ENABLE_HUSH_LOOPS
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struct pipe *loop_top = loop_top; /* just for compiler */
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struct pipe *loop_top = NULL;
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char *for_varname = NULL;
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char **for_lcur = NULL;
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char **for_list = NULL;
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smallint flag_run_loop = 0;
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smallint flag_goto_looptop = 0;
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#endif
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smallint flag_skip = 1;
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smalluint rcode = 0; /* probably just for compiler */
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#if ENABLE_HUSH_IF
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smalluint cond_code = 0;
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///experimentally off: last_cond_code seems to be bogus
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///smalluint last_cond_code = 0; /* need double-buffer to handle "elif" */
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#else
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enum { cond_code = 0, /* ///last_cond_code = 0 */ };
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enum { cond_code = 0, };
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#endif
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/*reserved_style*/ smallint rword IF_HAS_NO_KEYWORDS(= RES_NONE);
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/*reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
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/*enum reserved_style*/ smallint rword = RES_NONE;
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/*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
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debug_printf_exec("run_list start lvl %d\n", run_list_level + 1);
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#if ENABLE_HUSH_LOOPS
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/* check syntax for "for" */
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/* Check syntax for "for" */
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for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
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if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
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continue;
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@ -2108,20 +2113,16 @@ static int run_list(struct pipe *pi)
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}
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#endif /* JOB */
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/* Go through list of pipes, (maybe) executing them */
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for (; pi; pi = USE_HUSH_LOOPS( flag_goto_looptop ? loop_top : ) pi->next) {
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/* Go through list of pipes, (maybe) executing them. */
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for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
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IF_HAS_KEYWORDS(rword = pi->res_word;)
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IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
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debug_printf_exec(": rword=%d cond_code=%d last_cond_code=%d skip_more=%d flag_run_loop=%d\n",
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rword, cond_code, last_cond_code, skip_more_for_this_rword, flag_run_loop);
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debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
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rword, cond_code, skip_more_for_this_rword);
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#if ENABLE_HUSH_LOOPS
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if (rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) {
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/* start of a loop: remember it */
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flag_goto_looptop = 0; /* not yet reached final "done" */
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// if (!loop_top) { /* hmm why this check is needed? */
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// flag_run_loop = 0; /* suppose loop condition is false (for now) */
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loop_top = pi; /* remember where loop starts */
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// }
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/* start of a loop: remember where loop starts */
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loop_top = pi;
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}
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#endif
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if (rword == skip_more_for_this_rword && flag_skip) {
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@ -2134,18 +2135,21 @@ static int run_list(struct pipe *pi)
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flag_skip = 1;
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skip_more_for_this_rword = RES_XXXX;
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#if ENABLE_HUSH_IF
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/// if (rword == RES_THEN) // || rword == RES_ELSE)
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/// cond_code = last_cond_code;
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if (rword == RES_THEN && cond_code)
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continue; /* "if <false> THEN cmd": skip cmd */
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if (rword == RES_ELSE && !cond_code)
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//continue; /* "if <true> then ... ELSE cmd": skip cmd */
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break; //TEST
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if (rword == RES_ELIF && !cond_code)
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break; /* "if <true> then ... ELIF cmd": skip cmd and all following ones */
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if (cond_code) {
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if (rword == RES_THEN) {
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/* "if <false> THEN cmd": skip cmd */
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continue;
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}
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} else {
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if (rword == RES_ELSE || rword == RES_ELIF) {
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/* "if <true> then ... ELSE/ELIF cmd":
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* skip cmd and all following ones */
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break;
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}
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}
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#endif
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#if ENABLE_HUSH_LOOPS
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if (rword == RES_FOR && pi->num_progs) { /* hmm why "&& pi->num_progs"? */
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if (rword == RES_FOR) { /* && pi->num_progs - always == 1 */
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if (!for_lcur) {
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/* first loop through for */
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@ -2161,7 +2165,7 @@ static int run_list(struct pipe *pi)
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if (pi->next->res_word == RES_IN) {
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/* if no variable values after "in" we skip "for" */
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if (!pi->next->progs->argv)
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continue;
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break;
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vals = pi->next->progs->argv;
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} /* else: "for var; do..." -> assume "$@" list */
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/* create list of variable values */
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@ -2171,7 +2175,6 @@ static int run_list(struct pipe *pi)
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debug_print_strings("for_list", for_list);
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for_varname = pi->progs->argv[0];
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pi->progs->argv[0] = NULL;
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flag_run_loop = 1; /* "for" has no loop condition, loop... */
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}
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free(pi->progs->argv[0]);
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if (!*for_lcur) {
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@ -2179,33 +2182,22 @@ static int run_list(struct pipe *pi)
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free(for_list);
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for_list = NULL;
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for_lcur = NULL;
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flag_run_loop = 0; /* ... until end of value list */
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pi->progs->argv[0] = for_varname;
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continue;
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break;
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}
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/* insert next value from for_lcur */
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//TODO: does it need escaping?
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pi->progs->argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
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}
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if (rword == RES_IN) /* "for v IN list; do ..." - no pipe to execute here */
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if (rword == RES_IN) /* "for v IN list;..." - "in" has no cmds anyway */
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continue;
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if (rword == RES_DO) { /* "...; DO cmd; cmd" - this pipe is in loop body */
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if (!flag_run_loop)
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continue; /* we are skipping this iteration */
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}
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if (rword == RES_DONE) { /* end of loop? */
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if (flag_run_loop) {
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flag_goto_looptop = 1;
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// } else {
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// loop_top = NULL;
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}
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continue; //TEST /* "done" has no cmd anyway */
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if (rword == RES_DONE) {
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continue; /* "done" has no cmds too */
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}
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#endif
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#if ENABLE_HUSH_CASE
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if (rword == RES_CASE) {
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case_word = expand_strvec_to_string(pi->progs->argv);
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//bb_error_msg("case: arg:'%s' case_word:'%s'", pi->progs->argv[0], case_word);
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continue;
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}
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if (rword == RES_MATCH) {
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@ -2215,35 +2207,53 @@ static int run_list(struct pipe *pi)
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/* all prev words didn't match, does this one match? */
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pattern = expand_strvec_to_string(pi->progs->argv);
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/* TODO: which FNM_xxx flags to use? */
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/* ///last_ */ cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
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//bb_error_msg("fnmatch('%s','%s'):%d", pattern, case_word, cond_code);
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cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
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free(pattern);
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if (/* ///last_ */ cond_code == 0) { /* match! we will execute this branch */
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if (cond_code == 0) { /* match! we will execute this branch */
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free(case_word); /* make future "word)" stop */
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case_word = NULL;
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}
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continue;
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}
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if (rword == RES_CASEI) { /* inside of a case branch */
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if (/* ///last_ */ cond_code != 0)
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if (cond_code != 0)
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continue; /* not matched yet, skip this pipe */
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}
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#endif
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if (pi->num_progs == 0)
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continue;
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/* After analyzing all keywrds and conditions, we decided
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* to execute this pipe */
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/* After analyzing all keywords and conditions, we decided
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* to execute this pipe. NB: has to do checkjobs(NULL)
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* after run_pipe() to collect any background children,
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* even if list execution is to be stopped. */
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debug_printf_exec(": run_pipe with %d members\n", pi->num_progs);
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{
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int r;
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flag_break_continue = 0;
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rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
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if (r != -1) {
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/* We only ran a builtin: rcode was set by the return value
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* of run_pipe(), and we don't need to wait for anything. */
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/* we only ran a builtin: rcode is already known
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* and we don't need to wait for anything. */
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/* was it "break" or "continue"? */
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if (flag_break_continue) {
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smallint fbc = flag_break_continue;
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/* we might fall into outer *loop*,
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* don't want to break it too */
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flag_break_continue = 0;
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if (loop_top) {
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if (fbc == BC_BREAK)
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goto check_jobs_and_break;
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/* "continue": simulate end of loop */
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rword = RES_DONE;
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continue;
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}
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bb_error_msg("break/continue: only meaningful in a loop");
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/* bash compat: exit code is still 0 */
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}
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} else if (pi->followup == PIPE_BG) {
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/* What does bash do with attempts to background builtins? */
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/* Even bash 3.2 doesn't do that well with nested bg:
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/* what does bash do with attempts to background builtins? */
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/* even bash 3.2 doesn't do that well with nested bg:
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* try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
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* I'm NOT treating inner &'s as jobs */
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#if ENABLE_HUSH_JOB
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@ -2271,16 +2281,19 @@ static int run_list(struct pipe *pi)
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/* Analyze how result affects subsequent commands */
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#if ENABLE_HUSH_IF
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if (rword == RES_IF || rword == RES_ELIF)
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/* ///last_cond_code = */ cond_code = rcode;
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cond_code = rcode;
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#endif
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#if ENABLE_HUSH_LOOPS
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if (rword == RES_WHILE) {
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flag_run_loop = !rcode;
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debug_printf_exec(": setting flag_run_loop=%d\n", flag_run_loop);
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if (rcode)
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goto check_jobs_and_break;
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}
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if (rword == RES_UNTIL) {
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flag_run_loop = rcode;
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debug_printf_exec(": setting flag_run_loop=%d\n", flag_run_loop);
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if (!rcode) {
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check_jobs_and_break:
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checkjobs(NULL);
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break;
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}
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}
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#endif
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if ((rcode == 0 && pi->followup == PIPE_OR)
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@ -4498,3 +4511,15 @@ static int builtin_unset(char **argv)
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unset_local_var(argv[1]);
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return EXIT_SUCCESS;
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}
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static int builtin_break(char **argv UNUSED_PARAM)
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{
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flag_break_continue = BC_BREAK;
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return EXIT_SUCCESS;
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}
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static int builtin_continue(char **argv UNUSED_PARAM)
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{
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flag_break_continue = BC_CONTINUE;
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return EXIT_SUCCESS;
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}
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@ -2,9 +2,10 @@
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Command parsing
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Command parsing results in "pipe" structures. "Pipe" structure
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does not always correspond to what sh language calls "pipe",
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it also controls execution of if, while, etc statements.
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Command parsing results in a list of "pipe" structures.
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This list correspond not only to usual "pipe1 || pipe2 && pipe3"
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lists, but it also controls execution of if, while, etc statements.
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Every such statement is a list for hush. List consists of pipes.
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struct pipe fields:
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smallint res_word - "none" for normal commands,
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@ -18,7 +19,7 @@ Blocks of commands { pipe; pipe; } and (pipe; pipe) are represented
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as one pipe struct with one progs[0] element which is a "group" -
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struct child_prog can contain a list of pipes. Sometimes these
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"groups" are created implicitly, e.g. every control
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statement (if, while, etc) sits inside its own "pipe" struct).
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statement (if, while, etc) sits inside its own group.
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res_word controls statement execution. Examples:
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@ -41,6 +42,10 @@ res_word=NONE followup=SEQ
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pipe 4 res_word=NONE followup=(null)
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pipe 1 res_word=NONE followup=SEQ
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Above you see that if is a list, and it sits in a {} group
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implicitly created by hush. Also note two THEN res_word's -
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it is explained below.
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"if true; then { echo Hello; true; }; fi" -
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pipe 0 res_word=NONE followup=SEQ
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prog 0 group {}:
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