hush: explain run_list() in detail; small optimizations
function old new delta hush_main 785 786 +1 expand_variables 1447 1448 +1 builtin_exit 48 49 +1 builtin_eval 54 55 +1 run_list 2075 2055 -20 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 4/1 up/down: 4/-20) Total: -16 bytes
This commit is contained in:
Denis Vlasenko
parent
38c89210d6
commit
5e052cab17
207
shell/hush.c
207
shell/hush.c
@ -431,12 +431,12 @@ struct globals {
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#endif
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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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char **global_argv;
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int global_argc;
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int last_return_code;
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pid_t last_bg_pid;
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const char *ifs;
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const char *cwd;
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unsigned last_bg_pid;
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struct variable *top_var; /* = &shell_ver (set in main()) */
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struct variable shell_ver;
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#if ENABLE_FEATURE_SH_STANDALONE
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@ -2012,54 +2012,53 @@ static void debug_print_tree(struct pipe *pi, int lvl)
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* global data until exec/_exit (we can be a child after vfork!) */
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static int run_list(struct pipe *pi)
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{
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struct pipe *rpipe;
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#if ENABLE_HUSH_LOOPS
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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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int flag_rep = 0;
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#endif
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#if ENABLE_HUSH_CASE
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char *case_word = NULL;
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#endif
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int flag_skip = 1;
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int rcode = 0; /* probably for gcc only */
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int flag_restore = 0;
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#if ENABLE_HUSH_IF
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int if_code = 0, next_if_code = 0; /* need double-buffer to handle elif */
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#else
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enum { if_code = 0, next_if_code = 0 };
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#if ENABLE_HUSH_LOOPS
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struct pipe *loop_top;
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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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reserved_style rword IF_HAS_NO_KEYWORDS(= RES_NONE);
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reserved_style skip_more_for_this_rword = RES_XXXX;
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smallint flag_skip = 1;
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smalluint rcode = 0; /* probably for gcc only */
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#if ENABLE_HUSH_IF
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smalluint cond_code = 0;
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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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#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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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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for (rpipe = pi; rpipe; rpipe = rpipe->next) {
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if (rpipe->res_word != RES_FOR && rpipe->res_word != RES_IN)
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for (loop_top = pi; loop_top; loop_top = loop_top->next) {
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if (loop_top->res_word != RES_FOR && loop_top->res_word != RES_IN)
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continue;
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/* current word is FOR or IN (BOLD in comments below) */
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if (rpipe->next == NULL) {
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if (loop_top->next == NULL) {
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syntax("malformed for");
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debug_printf_exec("run_list lvl %d return 1\n", run_list_level);
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return 1;
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}
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/* "FOR v; do ..." and "for v IN a b; do..." are ok */
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if (rpipe->next->res_word == RES_DO)
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if (loop_top->next->res_word == RES_DO)
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continue;
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/* next word is not "do". It must be "in" then ("FOR v in ...") */
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if (rpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
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|| rpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
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if (loop_top->res_word == RES_IN /* "for v IN a b; not_do..."? */
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|| loop_top->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
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) {
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syntax("malformed for");
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debug_printf_exec("run_list lvl %d return 1\n", run_list_level);
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return 1;
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}
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}
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#else
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rpipe = NULL;
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#endif
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/* Past this point, all code paths should jump to ret: label
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@ -2108,21 +2107,24 @@ static int run_list(struct pipe *pi)
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}
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#endif /* JOB */
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for (; pi; pi = flag_restore ? rpipe : pi->next) {
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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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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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#if ENABLE_HUSH_LOOPS
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if (rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) {
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flag_restore = 0;
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if (!rpipe) {
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flag_rep = 0;
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rpipe = pi;
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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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}
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#endif
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debug_printf_exec(": rword=%d if_code=%d next_if_code=%d skip_more=%d\n",
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rword, if_code, next_if_code, skip_more_for_this_rword);
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if (rword == skip_more_for_this_rword && flag_skip) {
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/* it is "<false> && CMD ... */
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if (pi->followup == PIPE_SEQ)
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flag_skip = 0;
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continue;
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@ -2131,13 +2133,14 @@ static int run_list(struct pipe *pi)
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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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if_code = next_if_code;
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if (rword == RES_THEN && if_code)
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continue;
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if (rword == RES_ELSE && !if_code)
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continue;
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if (rword == RES_ELIF && !if_code)
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break;
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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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// TODO: break;?
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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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#endif
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#if ENABLE_HUSH_LOOPS
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if (rword == RES_FOR && pi->num_progs) {
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@ -2153,7 +2156,7 @@ static int run_list(struct pipe *pi)
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char **vals;
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vals = (char**)encoded_dollar_at_argv;
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if (rpipe->next->res_word == RES_IN) {
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if (loop_top->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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@ -2166,7 +2169,7 @@ 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_rep = 1;
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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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@ -2174,26 +2177,27 @@ 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_rep = 0;
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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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}
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/* insert next value from for_lcur */
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/* vda: does it need escaping? */
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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)
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if (rword == RES_IN) /* "for v IN list; do ..." - no pipe to execute here */
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continue;
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if (rword == RES_DO) {
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if (!flag_rep)
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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) {
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if (flag_rep) {
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flag_restore = 1;
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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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rpipe = NULL;
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loop_top = NULL;
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}
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//TODO: continue;? DONE has no cmd anyway
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}
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#endif
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#if ENABLE_HUSH_CASE
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@ -2203,69 +2207,82 @@ static int run_list(struct pipe *pi)
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continue;
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}
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if (rword == RES_MATCH) {
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if (case_word) {
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char *pattern = expand_strvec_to_string(pi->progs->argv);
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/* TODO: which FNM_xxx flags to use? */
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next_if_code = fnmatch(pattern, case_word, /*flags:*/ 0);
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//bb_error_msg("fnmatch('%s','%s'):%d", pattern, case_word, next_if_code);
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free(pattern);
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if (next_if_code == 0) {
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free(case_word);
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case_word = NULL;
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}
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continue;
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char *pattern;
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if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
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break;
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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, last_cond_code);
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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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free(case_word); /* make future "word)" stop */
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case_word = NULL;
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}
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break;
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continue;
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}
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if (rword == RES_CASEI) {
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if (next_if_code != 0)
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continue;
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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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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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debug_printf_exec(": run_pipe with %d members\n", pi->num_progs);
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rcode = run_pipe(pi);
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if (rcode != -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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} 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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* try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
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* I'm NOT treating inner &'s as jobs */
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{
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int r;
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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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} 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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* 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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if (run_list_level == 1)
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insert_bg_job(pi);
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if (run_list_level == 1)
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insert_bg_job(pi);
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#endif
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rcode = EXIT_SUCCESS;
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} else {
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rcode = 0; /* EXIT_SUCCESS */
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} else {
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#if ENABLE_HUSH_JOB
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if (run_list_level == 1 && interactive_fd) {
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/* waits for completion, then fg's main shell */
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rcode = checkjobs_and_fg_shell(pi);
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} else
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if (run_list_level == 1 && interactive_fd) {
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/* waits for completion, then fg's main shell */
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rcode = checkjobs_and_fg_shell(pi);
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debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
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} else
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#endif
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{ /* this one just waits for completion */
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rcode = checkjobs(pi);
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{ /* this one just waits for completion */
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rcode = checkjobs(pi);
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debug_printf_exec(": checkjobs returned %d\n", rcode);
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}
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}
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debug_printf_exec(": checkjobs returned %d\n", rcode);
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}
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debug_printf_exec(": setting last_return_code=%d\n", rcode);
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last_return_code = rcode;
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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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next_if_code = rcode; /* can be overwritten a number of times */
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last_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_rep = !last_return_code;
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if (rword == RES_UNTIL)
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flag_rep = last_return_code;
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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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}
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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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}
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#endif
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if ((rcode == EXIT_SUCCESS && pi->followup == PIPE_OR)
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|| (rcode != EXIT_SUCCESS && pi->followup == PIPE_AND)
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if ((rcode == 0 && pi->followup == PIPE_OR)
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|| (rcode != 0 && pi->followup == PIPE_AND)
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) {
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skip_more_for_this_rword = rword;
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}
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