hush: fix "while...do f1() {a;}; f1; f1 {b;}; f1; done" bug
This commit is contained in:
Denis Vlasenko
parent
75bccfa375
commit
ed055214bb
70
shell/hush.c
70
shell/hush.c
@ -330,7 +330,7 @@ struct redir_struct {
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/* note: for heredocs, rd_filename contains heredoc delimiter,
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* and subsequently heredoc itself; and rd_dup is a bitmask:
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* 1: do we need to trim leading tabs?
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* 2: is heredoc quoted (<<'dleim' syntax) ?
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* 2: is heredoc quoted (<<'delim' syntax) ?
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*/
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};
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typedef enum redir_type {
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@ -357,25 +357,42 @@ struct command {
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int assignment_cnt; /* how many argv[i] are assignments? */
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smallint is_stopped; /* is the command currently running? */
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smallint grp_type; /* GRP_xxx */
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#define GRP_NORMAL 0
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#define GRP_SUBSHELL 1
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#if ENABLE_HUSH_FUNCTIONS
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# define GRP_FUNCTION 2
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#endif
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struct pipe *group; /* if non-NULL, this "command" is { list },
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* ( list ), or a compound statement */
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#if !BB_MMU
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char *group_as_string;
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#endif
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#if ENABLE_HUSH_FUNCTIONS
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struct function *child_func;
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/* This field is used to prevent a bug here:
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* while...do f1() {a;}; f1; f1 {b;}; f1; done
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* When we execute "f1() {a;}" cmd, we create new function and clear
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* cmd->group, cmd->group_as_string, cmd->argv[0].
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* when we execute "f1 {b;}", we notice that f1 exists,
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* and that it's "parent cmd" struct is still "alive",
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* we put those fields back into cmd->xxx
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* (struct function has ->parent_cmd ptr to facilitate that).
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* When we loop back, we can execute "f1() {a;}" again and set f1 correctly.
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* Without this trick, loop would execute a;b;b;b;...
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* instead of correct sequence a;b;a;b;...
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* When command is freed, it severs the link
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* (sets ->child_func->parent_cmd to NULL).
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*/
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#endif
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char **argv; /* command name and arguments */
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struct redir_struct *redirects; /* I/O redirections */
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};
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/* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
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* and on execution these are substituted with their values.
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* Substitution can make _several_ words out of one argv[n]!
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* Example: argv[0]=='.^C*^C.' here: echo .$*.
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* References of the form ^C`cmd arg^C are `cmd arg` substitutions.
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*/
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#define GRP_NORMAL 0
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#define GRP_SUBSHELL 1
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#if ENABLE_HUSH_FUNCTIONS
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# define GRP_FUNCTION 2
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#endif
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struct redir_struct *redirects; /* I/O redirections */
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};
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struct pipe {
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struct pipe *next;
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@ -456,6 +473,7 @@ enum {
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struct function {
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struct function *next;
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char *name;
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struct command *parent_cmd;
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struct pipe *body;
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#if !BB_MMU
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char *body_as_string;
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@ -743,7 +761,6 @@ static void syntax_error_unexpected_ch(unsigned lineno, char ch)
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msg[0] = ch;
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msg[1] = '\0';
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die_if_script(lineno, "syntax error: unexpected %s", msg);
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xfunc_die();
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}
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#if HUSH_DEBUG < 2
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@ -2573,6 +2590,14 @@ static void free_pipe(struct pipe *pi, int indent)
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debug_printf_clean("%s end group\n", indenter(indent));
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command->group = NULL;
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}
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/* else is crucial here.
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* If group != NULL, child_func is meaningless */
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#if ENABLE_HUSH_FUNCTIONS
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else if (command->child_func) {
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debug_printf_exec("cmd %p releases child func at %p\n", command, command->child_func);
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command->child_func->parent_cmd = NULL;
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}
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#endif
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#if !BB_MMU
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free(command->group_as_string);
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command->group_as_string = NULL;
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@ -3173,9 +3198,24 @@ static int run_pipe(struct pipe *pi)
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while ((funcp = *funcpp) != NULL) {
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if (strcmp(funcp->name, command->argv[0]) == 0) {
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debug_printf_exec("replacing function '%s'\n", funcp->name);
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struct command *cmd = funcp->parent_cmd;
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debug_printf_exec("func %p parent_cmd %p\n", funcp, cmd);
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if (!cmd) {
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debug_printf_exec("freeing & replacing function '%s'\n", funcp->name);
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free(funcp->name);
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free_pipe_list(funcp->body, /* indent: */ 0);
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#if !BB_MMU
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free(funcp->body_as_string);
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#endif
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} else {
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debug_printf_exec("reinserting in tree & replacing function '%s'\n", funcp->name);
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cmd->argv[0] = funcp->name;
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cmd->group = funcp->body;
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#if !BB_MMU
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cmd->group_as_string = funcp->body_as_string;
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#endif
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}
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goto skip;
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}
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funcpp = &funcp->next;
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@ -3192,13 +3232,9 @@ static int run_pipe(struct pipe *pi)
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#endif
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command->group = NULL;
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command->argv[0] = NULL;
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free_strings(command->argv);
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command->argv = NULL;
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/* note: if we are in a loop, future "executions"
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* of func def will see it as null command since
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* command->group == NULL and command->argv == NULL */
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//this isn't exactly right: while...do f1() {a;}; f1; f1 {b;}; done
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//second loop will execute b!
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debug_printf_exec("cmd %p has child func at %p\n", command, funcp);
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funcp->parent_cmd = command;
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command->child_func = funcp;
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return EXIT_SUCCESS;
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}
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@ -62,7 +62,8 @@ HERE
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echo >/dev/null ${var%%*}
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set -- par1_$i par2_$i par3_$i par4_$i
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trap "echo trap$i" WINCH
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f() { echo $1; }
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f() { true; true; true; true; true; true; true; true; }
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f() { true; true; true; true; true; true; true; true; echo $1; }
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f >/dev/null
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: $((i++))
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done
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@ -127,7 +128,8 @@ HERE
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echo >/dev/null ${var%%*}
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set -- par1_$i par2_$i par3_$i par4_$i
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trap "echo trap$i" WINCH
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f() { echo $1; }
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f() { true; true; true; true; true; true; true; true; }
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f() { true; true; true; true; true; true; true; true; echo $1; }
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f >/dev/null
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: $((i++))
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done
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