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hush: fix "while...do f1() {a;}; f1; f1 {b;}; f1; done" bug

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This commit is contained in:
Denis Vlasenko 2009-04-11 10:37:10 +00:00
parent 75bccfa375
commit ed055214bb
2 changed files with 59 additions and 21 deletions
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74
shell/hush.c
View File

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

6
shell/hush_test/hush-z_slow/leak_all1.tests
View File

@ -62,7 +62,8 @@ HERE
echo >/dev/null ${var%%*}
set -- par1_$i par2_$i par3_$i par4_$i
trap "echo trap$i" WINCH
f() { echo $1; }
f() { true; true; true; true; true; true; true; true; }
f() { true; true; true; true; true; true; true; true; echo $1; }
f >/dev/null
: $((i++))
done
@ -127,7 +128,8 @@ HERE
echo >/dev/null ${var%%*}
set -- par1_$i par2_$i par3_$i par4_$i
trap "echo trap$i" WINCH
f() { echo $1; }
f() { true; true; true; true; true; true; true; true; }
f() { true; true; true; true; true; true; true; true; echo $1; }
f >/dev/null
: $((i++))
done