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ash: catch error in arithmetic expansion in PS1

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Setting PS1 to:

   PS1='$((123+))'

causes the shell to enter an infinite error loop:

   sh: arithmetic syntax error

Catch any exception raised by expandarg() in expandstr() and allow
processing to continue.

function                                             old     new   delta
expandstr                                            262     344     +82
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/0 up/down: 82/0)               Total: 82 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Ron Yorston 2019-04-18 09:49:13 +01:00 committed by Denys Vlasenko
parent 48645b8350
commit d1a2fa2a4e
1 changed files with 20 additions and 12 deletions
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18
shell/ash.c
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@ -13043,6 +13043,9 @@ expandstr(const char *ps, int syntax_type)
union node n;
int saveprompt;
struct parsefile *file_stop = g_parsefile;
volatile int saveint;
struct jmploc *volatile savehandler = exception_handler;
struct jmploc jmploc;
/* XXX Fix (char *) cast. */
setinputstring((char *)ps);
@ -13054,10 +13057,6 @@ expandstr(const char *ps, int syntax_type)
* Try a prompt with syntactically wrong command:
* PS1='$(date "+%H:%M:%S) > '
*/
{
volatile int saveint;
struct jmploc *volatile savehandler = exception_handler;
struct jmploc jmploc;
SAVE_INT(saveint);
if (setjmp(jmploc.loc) == 0) {
exception_handler = &jmploc;
@ -13065,7 +13064,6 @@ expandstr(const char *ps, int syntax_type)
}
exception_handler = savehandler;
RESTORE_INT(saveint);
}
doprompt = saveprompt;
@ -13077,7 +13075,17 @@ expandstr(const char *ps, int syntax_type)
n.narg.text = wordtext;
n.narg.backquote = backquotelist;
/* expandarg() might fail too:
* PS1='$((123+))'
*/
SAVE_INT(saveint);
if (setjmp(jmploc.loc) == 0) {
exception_handler = &jmploc;
expandarg(&n, NULL, EXP_QUOTED);
}
exception_handler = savehandler;
RESTORE_INT(saveint);
return stackblock();
}