Hi!
We've found that if the $HISTFILE doesn't exist and can't be created for some
reason (e.g., read-only NFS home) ksh may crash with segmentation fault when
trying to insert the last word of the previous command using the M-_ or M-.
keyboard shortcut.
Also, when the history file is accessible but empty, a garbage string is
printed.
Problem is in src/cmd/ksh93/edit/history.c : char *hist_word(...
line 1074:
if(!hp)
#if KSHELL
{
strncpy(string,((Shell_t*)hp->histshell)->lastarg,size);
return(string);
}
where hp is dereferenced while having NULL value.
We are using attached patch temporarily.
Regards,
Michal Hlavinka
diff -up ksh-20080202/src/cmd/ksh93/edit/emacs.c.histword ksh-20080202/src/cmd/ksh93/edit/emacs.c
--- ksh-20080202/src/cmd/ksh93/edit/emacs.c.histword 2009-04-06 16:06:01.000000000 +0200
+++ ksh-20080202/src/cmd/ksh93/edit/emacs.c 2009-04-06 16:06:56.000000000 +0200
@@ -895,7 +895,8 @@ static int escape(register Emacs_t* ep,r
genchar name[MAXLINE];
char buf[MAXLINE];
char *ptr;
- ptr = hist_word(buf,MAXLINE,(count?count:-1));
+ if(!(ptr = hist_word(buf,MAXLINE,(count?count:-1))))
+ break;
#if !KSHELL
if(ptr==0)
{
diff -up ksh-20080202/src/cmd/ksh93/edit/history.c.histword ksh-20080202/src/cmd/ksh93/edit/history.c
--- ksh-20080202/src/cmd/ksh93/edit/history.c.histword 2007-07-09 22:22:57.000000000 +0200
+++ ksh-20080202/src/cmd/ksh93/edit/history.c 2009-04-06 15:53:18.000000000 +0200
@@ -1072,10 +1072,7 @@ char *hist_word(char *string,int size,in
History_t *hp = hist_ptr;
if(!hp)
#if KSHELL
- {
- strncpy(string,((Shell_t*)hp->histshell)->lastarg,size);
- return(string);
- }
+ return NULL;
#else
return(NIL(char*));
#endif /* KSHELL */
diff -up ksh-20080202/src/cmd/ksh93/edit/vi.c.histword ksh-20080202/src/cmd/ksh93/edit/vi.c
--- ksh-20080202/src/cmd/ksh93/edit/vi.c.histword 2009-04-06 16:24:01.000000000 +0200
+++ ksh-20080202/src/cmd/ksh93/edit/vi.c 2009-04-06 16:24:34.000000000 +0200
@@ -2356,7 +2356,8 @@ addin:
genchar tmpbuf[MAXLINE];
if(vp->repeat_set==0)
vp->repeat = -1;
- p = (genchar*)hist_word((char*)tmpbuf,MAXLINE,vp->repeat);
+ if (!(p = (genchar*)hist_word((char*)tmpbuf,MAXLINE,vp->repeat)))
+ break;
#if !KSHELL
if(p==0)
{
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