Mail Archives: cygwin/2000/09/21/17:57:41
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When you execute
date +"%Z"
the date.exe program consumes all available memory until it
terminates. The reason is that "%Z" results in an empty string
if the time zone is not set appropriately.
Looking at the code in src/shellutils/src/date.c:341 , we see
the problem -- strftime(), which is used to format the date
string, returns 0 both when the date string is empty and when
it ran out of memory. In my opinion, this is quite sick behaviour
-- but well, we can't get around strftime() if we want to be
POSIXly correct.
So I think the only bulletproof solution is to make sure that
the date string CANNOT be empty after calling strftime().
The patch attached does just that:
int in_length = strlen(formatstr);
char *safe_format = (char *)malloc(in_length+2);
*safe_format = 'X'; /* force non-empty result ! */
strcpy(safe_format+1, formatstr);
out_length = in_length;
do {
out_length += 200;
out = (char *) xrealloc (out, out_length);
}
while (strftime (out, out_length, safe_format, tm) == 0);
printf ("%s\n", out+1);
free(out);
free(safe_format);
I compiled and tested with gcc 2.95.2 -- date.exe becomes 1536 bytes
larger (most probably due to using strcpy() and strlen() ) but it's
safe now...
[/] diff -c src/shellutils/src/date.c.orig src/shellutils/src/date.c > date_patch.txt
Cheers,
Martin
--
---------------------------------/()\-----------------------------------
DI Martin Oberhuber mailto:martin DOT oberhuber AT windriver DOT com
Field Support Engineer Phone (UTC +1h): +43 (662) 457915-85
TakeFive Software GmbH, a Wind River Company Fax: +43 (662) 457915-6
Jakob-Haringer-Str.8, A-5020 Salzburg, Austria http://www.windriver.com
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*** src/shellutils/src/date.c.orig Tue Sep 19 11:49:45 2000=0A=
--- src/shellutils/src/date.c Thu Sep 21 23:37:29 2000=0A=
***************=0A=
*** 310,317 ****=0A=
show_date (const char *format, time_t when)=0A=
{=0A=
struct tm *tm;=0A=
char *out =3D NULL;=0A=
! size_t out_length =3D 0;=0A=
=0A=
tm =3D localtime (&when);=0A=
=0A=
--- 310,319 ----=0A=
show_date (const char *format, time_t when)=0A=
{=0A=
struct tm *tm;=0A=
+ char *safe_format;=0A=
+ size_t in_length;=0A=
char *out =3D NULL;=0A=
! size_t out_length;=0A=
=0A=
tm =3D localtime (&when);=0A=
=0A=
***************=0A=
*** 336,350 ****=0A=
return;=0A=
}=0A=
=0A=
do=0A=
{=0A=
out_length +=3D 200;=0A=
out =3D (char *) xrealloc (out, out_length);=0A=
}=0A=
! while (strftime (out, out_length, format, tm) =3D=3D 0);=0A=
=0A=
! printf ("%s\n", out);=0A=
free (out);=0A=
}=0A=
=0A=
static void=0A=
--- 338,357 ----=0A=
return;=0A=
}=0A=
=0A=
+ out_length =3D in_length =3D strlen(format);=0A=
+ safe_format =3D (char *)malloc(in_length+2);=0A=
+ *safe_format =3D 'X';=0A=
+ strcpy(safe_format+1, format);=0A=
do=0A=
{=0A=
out_length +=3D 200;=0A=
out =3D (char *) xrealloc (out, out_length);=0A=
}=0A=
! while (strftime (out, out_length, safe_format, tm) =3D=3D 0);=0A=
=0A=
! printf ("%s\n", out+1);=0A=
free (out);=0A=
+ free (safe_format);=0A=
}=0A=
=0A=
static void=0A=
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