Better handling for realpath() failures in windows_make_so() on Cygwin
Commit Message
Fix a memory leak which would occur in the case when the result of realpath() is
greater than or equal to SO_NAME_MAX_PATH_SIZE.
Distinguish between realpath() failing (returning NULL), and returning a path
greather than or equal to SO_NAME_MAX_PATH_SIZE.
Warn rather than stopping with an error in both those cases.
Original patch from Tim Chick. Memory leak fix by Corinna Vinschen.
See also https://cygwin.com/ml/cygwin/2015-11/msg00353.html
gdb/ChangeLog:
2016-01-20 Jon Turney <jon.turney@dronecode.org.uk>
* windows-nat.c (windows_make_so): Fix memory leak when realpath
returns a path >= SO_NAME_MAX_PATH_SIZE. Distinguish that case
from realpath failing. Warn rather than stopping with an error in
both cases.
---
gdb/ChangeLog | 7 +++++++
gdb/windows-nat.c | 15 ++++++++++++---
2 files changed, 19 insertions(+), 3 deletions(-)
Comments
#define SO_NAME_MAX_PATH_SIZE 512 /* FIXME: Should be dynamic */
How about just removing the limit altogether?
Basically, make struct so_list::so_original_name and
struct so_list::so_name pointers instead of arrays?
Thanks,
Pedro Alves
On 20/01/2016 16:19, Pedro Alves wrote:
> #define SO_NAME_MAX_PATH_SIZE 512 /* FIXME: Should be dynamic */
>
> How about just removing the limit altogether?
>
> Basically, make struct so_list::so_original_name and
> struct so_list::so_name pointers instead of arrays?
I'm sorry, while that would be nice to have, that's not a project that I
can take on currently.
In the meantime, please consider approving this patch, or tell me what I
can do to make it acceptable, since it does fix an actual problem that
affects some users.
On 03/09/2016 05:49 PM, Jon Turney wrote:
> On 20/01/2016 16:19, Pedro Alves wrote:
>> #define SO_NAME_MAX_PATH_SIZE 512 /* FIXME: Should be dynamic */
>>
>> How about just removing the limit altogether?
>>
>> Basically, make struct so_list::so_original_name and
>> struct so_list::so_name pointers instead of arrays?
>
> I'm sorry, while that would be nice to have, that's not a project that I
> can take on currently.
>
> In the meantime, please consider approving this patch, or tell me what I
> can do to make it acceptable, since it does fix an actual problem that
> affects some users.
It's not a big change, I think. Instead of strcpy'ing strings into
so->so_original_name and so->so_name, we'd just xfree the old
strings and xstrdup new ones. And then in free_so, we xfree
so->so_original_name and so->so_name. All other code that refers to
so->so_original_name / so->so_name should not need to change, as arrays
decay to pointers anyway.
If you want to avoid convert all targets at once, it's still quite
doable. Add a new make_so_list() to solib.c that just does:
struct so_list *
make_so_list (void)
{
struct so_list *new_solib = XCNEW (struct so_list);
new_solib->so_name = xcalloc (1, SO_NAME_MAX_PATH_SIZE);
new_solib->so_original_name = xcalloc (1, SO_NAME_MAX_PATH_SIZE);
return new_solib;
}
and do a trivial replace of these XCNEW/XNEW by a call to make_so_list:
solib-aix.c: struct so_list *new_solib = XCNEW (struct so_list);
solib-dsbt.c: sop = XCNEW (struct so_list);
solib-frv.c: sop = XCNEW (struct so_list);
solib-spu.c: newobj = XCNEW (struct so_list);
solib-spu.c: newobj = XCNEW (struct so_list);
solib-svr4.c: newobj = XCNEW (struct so_list);
solib-svr4.c: new_elem = XCNEW (struct so_list);
solib-svr4.c: newobj = XCNEW (struct so_list);
solib-svr4.c: newobj = XCNEW (struct so_list);
solib-target.c: new_solib = XCNEW (struct so_list);
windows-nat.c: so = XCNEW (struct so_list);
solib-svr4.c: newobj = XNEW (struct so_list);
Then you can adjust the windows-nat.c solib-target.c files (the ones
Windows uses), and leave the rest to someone else (though I imagine
converting all others would be trivial too).
Once all are converted, we can remove the initial allocations in
make_so_list.
Thanks,
Pedro Alves
@@ -642,13 +642,22 @@ windows_make_so (const char *name, LPVOID load_addr)
else
{
char *rname = realpath (name, NULL);
- if (rname && strlen (rname) < SO_NAME_MAX_PATH_SIZE)
+ if (rname)
{
- strcpy (so->so_name, rname);
+ if (strlen (rname) < SO_NAME_MAX_PATH_SIZE)
+ strcpy (so->so_name, rname);
+ else
+ {
+ warning (_("dll path \"%s\" too long"), rname);
+ strcpy (so->so_name, so->so_original_name);
+ }
free (rname);
}
else
- error (_("dll path too long"));
+ {
+ warning (_("dll path for \"%s\" can not be evaluated"), name);
+ strcpy (so->so_name, so->so_original_name);
+ }
}
/* Record cygwin1.dll .text start/end. */
p = strchr (so->so_name, '\0') - (sizeof ("/cygwin1.dll") - 1);