"ps -e" without procfs(5)

[Mikolaj Golub]

On Sat, 5 Nov 2011 21:45:53 +0200 Kostik Belousov wrote:

 KB> On Sat, Nov 05, 2011 at 08:59:21PM +0200, Mikolaj Golub wrote:
 >> 
 >> On Sat, 5 Nov 2011 17:44:43 +0200 Kostik Belousov wrote:
 >> 
 >>  >>  KB> I think that the aux vector must be naturally aligned. You can return
 >>  >>  KB> ENOEXEC early if vptr is not aligned.
 >>  >> 
 >>  >> Not sure I see what you mean. vptr for auxv is calculated just couple lines
 >>  >> above, and I check the result here, in the part common for all vector types.
 >>  KB> You do not check for the alignment. Am I wrong ?
 >> 
 >> I see now. If natural alignment means "addr % sizeof(aux) == 0" then the aux
 >> vectors are not naturally aligned. After adding this check:
 >> 
 >>     if (vptr % sizeof(aux) != 0)
 >>             return (ENOEXEC);
 KB> No, the natural alignment of the structure is the alignment of the most
 KB> demanding member. So it is 4 bytes on 32bit, and 8 bytes on 64.

 >> 
 >> I started to observe many ENOEXEC errors. Adding printf showed that the
 >> vectors are half size aligned.
 >> 
 >> On i386:
 >> 
 >> get_proc_vector(pid = getty[3442], type = 2): vptr (2143284876) % sizeof(aux) (8) = 4)
 >> 
 >> On amd64:
 >> 
 >> get_proc_vector(pid = getty[2425], type = 2): vptr (140737488346568) % sizeof(aux) (16) = 8)
 >> 
 >> Looking at exec_copyout_strings() from kern_exec.c, how destp is calculated, I
 >> think they are sizeof(char *) aligned.
 >> 
 >> Do you think it is worth adding the check for sizeof(char *) alignment?
 >> 
 >>     if (vptr % (sizeof(char *) != 0)
 >>             return (ENOEXEC);
 KB> I suggest to use #if __ELF_WORD_SIZE == 32 or 64.

Thanks. The updated patch:

http://people.freebsd.org/~trociny/env.sys.3.patch

-- 
Mikolaj Golub