[klibc] sample sleep command killed

[Phil Howard]

On Wed, Jul 14, 2010 at 7:34 AM, Phil Howard <kunnskaperen at gmail.com> wrote:
> I re-wrote the compile script to build klibc (cleaning up how I do it,
> and how to find the source tarballs).  It seems to be compiling fine.
> I tried several of the commands in usr/utils/static and most one.
> However, the sleep command fails in a strange way (EINVAL on execve):
>
> ================================================================
> faraday/phil /home/phil/klibc-project-0 581> strace -ftt -s 96
> klibc-1.5.18/usr/utils/static/true
> 07:33:08.185542 execve("klibc-1.5.18/usr/utils/static/true",
> ["klibc-1.5.18/usr/utils/static/true"], [/* 38 vars */]) = 0
> 07:33:08.185880 _exit(0)                = ?
> Process 29017 detached
> faraday/phil /home/phil/klibc-project-0 582> strace -ftt -s 96
> klibc-1.5.18/usr/utils/static/sleep 6
> 07:33:10.636524 execve("klibc-1.5.18/usr/utils/static/sleep",
> ["klibc-1.5.18/usr/utils/static/sleep", "6"], [/* 38 vars */]) = -1
> EINVAL (Invalid argument)
> 07:33:10.636930 +++ killed by SIGKILL +++
> Process 29020 detached
> faraday/phil /home/phil/klibc-project-0 583> ldd
> klibc-1.5.18/usr/utils/static/true klibc-1.5.18/usr/utils/static/sleep
> klibc-1.5.18/usr/utils/static/true:
>        not a dynamic executable
> klibc-1.5.18/usr/utils/static/sleep:
>        not a dynamic executable
> faraday/phil /home/phil/klibc-project-0 584> file
> klibc-1.5.18/usr/utils/static/true klibc-1.5.18/usr/utils/static/sleep
> klibc-1.5.18/usr/utils/static/true:  ELF 32-bit LSB executable, Intel
> 80386, version 1 (SYSV), statically linked, stripped
> klibc-1.5.18/usr/utils/static/sleep: ELF 32-bit LSB executable, Intel
> 80386, version 1 (SYSV), statically linked, stripped
> faraday/phil /home/phil/klibc-project-0 585> ls -dl
> klibc-1.5.18/usr/utils/static/true klibc-1.5.18/usr/utils/static/sleep
> -rwxr-xr-x 1 phil phil 4168 2010-07-14 07:17 klibc-1.5.18/usr/utils/static/sleep
> -rwxr-xr-x 1 phil phil  548 2010-07-14 07:17 klibc-1.5.18/usr/utils/static/true
> faraday/phil /home/phil/klibc-project-0 586>
> ================================================================
>
> I'm guessing execve thinks this can't be executed for some reason.
> Even so, SIGKILL seems strange (shouldn't the shell forked child just
> report the execve failure, instead?).  Any ideas where I should look,
> next?
>

I've narrowed down why the kernel won't execute it.  A load address
violates the ELF alignment requirement.  Why the linker made this, I
have no idea.  Why it did so ONLY for the sleep command is curious (I
checked them all and only the sleep command is broken).  I'll next try
to setup a newer binutils  (the script I'm writing will later be
building a binutils from source as part of the process).

Here is the "readelf -a" output for the broken sleep command.  See the
2nd "LOAD" type line.  It should be 0x000f64.

================================================================
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Intel 80386
  Version:                           0x1
  Entry point address:               0x8048094
  Start of program headers:          52 (bytes into file)
  Start of section headers:          3968 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         3
  Size of section headers:           40 (bytes)
  Number of section headers:         5
  Section header string table index: 4

Section Headers:
  [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
  [ 0]                   NULL            00000000 000000 000000 00      0   0  0
  [ 1] .text             PROGBITS        08048094 000094 000ce0 00  AX  0   0  4
  [ 2] .rodata           PROGBITS        08048d80 000d80 0001e1 00   A  0   0 32
  [ 3] .bss              NOBITS          08049f64 000f61 000014 00  WA  0   0  4
  [ 4] .shstrtab         STRTAB          00000000 000f61 00001e 00      0   0  1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings)
  I (info), L (link order), G (group), x (unknown)
  O (extra OS processing required) o (OS specific), p (processor specific)

There are no section groups in this file.

Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x000000 0x08048000 0x08048000 0x00f61 0x00f61 R E 0x1000
  LOAD           0x000f61 0x08049f64 0x08049f64 0x00000 0x00014 RW  0x1000
  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RWE 0x4

 Section to Segment mapping:
  Segment Sections...
   00     .text .rodata
   01     .bss
   02

There is no dynamic section in this file.

There are no relocations in this file.

There are no unwind sections in this file.

No version information found in this file.
================================================================