Bash can't start a programme that's there and has all the right permissions

Question

This is a gentoo server. There's a programme prog that can't execute. (Yes the execute permission is set)

About the file

$ ls
prog
$ ./prog
bash: ./prog: No such file or directory
$ file prog
prog: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.5, dynamically linked (uses shared libs), not stripped
$ pwd
/usr/local/bin
$ /usr/local/bin/prog
bash: /usr/local/bin/prog: No such file or directory
$ less prog | head
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

I have a fancy less, to show that it's an actual executable, here's some more data:

$ xxd prog |head
0000000: 7f45 4c46 0101 0100 0000 0000 0000 0000  .ELF............
0000010: 0200 0300 0100 0000 c092 0408 3400 0000  ............4...
0000020: 0401 0a00 0000 0000 3400 2000 0700 2800  ........4. ...(.
0000030: 2600 2300 0600 0000 3400 0000 3480 0408  &.#.....4...4...
0000040: 3480 0408 e000 0000 e000 0000 0500 0000  4...............
0000050: 0400 0000 0300 0000 1401 0000 1481 0408  ................
0000060: 1481 0408 1300 0000 1300 0000 0400 0000  ................
0000070: 0100 0000 0100 0000 0000 0000 0080 0408  ................
0000080: 0080 0408 21f1 0500 21f1 0500 0500 0000  ....!...!.......
0000090: 0010 0000 0100 0000 40f1 0500 4081 0a08  ........@...@...

and

$ ls -l prog
-rwxrwxr-x 1 1000 devs 725706 Aug  6  2007 prog

$ ldd prog
      not a dynamic executable

$ strace ./prog
1249403877.639076 execve("./prog", ["./prog"], [/* 27 vars */]) = -1 ENOENT (No such file or directory)
1249403877.640645 dup(2)                = 3
1249403877.640875 fcntl(3, F_GETFL)     = 0x8002 (flags O_RDWR|O_LARGEFILE)
1249403877.641143 fstat(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
1249403877.641484 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b3b8954a000
1249403877.641747 lseek(3, 0, SEEK_CUR) = -1 ESPIPE (Illegal seek)
1249403877.642045 write(3, "strace: exec: No such file or dir"..., 40strace: exec: No such file or directory
) = 40
1249403877.642324 close(3)              = 0
1249403877.642531 munmap(0x2b3b8954a000, 4096) = 0
1249403877.642735 exit_group(1)         = ?

About the server

FTR the server is a xen domU, and the programme is a closed source linux application. This VM is a copy of another VM that has the same root filesystem (including this programme), that works fine.

I've tried all the above as root and same problem.

Did I mention the root filesystem is mounted over NFS. However it's mounted 'defaults,nosuid', which should include execute. Also I am able to run many other programmes from that mounted drive

/proc/cpuinfo:

processor   : 0
vendor_id   : GenuineIntel
cpu family  : 15
model       : 4
model name  :                   Intel(R) Xeon(TM) CPU 3.00GHz
stepping    : 1
cpu MHz     : 2992.692
cache size  : 1024 KB
fpu     : yes
fpu_exception   : yes
cpuid level : 5
wp      : yes
flags       : fpu tsc msr pae mce cx8 apic mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl cid cx16 xtpr
bogmips : 5989.55
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:

Example of a file that I can run

I can run other programmes on that mounted filesystem on that server. For example:

$ ls -l ls
-rwxr-xr-x 1 root root 105576 Jul 25 17:14 ls
$ file ls
ls: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), stripped
$ ./ls
attr        cat    cut        echo        getfacl   ln    more       
... (you get the idea) ...
rmdir       sort       tty
$ less ls | head
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1

Answer 1

The lm flag in your /proc/cpuinfo indicates that your server has a 64 bit CPU.

The info from file prog indicates that the program is compiled for 32 bit architectures. Try installing the 32 libraries. I'm not familiar with how to do this in Gentoo, but maybe this Gentoo wiki article can help.

I have had a simliar problem (bash reporting the file not being found) while trying to run the Android Debug Bridge on a 64 bit installation of Ubuntu, because it is compiled for 32 bit.

Answer 2

Try the following:

ldd /usr/local/bin/prog

Or run it under strace:

strace /usr/local/bin/prog

I would guess the program is linked against a shared library that is either missing, or compiled for the wrong architecture. Given that it's closed source, either is possible.

Answer 3

What about setting the exec flag on the file system mount?

mount -o remount,exec server:/path /mntpoint

If the exec flag is not set for a file system, no executable can be run from that file system.

Answer 4

Can you get the results for,

• which prog
• cat /proc/cpuinfo -- i assume you have /proc

---

Small pointers,

1. Can you run some other executable successfully that also shows 32-bit?
   • Can you run some other executable also over the mount point
     (you could copy one there on the server machine, should appear over the mount after the copy)

Answer 5

The file might not really be named 'prog'. Unix lets you use any character in a filename, including backspace, space, etc. For example, the file could be named 'p^Hprog ' and all you'd see is "prog". Since you've got bash, you can take advantage of autocomplete:

> ls ./[TAB] # where [TAB] means you hit the tab key

if that matches anything, you could

> mv ./[TAB]

If you're writing code, you'd want to list all files in the directory and show hex values for each character in the file name.

Answer 6

$ less prog | head
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)

That's suspicious (unless you have an advanced LESSPIPE)... can you do

ls -l prog

(for size)

xxd prog | head

(for actual contents)

Also, try renaming it to myprog and then running ./myprog

Answer 7

Yes I realize this question is two years old. But here's a possible answer:

execve() returns ENOENT when it can't find the ELF interpreter. In my case, I needed a symlink from /lib/ld_lsb.so.3 -> ld_linux.so.2. This is the Linux Standard Base specified location for the ELF interpreter. There may be a package in your distribution that supplies this symlink, probably named something like 'lsb'.

Answer 8

I found this tidbit buried inside a PDF:

To install 32-bit runtime support, Execute the following commands:

• $ sudo apt-get update
• $ sudo apt-get install ia32-libs

Note that this installs over 200 packages, and takes several minutes to complete.

Doing this allowed me to run under 64-bit Linux:ldd to work, as well as, for instance, the NVIDIA nvflash binary ...