CODEWITHSUNDEEP
linuxgdbexecstrace
Benoît
Benoît

Reputation: 3543

How do i a debug exec* = -1 ENOENT?

I'm building this binary from assembly and trying to link it (probably badly) with libc. But my program won't start, execve likely fails to finding something. How can I debug it ?

$ file ctime
ctime: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 3.2.0, not stripped

$ strace -f ./ctime
execve("./ctime", ["./ctime"], [/* 19 vars */]) = -1 ENOENT (No such file or directory)
fstat64(2, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
write(2, "strace: exec: No such file or di"..., 40strace: exec: No such file or directory
) = 40
getpid()                                = 13784
exit_group(1)                           = ?
+++ exited with 1 +++

$ gdb ./ctime
GNU gdb (Raspbian 7.12-6) 7.12.0.20161007-git
Reading symbols from ./ctime...done.
(gdb) r
Starting program: ./ctime
/bin/bash: ./ctime: No such file or directory
During startup program exited with code 127.

Upvotes: 2

Views: 1304

Answers (1)

ks1322
ks1322

Reputation: 35825

How can I debug it ?

See ERRORS section for ENOENT error in man execve:

ENOENT The file filename or a script or ELF interpreter does not
      exist, or a shared library needed for the file or interpreter
      cannot be found.

One of the most likely reasons of this error is: "ELF interpreter does not exist". Use this command to see the current path to ELF interpreter in your binary:

readelf -l ctime | grep "Requesting program interpreter"

It is likely what your program fails to find when starting.

Upvotes: 2

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