Linux System Call Error Codes
In computing, a system call is the programmatic way in which a computer program requests a service from the kernel of the operating system it is executed on. A system call is a way for programs to interact with the operating system. A computer program makes a system call when it makes a request to the operating system’s kernel. System call provides the services of the operating system to the user programs via Application Program Interface(API). It provides an interface between a process and operating system to allow user-level processes to request services of the operating system. System calls are the only entry points into the kernel system. All programs needing resources must use system calls.
The below list gives the system call error codes. This can be useful in interpreting the command output while using linux debugging tool like strace.
| ERROR CODE | DESCRIPTION |
| E2BIG | Argument list too long (POSIX.1) |
| EACCES | Permission denied (POSIX.1) |
| EADDRINUSE | Address already in use (POSIX.1) |
| EADDRNOTAVAIL | Address not available (POSIX.1) |
| EAFNOSUPPORT | Address family not supported (POSIX.1) |
| EAGAIN | Resource temporarily unavailable (may be the same value as EWOULDBLOCK) (POSIX.1) |
| EALREADY | Connection already in progress (POSIX.1) |
| EBADE | Invalid exchange |
| EBADF | Bad file descriptor (POSIX.1) |
| EBADFD | File descriptor in bad state |
| EBADMSG | Bad message (POSIX.1) |
| EBADR | Invalid request descriptor |
| EBADRQC | Invalid request code |
| EBADSLT | Invalid slot |
| EBUSY | Device or resource busy (POSIX.1) |
| ECANCELED | Operation canceled (POSIX.1) |
| ECHILD | No child processes (POSIX.1) |
| ECHRNG | Channel number out of range |
| ECOMM | Communication error on send |
| ECONNABORTED | Connection aborted (POSIX.1) |
| ECONNREFUSED | Connection refused (POSIX.1) |
| ECONNRESET | Connection reset (POSIX.1) |
| EDEADLK | Resource deadlock avoided (POSIX.1) |
| EDEADLOCK | Synonym for EDEADLK |
| EDESTADDRREQ | Destination address required (POSIX.1) |
| EDOM | Mathematics argument out of domain of function (POSIX.1, C99) |
| EDQUOT | Disk quota exceeded (POSIX.1) |
| EEXIST | File exists (POSIX.1) |
| EFAULT | Bad address (POSIX.1) |
| EFBIG | File too large (POSIX.1) |
| EHOSTDOWN | Host is down |
| EHOSTUNREACH | Host is unreachable (POSIX.1) |
| EIDRM | Identifier removed (POSIX.1) |
| EILSEQ | Illegal byte sequence (POSIX.1, C99) |
| EINPROGRESS | Operation in progress (POSIX.1) |
| EINTR | Interrupted function call (POSIX.1); see signal(7). |
| EINVAL | Invalid argument (POSIX.1) |
| EIO | Input/output error (POSIX.1) |
| EISCONN | Socket is connected (POSIX.1) |
| EISDIR | Is a directory (POSIX.1) |
| EISNAM | Is a named type file |
| EKEYEXPIRED | Key has expired |
| EKEYREJECTED | Key was rejected by service |
| EKEYREVOKED | Key has been revoked |
| EL2HLT | Level 2 halted |
| EL2NSYNC | Level 2 not synchronized |
| EL3HLT | Level 3 halted |
| EL3RST | Level 3 halted |
| ELIBACC | Cannot access a needed shared library |
| ELIBBAD | Accessing a corrupted shared library |
| ELIBMAX | Attempting to link in too many shared libraries |
| ELIBSCN | lib section in a.out corrupted |
| ELIBEXEC | Cannot exec a shared library directly |
| ELOOP | Too many levels of symbolic links (POSIX.1) |
| EMEDIUMTYPE | Wrong medium type |
| EMFILE | Too many open files (POSIX.1) |
| EMLINK | Too many links (POSIX.1) |
| EMSGSIZE | Message too long (POSIX.1) |
| EMULTIHOP | Multihop attempted (POSIX.1) |
| ENAMETOOLONG | Filename too long (POSIX.1) |
| ENETDOWN | Network is down (POSIX.1) |
| ENETRESET | Connection aborted by network (POSIX.1) |
| ENETUNREACH | Network unreachable (POSIX.1) |
| ENFILE | Too many open files in system (POSIX.1) |
| ENOBUFS | No buffer space available (POSIX.1 (XSI STREAMS option)) |
| ENODATA | No message is available on the STREAM head read queue (POSIX.1) |
| ENODEV | No such device (POSIX.1) |
| ENOENT | No such file or directory (POSIX.1) |
| ENOEXEC | Exec format error (POSIX.1) |
| ENOKEY | Required key not available |
| ENOLCK | No locks available (POSIX.1) |
| ENOLINK | Link has been severed (POSIX.1) |
| ENOMEDIUM | No medium found |
| ENOMEM | Not enough space (POSIX.1) |
| ENOMSG | No message of the desired type (POSIX.1) |
| ENONET | Machine is not on the network |
| ENOPKG | Package not installed |
| ENOPROTOOPT | Protocol not available (POSIX.1) |
| ENOSPC | No space left on device (POSIX.1) |
| ENOSR | No STREAM resources (POSIX.1 (XSI STREAMS option)) |
| ENOSTR | Not a STREAM (POSIX.1 (XSI STREAMS option)) |
| ENOSYS | Function not implemented (POSIX.1) |
| ENOTBLK | Block device required |
| ENOTCONN | The socket is not connected (POSIX.1) |
| ENOTDIR | Not a directory (POSIX.1) |
| ENOTEMPTY | Directory not empty (POSIX.1) |
| ENOTSOCK | Not a socket (POSIX.1) |
| ENOTSUP | Operation not supported (POSIX.1) |
| ENOTTY | Inappropriate I/O control operation (POSIX.1) |
| ENOTUNIQ | Name not unique on network |
| ENXIO | No such device or address (POSIX.1) |
| EOPNOTSUPP | Operation not supported on socket (POSIX.1) (ENOTSUP and EOPNOTSUPP have the same value on Linux, but according to POSIX.1 these error values should be distinct.) |
| EOVERFLOW | Value too large to be stored in data type (POSIX.1) |
| EPERM | Operation not permitted (POSIX.1) |
| EPFNOSUPPORT | Protocol family not supported |
| EPIPE | Broken pipe (POSIX.1) |
| EPROTO | Protocol error (POSIX.1) |
| EPROTONOSUPPORT | Protocol not supported (POSIX.1) |
| EPROTOTYPE | Protocol wrong type for socket (POSIX.1) |
| ERANGE | Result too large (POSIX.1, C99) |
| EREMCHG | Remote address changed |
| EREMOTE | Object is remote |
| EREMOTEIO | Remote I/O error |
| ERESTART | Interrupted system call should be restarted |
| EROFS | Read-only file system (POSIX.1) |
| ESHUTDOWN | Cannot send after transport endpoint shutdown |
| ESPIPE | Invalid seek (POSIX.1) |
| ESOCKTNOSUPPORT | Socket type not supported |
| ESRCH | No such process (POSIX.1) |
| ESTALE | Stale file handle (POSIX.1) This error can occur for NFS and for other file systems |
| ESTRPIPE | Streams pipe error |
| ETIME | Stale file handle (POSIX.1) This error can occur for NFS and for other file systems |
| ETIMEDOUT | Connection timed out (POSIX.1) |
| ETXTBSY | Text file busy (POSIX.1) |
| EUCLEAN | Structure needs cleaning |
| EUNATCH | Protocol driver not attached |
| EUSERS | Too many users |
| EWOULDBLOCK | Operation would block (may be same value as EAGAIN) (POSIX.1) |
| EXDEV | Improper link (POSIX.1) |
| EXFULL | Exchange full |