EXECVE(2)

NAME
execve - execute program

SYNOPSIS
#include <unistd.h>

int execve (const char *filename, char *const argv [], char *const envp[]);

DESCRIPTION
execve() executes the program pointed to by filename. filename must be either a binary executable, or a script starting with a line of the form "#! interpreter [arg]". In the latter case, the interpreter must be a valid pathname for an executable which is not itself a script, which will be invoked as interpreter [arg] filename. execve() does not return on success, and the text, data, bss, and stack of the calling process are overwritten by that of the program loaded. The program invoked inherits the calling process's PID, and any open file descriptors that are not set to close on exec. Signals pending on the parent process are cleared. Any signals set to be caught by the calling process are reset to their default behaviour. If the current program is being ptraced, a SIGTRAP is sent to it after a successful execve(). If the executable is an a.out dynamically-linked binary executable containing shared-library stubs, the Linux dynamic linker ld.so(8) is called at the start of execution to bring needed shared libraries into core and link the executable with them. If the executable is a dynamically-linked ELF executable, the interpreter named in the PT_INTERP segment is used to load the needed shared libraries. This interpreter is typically /lib/ld-linux.so.1 for binaries linked with the Linux libc version 5, or /lib/ld-linux.so.2 for binaries linked with the GNU libc version 2.

RETURN VALUE
On success, execve() does not return, on error -1 is returned, and errno is set appropriately.

ERRORS

EACCES
    The file or a script interpreter is not a regular file.

EACCES
    Execute permission is denied for the file or a script interpreter.

EACCES
    The file system is mounted noexec.

EPERM
    The file system is mounted nosuid, the user is not the superuser, and the file has an SUID or SGID bit set.

EPERM
    The process is being traced, the user is not the superuser and the file has an SUID or SGID bit set.

E2BIG
    The argument list is too big.

ENOEXEC
    An executable is not in a recognised format, is for the wrong architecture, or has some other format error that means it cannot be executed.

EFAULT
    filename points outside your accessible address space.

ENAMETOOLONG
    filename is too long.

ENOENT
    The file filename or a script or ELF interpreter does not exist.

ENOMEM
    Insufficient kernel memory was available.

ENOTDIR
    A component of the path prefix of filename or a script or ELF interpreter is not a directory.

EACCES
    Search permission is denied on a component of the path prefix of filename or the name of a script interpreter.

ELOOP
    Too many symbolic links were encountered in resolving filename or the name of a script or ELF interpreter.

ETXTBUSY
    Executable was open for writing by one or more processes.

EIO An I/O error occurred.

ENFILE
    The limit on the total number of files open on the system has been reached.

EMFILE
    The process has the maximum number of files open.

EINVAL
    An ELF executable had more than one PT_INTERP segment (i.e., tried to name more than one interpreter).

EISDIR
    An ELF interpreter was a directory.

ELIBBAD
    An ELF interpreter was not in a recognised format.

CONFORMING TO
SVr4, SVID, X/OPEN, BSD 4.3. POSIX does not document the #! behavior but is otherwise compatible. SVr4 documents additional error conditions EAGAIN, EINTR, ELIBACC, ENOLINK, EMULTIHOP; POSIX does not document ETXTBSY, EPERM, EFAULT, ELOOP, EIO, ENFILE, EMFILE, EINVAL, EISDIR or ELIBBAD error conditions.

NOTES
SUID and SGID processes can not be ptrace()d SUID or SGID. A maximum line length of 127 characters is allowed for the first line in a #! executable shell script. Linux ignores the SUID and SGID bits on scripts.

SEE ALSO
ld.so(8), execl(3), fork(2)