MAN page from Mandrake Other man-pages-gz-1.21-2.noarch.rpm

EXECVE

Section: Linux Programmer's Manual (2)
Updated: 3 September 1997
Index

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 scriptstarting with a line of the form "#! interpreter [arg]".In the latter case, the interpreter must be a valid pathname for anexecutable which is not itself a script, which will be invoked asinterpreter [arg] filename.

execve() does not return on success, and the text, data, bss, andstack of the calling process are overwritten by that of the programloaded. The program invoked inherits the calling process's PID, and anyopen file descriptors that are not set to close on exec. Signals pendingon the parent process are cleared. Any signals set to be caught bythe calling process are reset to their default behaviour.

If the current program is being ptraced, a SIGTRAP is sent to itafter a successful execve().

If the executable is an a.out dynamically-linked binary executable containingshared-library stubs, the Linux dynamic linkerld.so(8)is called at the start of execution to bring needed shared libraries into coreand link the executable with them.

If the executable is a dynamically-linked ELF executable, theinterpreter named in the PT_INTERP segment is used to load the neededshared libraries. This interpreter is typically/lib/ld-linux.so.1 for binaries linked with the Linux libcversion 5, or /lib/ld-linux.so.2 for binaries linked with theGNU libc version 2.

RETURN VALUE

On success, execve() does not return, on error -1 is returned, anderrnois 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 mountednoexec.
EPERM: The file system is mountednosuid,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 thefile 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 wrongarchitecture, or has some other format error that means it cannot beexecuted.
EFAULT: filenamepoints outside your accessible address space.
ENAMETOOLONG: filenameis too long.
ENOENT: The file filenameor a script or ELF interpreter does not exist.
ENOMEM: Insufficient kernel memory was available.
ENOTDIR: A component of the path prefix offilenameor a script or ELF interpreter is not a directory.
EACCES: Search permission is denied on a component of the path prefix offilenameor the name of a script interpreter.
ELOOP: Too many symbolic links were encountered in resolvingfilenameor 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 toname 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 #! behaviorbut is otherwise compatible. SVr4 documents additional errorconditions EAGAIN, EINTR, ELIBACC, ENOLINK, EMULTIHOP; POSIX does notdocument 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 ina #! executable shell script.

Linux ignores the SUID and SGID bits on scripts.

This document was created byman2html,using the manual pages.