.\" Hey Emacs! This file is -*- nroff -*- source. .\" .\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992 .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .\" Modified by Michael Haardt .\" Modified Wed Jul 21 22:47:01 1993 by Rik Faith .\" Modified 21 Aug 1994 by Michael Chastain : .\" Fixed typoes. .\" Modified Fri Jan 31 16:24:28 1997 by Eric S. Raymond .\" .TH EXECVE 2 "3 September 1997" "Linux 2.0.30" "Linux Programmer's Manual" .SH NAME execve \- execute program .SH SYNOPSIS .B #include .sp .BI "int execve (const char *" filename ", char *const " argv .BI "[], char *const " envp []); .SH DESCRIPTION \fBexecve()\fP executes the program pointed to by \fIfilename\fP. \fIfilename\fP must be either a binary executable, or a script starting with a line of the form "\fB#! \fIinterpreter \fR[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 \fBinterpreter\fR [arg] \fIfilename\fR. \fBexecve()\fP 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 \fBSIGTRAP\fP is sent to it after a successful \fBexecve()\fP. If the executable is an a.out dynamically-linked binary executable containing shared-library stubs, the Linux dynamic linker .IR 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 \fI/lib/ld-linux.so.1\fR for binaries linked with the Linux libc version 5, or \fI/lib/ld-linux.so.2\fR for binaries linked with the GNU libc version 2. .SH "RETURN VALUE" On success, \fBexecve()\fP does not return, on error \-1 is returned, and .I errno is set appropriately. .SH ERRORS .TP .B EACCES The file or a script interpreter is not a regular file. .TP .B EACCES Execute permission is denied for the file or a script interpreter. .TP .B EACCES The file system is mounted .IR noexec . .TP .B EPERM The file system is mounted .IR nosuid , the user is not the superuser, and the file has an SUID or SGID bit set. .TP .B EPERM The process is being traced, the user is not the superuser and the file has an SUID or SGID bit set. .TP .B E2BIG The argument list is too big. .TP .B 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. .TP .B EFAULT .I filename points outside your accessible address space. .TP .B ENAMETOOLONG .I filename is too long. .TP .B ENOENT The file .I filename or a script or ELF interpreter does not exist. .TP .B ENOMEM Insufficient kernel memory was available. .TP .B ENOTDIR A component of the path prefix of .I filename or a script or ELF interpreter is not a directory. .TP .B EACCES Search permission is denied on a component of the path prefix of .I filename or the name of a script interpreter. .TP .B ELOOP Too many symbolic links were encountered in resolving .I filename or the name of a script or ELF interpreter. .TP .B ETXTBUSY Executable was open for writing by one or more processes. .TP .B EIO An I/O error occurred. .TP .B ENFILE The limit on the total number of files open on the system has been reached. .TP .B EMFILE The process has the maximum number of files open. .TP .B EINVAL An ELF executable had more than one PT_INTERP segment (i.e., tried to name more than one interpreter). .TP .B EISDIR An ELF interpreter was a directory. .TP .B ELIBBAD An ELF interpreter was not in a recognised format. .SH "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. .SH NOTES SUID and SGID processes can not be \fBptrace()\fPd 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. .SH "SEE ALSO" .BR ld.so "(8)," .BR execl "(3)," .BR fork (2)