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]
argv is an array of argument strings passed to the new program.
envp is an array of strings, conventionally of the form
key=value, which are passed as environment to the new program. Both
argv and envp must be terminated by a null pointer. The argument
vector and environment can be accessed by the called program's main function,
when it is defined as int main(intargc, char *argv, char
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 calling
process are cleared. Any signals set to be caught by the calling process are
reset to their default behaviour. The SIGCHLD signal (when set to SIG_IGN) may
or may not be reset to SIG_DFL.
If the current program is being ptraced, a SIGTRAP is sent to it after a
If the set-uid bit is set on the program file pointed to by filename the
effective user ID of the calling process is changed to that of the owner of
the program file. Similarly, when the set-gid bit of the program file is set
the effective group ID of the calling process is set to the group of the
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.
The result of mounting a filesystem nosuid vary between Linux kernel
versions: some will refuse execution of SUID/SGID executables when this would
give the user powers she did not have already (and return EPERM), some will
just ignore the SUID/SGID bits and exec successfully.
A maximum line length of 127 characters is allowed for the first line in a #!
executable shell script.
With Unix V6 the argument list of an exec call was ended by 0, while the
argument list of main was ended by -1. Thus, this argument list was not
directly usable in a further exec call. Since Unix V7 both are NULL.