Exec (system call)

In computing, exec is a functionality of an operating system that runs an in the context of an already existing process, replacing the previous executable. This act is also referred to as an overlay. It is especially important in Unix-like systems, although it exists elsewhere. As no new process is created, the process identifier (PID) does not change, but the machine code, data, heap, and stack of the process are replaced by those of the new program. The exec call is available for many programming languages including compilable languages and some scripting languages. In OS command interpreters, the built-in command replaces the shell process with the specified program. Interfaces to exec and its implementations vary. Depending on programming language it may be accessible via one or more functions, and depending on operating system it may be represented with one or more actual system calls. For this reason exec is sometimes described as a collection of functions. Standard names of such functions in C are , , , , , and (see below), but not "exec" itself. The Linux kernel has one corresponding system call named "execve", whereas all aforementioned functions are user-space wrappers around it. Higher-level languages usually provide one call named . The POSIX standard declares exec functions in the header file, in the C language. The same functions are declared in for DOS (see below), OS/2, and Microsoft Windows. int execl(char const *path, char const *arg0, ...); int execle(char const *path, char const *arg0, ..., char const *envp[]); int execlp(char const *file, char const *arg0, ...); int execv(char const *path, char const *argv[]); int execve(char const *path, char const *argv[], char const *envp[]); int execvp(char const *file, char const *argv[]); int fexecve(int fd, char *const argv[], char *const envp[]); Some implementations provide these functions named with a leading underscore (e.g. _execl). The base of each is exec (execute), followed by one or more letters: e – An array of pointers to environment variables is explicitly passed to the new process image.

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (5)

Related units (1)

Related concepts (8)

Related courses (4)

Related lectures (30)

CS-300: Data-intensive systems

The purpose of this course is to discuss the design of database and operating systems concepts using a hands-on approach.

CS-323: Introduction to operating systems

Introduction to basic concepts of operating systems.

ME-213: Programmation pour ingénieur

Mettre en pratique les bases de la programmation vues au semestre précédent. Développer un logiciel structuré. Méthode de debug d'un logiciel. Introduction à la programmation scientifique. Introductio

Command-line interface

A command-line interface (CLI) is a means of interacting with a device or computer program with commands from a user or client, and responses from the device or program, in the form of lines of text. Such access was first provided by computer terminals starting in the mid-1960s. This provided an interactive environment not available with punched cards or other input methods. Operating system command-line interfaces are often implemented with command-line interpreters or command-line processors.

Fork (system call)

In computing, particularly in the context of the Unix operating system and its workalikes, fork is an operation whereby a process creates a copy of itself. It is an interface which is required for compliance with the POSIX and Single UNIX Specification standards. It is usually implemented as a C standard library wrapper to the fork, clone, or other system calls of the kernel. Fork is the primary method of process creation on Unix-like operating systems. In multitasking operating systems, processes (running programs) need a way to create new processes, e.

Exit status

In computing, the exit status, or exit code, of a terminated process is an integer number that is made available to its parent process (or caller). In DOS, this may be referred to as an errorlevel. When computer programs are executed, the operating system creates an abstract entity called a process in which the book-keeping for that program is maintained. In multitasking operating systems such as Unix or Linux, new processes can be created by active processes.

Preventing Use-After-Free Attacks with Fast Forward Allocation

Sanidhya Kashyap, Jungwon Lim

Memory-unsafe languages are widely used to implement critical systems like kernels and browsers, leading to thousands of memory safety issues every year. A use-after-free bug is a temporal memory error where the program accidentally visits a freed memory l ...

USENIX ASSOC2021

Although automatic gaze estimation is very important to a large variety of application areas, it is difficult to train accurate and robust gaze models, in great part due to the difficulty in collecting large and diverse data (annotating 3D gaze is expensiv ...

IEEE2020

PoLPer: Process-Aware Restriction of Over-Privileged Setuid Calls in Legacy Applications

Mathias Josef Payer, Zhenyu Wu

setuid system calls enable critical functions such as user authentications and modular privileged components. Such operations must only be executed after careful validation. However, current systems do not perform rigorous checks, allowing exploitation of ...

ASSOC COMPUTING MACHINERY2019

Processes: Overview and Management CS-323: Introduction to operating systems

Covers the basics of processes in operating systems, including creation, memory layout, state transitions, virtualization, APIs, and program execution.

Introduction to Operating Systems

Covers the fundamentals of operating systems, including core services, system calls, design goals, and challenges.

Rethinking OSes for Datacenters

Explores Junction, a new approach combining kernel bypass with resource multiplexing for improved datacenter OS performance.