abnormal termination [Open Group 2008]
Abnormal termination occurs when requested by the abort() function or when some signals are received. See also normal termination.
async-signal-safe function [ISO/IEC 9945:2008]
A function that may be invoked, without restriction, from signal-catching functions. No function [defined in ISO/IEC 9945] is async-signal-safe unless explicitly described as such. See also asynchronous-safe.
asynchronous-safe function [GNU Pth]
A function is asynchronous-safe, or asynchronous-signal safe, if it can be called safely and without side effects from within a signal handler context. That is, it must be able to be interrupted at any point to run linearly out of sequence without causing an inconsistent state. It must also function properly when global data might itself be in an inconsistent state. Some asynchronous-safe operations are listed here:
- call the
signal()function to reinstall a signal handler - unconditionally modify a
volatile sig_atomic_tvariable (as modification to this type is atomic) - call the
_Exit()function to immediately terminate program execution - invoke an asynchronous-safe function, as specified by your implementation
Few functions are portably asynchronous-safe. If a function performs any other operations, it is probably not portably asynchronous-safe.
availability [IEEE Std 610.12 1990]
The degree to which a system or component is operational and accessible when required for use. Often expressed as a probability.
conforming [ISO/IEC 9899-1999]
Conforming programs may depend on nonportable features of a conforming implementation.
data race [ISO/IEC 9899:2011]
The execution of a program contains a data race if it contains two conflicting actions in different threads, at least one of which is not atomic, and neither happens before the other. Any such data race results in undefined behavior.
denial-of-service attack
Also DoS attack. An attempt to make a computer resource unavailable to its intended users.
error tolerance [IEEE Std 610.12 1990]
The ability of a system or component to continue normal operation despite the presence of erroneous inputs.
exploit [Seacord 2005a]
A piece of software or a technique that takes advantage of a security vulnerability to violate an explicit or implicit security policy.
fail safe [IEEE Std 610.12 1990]
Pertaining to a system or component that automatically places itself in a safe operating mode in the event of a failure; for example, a traffic light that reverts to blinking red in all directions when normal operation fails.
fail soft [IEEE Std 610.12 1990]
Pertaining to a system or component that continues to provide partial operational capability in the event of certain failures; for example, a traffic light that continues to alternate between red and green if the yellow light fails.
fault tolerance [IEEE Std 610.12 1990]
The ability of a system or component to continue normal operation despite the presence of hardware or software faults.
freestanding environment [ISO/IEC 9899-1999]
An environment in which C program execution may take place without any benefit of an operating system. Program startup might occur at some function other than main(), complex types might not be implemented, and only certain minimal library facilities are guaranteed to be available.
function-like macro [ISO/IEC 9899-1999]
A #define preprocessing directive that defines an identifier immediately followed by zero or more parameters, the ellipsis (...), or a combination of the two, enclosed in parentheses, similar syntactically to a function call. Subsequent instances of the macro name followed by a parenthesized list of arguments in a translation unit are replaced by the replacement list of preprocessing tokens that constitute the remainder of the directive. See also object-like macro and unsafe function-like macro.
hosted environment [ISO/IEC 9899-1999]
An environment that is not freestanding. Program startup occurs at main(), complex types are implemented, and all C standard library facilities are available.
implementation [ISO/IEC 9899-1999]
Particular set of software, running in a particular translation environment under particular control options, that performs translation of programs for, and supports execution of functions in, a particular execution environment.
implementation-defined behavior [ISO/IEC 9899-1999]
Unspecified behavior whereby each implementation documents how the choice is made.
incomplete type [ISO/IEC 9899-1999]
A type that describes an identifier but lacks information needed to determine the size of the identifier.
indeterminate value [ISO/IEC 9899-1999]
Either an unspecified value or a trap representation.
invalid pointer
A pointer that is not a valid pointer.
liveness
Every operation or method invocation executes to completion without interruptions, even if it goes against safety.
locale-specific behavior [ISO/IEC 9899-1999]
Behavior that depends on local conventions of nationality, culture, and language that each implementation documents.
lvalue [ISO/IEC 9899-1999]
An expression with an object type or an incomplete type other than void. The name lvalue comes originally from the assignment expression E1 = E2, in which the left operand E1 is required to be a (modifiable) lvalue. It is perhaps better considered as representing an object "locator value".
mitigation [Seacord 2005a]
Methods, techniques, processes, tools, or runtime libraries that can prevent or limit exploits against vulnerabilities.
normal termination [Open Group 2008]
Normal termination occurs by a return from main(), when requested with the exit(), _exit(), or _Exit() functions; or when the last thread in the process terminates by returning from its start function, by calling the pthread_exit() function, or through cancellation. See also abnormal termination.
object-like macro [ISO/IEC 9899-1999]
A #define preprocessing directive that defines an identifier with no parentheses. Subsequent instances of the macro name in a translation unit are replaced by the replacement list of preprocessing tokens that constitute the remainder of the directive. See also function-like macro.
reentrant [Dowd 2006]
A function is reentrant if multiple instances of the same function can run in the same address space concurrently without creating the potential for inconsistent states.
reliability [IEEE Std 610.12 1990]
The ability of a system or component to perform its required functions under stated conditions for a specified period of time.
robustness [IEEE Std 610.12 1990]
The degree to which a system or component can function correctly in the presence of invalid inputs or stressful environmental conditions.
rvalue [ISO/IEC 9899-1999]
Value of an expression.
security flaw [Seacord 2005a]
A software defect that poses a potential security risk.
security policy [Internet Society 2000]
A set of rules and practices that specify or regulate how a system or organization provides security services to protect sensitive and critical system resources.
sequence point C99 [ISO/IEC 9899-1999]
Evaluation of an expression may produce side effects. At specific points in the execution sequence called sequence points, all side effects of previous evaluations have completed, and no side effects of subsequent evaluations have yet taken place.
side effect [ISO/IEC 9899-1999]
Changes in the state of the execution environment achieved by accessing a volatile object, modifying an object, modifying a file, or calling a function that does any of those operations.
Note: The IEC 60559 standard for binary floating-point arithmetic requires certain user-accessible status flags and control modes. Floating-point operations implicitly set the status flags; modes affect result values of floating-point operations. Implementations that support such floating-point state are required to regard changes to it as side effects. These are detailed in Annex F of the C Standard.
strictly conforming [ISO/IEC 9899-1999]
A strictly conforming program is one that uses only those features of the language and library specified in the international standard. Strictly conforming programs are intended to be maximally portable among conforming implementations and can't, for example, depend on implementation-defined behavior.
trap representation [ISO/IEC 9899-1999]
Object representation that does not represent a value of the object type. Attempting to read the value of an object that has a trap representation other than by an expression that has a character type is undefined. Producing such a representation by a side effect that modifies all or any part of the object other than by an expression that has a character type is undefined.
undefined behavior [ISO/IEC 9899-1999]
Behavior, upon use of a nonportable or erroneous program construct or of erroneous data, for which the standard imposes no requirements. An example of undefined behavior is the behavior on integer overflow.
unsafe function-like macro
A function-like macro whose expansion causes one or more of its arguments not to be evaluated exactly once.
unspecified behavior [ISO/IEC 9899-1999]
Behavior for which the standard provides two or more possibilities and imposes no further requirements on which is chosen in any instance.
unspecified value [ISO/IEC 9899-1999]
A valid value of the relevant type where the C Standard imposes no requirements on which value is chosen in any instance. An unspecified value cannot be a trap representation.
valid pointer
A pointer that refers to an element within an array or one past the last element of an array. For the purposes of this definition, a pointer to an object that is not an element of an array behaves the same as a pointer to the first element of an array of length one with the type of the object as its element type. (Cf 6.5.8p3)
For the purposes of this definition, an object can be considered to be an array of a certain number of bytes; that number is the size of the object, as produced by the sizeof operator.
validation [IEC 61508-4]
Confirmation by examination and provision of objective evidence that the particular requirements for a specific intended use are fulfilled.
verification [IEC 61508-4]
Confirmation by examination and provision of objective evidence that the requirements have been fulfilled.
vulnerability [Seacord 2005a]
A set of conditions that allows an attacker to violate an explicit or implicit security policy.