HP-UX Reference (11i v3 07/02) - 4 File Formats (vol 8)

core(4) core(4)

NAME

core - format of core image ﬁle

DESCRIPTION

The HP-UX system writes out a ﬁle containing a core image of a terminated process when certain signals

are received (see signal(5) for the list of reasons). The most common causes are memory violations, illegal

instructions, ﬂoating point exceptions, bus errors, and user-generated quit signals. The core image ﬁle is

called

core and is written in the process’s working directory (provided it is allowed by normal access con-

trols). A process with an effective user ID different from its real user ID does not produce a core image.

The ﬁle contains sufﬁcient information to determine what the process was doing at the time of its termina-

tion. Core ﬁle contents consist of objects that represent different segments of a process. Each object is pre-

ceded by a corehead data structure, and each

corehead data structure describes the corresponding

object following it. The structure is deﬁned in

<sys/core.h> , and includes the following members:

int type;

space_t space;

caddr_t addr;

size_t len;

The space and addr members specify the virtual memory address in the process where the described object

began. The len member is the length of the object in bytes.

The following possible values for type are deﬁned in <sys/core.h> :

CORE_DATA Process data as it existed at the time the core image was created. This includes

initialized data, uninitialized data, and the heap at the time the core image is gen-

erated.

CORE_EXEC A compiler-dependent data structure containing the exec data structure, the magic

number of the executable ﬁle, and the command (see the declaration of the

proc_exec structure in <sys/core.h> ).

CORE_FORMAT The version number of the core format produced. This number changes with each

HP-UX release where the core format itself has changed. However, it does not

necessarily change with every HP-UX release. CORE_FORMAT can thus be

easily used by core-reading tools to determine whether they are compatible with a

given core image. This type is expressed by a four-byte binary integer.

CORE_KERNEL The null-terminated version string associated with the kernel at the time the core

image was generated.

CORE_PROC An architecture-dependent data structure containing per-process information such

as hardware register contents. See the declaration of the proc_info structure

in <sys/core.h> .

CORE_STACK Process stack contents at the time the core image was created.

Objects dumped in a core image ﬁle are not arranged in any particular order. Use corehead

informa-

tion to determine the type of the object that immediately follows it.