BESCHREIBUNG
Die Standardaktion bestimmter Signale besteht darin, einen Prozess zum Beenden zu veranlassen und eine Core-Dump-Datei zu erstellen. Dabei handelt es sich um eine Festplattendatei, die zum Zeitpunkt der Beendigung ein Abbild des Prozessspeichers enthält. Dieses Image kann in einem Debugger (z. B. gdb (1)) verwendet werden, um den Status des Programms zum Zeitpunkt seiner Beendigung zu überprüfen. Eine Liste der Signale, die dazu führen, dass ein Prozess den Kern auslagert, finden Sie in Signal (7).
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Unter verschiedenen Umständen wird keine Core-Dump-Datei erstellt:
* The process does not have permission to write the core file. (By
default, the core file is called core or core.pid, where pid is
the ID of the process that dumped core, and is created in the
current working directory. See below for details on naming.)
Writing the core file will fail if the directory in which it is to
be created is nonwritable, or if a file with the same name exists
and is not writable or is not a regular file (e.g., it is a
directory or a symbolic link).
* A (writable, regular) file with the same name as would be used for
the core dump already exists, but there is more than one hard link
to that file.
* The filesystem where the core dump file would be created is full;
or has run out of inodes; or is mounted read-only; or the user has
reached their quota for the filesystem.
* The directory in which the core dump file is to be created does
not exist.
* The RLIMIT_CORE (core file size) or RLIMIT_FSIZE (file size)
resource limits for the process are set to zero; see getrlimit(2)
and the documentation of the shell's ulimit command (limit in
csh(1)).
* The binary being executed by the process does not have read
permission enabled.
* The process is executing a set-user-ID (set-group-ID) program that
is owned by a user (group) other than the real user (group) ID of
the process, or the process is executing a program that has file
capabilities (see capabilities(7)). (However, see the description
of the prctl(2) PR_SET_DUMPABLE operation, and the description of
the /proc/sys/fs/suid_dumpable file in proc(5).)
* (Since Linux 3.7) The kernel was configured without the
CONFIG_COREDUMP option.
Außerdem kann ein Core-Dump einen Teil des Adressraums des Prozesses ausschließen, wenn das madvise (2) -MADV_DONTDUMP-Flag verwendet wurde.
Benennung von Core-Dump-Dateien
Standardmäßig wird eine Core-Dump-Datei als Core bezeichnet. In der Datei / proc / sys / kernel / core_pattern (seit Linux 2.6 und 2.4.21) kann jedoch eine Vorlage zum Benennen von Core-Dump-Dateien definiert werden. Die Vorlage kann% -Spezifizierer enthalten, die beim Erstellen einer Kerndatei durch die folgenden Werte ersetzt werden:
%% a single % character
%c core file size soft resource limit of crashing process (since
Linux 2.6.24)
%d dump mode—same as value returned by prctl(2) PR_GET_DUMPABLE
(since Linux 3.7)
%e executable filename (without path prefix)
%E pathname of executable, with slashes ('/') replaced by
exclamation marks ('!') (since Linux 3.0).
%g (numeric) real GID of dumped process
%h hostname (same as nodename returned by uname(2))
%i TID of thread that triggered core dump, as seen in the PID
namespace in which the thread resides (since Linux 3.18)
%I TID of thread that triggered core dump, as seen in the
initial PID namespace (since Linux 3.18)
%p PID of dumped process, as seen in the PID namespace in which
the process resides
%P PID of dumped process, as seen in the initial PID namespace
(since Linux 3.12)
%s number of signal causing dump
%t time of dump, expressed as seconds since the Epoch,
1970-01-01 00:00:00 +0000 (UTC)
%u (numeric) real UID of dumped process
gdb path-to-your-binary path-to-corefile,info stackgefolgt vonCtrl-d. Das einzig Besorgniserregende ist, dass Core-Dumping für Sie normal ist.