diff options
Diffstat (limited to 'share/man')
| -rw-r--r-- | share/man/man5/core.5 | 167 |
1 files changed, 68 insertions, 99 deletions
diff --git a/share/man/man5/core.5 b/share/man/man5/core.5 index ec8f3e4606a..fb431d69277 100644 --- a/share/man/man5/core.5 +++ b/share/man/man5/core.5 @@ -1,4 +1,4 @@ -.\" $OpenBSD: core.5,v 1.19 2015/09/10 17:55:21 schwarze Exp $ +.\" $OpenBSD: core.5,v 1.20 2016/08/16 04:14:34 guenther Exp $ .\" $NetBSD: core.5,v 1.4 1994/11/30 19:31:11 jtc Exp $ .\" .\" Copyright (c) 1980, 1991, 1993 @@ -30,27 +30,32 @@ .\" .\" @(#)core.5 8.3 (Berkeley) 12/11/93 .\" -.Dd $Mdocdate: September 10 2015 $ +.Dd $Mdocdate: August 16 2016 $ .Dt CORE 5 .Os .Sh NAME .Nm core .Nd memory image file format .Sh SYNOPSIS -.In sys/param.h -.In sys/core.h +.In sys/types.h +.In sys/exec_elf.h .Sh DESCRIPTION A small number of signals which cause abnormal termination of a process also cause a record of the process's in-core state to be written to disk for later examination by one of the available debuggers (see .Xr sigaction 2 ) . -This memory image is written to a file named +.Pp +By default, this memory image is written to a file named .Pa programname.core in the working directory, provided the terminated process had write -permission in the directory, and provided the abnormality did not cause -a system crash. -(In this event, the decision to save the core file is arbitrary, see -.Xr savecore 8 . ) +permission in the directory, +and the terminated process either had an effective user ID of zero or +had never changed user or group ID. +See the description of +.Dv KERN_NOSUIDCOREDUMP +in +.Xr sysctl 3 +for other options. .Pp The maximum size of a .Pa programname.core @@ -60,99 +65,59 @@ Files which would be larger than the limit are not created. .Pp The .Pa programname.core -file consists of the u-area, whose size (in pages) is defined by the -.Dv UPAGES -manifest in the -.In machine/param.h -file. -The u-area starts with a -.Fa user -structure as given in -.In sys/user.h . -The remainder of the -.Pa programname.core -file consists of the data pages followed by the stack pages of the -process image. -The amount of data space image in the -.Pa programname.core -file is given (in pages) by the variable -.Fa u_dsize -in the u-area. -The amount of stack image in the core file is given (in pages) by the variable -.Fa u_ssize -in the u-area. -The size of a -.Dq page -is given by the constant -.Dv PAGE_SIZE , -defined in -.In machine/param.h . -The -.Fa user -structure is defined as: -.Bd -unfilled -offset indent -struct user { - struct pcb u_pcb; - - struct pstats u_stats; - - /* - * Remaining fields only for core dump and/or ptrace-- - * not valid at other times! - */ - struct kinfo_proc u_kproc; - struct md_coredump u_md; -}; -.Ed -.Pp -.Fa md_coredump -is defined in the header file -.In machine/pcb.h . +file is in the ELF binary file format with an +.Va e_type +of +.Dv ET_CORE . +It has no section header table and a segment header that contains +.Dv PT_LOAD +and +.Dv PT_NOTE +segments that describe the state of the process when terminated. .Pp -The on-disk core file consists of a header followed by a number of segments. -Each segment is preceded by a -.Fa coreseg -structure giving the segment's type, -the virtual address where the bits resided in process address space -and the size of the segment. +The +.Dv PT_LOAD +segments hold images of the process memory when it was terminated. +Device mappings are excluded, +as are read-only mappings that do not have private mapping changes. +Each segment's +.Va p_vaddr , +.Va p_memsz , +and +.Va p_flags +specify the address, size, and access protection of the memory +segment it describes. .Pp -The core header specifies the lengths of the core header itself and -each of the following core segment headers to allow for any machine -dependent alignment requirements. -.Bd -unfilled -offset indent -struct coreseg { - u_int32_t c_midmag; /* magic, id, flags */ - u_long c_addr; /* Virtual address of segment */ - u_long c_size; /* Size of this segment */ -}; -.Ed -.Bd -unfilled -offset indent -struct core { - u_int32_t c_midmag; /* magic, id, flags */ - u_int16_t c_hdrsize; /* Size of this header (machdep algn) */ - u_int16_t c_seghdrsize; /* Size of a segment header */ - u_int32_t c_nseg; /* # of core segments */ - char c_name[MAXCOMLEN+1]; /* Copy of p->p_comm */ - u_int32_t c_signo; /* Killing signal */ - u_long c_ucode; /* Hmm ? */ - u_long c_cpusize; /* Size of machine dependent segment */ - u_long c_tsize; /* Size of traditional text segment */ - u_long c_dsize; /* Size of traditional data segment */ - u_long c_ssize; /* Size of traditional stack segment */ -}; -.Ed +The +.Dv PT_NOTE +segment contains notes describing the kernel state and CPU registers +of each thread in the process. +Note describing the process as a whole have the name +.Dq OpenBSD +An +.Dv NT_OPENBSD_PROCINFO +note is included containing an +.Vt elfcore_procinfo +structure with information about the kernel state of the process. +An +.Dv NT_OPENBSD_AUXV +note is included containing a copy of the original process environment strings. +On sparc and sparc64, an +.Dv NT_OPENBSD_WCOOKIE +note is included containing the process's +.Sq window cookie . .Pp -The core structure's -.Fa c_midmag field -is an a.out-style midmag number with a -.Dv COREMAGIC -magic number. -and flags from the following list: -.Bd -unfilled -offset indent -#define CORE_CPU 1 -#define CORE_DATA 2 -#define CORE_STACK 4 -.Ed +Notes describing the individual threads in the process have names +in the format +.Dq OpenBSD@%d +where the suffix is the thread ID. +For each thread, an +.Dv NT_OPENBSD_REGS +note is included containing the state of the regular registers of +the thread and, on architectures other than luna88k and sgi, an +.Dv NT_OPENBSD_FPREGS +note is also included containing the state of the floating-point +registers of the thread. .Sh SEE ALSO .Xr gdb 1 , .Xr setrlimit 2 , @@ -163,6 +128,10 @@ A .Nm file format appeared in .At v3 . +.Ox 2.0 +started using the ELF format for some architectures. +All architectures used ELF starting in +.Ox 5.4 . .Sh CAVEATS Programs which are started with either the set-user-ID or set-group-ID bits set, |