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ELF coredump: define several useful flags for the coredump operations

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- SVC_ALL request dumping all map entries, including those marked as
  non-dumpable
- SVC_NOCOMPRESS disallows compressing the dump regardless of the sysctl
  policy
- SVC_PC_COREDUMP is provided for future use by userspace core dump
  request

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D29955
This commit is contained in:
Konstantin Belousov 2021-04-24 14:45:01 +03:00
parent 5bc3c61780
commit 86ffb3d1a0
2 changed files with 25 additions and 11 deletions
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31
sys/kern/imgact_elf.c
View File

@ -1655,7 +1655,7 @@ int
__elfN(coredump)(struct thread *td, struct vnode *vp, off_t limit, int flags)
{
struct ucred *cred = td->td_ucred;
int error = 0;
int compm, error = 0;
struct sseg_closure seginfo;
struct note_info_list notelst;
struct coredump_params params;
@ -1706,9 +1706,13 @@ __elfN(coredump)(struct thread *td, struct vnode *vp, off_t limit, int flags)
}
/* Create a compression stream if necessary. */
if (compress_user_cores != 0) {
compm = compress_user_cores;
if ((flags & (SVC_PT_COREDUMP | SVC_NOCOMPRESS)) == SVC_PT_COREDUMP &&
compm == 0)
compm = COMPRESS_GZIP;
if (compm != 0) {
params.comp = compressor_init(core_compressed_write,
compress_user_cores, CORE_BUF_SIZE,
compm, CORE_BUF_SIZE,
compress_user_cores_level, &params);
if (params.comp == NULL) {
error = EFAULT;
@ -1826,12 +1830,15 @@ each_dumpable_segment(struct thread *td, segment_callback func, void *closure,
* are marked MAP_ENTRY_NOCOREDUMP now so we no longer
* need to arbitrarily ignore such segments.
*/
if (elf_legacy_coredump) {
if ((entry->protection & VM_PROT_RW) != VM_PROT_RW)
continue;
} else {
if ((entry->protection & VM_PROT_ALL) == 0)
continue;
if ((flags & SVC_ALL) == 0) {
if (elf_legacy_coredump) {
if ((entry->protection & VM_PROT_RW) !=
VM_PROT_RW)
continue;
} else {
if ((entry->protection & VM_PROT_ALL) == 0)
continue;
}
}
/*
@ -1840,9 +1847,11 @@ each_dumpable_segment(struct thread *td, segment_callback func, void *closure,
* madvise(2). Do not dump submaps (i.e. parts of the
* kernel map).
*/
if (entry->eflags & (MAP_ENTRY_NOCOREDUMP|MAP_ENTRY_IS_SUB_MAP))
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
continue;
if ((entry->eflags & MAP_ENTRY_NOCOREDUMP) != 0 &&
(flags & SVC_ALL) == 0)
continue;
if ((object = entry->object.vm_object) == NULL)
continue;

5
sys/sys/sysent.h
View File

@ -171,6 +171,11 @@ struct sysentvec {
#define SV_ABI_CLOUDABI 17
#define SV_ABI_UNDEF 255
/* sv_coredump flags */
#define SVC_PT_COREDUMP 0x00000001 /* dump requested by ptrace(2) */
#define SVC_NOCOMPRESS 0x00000002 /* disable compression. */
#define SVC_ALL 0x00000004 /* dump everything */
#ifdef _KERNEL
extern struct sysentvec aout_sysvec;
extern struct sysent sysent[];