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Copy the e_machine and e_flags fields from the binary into an ELF core dump.

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In the kernel, cache the machine and flags fields from ELF header to use in
the ELF header of a core dump. For gcore, the copy these fields over from
the ELF header in the binary.

This matters for platforms which encode ABI information in the flags field
(such as o32 vs n32 on MIPS).

Reviewed by:	kib
Sponsored by:	DARPA / AFRL
Differential Revision:	https://reviews.freebsd.org/D9392
This commit is contained in:
John Baldwin 2017-02-07 20:34:03 +00:00
parent e0f389edab
commit 885f13dc96
3 changed files with 23 additions and 15 deletions
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10
sys/kern/imgact_elf.c
View File

@ -1055,6 +1055,8 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
imgp->interpreted = 0;
imgp->reloc_base = addr;
imgp->proc->p_osrel = osrel;
imgp->proc->p_elf_machine = hdr->e_machine;
imgp->proc->p_elf_flags = hdr->e_flags;
ret:
free(interp_buf, M_TEMP);
@ -1655,15 +1657,11 @@ __elfN(puthdr)(struct thread *td, void *hdr, size_t hdrsize, int numsegs,
ehdr->e_ident[EI_ABIVERSION] = 0;
ehdr->e_ident[EI_PAD] = 0;
ehdr->e_type = ET_CORE;
#if defined(COMPAT_FREEBSD32) && __ELF_WORD_SIZE == 32
ehdr->e_machine = ELF_ARCH32;
#else
ehdr->e_machine = ELF_ARCH;
#endif
ehdr->e_machine = td->td_proc->p_elf_machine;
ehdr->e_version = EV_CURRENT;
ehdr->e_entry = 0;
ehdr->e_phoff = sizeof(Elf_Ehdr);
ehdr->e_flags = 0;
ehdr->e_flags = td->td_proc->p_elf_flags;
ehdr->e_ehsize = sizeof(Elf_Ehdr);
ehdr->e_phentsize = sizeof(Elf_Phdr);
ehdr->e_shentsize = sizeof(Elf_Shdr);

5
sys/sys/proc.h
View File

@ -617,8 +617,11 @@ struct proc {
our subtree. */
u_int p_xexit; /* (c) Exit code. */
u_int p_xsig; /* (c) Stop/kill sig. */
uint16_t p_elf_machine; /* (x) ELF machine type */
uint64_t p_elf_flags; /* (x) ELF flags */
/* End area that is copied on creation. */
#define p_endcopy p_xsig
#define p_endcopy p_elf_flags
struct pgrp *p_pgrp; /* (c + e) Pointer to process group. */
struct knlist *p_klist; /* (c) Knotes attached to this proc. */
int p_numthreads; /* (c) Number of threads. */

23
usr.bin/gcore/elfcore.c
View File

@ -117,8 +117,8 @@ static void *elf_note_procstat_psstrings(void *, size_t *);
static void *elf_note_procstat_rlimit(void *, size_t *);
static void *elf_note_procstat_umask(void *, size_t *);
static void *elf_note_procstat_vmmap(void *, size_t *);
static void elf_puthdr(pid_t, vm_map_entry_t, void *, size_t, size_t, size_t,
int);
static void elf_puthdr(int, pid_t, vm_map_entry_t, void *, size_t, size_t,
size_t, int);
static void elf_putnote(int, notefunc_t, void *, struct sbuf *);
static void elf_putnotes(pid_t, struct sbuf *, size_t *);
static void freemap(vm_map_entry_t);
@ -178,7 +178,7 @@ elf_detach(void)
* Write an ELF coredump for the given pid to the given fd.
*/
static void
elf_coredump(int efd __unused, int fd, pid_t pid)
elf_coredump(int efd, int fd, pid_t pid)
{
vm_map_entry_t map;
struct sseg_closure seginfo;
@ -230,7 +230,7 @@ elf_coredump(int efd __unused, int fd, pid_t pid)
hdr = sbuf_data(sb);
segoff = sbuf_len(sb);
/* Fill in the header. */
elf_puthdr(pid, map, hdr, hdrsize, notesz, segoff, seginfo.count);
elf_puthdr(efd, pid, map, hdr, hdrsize, notesz, segoff, seginfo.count);
n = write(fd, hdr, segoff);
if (n == -1)
@ -420,14 +420,21 @@ elf_putnote(int type, notefunc_t notefunc, void *arg, struct sbuf *sb)
* Generate the ELF coredump header.
*/
static void
elf_puthdr(pid_t pid, vm_map_entry_t map, void *hdr, size_t hdrsize,
elf_puthdr(int efd, pid_t pid, vm_map_entry_t map, void *hdr, size_t hdrsize,
size_t notesz, size_t segoff, int numsegs)
{
Elf_Ehdr *ehdr;
Elf_Ehdr *ehdr, binhdr;
Elf_Phdr *phdr;
Elf_Shdr *shdr;
struct phdr_closure phc;
ssize_t cnt;
cnt = read(efd, &binhdr, sizeof(binhdr));
if (cnt < 0)
err(1, "Failed to re-read ELF header");
else if (cnt != sizeof(binhdr))
errx(1, "Failed to re-read ELF header");
ehdr = (Elf_Ehdr *)hdr;
ehdr->e_ident[EI_MAG0] = ELFMAG0;
@ -441,11 +448,11 @@ elf_puthdr(pid_t pid, vm_map_entry_t map, void *hdr, size_t hdrsize,
ehdr->e_ident[EI_ABIVERSION] = 0;
ehdr->e_ident[EI_PAD] = 0;
ehdr->e_type = ET_CORE;
ehdr->e_machine = ELF_ARCH;
ehdr->e_machine = binhdr.e_machine;
ehdr->e_version = EV_CURRENT;
ehdr->e_entry = 0;
ehdr->e_phoff = sizeof(Elf_Ehdr);
ehdr->e_flags = 0;
ehdr->e_flags = binhdr.e_flags;
ehdr->e_ehsize = sizeof(Elf_Ehdr);
ehdr->e_phentsize = sizeof(Elf_Phdr);
ehdr->e_shentsize = sizeof(Elf_Shdr);