PERFORCE change 78778 for review
Peter Wemm
peter at FreeBSD.org
Tue Jun 21 20:25:20 GMT 2005
http://perforce.freebsd.org/chv.cgi?CH=78778
Change 78778 by peter at peter_daintree on 2005/06/21 20:24:48
Read ELF crashdumps
Affected files ...
.. //depot/projects/hammer/lib/libkvm/kvm_amd64.c#7 edit
Differences ...
==== //depot/projects/hammer/lib/libkvm/kvm_amd64.c#7 (text+ko) ====
@@ -53,6 +53,7 @@
#include <sys/user.h>
#include <sys/proc.h>
#include <sys/stat.h>
+#include <sys/mman.h>
#include <stdlib.h>
#include <unistd.h>
#include <nlist.h>
@@ -61,6 +62,8 @@
#include <vm/vm.h>
#include <vm/vm_param.h>
+#include <machine/elf.h>
+
#include <limits.h>
#include "kvm_private.h"
@@ -71,18 +74,67 @@
#endif
struct vmstate {
+ void *mmapbase;
+ size_t mmapsize;
pml4_entry_t *PML4;
};
+/*
+ * Map the ELF headers into the process' address space. We do this in two
+ * steps: first the ELF header itself and using that information the whole
+ * set of headers.
+ */
+static int
+_kvm_maphdrs(kvm_t *kd, size_t sz)
+{
+ struct vmstate *vm = kd->vmst;
+
+ /* munmap() previous mmap(). */
+ if (vm->mmapbase != NULL) {
+ munmap(vm->mmapbase, vm->mmapsize);
+ vm->mmapbase = NULL;
+ }
+
+ vm->mmapsize = sz;
+ vm->mmapbase = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0);
+ if (vm->mmapbase == MAP_FAILED) {
+ _kvm_err(kd, kd->program, "cannot mmap corefile");
+ return (-1);
+ }
+
+ return (0);
+}
+
+/*
+ * Translate a physical memory address to a file-offset in the crash-dump.
+ */
+static size_t
+_kvm_pa2off(kvm_t *kd, uint64_t pa, u_long *ofs)
+{
+ Elf_Ehdr *e = kd->vmst->mmapbase;
+ Elf_Phdr *p = (Elf_Phdr*)((char*)e + e->e_phoff);
+ int n = e->e_phnum;
+
+ while (n && (pa < p->p_paddr || pa >= p->p_paddr + p->p_memsz))
+ p++, n--;
+ if (n == 0)
+ return (0);
+
+ *ofs = (pa - p->p_paddr) + p->p_offset;
+ return (PAGE_SIZE - ((size_t)pa & PAGE_MASK));
+}
+
void
_kvm_freevtop(kvm_t *kd)
{
- if (kd->vmst != 0) {
- if (kd->vmst->PML4) {
- free(kd->vmst->PML4);
- }
- free(kd->vmst);
- }
+ struct vmstate *vm = kd->vmst;
+
+ if (vm->mmapbase != NULL)
+ munmap(vm->mmapbase, vm->mmapsize);
+ if (vm->PML4)
+ free(vm->PML4);
+ free(vm);
+ kd->vmst = NULL;
}
int
@@ -93,15 +145,24 @@
u_long pa;
u_long kernbase;
pml4_entry_t *PML4;
+ Elf_Ehdr *ehdr;
+ size_t hdrsz;
- vm = (struct vmstate *)_kvm_malloc(kd, sizeof(*vm));
- if (vm == 0) {
+ kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*vm));
+ if (kd->vmst == 0) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}
- kd->vmst = vm;
vm->PML4 = 0;
+ if (_kvm_maphdrs(kd, sizeof(Elf_Ehdr)) == -1)
+ return (-1);
+
+ ehdr = kd->vmst->mmapbase;
+ hdrsz = ehdr->e_phoff + ehdr->e_phentsize * ehdr->e_phnum;
+ if (_kvm_maphdrs(kd, hdrsz) == -1)
+ return (-1);
+
nlist[0].n_name = "kernbase";
nlist[1].n_name = 0;
@@ -132,8 +193,8 @@
return (0);
}
-static int
-_kvm_vatop(kvm_t *kd, u_long va, u_long *pa)
+int
+_kvm_kvatop(kvm_t *kd, u_long va, u_long *pa)
{
struct vmstate *vm;
u_long offset;
@@ -149,9 +210,11 @@
u_long pdeindex;
u_long pteindex;
int i;
+ u_long ofs;
+ size_t s;
if (ISALIVE(kd)) {
- _kvm_err(kd, 0, "kvm_vatop called in live kernel!");
+ _kvm_err(kd, 0, "kvm_kvatop called in live kernel!");
return((off_t)0);
}
@@ -175,13 +238,17 @@
pdpeindex = (va >> PDPSHIFT) & (NPDPEPG-1);
pdpe_pa = ((u_long)pml4e & PG_FRAME) + (pdpeindex * sizeof(pdp_entry_t));
- /* XXX This has to be a physical address read, kvm_read is virtual */
- if (lseek(kd->pmfd, pdpe_pa, 0) == -1) {
- _kvm_syserr(kd, kd->program, "_kvm_vatop: lseek pdpe_pa");
+ s = _kvm_pa2off(kd, pdpe_pa, &ofs);
+ if (s <= sizeof pdpe) {
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: pdpe_pa not found");
+ goto invalid;
+ }
+ if (lseek(kd->pmfd, ofs, 0) == -1) {
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: lseek pdpe_pa");
goto invalid;
}
if (read(kd->pmfd, &pdpe, sizeof pdpe) != sizeof pdpe) {
- _kvm_syserr(kd, kd->program, "_kvm_vatop: read pdpe");
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: read pdpe");
goto invalid;
}
if (((u_long)pdpe & PG_V) == 0)
@@ -191,13 +258,17 @@
pdeindex = (va >> PDRSHIFT) & (NPDEPG-1);
pde_pa = ((u_long)pdpe & PG_FRAME) + (pdeindex * sizeof(pd_entry_t));
- /* XXX This has to be a physical address read, kvm_read is virtual */
- if (lseek(kd->pmfd, pde_pa, 0) == -1) {
- _kvm_syserr(kd, kd->program, "_kvm_vatop: lseek pde_pa");
+ s = _kvm_pa2off(kd, pde_pa, &ofs);
+ if (s <= sizeof pde) {
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: pde_pa not found");
+ goto invalid;
+ }
+ if (lseek(kd->pmfd, ofs, 0) == -1) {
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: lseek pde_pa");
goto invalid;
}
if (read(kd->pmfd, &pde, sizeof pde) != sizeof pde) {
- _kvm_syserr(kd, kd->program, "_kvm_vatop: read pde");
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: read pde");
goto invalid;
}
if (((u_long)pde & PG_V) == 0)
@@ -216,13 +287,17 @@
pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pt_entry_t));
- /* XXX This has to be a physical address read, kvm_read is virtual */
+ s = _kvm_pa2off(kd, pte_pa, &ofs);
+ if (s <= sizeof pte) {
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: pte_pa not found");
+ goto invalid;
+ }
if (lseek(kd->pmfd, pte_pa, 0) == -1) {
- _kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: lseek");
goto invalid;
}
if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
- _kvm_syserr(kd, kd->program, "_kvm_vatop: read");
+ _kvm_syserr(kd, kd->program, "_kvm_kvatop: read");
goto invalid;
}
if (((u_long)pte & PG_V) == 0)
@@ -235,9 +310,3 @@
_kvm_err(kd, 0, "invalid address (%x)", va);
return (0);
}
-
-int
-_kvm_kvatop(kvm_t *kd, u_long va, u_long *pa)
-{
- return (_kvm_vatop(kd, va, pa));
-}
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