Date: Tue, 21 Jun 2005 20:25:18 GMT From: Peter Wemm <peter@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 78778 for review Message-ID: <200506212025.j5LKPIfX064935@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=78778 Change 78778 by peter@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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