From:Suzuki K. Poulose <[email protected]> Build the ELF header on the fly for the very first read request. The ELF Header, Program Headers are stored in a buffer for processing future read() requests.
gencore-elf.c contains the ELF class specific functions. Signed-off-by: Suzuki K. Poulose <[email protected]> Signed-off-by: Ananth N.Mavinakayanahalli <[email protected]> --- fs/proc/Makefile | 2 - fs/proc/gencore-elf.c | 181 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/proc/gencore.h | 7 ++ 3 files changed, 189 insertions(+), 1 deletion(-) create mode 100644 fs/proc/gencore-elf.c diff --git a/fs/proc/Makefile b/fs/proc/Makefile index a456c22..d231ac3 100644 --- a/fs/proc/Makefile +++ b/fs/proc/Makefile @@ -23,7 +23,7 @@ proc-y += version.o proc-y += softirqs.o proc-y += namespaces.o proc-y += self.o -proc-$(CONFIG_ELF_CORE) += gencore.o +proc-$(CONFIG_ELF_CORE) += gencore.o gencore-elf.o proc-$(CONFIG_PROC_SYSCTL) += proc_sysctl.o proc-$(CONFIG_NET) += proc_net.o proc-$(CONFIG_PROC_KCORE) += kcore.o diff --git a/fs/proc/gencore-elf.c b/fs/proc/gencore-elf.c new file mode 100644 index 0000000..0a245f0 --- /dev/null +++ b/fs/proc/gencore-elf.c @@ -0,0 +1,181 @@ +/* + * Application core dump - ELF Class specific code + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2010 + * + * Authors: + * Suzuki K. Poulose <[email protected]> + */ + +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/freezer.h> +#include <linux/elf.h> +#include <linux/elfcore.h> +#include <linux/elfcore-internal.h> + +#ifdef CORE_DUMP_USE_REGSET +#include <linux/regset.h> +#endif + +#include "gencore.h" + +static void get_elfhdr_size(struct core_proc *cp) +{ + struct vm_area_struct *gate_vma; + int segs; + + segs = cp->task->mm->map_count; + segs += elf_core_extra_phdrs(); + + gate_vma = get_gate_vma(cp->task->mm); + if (gate_vma != NULL) + segs++; + + /* One phdr for PT_NOTE */ + segs++; + + cp->nphdrs = segs; + cp->elf_buflen = sizeof(struct elfhdr) + + (cp->nphdrs * sizeof(struct elf_phdr)); + cp->elf_buflen = roundup(cp->elf_buflen, ELF_EXEC_PAGESIZE); + + return; +} + +/* + * Fill the elf_hdr and the phdrs + * Returns 0 on success. On error, returns errno + */ +static int create_elf_header(struct core_proc *cp) +{ + struct elfhdr *elf = (struct elfhdr *)cp->elf_buf; + struct elf_phdr *note; + struct vm_area_struct *vma, *gate_vma = get_gate_vma(cp->task->mm); + char *bufp; + off_t dataoff, offset; + short e_phnum = (cp->nphdrs > PN_XNUM ? PN_XNUM : cp->nphdrs); + size_t exphdrs_sz = 0; + unsigned long limit = elf_core_extra_phdrs() * sizeof(struct elf_phdr); + +#ifdef CORE_DUMP_USE_REGSET + const struct user_regset_view *view = task_user_regset_view(cp->task); + + fill_elf_header(elf, e_phnum, view->e_machine, view->e_flags); +#else + fill_elf_header(elf, e_phnum, ELF_ARCH, ELF_CORE_EFLAGS); +#endif + offset = sizeof(struct elfhdr); + bufp = cp->elf_buf + offset; + dataoff = offset + (cp->nphdrs * sizeof(struct elf_phdr)); + + /* Setup ELF PT_NOTE */ + note = (struct elf_phdr*)bufp; + bufp += sizeof(struct elf_phdr); + offset += sizeof(struct elf_phdr); + note->p_type = PT_NOTE; + note->p_offset = dataoff; + note->p_vaddr = 0; + note->p_paddr = 0; + /* TODO: Needs to be populated with the size of the notes section */ + note->p_memsz = 0; + note->p_flags = 0; + note->p_align = 0; + + dataoff = cp->elf_buflen; + + /* Write the phdrs for memory segments */ + down_read(&cp->task->mm->mmap_sem); + for (vma = first_vma(cp->task, gate_vma); vma != NULL; + vma = next_vma(vma, gate_vma)) { + struct elf_phdr *phdr = (struct elf_phdr *)bufp; + + bufp += sizeof(struct elf_phdr); + offset += sizeof(struct elf_phdr); + + phdr->p_type = PT_LOAD; + phdr->p_offset = dataoff; + phdr->p_vaddr = vma->vm_start; + phdr->p_paddr = 0; + phdr->p_filesz = vma_dump_size(cp->task, vma, cp->task->mm->flags); + phdr->p_memsz = vma->vm_end - vma->vm_start; + phdr->p_flags = (vma->vm_flags & VM_READ) ? PF_R : 0; + if (vma->vm_flags & VM_WRITE) + phdr->p_flags |= PF_W; + if (vma->vm_flags & VM_EXEC) + phdr->p_flags |= PF_X; + phdr->p_align = ELF_EXEC_PAGESIZE; + if (!(phdr->p_flags & (PF_R | PF_W | PF_X))) + phdr->p_filesz=0; + dataoff += phdr->p_filesz; + } + up_read(&cp->task->mm->mmap_sem); + + if (!elf_core_copy_extra_phdrs(bufp, dataoff, &exphdrs_sz, limit)) + return -EIO; + bufp += exphdrs_sz; + dataoff += elf_core_extra_data_size(); + + if (e_phnum == PN_XNUM) { + cp->shdr = kzalloc(sizeof(struct elf_shdr), GFP_KERNEL); + if (!cp->shdr) + return -ENOMEM; + fill_extnum_info(elf, (struct elf_shdr *)cp->shdr, + dataoff, cp->nphdrs); + dataoff += sizeof(struct elf_shdr); + } + + return 0; +} + +ssize_t elf_read_gencore(struct core_proc *cp, char __user *buffer, + size_t buflen, loff_t *fpos) +{ + ssize_t ret = 0; + + if (!cp->elf_buf) { + get_elfhdr_size(cp); + + cp->elf_buf = kzalloc(cp->elf_buflen, GFP_KERNEL); + if (!cp->elf_buf) { + ret = -ENOMEM; + goto out; + } + + ret = create_elf_header(cp); + if (ret < 0) + goto out; + } + + if (*fpos < cp->elf_buflen) { + size_t bcp = cp->elf_buflen - *fpos; + + bcp = (bcp < buflen) ? bcp : buflen; + if (copy_to_user(buffer, (cp->elf_buf + *fpos), bcp)) { + ret = -EFAULT; + goto out; + } else { + ret = bcp; + *fpos += bcp; + buflen -= bcp; + buffer += bcp; + } + } +out: + return ret; +} + diff --git a/fs/proc/gencore.h b/fs/proc/gencore.h index 1a88e24..6c1d57c 100644 --- a/fs/proc/gencore.h +++ b/fs/proc/gencore.h @@ -11,6 +11,13 @@ struct core_proc { struct task_struct *task; struct completion hold; struct callback_head twork; + void *shdr; /* elf_shdr, in case nphdrs > PN_XNUM */ + char *elf_buf; /* buffer for elf_hdr + phdrs + notes */ + size_t elf_buflen; /* size of elf_buf */ + size_t nphdrs; /* number of phdrs */ }; +extern ssize_t elf_read_gencore(struct core_proc *cp, char __user *buffer, + size_t buflen, loff_t *foffset); + #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
