From 4206d3aa1978e44f58bfa4e1c9d8d35cbf19c187 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Wed, 30 Jan 2008 13:31:45 +0100 Subject: elf core dump: notes user_regset This modifies the ELF core dump code under #ifdef CORE_DUMP_USE_REGSET. It changes nothing when this macro is not defined. When it's #define'd by some arch header (e.g. asm/elf.h), the arch must support the user_regset (linux/regset.h) interface for reading thread state. This provides an alternate version of note segment writing that is based purely on the user_regset interfaces. When CORE_DUMP_USE_REGSET is set, the arch need not define macros such as ELF_CORE_COPY_REGS and ELF_ARCH. All that information is taken from the user_regset data structures. The core dumps come out exactly the same if arch's definitions for its user_regset details are correct. Signed-off-by: Roland McGrath Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- fs/binfmt_elf.c | 224 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 224 insertions(+) (limited to 'fs/binfmt_elf.c') diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 4510429b973..786ee275ec0 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1528,6 +1528,228 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm) fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv); } +#ifdef CORE_DUMP_USE_REGSET +#include + +struct elf_thread_core_info { + struct elf_thread_core_info *next; + struct task_struct *task; + struct elf_prstatus prstatus; + struct memelfnote notes[0]; +}; + +struct elf_note_info { + struct elf_thread_core_info *thread; + struct memelfnote psinfo; + struct memelfnote auxv; + size_t size; + int thread_notes; +}; + +static int fill_thread_core_info(struct elf_thread_core_info *t, + const struct user_regset_view *view, + long signr, size_t *total) +{ + unsigned int i; + + /* + * NT_PRSTATUS is the one special case, because the regset data + * goes into the pr_reg field inside the note contents, rather + * than being the whole note contents. We fill the reset in here. + * We assume that regset 0 is NT_PRSTATUS. + */ + fill_prstatus(&t->prstatus, t->task, signr); + (void) view->regsets[0].get(t->task, &view->regsets[0], + 0, sizeof(t->prstatus.pr_reg), + &t->prstatus.pr_reg, NULL); + + fill_note(&t->notes[0], "CORE", NT_PRSTATUS, + sizeof(t->prstatus), &t->prstatus); + *total += notesize(&t->notes[0]); + + /* + * Each other regset might generate a note too. For each regset + * that has no core_note_type or is inactive, we leave t->notes[i] + * all zero and we'll know to skip writing it later. + */ + for (i = 1; i < view->n; ++i) { + const struct user_regset *regset = &view->regsets[i]; + if (regset->core_note_type && + (!regset->active || regset->active(t->task, regset))) { + int ret; + size_t size = regset->n * regset->size; + void *data = kmalloc(size, GFP_KERNEL); + if (unlikely(!data)) + return 0; + ret = regset->get(t->task, regset, + 0, size, data, NULL); + if (unlikely(ret)) + kfree(data); + else { + if (regset->core_note_type != NT_PRFPREG) + fill_note(&t->notes[i], "LINUX", + regset->core_note_type, + size, data); + else { + t->prstatus.pr_fpvalid = 1; + fill_note(&t->notes[i], "CORE", + NT_PRFPREG, size, data); + } + *total += notesize(&t->notes[i]); + } + } + } + + return 1; +} + +static int fill_note_info(struct elfhdr *elf, int phdrs, + struct elf_note_info *info, + long signr, struct pt_regs *regs) +{ + struct task_struct *dump_task = current; + const struct user_regset_view *view = task_user_regset_view(dump_task); + struct elf_thread_core_info *t; + struct elf_prpsinfo *psinfo; + struct task_struct *g, *p; + unsigned int i; + + info->size = 0; + info->thread = NULL; + + psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL); + fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo); + + if (psinfo == NULL) + return 0; + + /* + * Figure out how many notes we're going to need for each thread. + */ + info->thread_notes = 0; + for (i = 0; i < view->n; ++i) + if (view->regsets[i].core_note_type != 0) + ++info->thread_notes; + + /* + * Sanity check. We rely on regset 0 being in NT_PRSTATUS, + * since it is our one special case. + */ + if (unlikely(info->thread_notes == 0) || + unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) { + WARN_ON(1); + return 0; + } + + /* + * Initialize the ELF file header. + */ + fill_elf_header(elf, phdrs, + view->e_machine, view->e_flags, view->ei_osabi); + + /* + * Allocate a structure for each thread. + */ + rcu_read_lock(); + do_each_thread(g, p) + if (p->mm == dump_task->mm) { + t = kzalloc(offsetof(struct elf_thread_core_info, + notes[info->thread_notes]), + GFP_ATOMIC); + if (unlikely(!t)) { + rcu_read_unlock(); + return 0; + } + t->task = p; + if (p == dump_task || !info->thread) { + t->next = info->thread; + info->thread = t; + } else { + /* + * Make sure to keep the original task at + * the head of the list. + */ + t->next = info->thread->next; + info->thread->next = t; + } + } + while_each_thread(g, p); + rcu_read_unlock(); + + /* + * Now fill in each thread's information. + */ + for (t = info->thread; t != NULL; t = t->next) + if (!fill_thread_core_info(t, view, signr, &info->size)) + return 0; + + /* + * Fill in the two process-wide notes. + */ + fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm); + info->size += notesize(&info->psinfo); + + fill_auxv_note(&info->auxv, current->mm); + info->size += notesize(&info->auxv); + + return 1; +} + +static size_t get_note_info_size(struct elf_note_info *info) +{ + return info->size; +} + +/* + * Write all the notes for each thread. When writing the first thread, the + * process-wide notes are interleaved after the first thread-specific note. + */ +static int write_note_info(struct elf_note_info *info, + struct file *file, loff_t *foffset) +{ + bool first = 1; + struct elf_thread_core_info *t = info->thread; + + do { + int i; + + if (!writenote(&t->notes[0], file, foffset)) + return 0; + + if (first && !writenote(&info->psinfo, file, foffset)) + return 0; + if (first && !writenote(&info->auxv, file, foffset)) + return 0; + + for (i = 1; i < info->thread_notes; ++i) + if (t->notes[i].data && + !writenote(&t->notes[i], file, foffset)) + return 0; + + first = 0; + t = t->next; + } while (t); + + return 1; +} + +static void free_note_info(struct elf_note_info *info) +{ + struct elf_thread_core_info *threads = info->thread; + while (threads) { + unsigned int i; + struct elf_thread_core_info *t = threads; + threads = t->next; + WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus); + for (i = 1; i < info->thread_notes; ++i) + kfree(t->notes[i].data); + kfree(t); + } + kfree(info->psinfo.data); +} + +#else + /* Here is the structure in which status of each thread is captured. */ struct elf_thread_status { @@ -1748,6 +1970,8 @@ static void free_note_info(struct elf_note_info *info) #endif } +#endif + static struct vm_area_struct *first_vma(struct task_struct *tsk, struct vm_area_struct *gate_vma) { -- cgit v1.2.3