From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: AndrĂ© Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- fs/proc/kcore.c | 644 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 644 insertions(+) create mode 100644 fs/proc/kcore.c (limited to 'fs/proc/kcore.c') diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c new file mode 100644 index 000000000..91a4e6426 --- /dev/null +++ b/fs/proc/kcore.c @@ -0,0 +1,644 @@ +/* + * fs/proc/kcore.c kernel ELF core dumper + * + * Modelled on fs/exec.c:aout_core_dump() + * Jeremy Fitzhardinge + * ELF version written by David Howells + * Modified and incorporated into 2.3.x by Tigran Aivazian + * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian + * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +#define CORE_STR "CORE" + +#ifndef ELF_CORE_EFLAGS +#define ELF_CORE_EFLAGS 0 +#endif + +static struct proc_dir_entry *proc_root_kcore; + + +#ifndef kc_vaddr_to_offset +#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET) +#endif +#ifndef kc_offset_to_vaddr +#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET) +#endif + +/* An ELF note in memory */ +struct memelfnote +{ + const char *name; + int type; + unsigned int datasz; + void *data; +}; + +static LIST_HEAD(kclist_head); +static DEFINE_RWLOCK(kclist_lock); +static int kcore_need_update = 1; + +void +kclist_add(struct kcore_list *new, void *addr, size_t size, int type) +{ + new->addr = (unsigned long)addr; + new->size = size; + new->type = type; + + write_lock(&kclist_lock); + list_add_tail(&new->list, &kclist_head); + write_unlock(&kclist_lock); +} + +static size_t get_kcore_size(int *nphdr, size_t *elf_buflen) +{ + size_t try, size; + struct kcore_list *m; + + *nphdr = 1; /* PT_NOTE */ + size = 0; + + list_for_each_entry(m, &kclist_head, list) { + try = kc_vaddr_to_offset((size_t)m->addr + m->size); + if (try > size) + size = try; + *nphdr = *nphdr + 1; + } + *elf_buflen = sizeof(struct elfhdr) + + (*nphdr + 2)*sizeof(struct elf_phdr) + + 3 * ((sizeof(struct elf_note)) + + roundup(sizeof(CORE_STR), 4)) + + roundup(sizeof(struct elf_prstatus), 4) + + roundup(sizeof(struct elf_prpsinfo), 4) + + roundup(sizeof(struct task_struct), 4); + *elf_buflen = PAGE_ALIGN(*elf_buflen); + return size + *elf_buflen; +} + +static void free_kclist_ents(struct list_head *head) +{ + struct kcore_list *tmp, *pos; + + list_for_each_entry_safe(pos, tmp, head, list) { + list_del(&pos->list); + kfree(pos); + } +} +/* + * Replace all KCORE_RAM/KCORE_VMEMMAP information with passed list. + */ +static void __kcore_update_ram(struct list_head *list) +{ + int nphdr; + size_t size; + struct kcore_list *tmp, *pos; + LIST_HEAD(garbage); + + write_lock(&kclist_lock); + if (kcore_need_update) { + list_for_each_entry_safe(pos, tmp, &kclist_head, list) { + if (pos->type == KCORE_RAM + || pos->type == KCORE_VMEMMAP) + list_move(&pos->list, &garbage); + } + list_splice_tail(list, &kclist_head); + } else + list_splice(list, &garbage); + kcore_need_update = 0; + proc_root_kcore->size = get_kcore_size(&nphdr, &size); + write_unlock(&kclist_lock); + + free_kclist_ents(&garbage); +} + + +#ifdef CONFIG_HIGHMEM +/* + * If no highmem, we can assume [0...max_low_pfn) continuous range of memory + * because memory hole is not as big as !HIGHMEM case. + * (HIGHMEM is special because part of memory is _invisible_ from the kernel.) + */ +static int kcore_update_ram(void) +{ + LIST_HEAD(head); + struct kcore_list *ent; + int ret = 0; + + ent = kmalloc(sizeof(*ent), GFP_KERNEL); + if (!ent) + return -ENOMEM; + ent->addr = (unsigned long)__va(0); + ent->size = max_low_pfn << PAGE_SHIFT; + ent->type = KCORE_RAM; + list_add(&ent->list, &head); + __kcore_update_ram(&head); + return ret; +} + +#else /* !CONFIG_HIGHMEM */ + +#ifdef CONFIG_SPARSEMEM_VMEMMAP +/* calculate vmemmap's address from given system ram pfn and register it */ +static int +get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head) +{ + unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT; + unsigned long nr_pages = ent->size >> PAGE_SHIFT; + unsigned long start, end; + struct kcore_list *vmm, *tmp; + + + start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK; + end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1; + end = PAGE_ALIGN(end); + /* overlap check (because we have to align page */ + list_for_each_entry(tmp, head, list) { + if (tmp->type != KCORE_VMEMMAP) + continue; + if (start < tmp->addr + tmp->size) + if (end > tmp->addr) + end = tmp->addr; + } + if (start < end) { + vmm = kmalloc(sizeof(*vmm), GFP_KERNEL); + if (!vmm) + return 0; + vmm->addr = start; + vmm->size = end - start; + vmm->type = KCORE_VMEMMAP; + list_add_tail(&vmm->list, head); + } + return 1; + +} +#else +static int +get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head) +{ + return 1; +} + +#endif + +static int +kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg) +{ + struct list_head *head = (struct list_head *)arg; + struct kcore_list *ent; + + ent = kmalloc(sizeof(*ent), GFP_KERNEL); + if (!ent) + return -ENOMEM; + ent->addr = (unsigned long)__va((pfn << PAGE_SHIFT)); + ent->size = nr_pages << PAGE_SHIFT; + + /* Sanity check: Can happen in 32bit arch...maybe */ + if (ent->addr < (unsigned long) __va(0)) + goto free_out; + + /* cut not-mapped area. ....from ppc-32 code. */ + if (ULONG_MAX - ent->addr < ent->size) + ent->size = ULONG_MAX - ent->addr; + + /* cut when vmalloc() area is higher than direct-map area */ + if (VMALLOC_START > (unsigned long)__va(0)) { + if (ent->addr > VMALLOC_START) + goto free_out; + if (VMALLOC_START - ent->addr < ent->size) + ent->size = VMALLOC_START - ent->addr; + } + + ent->type = KCORE_RAM; + list_add_tail(&ent->list, head); + + if (!get_sparsemem_vmemmap_info(ent, head)) { + list_del(&ent->list); + goto free_out; + } + + return 0; +free_out: + kfree(ent); + return 1; +} + +static int kcore_update_ram(void) +{ + int nid, ret; + unsigned long end_pfn; + LIST_HEAD(head); + + /* Not inialized....update now */ + /* find out "max pfn" */ + end_pfn = 0; + for_each_node_state(nid, N_MEMORY) { + unsigned long node_end; + node_end = node_end_pfn(nid); + if (end_pfn < node_end) + end_pfn = node_end; + } + /* scan 0 to max_pfn */ + ret = walk_system_ram_range(0, end_pfn, &head, kclist_add_private); + if (ret) { + free_kclist_ents(&head); + return -ENOMEM; + } + __kcore_update_ram(&head); + return ret; +} +#endif /* CONFIG_HIGHMEM */ + +/*****************************************************************************/ +/* + * determine size of ELF note + */ +static int notesize(struct memelfnote *en) +{ + int sz; + + sz = sizeof(struct elf_note); + sz += roundup((strlen(en->name) + 1), 4); + sz += roundup(en->datasz, 4); + + return sz; +} /* end notesize() */ + +/*****************************************************************************/ +/* + * store a note in the header buffer + */ +static char *storenote(struct memelfnote *men, char *bufp) +{ + struct elf_note en; + +#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0) + + en.n_namesz = strlen(men->name) + 1; + en.n_descsz = men->datasz; + en.n_type = men->type; + + DUMP_WRITE(&en, sizeof(en)); + DUMP_WRITE(men->name, en.n_namesz); + + /* XXX - cast from long long to long to avoid need for libgcc.a */ + bufp = (char*) roundup((unsigned long)bufp,4); + DUMP_WRITE(men->data, men->datasz); + bufp = (char*) roundup((unsigned long)bufp,4); + +#undef DUMP_WRITE + + return bufp; +} /* end storenote() */ + +/* + * store an ELF coredump header in the supplied buffer + * nphdr is the number of elf_phdr to insert + */ +static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) +{ + struct elf_prstatus prstatus; /* NT_PRSTATUS */ + struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */ + struct elf_phdr *nhdr, *phdr; + struct elfhdr *elf; + struct memelfnote notes[3]; + off_t offset = 0; + struct kcore_list *m; + + /* setup ELF header */ + elf = (struct elfhdr *) bufp; + bufp += sizeof(struct elfhdr); + offset += sizeof(struct elfhdr); + memcpy(elf->e_ident, ELFMAG, SELFMAG); + elf->e_ident[EI_CLASS] = ELF_CLASS; + elf->e_ident[EI_DATA] = ELF_DATA; + elf->e_ident[EI_VERSION]= EV_CURRENT; + elf->e_ident[EI_OSABI] = ELF_OSABI; + memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD); + elf->e_type = ET_CORE; + elf->e_machine = ELF_ARCH; + elf->e_version = EV_CURRENT; + elf->e_entry = 0; + elf->e_phoff = sizeof(struct elfhdr); + elf->e_shoff = 0; + elf->e_flags = ELF_CORE_EFLAGS; + elf->e_ehsize = sizeof(struct elfhdr); + elf->e_phentsize= sizeof(struct elf_phdr); + elf->e_phnum = nphdr; + elf->e_shentsize= 0; + elf->e_shnum = 0; + elf->e_shstrndx = 0; + + /* setup ELF PT_NOTE program header */ + nhdr = (struct elf_phdr *) bufp; + bufp += sizeof(struct elf_phdr); + offset += sizeof(struct elf_phdr); + nhdr->p_type = PT_NOTE; + nhdr->p_offset = 0; + nhdr->p_vaddr = 0; + nhdr->p_paddr = 0; + nhdr->p_filesz = 0; + nhdr->p_memsz = 0; + nhdr->p_flags = 0; + nhdr->p_align = 0; + + /* setup ELF PT_LOAD program header for every area */ + list_for_each_entry(m, &kclist_head, list) { + phdr = (struct elf_phdr *) bufp; + bufp += sizeof(struct elf_phdr); + offset += sizeof(struct elf_phdr); + + phdr->p_type = PT_LOAD; + phdr->p_flags = PF_R|PF_W|PF_X; + phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff; + phdr->p_vaddr = (size_t)m->addr; + phdr->p_paddr = 0; + phdr->p_filesz = phdr->p_memsz = m->size; + phdr->p_align = PAGE_SIZE; + } + + /* + * Set up the notes in similar form to SVR4 core dumps made + * with info from their /proc. + */ + nhdr->p_offset = offset; + + /* set up the process status */ + notes[0].name = CORE_STR; + notes[0].type = NT_PRSTATUS; + notes[0].datasz = sizeof(struct elf_prstatus); + notes[0].data = &prstatus; + + memset(&prstatus, 0, sizeof(struct elf_prstatus)); + + nhdr->p_filesz = notesize(¬es[0]); + bufp = storenote(¬es[0], bufp); + + /* set up the process info */ + notes[1].name = CORE_STR; + notes[1].type = NT_PRPSINFO; + notes[1].datasz = sizeof(struct elf_prpsinfo); + notes[1].data = &prpsinfo; + + memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo)); + prpsinfo.pr_state = 0; + prpsinfo.pr_sname = 'R'; + prpsinfo.pr_zomb = 0; + + strcpy(prpsinfo.pr_fname, "vmlinux"); + strlcpy(prpsinfo.pr_psargs, saved_command_line, sizeof(prpsinfo.pr_psargs)); + + nhdr->p_filesz += notesize(¬es[1]); + bufp = storenote(¬es[1], bufp); + + /* set up the task structure */ + notes[2].name = CORE_STR; + notes[2].type = NT_TASKSTRUCT; + notes[2].datasz = sizeof(struct task_struct); + notes[2].data = current; + + nhdr->p_filesz += notesize(¬es[2]); + bufp = storenote(¬es[2], bufp); + +} /* end elf_kcore_store_hdr() */ + +/*****************************************************************************/ +/* + * read from the ELF header and then kernel memory + */ +static ssize_t +read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) +{ + ssize_t acc = 0; + size_t size, tsz; + size_t elf_buflen; + int nphdr; + unsigned long start; + + read_lock(&kclist_lock); + size = get_kcore_size(&nphdr, &elf_buflen); + + if (buflen == 0 || *fpos >= size) { + read_unlock(&kclist_lock); + return 0; + } + + /* trim buflen to not go beyond EOF */ + if (buflen > size - *fpos) + buflen = size - *fpos; + + /* construct an ELF core header if we'll need some of it */ + if (*fpos < elf_buflen) { + char * elf_buf; + + tsz = elf_buflen - *fpos; + if (buflen < tsz) + tsz = buflen; + elf_buf = kzalloc(elf_buflen, GFP_ATOMIC); + if (!elf_buf) { + read_unlock(&kclist_lock); + return -ENOMEM; + } + elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen); + read_unlock(&kclist_lock); + if (copy_to_user(buffer, elf_buf + *fpos, tsz)) { + kfree(elf_buf); + return -EFAULT; + } + kfree(elf_buf); + buflen -= tsz; + *fpos += tsz; + buffer += tsz; + acc += tsz; + + /* leave now if filled buffer already */ + if (buflen == 0) + return acc; + } else + read_unlock(&kclist_lock); + + /* + * Check to see if our file offset matches with any of + * the addresses in the elf_phdr on our list. + */ + start = kc_offset_to_vaddr(*fpos - elf_buflen); + if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) + tsz = buflen; + + while (buflen) { + struct kcore_list *m; + + read_lock(&kclist_lock); + list_for_each_entry(m, &kclist_head, list) { + if (start >= m->addr && start < (m->addr+m->size)) + break; + } + read_unlock(&kclist_lock); + + if (&m->list == &kclist_head) { + if (clear_user(buffer, tsz)) + return -EFAULT; + } else if (is_vmalloc_or_module_addr((void *)start)) { + char * elf_buf; + + elf_buf = kzalloc(tsz, GFP_KERNEL); + if (!elf_buf) + return -ENOMEM; + vread(elf_buf, (char *)start, tsz); + /* we have to zero-fill user buffer even if no read */ + if (copy_to_user(buffer, elf_buf, tsz)) { + kfree(elf_buf); + return -EFAULT; + } + kfree(elf_buf); + } else { + if (kern_addr_valid(start)) { + unsigned long n; + + n = copy_to_user(buffer, (char *)start, tsz); + /* + * We cannot distinguish between fault on source + * and fault on destination. When this happens + * we clear too and hope it will trigger the + * EFAULT again. + */ + if (n) { + if (clear_user(buffer + tsz - n, + n)) + return -EFAULT; + } + } else { + if (clear_user(buffer, tsz)) + return -EFAULT; + } + } + buflen -= tsz; + *fpos += tsz; + buffer += tsz; + acc += tsz; + start += tsz; + tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen); + } + + return acc; +} + + +static int open_kcore(struct inode *inode, struct file *filp) +{ + if (!capable(CAP_SYS_RAWIO)) + return -EPERM; + if (kcore_need_update) + kcore_update_ram(); + if (i_size_read(inode) != proc_root_kcore->size) { + mutex_lock(&inode->i_mutex); + i_size_write(inode, proc_root_kcore->size); + mutex_unlock(&inode->i_mutex); + } + return 0; +} + + +static const struct file_operations proc_kcore_operations = { + .read = read_kcore, + .open = open_kcore, + .llseek = default_llseek, +}; + +/* just remember that we have to update kcore */ +static int __meminit kcore_callback(struct notifier_block *self, + unsigned long action, void *arg) +{ + switch (action) { + case MEM_ONLINE: + case MEM_OFFLINE: + write_lock(&kclist_lock); + kcore_need_update = 1; + write_unlock(&kclist_lock); + } + return NOTIFY_OK; +} + +static struct notifier_block kcore_callback_nb __meminitdata = { + .notifier_call = kcore_callback, + .priority = 0, +}; + +static struct kcore_list kcore_vmalloc; + +#ifdef CONFIG_ARCH_PROC_KCORE_TEXT +static struct kcore_list kcore_text; +/* + * If defined, special segment is used for mapping kernel text instead of + * direct-map area. We need to create special TEXT section. + */ +static void __init proc_kcore_text_init(void) +{ + kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT); +} +#else +static void __init proc_kcore_text_init(void) +{ +} +#endif + +#if defined(CONFIG_MODULES) && defined(MODULES_VADDR) +/* + * MODULES_VADDR has no intersection with VMALLOC_ADDR. + */ +struct kcore_list kcore_modules; +static void __init add_modules_range(void) +{ + if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) { + kclist_add(&kcore_modules, (void *)MODULES_VADDR, + MODULES_END - MODULES_VADDR, KCORE_VMALLOC); + } +} +#else +static void __init add_modules_range(void) +{ +} +#endif + +static int __init proc_kcore_init(void) +{ + proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, + &proc_kcore_operations); + if (!proc_root_kcore) { + pr_err("couldn't create /proc/kcore\n"); + return 0; /* Always returns 0. */ + } + /* Store text area if it's special */ + proc_kcore_text_init(); + /* Store vmalloc area */ + kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, + VMALLOC_END - VMALLOC_START, KCORE_VMALLOC); + add_modules_range(); + /* Store direct-map area from physical memory map */ + kcore_update_ram(); + register_hotmemory_notifier(&kcore_callback_nb); + + return 0; +} +fs_initcall(proc_kcore_init); -- cgit v1.2.3-54-g00ecf