diff options
Diffstat (limited to 'fs/proc/kcore.c')
| -rw-r--r-- | fs/proc/kcore.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c new file mode 100644 index 000000000000..1c7da988fcc3 --- /dev/null +++ b/fs/proc/kcore.c @@ -0,0 +1,404 @@ +/* + * fs/proc/kcore.c kernel ELF core dumper + * + * Modelled on fs/exec.c:aout_core_dump() + * Jeremy Fitzhardinge <jeremy@sw.oz.au> + * ELF version written by David Howells <David.Howells@nexor.co.uk> + * Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com> + * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com> + * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com> + */ + +#include <linux/config.h> +#include <linux/mm.h> +#include <linux/proc_fs.h> +#include <linux/user.h> +#include <linux/a.out.h> +#include <linux/elf.h> +#include <linux/elfcore.h> +#include <linux/vmalloc.h> +#include <linux/highmem.h> +#include <linux/init.h> +#include <asm/uaccess.h> +#include <asm/io.h> + + +static int open_kcore(struct inode * inode, struct file * filp) +{ + return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; +} + +static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *); + +struct file_operations proc_kcore_operations = { + .read = read_kcore, + .open = open_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 + +#define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) + +/* An ELF note in memory */ +struct memelfnote +{ + const char *name; + int type; + unsigned int datasz; + void *data; +}; + +static struct kcore_list *kclist; +static DEFINE_RWLOCK(kclist_lock); + +void +kclist_add(struct kcore_list *new, void *addr, size_t size) +{ + new->addr = (unsigned long)addr; + new->size = size; + + write_lock(&kclist_lock); + new->next = kclist; + kclist = new; + 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; + + for (m=kclist; m; m=m->next) { + 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) + 4) + + sizeof(struct elf_prstatus) + + sizeof(struct elf_prpsinfo) + + sizeof(struct task_struct); + *elf_buflen = PAGE_ALIGN(*elf_buflen); + return size + *elf_buflen; +} + + +/*****************************************************************************/ +/* + * determine size of ELF note + */ +static int notesize(struct memelfnote *en) +{ + int sz; + + sz = sizeof(struct elf_note); + sz += roundup(strlen(en->name), 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); + 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; +#if defined(CONFIG_H8300) + elf->e_flags = ELF_FLAGS; +#else + elf->e_flags = 0; +#endif + 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 */ + for (m=kclist; m; m=m->next) { + 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"; + 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"; + 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"); + strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ); + + nhdr->p_filesz += notesize(¬es[1]); + bufp = storenote(¬es[1], bufp); + + /* set up the task structure */ + notes[2].name = "CORE"; + 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); + proc_root_kcore->size = 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 = kmalloc(elf_buflen, GFP_ATOMIC); + if (!elf_buf) { + read_unlock(&kclist_lock); + return -ENOMEM; + } + memset(elf_buf, 0, elf_buflen); + 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); + for (m=kclist; m; m=m->next) { + if (start >= m->addr && start < (m->addr+m->size)) + break; + } + read_unlock(&kclist_lock); + + if (m == NULL) { + if (clear_user(buffer, tsz)) + return -EFAULT; + } else if ((start >= VMALLOC_START) && (start < VMALLOC_END)) { + char * elf_buf; + struct vm_struct *m; + unsigned long curstart = start; + unsigned long cursize = tsz; + + elf_buf = kmalloc(tsz, GFP_KERNEL); + if (!elf_buf) + return -ENOMEM; + memset(elf_buf, 0, tsz); + + read_lock(&vmlist_lock); + for (m=vmlist; m && cursize; m=m->next) { + unsigned long vmstart; + unsigned long vmsize; + unsigned long msize = m->size - PAGE_SIZE; + + if (((unsigned long)m->addr + msize) < + curstart) + continue; + if ((unsigned long)m->addr > (curstart + + cursize)) + break; + vmstart = (curstart < (unsigned long)m->addr ? + (unsigned long)m->addr : curstart); + if (((unsigned long)m->addr + msize) > + (curstart + cursize)) + vmsize = curstart + cursize - vmstart; + else + vmsize = (unsigned long)m->addr + + msize - vmstart; + curstart = vmstart + vmsize; + cursize -= vmsize; + /* don't dump ioremap'd stuff! (TA) */ + if (m->flags & VM_IOREMAP) + continue; + memcpy(elf_buf + (vmstart - start), + (char *)vmstart, vmsize); + } + read_unlock(&vmlist_lock); + 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 distingush 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, + tsz - 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; +} |