/* * fs/proc/kcore.c kernel ELF/AOUT 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 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 *, size_t, loff_t *); struct file_operations proc_kcore_operations = { read: read_kcore, open: open_kcore, }; #ifdef CONFIG_KCORE_AOUT static ssize_t read_kcore(struct file *file, char *buf, size_t count, loff_t *ppos) { unsigned long long p = *ppos, memsize; ssize_t read; ssize_t count1; char * pnt; struct user dump; #if defined (__i386__) || defined (__mc68000__) || defined(__x86_64__) # define FIRST_MAPPED PAGE_SIZE /* we don't have page 0 mapped on x86.. */ #else # define FIRST_MAPPED 0 #endif memset(&dump, 0, sizeof(struct user)); dump.magic = CMAGIC; dump.u_dsize = (virt_to_phys(high_memory) >> PAGE_SHIFT); #if defined (__i386__) || defined(__x86_64__) dump.start_code = PAGE_OFFSET; #endif #ifdef __alpha__ dump.start_data = PAGE_OFFSET; #endif memsize = virt_to_phys(high_memory); if (p >= memsize) return 0; if (count > memsize - p) count = memsize - p; read = 0; if (p < sizeof(struct user) && count > 0) { count1 = count; if (p + count1 > sizeof(struct user)) count1 = sizeof(struct user)-p; pnt = (char *) &dump + p; if (copy_to_user(buf,(void *) pnt, count1)) return -EFAULT; buf += count1; p += count1; count -= count1; read += count1; } if (count > 0 && p < PAGE_SIZE + FIRST_MAPPED) { count1 = PAGE_SIZE + FIRST_MAPPED - p; if (count1 > count) count1 = count; if (clear_user(buf, count1)) return -EFAULT; buf += count1; p += count1; count -= count1; read += count1; } if (count > 0) { if (copy_to_user(buf, (void *) (PAGE_OFFSET+p-PAGE_SIZE), count)) return -EFAULT; read += count; } *ppos += read; return read; } #else /* CONFIG_KCORE_AOUT */ #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; }; extern char saved_command_line[]; static size_t get_kcore_size(int *num_vma, size_t *elf_buflen) { size_t try, size; struct vm_struct *m; *num_vma = 0; size = ((size_t)high_memory - PAGE_OFFSET + PAGE_SIZE); if (!vmlist) { *elf_buflen = PAGE_SIZE; return (size); } for (m=vmlist; m; m=m->next) { try = (size_t)m->addr + m->size; if (try > size) size = try; *num_vma = *num_vma + 1; } *elf_buflen = sizeof(struct elfhdr) + (*num_vma + 2)*sizeof(struct elf_phdr) + 3 * sizeof(struct memelfnote); *elf_buflen = PAGE_ALIGN(*elf_buflen); return (size - PAGE_OFFSET + *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 * num_vma is the number of elements in vmlist */ static void elf_kcore_store_hdr(char *bufp, int num_vma, 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 vm_struct *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; 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 = 0; elf->e_ehsize = sizeof(struct elfhdr); elf->e_phentsize= sizeof(struct elf_phdr); elf->e_phnum = 2 + num_vma; 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 the * virtual range 0xc0000000 -> high_memory */ 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 = dataoff; phdr->p_vaddr = PAGE_OFFSET; phdr->p_paddr = __pa(PAGE_OFFSET); phdr->p_filesz = phdr->p_memsz = ((unsigned long)high_memory - PAGE_OFFSET); phdr->p_align = PAGE_SIZE; /* setup ELF PT_LOAD program header for every vmalloc'd area */ for (m=vmlist; m; m=m->next) { if (m->flags & VM_IOREMAP) /* don't dump ioremap'd stuff! (TA) */ continue; 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 = (size_t)m->addr - PAGE_OFFSET + dataoff; phdr->p_vaddr = (size_t)m->addr; phdr->p_paddr = __pa(m->addr); 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 *buffer, size_t buflen, loff_t *fpos) { ssize_t acc = 0; size_t size, tsz; size_t elf_buflen; int num_vma; unsigned long start; read_lock(&vmlist_lock); proc_root_kcore->size = size = get_kcore_size(&num_vma, &elf_buflen); if (buflen == 0 || *fpos >= size) { read_unlock(&vmlist_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(&vmlist_lock); return -ENOMEM; } memset(elf_buf, 0, elf_buflen); elf_kcore_store_hdr(elf_buf, num_vma, elf_buflen); read_unlock(&vmlist_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(&vmlist_lock); /* where page 0 not mapped, write zeros into buffer */ #if defined (__i386__) || defined (__mc68000__) || defined(__x86_64__) if (*fpos < PAGE_SIZE + elf_buflen) { /* work out how much to clear */ tsz = PAGE_SIZE + elf_buflen - *fpos; if (buflen < tsz) tsz = buflen; /* write zeros to buffer */ if (clear_user(buffer, tsz)) return -EFAULT; buflen -= tsz; *fpos += tsz; buffer += tsz; acc += tsz; /* leave now if filled buffer already */ if (buflen == 0) return tsz; } #endif /* fill the remainder of the buffer from kernel VM space */ start = (unsigned long)__va(*fpos - elf_buflen); if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) tsz = buflen; while (buflen) { 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 ((start > PAGE_OFFSET) && (start < (unsigned long)high_memory)) { if (kern_addr_valid(start)) { if (copy_to_user(buffer, (char *)start, tsz)) return -EFAULT; } else { if (clear_user(buffer, tsz)) 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; } #endif /* CONFIG_KCORE_AOUT */