diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /kernel/ptrace.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'kernel/ptrace.c')
-rw-r--r-- | kernel/ptrace.c | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c new file mode 100644 index 000000000000..88b306c4e841 --- /dev/null +++ b/kernel/ptrace.c @@ -0,0 +1,389 @@ +/* + * linux/kernel/ptrace.c + * + * (C) Copyright 1999 Linus Torvalds + * + * Common interfaces for "ptrace()" which we do not want + * to continually duplicate across every architecture. + */ + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/errno.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> +#include <linux/smp_lock.h> +#include <linux/ptrace.h> +#include <linux/security.h> + +#include <asm/pgtable.h> +#include <asm/uaccess.h> + +/* + * ptrace a task: make the debugger its new parent and + * move it to the ptrace list. + * + * Must be called with the tasklist lock write-held. + */ +void __ptrace_link(task_t *child, task_t *new_parent) +{ + if (!list_empty(&child->ptrace_list)) + BUG(); + if (child->parent == new_parent) + return; + list_add(&child->ptrace_list, &child->parent->ptrace_children); + REMOVE_LINKS(child); + child->parent = new_parent; + SET_LINKS(child); +} + +/* + * Turn a tracing stop into a normal stop now, since with no tracer there + * would be no way to wake it up with SIGCONT or SIGKILL. If there was a + * signal sent that would resume the child, but didn't because it was in + * TASK_TRACED, resume it now. + * Requires that irqs be disabled. + */ +void ptrace_untrace(task_t *child) +{ + spin_lock(&child->sighand->siglock); + if (child->state == TASK_TRACED) { + if (child->signal->flags & SIGNAL_STOP_STOPPED) { + child->state = TASK_STOPPED; + } else { + signal_wake_up(child, 1); + } + } + spin_unlock(&child->sighand->siglock); +} + +/* + * unptrace a task: move it back to its original parent and + * remove it from the ptrace list. + * + * Must be called with the tasklist lock write-held. + */ +void __ptrace_unlink(task_t *child) +{ + if (!child->ptrace) + BUG(); + child->ptrace = 0; + if (!list_empty(&child->ptrace_list)) { + list_del_init(&child->ptrace_list); + REMOVE_LINKS(child); + child->parent = child->real_parent; + SET_LINKS(child); + } + + if (child->state == TASK_TRACED) + ptrace_untrace(child); +} + +/* + * Check that we have indeed attached to the thing.. + */ +int ptrace_check_attach(struct task_struct *child, int kill) +{ + int ret = -ESRCH; + + /* + * We take the read lock around doing both checks to close a + * possible race where someone else was tracing our child and + * detached between these two checks. After this locked check, + * we are sure that this is our traced child and that can only + * be changed by us so it's not changing right after this. + */ + read_lock(&tasklist_lock); + if ((child->ptrace & PT_PTRACED) && child->parent == current && + (!(child->ptrace & PT_ATTACHED) || child->real_parent != current) + && child->signal != NULL) { + ret = 0; + spin_lock_irq(&child->sighand->siglock); + if (child->state == TASK_STOPPED) { + child->state = TASK_TRACED; + } else if (child->state != TASK_TRACED && !kill) { + ret = -ESRCH; + } + spin_unlock_irq(&child->sighand->siglock); + } + read_unlock(&tasklist_lock); + + if (!ret && !kill) { + wait_task_inactive(child); + } + + /* All systems go.. */ + return ret; +} + +int ptrace_attach(struct task_struct *task) +{ + int retval; + task_lock(task); + retval = -EPERM; + if (task->pid <= 1) + goto bad; + if (task == current) + goto bad; + if (!task->mm) + goto bad; + if(((current->uid != task->euid) || + (current->uid != task->suid) || + (current->uid != task->uid) || + (current->gid != task->egid) || + (current->gid != task->sgid) || + (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE)) + goto bad; + rmb(); + if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE)) + goto bad; + /* the same process cannot be attached many times */ + if (task->ptrace & PT_PTRACED) + goto bad; + retval = security_ptrace(current, task); + if (retval) + goto bad; + + /* Go */ + task->ptrace |= PT_PTRACED | ((task->real_parent != current) + ? PT_ATTACHED : 0); + if (capable(CAP_SYS_PTRACE)) + task->ptrace |= PT_PTRACE_CAP; + task_unlock(task); + + write_lock_irq(&tasklist_lock); + __ptrace_link(task, current); + write_unlock_irq(&tasklist_lock); + + force_sig_specific(SIGSTOP, task); + return 0; + +bad: + task_unlock(task); + return retval; +} + +int ptrace_detach(struct task_struct *child, unsigned int data) +{ + if ((unsigned long) data > _NSIG) + return -EIO; + + /* Architecture-specific hardware disable .. */ + ptrace_disable(child); + + /* .. re-parent .. */ + child->exit_code = data; + + write_lock_irq(&tasklist_lock); + __ptrace_unlink(child); + /* .. and wake it up. */ + if (child->exit_state != EXIT_ZOMBIE) + wake_up_process(child); + write_unlock_irq(&tasklist_lock); + + return 0; +} + +/* + * Access another process' address space. + * Source/target buffer must be kernel space, + * Do not walk the page table directly, use get_user_pages + */ + +int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) +{ + struct mm_struct *mm; + struct vm_area_struct *vma; + struct page *page; + void *old_buf = buf; + + mm = get_task_mm(tsk); + if (!mm) + return 0; + + down_read(&mm->mmap_sem); + /* ignore errors, just check how much was sucessfully transfered */ + while (len) { + int bytes, ret, offset; + void *maddr; + + ret = get_user_pages(tsk, mm, addr, 1, + write, 1, &page, &vma); + if (ret <= 0) + break; + + bytes = len; + offset = addr & (PAGE_SIZE-1); + if (bytes > PAGE_SIZE-offset) + bytes = PAGE_SIZE-offset; + + maddr = kmap(page); + if (write) { + copy_to_user_page(vma, page, addr, + maddr + offset, buf, bytes); + set_page_dirty_lock(page); + } else { + copy_from_user_page(vma, page, addr, + buf, maddr + offset, bytes); + } + kunmap(page); + page_cache_release(page); + len -= bytes; + buf += bytes; + addr += bytes; + } + up_read(&mm->mmap_sem); + mmput(mm); + + return buf - old_buf; +} + +int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) +{ + int copied = 0; + + while (len > 0) { + char buf[128]; + int this_len, retval; + + this_len = (len > sizeof(buf)) ? sizeof(buf) : len; + retval = access_process_vm(tsk, src, buf, this_len, 0); + if (!retval) { + if (copied) + break; + return -EIO; + } + if (copy_to_user(dst, buf, retval)) + return -EFAULT; + copied += retval; + src += retval; + dst += retval; + len -= retval; + } + return copied; +} + +int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) +{ + int copied = 0; + + while (len > 0) { + char buf[128]; + int this_len, retval; + + this_len = (len > sizeof(buf)) ? sizeof(buf) : len; + if (copy_from_user(buf, src, this_len)) + return -EFAULT; + retval = access_process_vm(tsk, dst, buf, this_len, 1); + if (!retval) { + if (copied) + break; + return -EIO; + } + copied += retval; + src += retval; + dst += retval; + len -= retval; + } + return copied; +} + +static int ptrace_setoptions(struct task_struct *child, long data) +{ + child->ptrace &= ~PT_TRACE_MASK; + + if (data & PTRACE_O_TRACESYSGOOD) + child->ptrace |= PT_TRACESYSGOOD; + + if (data & PTRACE_O_TRACEFORK) + child->ptrace |= PT_TRACE_FORK; + + if (data & PTRACE_O_TRACEVFORK) + child->ptrace |= PT_TRACE_VFORK; + + if (data & PTRACE_O_TRACECLONE) + child->ptrace |= PT_TRACE_CLONE; + + if (data & PTRACE_O_TRACEEXEC) + child->ptrace |= PT_TRACE_EXEC; + + if (data & PTRACE_O_TRACEVFORKDONE) + child->ptrace |= PT_TRACE_VFORK_DONE; + + if (data & PTRACE_O_TRACEEXIT) + child->ptrace |= PT_TRACE_EXIT; + + return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; +} + +static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data) +{ + siginfo_t lastinfo; + int error = -ESRCH; + + read_lock(&tasklist_lock); + if (likely(child->sighand != NULL)) { + error = -EINVAL; + spin_lock_irq(&child->sighand->siglock); + if (likely(child->last_siginfo != NULL)) { + lastinfo = *child->last_siginfo; + error = 0; + } + spin_unlock_irq(&child->sighand->siglock); + } + read_unlock(&tasklist_lock); + if (!error) + return copy_siginfo_to_user(data, &lastinfo); + return error; +} + +static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data) +{ + siginfo_t newinfo; + int error = -ESRCH; + + if (copy_from_user(&newinfo, data, sizeof (siginfo_t))) + return -EFAULT; + + read_lock(&tasklist_lock); + if (likely(child->sighand != NULL)) { + error = -EINVAL; + spin_lock_irq(&child->sighand->siglock); + if (likely(child->last_siginfo != NULL)) { + *child->last_siginfo = newinfo; + error = 0; + } + spin_unlock_irq(&child->sighand->siglock); + } + read_unlock(&tasklist_lock); + return error; +} + +int ptrace_request(struct task_struct *child, long request, + long addr, long data) +{ + int ret = -EIO; + + switch (request) { +#ifdef PTRACE_OLDSETOPTIONS + case PTRACE_OLDSETOPTIONS: +#endif + case PTRACE_SETOPTIONS: + ret = ptrace_setoptions(child, data); + break; + case PTRACE_GETEVENTMSG: + ret = put_user(child->ptrace_message, (unsigned long __user *) data); + break; + case PTRACE_GETSIGINFO: + ret = ptrace_getsiginfo(child, (siginfo_t __user *) data); + break; + case PTRACE_SETSIGINFO: + ret = ptrace_setsiginfo(child, (siginfo_t __user *) data); + break; + default: + break; + } + + return ret; +} |