diff options
Diffstat (limited to 'fs/proc/base.c')
| -rw-r--r-- | fs/proc/base.c | 207 |
1 files changed, 197 insertions, 10 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 286a422f440e..1d540b3f226f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -196,18 +196,205 @@ static int proc_root_link(struct dentry *dentry, struct path *path) return result; } -static int proc_pid_cmdline(struct seq_file *m, struct pid_namespace *ns, - struct pid *pid, struct task_struct *task) +static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf, + size_t _count, loff_t *pos) { + struct task_struct *tsk; + struct mm_struct *mm; + char *page; + unsigned long count = _count; + unsigned long arg_start, arg_end, env_start, env_end; + unsigned long len1, len2, len; + unsigned long p; + char c; + ssize_t rv; + + BUG_ON(*pos < 0); + + tsk = get_proc_task(file_inode(file)); + if (!tsk) + return -ESRCH; + mm = get_task_mm(tsk); + put_task_struct(tsk); + if (!mm) + return 0; + /* Check if process spawned far enough to have cmdline. */ + if (!mm->env_end) { + rv = 0; + goto out_mmput; + } + + page = (char *)__get_free_page(GFP_TEMPORARY); + if (!page) { + rv = -ENOMEM; + goto out_mmput; + } + + down_read(&mm->mmap_sem); + arg_start = mm->arg_start; + arg_end = mm->arg_end; + env_start = mm->env_start; + env_end = mm->env_end; + up_read(&mm->mmap_sem); + + BUG_ON(arg_start > arg_end); + BUG_ON(env_start > env_end); + + len1 = arg_end - arg_start; + len2 = env_end - env_start; + /* - * Rely on struct seq_operations::show() being called once - * per internal buffer allocation. See single_open(), traverse(). + * Inherently racy -- command line shares address space + * with code and data. */ - BUG_ON(m->size < PAGE_SIZE); - m->count += get_cmdline(task, m->buf, PAGE_SIZE); - return 0; + rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0); + if (rv <= 0) + goto out_free_page; + + rv = 0; + + if (c == '\0') { + /* Command line (set of strings) occupies whole ARGV. */ + if (len1 <= *pos) + goto out_free_page; + + p = arg_start + *pos; + len = len1 - *pos; + while (count > 0 && len > 0) { + unsigned int _count; + int nr_read; + + _count = min3(count, len, PAGE_SIZE); + nr_read = access_remote_vm(mm, p, page, _count, 0); + if (nr_read < 0) + rv = nr_read; + if (nr_read <= 0) + goto out_free_page; + + if (copy_to_user(buf, page, nr_read)) { + rv = -EFAULT; + goto out_free_page; + } + + p += nr_read; + len -= nr_read; + buf += nr_read; + count -= nr_read; + rv += nr_read; + } + } else { + /* + * Command line (1 string) occupies ARGV and maybe + * extends into ENVP. + */ + if (len1 + len2 <= *pos) + goto skip_argv_envp; + if (len1 <= *pos) + goto skip_argv; + + p = arg_start + *pos; + len = len1 - *pos; + while (count > 0 && len > 0) { + unsigned int _count, l; + int nr_read; + bool final; + + _count = min3(count, len, PAGE_SIZE); + nr_read = access_remote_vm(mm, p, page, _count, 0); + if (nr_read < 0) + rv = nr_read; + if (nr_read <= 0) + goto out_free_page; + + /* + * Command line can be shorter than whole ARGV + * even if last "marker" byte says it is not. + */ + final = false; + l = strnlen(page, nr_read); + if (l < nr_read) { + nr_read = l; + final = true; + } + + if (copy_to_user(buf, page, nr_read)) { + rv = -EFAULT; + goto out_free_page; + } + + p += nr_read; + len -= nr_read; + buf += nr_read; + count -= nr_read; + rv += nr_read; + + if (final) + goto out_free_page; + } +skip_argv: + /* + * Command line (1 string) occupies ARGV and + * extends into ENVP. + */ + if (len1 <= *pos) { + p = env_start + *pos - len1; + len = len1 + len2 - *pos; + } else { + p = env_start; + len = len2; + } + while (count > 0 && len > 0) { + unsigned int _count, l; + int nr_read; + bool final; + + _count = min3(count, len, PAGE_SIZE); + nr_read = access_remote_vm(mm, p, page, _count, 0); + if (nr_read < 0) + rv = nr_read; + if (nr_read <= 0) + goto out_free_page; + + /* Find EOS. */ + final = false; + l = strnlen(page, nr_read); + if (l < nr_read) { + nr_read = l; + final = true; + } + + if (copy_to_user(buf, page, nr_read)) { + rv = -EFAULT; + goto out_free_page; + } + + p += nr_read; + len -= nr_read; + buf += nr_read; + count -= nr_read; + rv += nr_read; + + if (final) + goto out_free_page; + } +skip_argv_envp: + ; + } + +out_free_page: + free_page((unsigned long)page); +out_mmput: + mmput(mm); + if (rv > 0) + *pos += rv; + return rv; } +static const struct file_operations proc_pid_cmdline_ops = { + .read = proc_pid_cmdline_read, + .llseek = generic_file_llseek, +}; + static int proc_pid_auxv(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -2572,7 +2759,7 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_HAVE_ARCH_TRACEHOOK ONE("syscall", S_IRUSR, proc_pid_syscall), #endif - ONE("cmdline", S_IRUGO, proc_pid_cmdline), + REG("cmdline", S_IRUGO, proc_pid_cmdline_ops), ONE("stat", S_IRUGO, proc_tgid_stat), ONE("statm", S_IRUGO, proc_pid_statm), REG("maps", S_IRUGO, proc_pid_maps_operations), @@ -2918,11 +3105,11 @@ static const struct pid_entry tid_base_stuff[] = { #ifdef CONFIG_HAVE_ARCH_TRACEHOOK ONE("syscall", S_IRUSR, proc_pid_syscall), #endif - ONE("cmdline", S_IRUGO, proc_pid_cmdline), + REG("cmdline", S_IRUGO, proc_pid_cmdline_ops), ONE("stat", S_IRUGO, proc_tid_stat), ONE("statm", S_IRUGO, proc_pid_statm), REG("maps", S_IRUGO, proc_tid_maps_operations), -#ifdef CONFIG_CHECKPOINT_RESTORE +#ifdef CONFIG_PROC_CHILDREN REG("children", S_IRUGO, proc_tid_children_operations), #endif #ifdef CONFIG_NUMA |