diff options
Diffstat (limited to 'fs/proc/base.c')
| -rw-r--r-- | fs/proc/base.c | 1086 |
1 files changed, 568 insertions, 518 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 6afff725a8c9..6ba7785319de 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -74,6 +74,16 @@ #include <linux/poll.h> #include "internal.h" +/* NOTE: + * Implementing inode permission operations in /proc is almost + * certainly an error. Permission checks need to happen during + * each system call not at open time. The reason is that most of + * what we wish to check for permissions in /proc varies at runtime. + * + * The classic example of a problem is opening file descriptors + * in /proc for a task before it execs a suid executable. + */ + /* * For hysterical raisins we keep the same inumbers as in the old procfs. * Feel free to change the macro below - just keep the range distinct from @@ -121,6 +131,8 @@ enum pid_directory_inos { PROC_TGID_ATTR_PREV, PROC_TGID_ATTR_EXEC, PROC_TGID_ATTR_FSCREATE, + PROC_TGID_ATTR_KEYCREATE, + PROC_TGID_ATTR_SOCKCREATE, #endif #ifdef CONFIG_AUDITSYSCALL PROC_TGID_LOGINUID, @@ -162,6 +174,8 @@ enum pid_directory_inos { PROC_TID_ATTR_PREV, PROC_TID_ATTR_EXEC, PROC_TID_ATTR_FSCREATE, + PROC_TID_ATTR_KEYCREATE, + PROC_TID_ATTR_SOCKCREATE, #endif #ifdef CONFIG_AUDITSYSCALL PROC_TID_LOGINUID, @@ -173,6 +187,9 @@ enum pid_directory_inos { PROC_TID_FD_DIR = 0x8000, /* 0x8000-0xffff */ }; +/* Worst case buffer size needed for holding an integer. */ +#define PROC_NUMBUF 10 + struct pid_entry { int type; int len; @@ -275,6 +292,8 @@ static struct pid_entry tgid_attr_stuff[] = { E(PROC_TGID_ATTR_PREV, "prev", S_IFREG|S_IRUGO), E(PROC_TGID_ATTR_EXEC, "exec", S_IFREG|S_IRUGO|S_IWUGO), E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO), + E(PROC_TGID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO), + E(PROC_TGID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO), {0,0,NULL,0} }; static struct pid_entry tid_attr_stuff[] = { @@ -282,6 +301,8 @@ static struct pid_entry tid_attr_stuff[] = { E(PROC_TID_ATTR_PREV, "prev", S_IFREG|S_IRUGO), E(PROC_TID_ATTR_EXEC, "exec", S_IFREG|S_IRUGO|S_IWUGO), E(PROC_TID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO), + E(PROC_TID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO), + E(PROC_TID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO), {0,0,NULL,0} }; #endif @@ -290,12 +311,15 @@ static struct pid_entry tid_attr_stuff[] = { static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) { - struct task_struct *task = proc_task(inode); - struct files_struct *files; + struct task_struct *task = get_proc_task(inode); + struct files_struct *files = NULL; struct file *file; - int fd = proc_type(inode) - PROC_TID_FD_DIR; + int fd = proc_fd(inode); - files = get_files_struct(task); + if (task) { + files = get_files_struct(task); + put_task_struct(task); + } if (files) { /* * We are not taking a ref to the file structure, so we must @@ -327,29 +351,33 @@ static struct fs_struct *get_fs_struct(struct task_struct *task) return fs; } -static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) +static int get_nr_threads(struct task_struct *tsk) { - struct fs_struct *fs = get_fs_struct(proc_task(inode)); - int result = -ENOENT; - if (fs) { - read_lock(&fs->lock); - *mnt = mntget(fs->pwdmnt); - *dentry = dget(fs->pwd); - read_unlock(&fs->lock); - result = 0; - put_fs_struct(fs); + /* Must be called with the rcu_read_lock held */ + unsigned long flags; + int count = 0; + + if (lock_task_sighand(tsk, &flags)) { + count = atomic_read(&tsk->signal->count); + unlock_task_sighand(tsk, &flags); } - return result; + return count; } -static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) +static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) { - struct fs_struct *fs = get_fs_struct(proc_task(inode)); + struct task_struct *task = get_proc_task(inode); + struct fs_struct *fs = NULL; int result = -ENOENT; + + if (task) { + fs = get_fs_struct(task); + put_task_struct(task); + } if (fs) { read_lock(&fs->lock); - *mnt = mntget(fs->rootmnt); - *dentry = dget(fs->root); + *mnt = mntget(fs->pwdmnt); + *dentry = dget(fs->pwd); read_unlock(&fs->lock); result = 0; put_fs_struct(fs); @@ -357,42 +385,16 @@ static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vf return result; } - -/* Same as proc_root_link, but this addionally tries to get fs from other - * threads in the group */ -static int proc_task_root_link(struct inode *inode, struct dentry **dentry, - struct vfsmount **mnt) +static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) { - struct fs_struct *fs; + struct task_struct *task = get_proc_task(inode); + struct fs_struct *fs = NULL; int result = -ENOENT; - struct task_struct *leader = proc_task(inode); - task_lock(leader); - fs = leader->fs; - if (fs) { - atomic_inc(&fs->count); - task_unlock(leader); - } else { - /* Try to get fs from other threads */ - task_unlock(leader); - read_lock(&tasklist_lock); - if (pid_alive(leader)) { - struct task_struct *task = leader; - - while ((task = next_thread(task)) != leader) { - task_lock(task); - fs = task->fs; - if (fs) { - atomic_inc(&fs->count); - task_unlock(task); - break; - } - task_unlock(task); - } - } - read_unlock(&tasklist_lock); + if (task) { + fs = get_fs_struct(task); + put_task_struct(task); } - if (fs) { read_lock(&fs->lock); *mnt = mntget(fs->rootmnt); @@ -404,7 +406,6 @@ static int proc_task_root_link(struct inode *inode, struct dentry **dentry, return result; } - #define MAY_PTRACE(task) \ (task == current || \ (task->parent == current && \ @@ -535,142 +536,22 @@ static int proc_oom_score(struct task_struct *task, char *buffer) /************************************************************************/ /* permission checks */ - -/* If the process being read is separated by chroot from the reading process, - * don't let the reader access the threads. - * - * note: this does dput(root) and mntput(vfsmnt) on exit. - */ -static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt) -{ - struct dentry *de, *base; - struct vfsmount *our_vfsmnt, *mnt; - int res = 0; - - read_lock(¤t->fs->lock); - our_vfsmnt = mntget(current->fs->rootmnt); - base = dget(current->fs->root); - read_unlock(¤t->fs->lock); - - spin_lock(&vfsmount_lock); - de = root; - mnt = vfsmnt; - - while (mnt != our_vfsmnt) { - if (mnt == mnt->mnt_parent) - goto out; - de = mnt->mnt_mountpoint; - mnt = mnt->mnt_parent; - } - - if (!is_subdir(de, base)) - goto out; - spin_unlock(&vfsmount_lock); - -exit: - dput(base); - mntput(our_vfsmnt); - dput(root); - mntput(vfsmnt); - return res; -out: - spin_unlock(&vfsmount_lock); - res = -EACCES; - goto exit; -} - -static int proc_check_root(struct inode *inode) -{ - struct dentry *root; - struct vfsmount *vfsmnt; - - if (proc_root_link(inode, &root, &vfsmnt)) /* Ewww... */ - return -ENOENT; - return proc_check_chroot(root, vfsmnt); -} - -static int proc_permission(struct inode *inode, int mask, struct nameidata *nd) -{ - if (generic_permission(inode, mask, NULL) != 0) - return -EACCES; - return proc_check_root(inode); -} - -static int proc_task_permission(struct inode *inode, int mask, struct nameidata *nd) -{ - struct dentry *root; - struct vfsmount *vfsmnt; - - if (generic_permission(inode, mask, NULL) != 0) - return -EACCES; - - if (proc_task_root_link(inode, &root, &vfsmnt)) - return -ENOENT; - - return proc_check_chroot(root, vfsmnt); -} - -extern struct seq_operations proc_pid_maps_op; -static int maps_open(struct inode *inode, struct file *file) -{ - struct task_struct *task = proc_task(inode); - int ret = seq_open(file, &proc_pid_maps_op); - if (!ret) { - struct seq_file *m = file->private_data; - m->private = task; - } - return ret; -} - -static struct file_operations proc_maps_operations = { - .open = maps_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, -}; - -#ifdef CONFIG_NUMA -extern struct seq_operations proc_pid_numa_maps_op; -static int numa_maps_open(struct inode *inode, struct file *file) -{ - struct task_struct *task = proc_task(inode); - int ret = seq_open(file, &proc_pid_numa_maps_op); - if (!ret) { - struct seq_file *m = file->private_data; - m->private = task; - } - return ret; -} - -static struct file_operations proc_numa_maps_operations = { - .open = numa_maps_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, -}; -#endif - -#ifdef CONFIG_MMU -extern struct seq_operations proc_pid_smaps_op; -static int smaps_open(struct inode *inode, struct file *file) +static int proc_fd_access_allowed(struct inode *inode) { - struct task_struct *task = proc_task(inode); - int ret = seq_open(file, &proc_pid_smaps_op); - if (!ret) { - struct seq_file *m = file->private_data; - m->private = task; + struct task_struct *task; + int allowed = 0; + /* Allow access to a task's file descriptors if it is us or we + * may use ptrace attach to the process and find out that + * information. + */ + task = get_proc_task(inode); + if (task) { + allowed = ptrace_may_attach(task); + put_task_struct(task); } - return ret; + return allowed; } -static struct file_operations proc_smaps_operations = { - .open = smaps_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, -}; -#endif - extern struct seq_operations mounts_op; struct proc_mounts { struct seq_file m; @@ -679,16 +560,19 @@ struct proc_mounts { static int mounts_open(struct inode *inode, struct file *file) { - struct task_struct *task = proc_task(inode); - struct namespace *namespace; + struct task_struct *task = get_proc_task(inode); + struct namespace *namespace = NULL; struct proc_mounts *p; int ret = -EINVAL; - task_lock(task); - namespace = task->namespace; - if (namespace) - get_namespace(namespace); - task_unlock(task); + if (task) { + task_lock(task); + namespace = task->namespace; + if (namespace) + get_namespace(namespace); + task_unlock(task); + put_task_struct(task); + } if (namespace) { ret = -ENOMEM; @@ -745,17 +629,21 @@ static struct file_operations proc_mounts_operations = { extern struct seq_operations mountstats_op; static int mountstats_open(struct inode *inode, struct file *file) { - struct task_struct *task = proc_task(inode); int ret = seq_open(file, &mountstats_op); if (!ret) { struct seq_file *m = file->private_data; - struct namespace *namespace; - task_lock(task); - namespace = task->namespace; - if (namespace) - get_namespace(namespace); - task_unlock(task); + struct namespace *namespace = NULL; + struct task_struct *task = get_proc_task(inode); + + if (task) { + task_lock(task); + namespace = task->namespace; + if (namespace) + get_namespace(namespace); + task_unlock(task); + put_task_struct(task); + } if (namespace) m->private = namespace; @@ -782,18 +670,27 @@ static ssize_t proc_info_read(struct file * file, char __user * buf, struct inode * inode = file->f_dentry->d_inode; unsigned long page; ssize_t length; - struct task_struct *task = proc_task(inode); + struct task_struct *task = get_proc_task(inode); + + length = -ESRCH; + if (!task) + goto out_no_task; if (count > PROC_BLOCK_SIZE) count = PROC_BLOCK_SIZE; + + length = -ENOMEM; if (!(page = __get_free_page(GFP_KERNEL))) - return -ENOMEM; + goto out; length = PROC_I(inode)->op.proc_read(task, (char*)page); if (length >= 0) length = simple_read_from_buffer(buf, count, ppos, (char *)page, length); free_page(page); +out: + put_task_struct(task); +out_no_task: return length; } @@ -810,12 +707,15 @@ static int mem_open(struct inode* inode, struct file* file) static ssize_t mem_read(struct file * file, char __user * buf, size_t count, loff_t *ppos) { - struct task_struct *task = proc_task(file->f_dentry->d_inode); + struct task_struct *task = get_proc_task(file->f_dentry->d_inode); char *page; unsigned long src = *ppos; int ret = -ESRCH; struct mm_struct *mm; + if (!task) + goto out_no_task; + if (!MAY_PTRACE(task) || !ptrace_may_attach(task)) goto out; @@ -865,6 +765,8 @@ out_put: out_free: free_page((unsigned long) page); out: + put_task_struct(task); +out_no_task: return ret; } @@ -877,15 +779,20 @@ static ssize_t mem_write(struct file * file, const char * buf, { int copied = 0; char *page; - struct task_struct *task = proc_task(file->f_dentry->d_inode); + struct task_struct *task = get_proc_task(file->f_dentry->d_inode); unsigned long dst = *ppos; + copied = -ESRCH; + if (!task) + goto out_no_task; + if (!MAY_PTRACE(task) || !ptrace_may_attach(task)) - return -ESRCH; + goto out; + copied = -ENOMEM; page = (char *)__get_free_page(GFP_USER); if (!page) - return -ENOMEM; + goto out; while (count > 0) { int this_len, retval; @@ -908,6 +815,9 @@ static ssize_t mem_write(struct file * file, const char * buf, } *ppos = dst; free_page((unsigned long) page); +out: + put_task_struct(task); +out_no_task: return copied; } #endif @@ -938,13 +848,18 @@ static struct file_operations proc_mem_operations = { static ssize_t oom_adjust_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { - struct task_struct *task = proc_task(file->f_dentry->d_inode); - char buffer[8]; + struct task_struct *task = get_proc_task(file->f_dentry->d_inode); + char buffer[PROC_NUMBUF]; size_t len; - int oom_adjust = task->oomkilladj; + int oom_adjust; loff_t __ppos = *ppos; - len = sprintf(buffer, "%i\n", oom_adjust); + if (!task) + return -ESRCH; + oom_adjust = task->oomkilladj; + put_task_struct(task); + + len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust); if (__ppos >= len) return 0; if (count > len-__ppos) @@ -958,15 +873,15 @@ static ssize_t oom_adjust_read(struct file *file, char __user *buf, static ssize_t oom_adjust_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - struct task_struct *task = proc_task(file->f_dentry->d_inode); - char buffer[8], *end; + struct task_struct *task; + char buffer[PROC_NUMBUF], *end; int oom_adjust; if (!capable(CAP_SYS_RESOURCE)) return -EPERM; - memset(buffer, 0, 8); - if (count > 6) - count = 6; + memset(buffer, 0, sizeof(buffer)); + if (count > sizeof(buffer) - 1) + count = sizeof(buffer) - 1; if (copy_from_user(buffer, buf, count)) return -EFAULT; oom_adjust = simple_strtol(buffer, &end, 0); @@ -974,7 +889,11 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf, return -EINVAL; if (*end == '\n') end++; + task = get_proc_task(file->f_dentry->d_inode); + if (!task) + return -ESRCH; task->oomkilladj = oom_adjust; + put_task_struct(task); if (end - buffer == 0) return -EIO; return end - buffer; @@ -985,22 +904,21 @@ static struct file_operations proc_oom_adjust_operations = { .write = oom_adjust_write, }; -static struct inode_operations proc_mem_inode_operations = { - .permission = proc_permission, -}; - #ifdef CONFIG_AUDITSYSCALL #define TMPBUFLEN 21 static ssize_t proc_loginuid_read(struct file * file, char __user * buf, size_t count, loff_t *ppos) { struct inode * inode = file->f_dentry->d_inode; - struct task_struct *task = proc_task(inode); + struct task_struct *task = get_proc_task(inode); ssize_t length; char tmpbuf[TMPBUFLEN]; + if (!task) + return -ESRCH; length = scnprintf(tmpbuf, TMPBUFLEN, "%u", audit_get_loginuid(task->audit_context)); + put_task_struct(task); return simple_read_from_buffer(buf, count, ppos, tmpbuf, length); } @@ -1010,13 +928,12 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf, struct inode * inode = file->f_dentry->d_inode; char *page, *tmp; ssize_t length; - struct task_struct *task = proc_task(inode); uid_t loginuid; if (!capable(CAP_AUDIT_CONTROL)) return -EPERM; - if (current != task) + if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) return -EPERM; if (count >= PAGE_SIZE) @@ -1040,7 +957,7 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf, goto out_free_page; } - length = audit_set_loginuid(task, loginuid); + length = audit_set_loginuid(current, loginuid); if (likely(length == 0)) length = count; @@ -1059,13 +976,16 @@ static struct file_operations proc_loginuid_operations = { static ssize_t seccomp_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { - struct task_struct *tsk = proc_task(file->f_dentry->d_inode); + struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode); char __buf[20]; loff_t __ppos = *ppos; size_t len; + if (!tsk) + return -ESRCH; /* no need to print the trailing zero, so use only len */ len = sprintf(__buf, "%u\n", tsk->seccomp.mode); + put_task_struct(tsk); if (__ppos >= len) return 0; if (count > len - __ppos) @@ -1079,29 +999,43 @@ static ssize_t seccomp_read(struct file *file, char __user *buf, static ssize_t seccomp_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - struct task_struct *tsk = proc_task(file->f_dentry->d_inode); + struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode); char __buf[20], *end; unsigned int seccomp_mode; + ssize_t result; + + result = -ESRCH; + if (!tsk) + goto out_no_task; /* can set it only once to be even more secure */ + result = -EPERM; if (unlikely(tsk->seccomp.mode)) - return -EPERM; + goto out; + result = -EFAULT; memset(__buf, 0, sizeof(__buf)); count = min(count, sizeof(__buf) - 1); if (copy_from_user(__buf, buf, count)) - return -EFAULT; + goto out; + seccomp_mode = simple_strtoul(__buf, &end, 0); if (*end == '\n') end++; + result = -EINVAL; if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) { tsk->seccomp.mode = seccomp_mode; set_tsk_thread_flag(tsk, TIF_SECCOMP); } else - return -EINVAL; + goto out; + result = -EIO; if (unlikely(!(end - __buf))) - return -EIO; - return end - __buf; + goto out; + result = end - __buf; +out: + put_task_struct(tsk); +out_no_task: + return result; } static struct file_operations proc_seccomp_operations = { @@ -1118,10 +1052,8 @@ static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd) /* We don't need a base pointer in the /proc filesystem */ path_release(nd); - if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE)) - goto out; - error = proc_check_root(inode); - if (error) + /* Are we allowed to snoop on the tasks file descriptors? */ + if (!proc_fd_access_allowed(inode)) goto out; error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt); @@ -1163,12 +1095,8 @@ static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int b struct dentry *de; struct vfsmount *mnt = NULL; - lock_kernel(); - - if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE)) - goto out; - error = proc_check_root(inode); - if (error) + /* Are we allowed to snoop on the tasks file descriptors? */ + if (!proc_fd_access_allowed(inode)) goto out; error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt); @@ -1179,7 +1107,6 @@ static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int b dput(de); mntput(mnt); out: - unlock_kernel(); return error; } @@ -1188,21 +1115,20 @@ static struct inode_operations proc_pid_link_inode_operations = { .follow_link = proc_pid_follow_link }; -#define NUMBUF 10 - static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir) { - struct inode *inode = filp->f_dentry->d_inode; - struct task_struct *p = proc_task(inode); + struct dentry *dentry = filp->f_dentry; + struct inode *inode = dentry->d_inode; + struct task_struct *p = get_proc_task(inode); unsigned int fd, tid, ino; int retval; - char buf[NUMBUF]; + char buf[PROC_NUMBUF]; struct files_struct * files; struct fdtable *fdt; retval = -ENOENT; - if (!pid_alive(p)) - goto out; + if (!p) + goto out_no_task; retval = 0; tid = p->pid; @@ -1213,7 +1139,7 @@ static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir) goto out; filp->f_pos++; case 1: - ino = fake_ino(tid, PROC_TID_INO); + ino = parent_ino(dentry); if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0) goto out; filp->f_pos++; @@ -1232,7 +1158,7 @@ static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir) continue; rcu_read_unlock(); - j = NUMBUF; + j = PROC_NUMBUF; i = fd; do { j--; @@ -1241,7 +1167,7 @@ static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir) } while (i); ino = fake_ino(tid, PROC_TID_FD_DIR + fd); - if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino, DT_LNK) < 0) { + if (filldir(dirent, buf+j, PROC_NUMBUF-j, fd+2, ino, DT_LNK) < 0) { rcu_read_lock(); break; } @@ -1251,6 +1177,8 @@ static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir) put_files_struct(files); } out: + put_task_struct(p); +out_no_task: return retval; } @@ -1262,16 +1190,18 @@ static int proc_pident_readdir(struct file *filp, int pid; struct dentry *dentry = filp->f_dentry; struct inode *inode = dentry->d_inode; + struct task_struct *task = get_proc_task(inode); struct pid_entry *p; ino_t ino; int ret; ret = -ENOENT; - if (!pid_alive(proc_task(inode))) + if (!task) goto out; ret = 0; - pid = proc_task(inode)->pid; + pid = task->pid; + put_task_struct(task); i = filp->f_pos; switch (i) { case 0: @@ -1354,22 +1284,19 @@ static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_st /* Common stuff */ ei = PROC_I(inode); - ei->task = NULL; inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; inode->i_ino = fake_ino(task->pid, ino); - if (!pid_alive(task)) - goto out_unlock; - /* * grab the reference to task. */ - get_task_struct(task); - ei->task = task; - ei->type = ino; + ei->pid = get_pid(task->pids[PIDTYPE_PID].pid); + if (!ei->pid) + goto out_unlock; + inode->i_uid = 0; inode->i_gid = 0; - if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) { + if (task_dumpable(task)) { inode->i_uid = task->euid; inode->i_gid = task->egid; } @@ -1379,7 +1306,6 @@ out: return inode; out_unlock: - ei->pde = NULL; iput(inode); return NULL; } @@ -1393,13 +1319,21 @@ out_unlock: * * Rewrite the inode's ownerships here because the owning task may have * performed a setuid(), etc. + * + * Before the /proc/pid/status file was created the only way to read + * the effective uid of a /process was to stat /proc/pid. Reading + * /proc/pid/status is slow enough that procps and other packages + * kept stating /proc/pid. To keep the rules in /proc simple I have + * made this apply to all per process world readable and executable + * directories. */ static int pid_revalidate(struct dentry *dentry, struct nameidata *nd) { struct inode *inode = dentry->d_inode; - struct task_struct *task = proc_task(inode); - if (pid_alive(task)) { - if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) { + struct task_struct *task = get_proc_task(inode); + if (task) { + if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) || + task_dumpable(task)) { inode->i_uid = task->euid; inode->i_gid = task->egid; } else { @@ -1407,59 +1341,75 @@ static int pid_revalidate(struct dentry *dentry, struct nameidata *nd) inode->i_gid = 0; } security_task_to_inode(task, inode); + put_task_struct(task); return 1; } d_drop(dentry); return 0; } +static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) +{ + struct inode *inode = dentry->d_inode; + struct task_struct *task; + generic_fillattr(inode, stat); + + rcu_read_lock(); + stat->uid = 0; + stat->gid = 0; + task = pid_task(proc_pid(inode), PIDTYPE_PID); + if (task) { + if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) || + task_dumpable(task)) { + stat->uid = task->euid; + stat->gid = task->egid; + } + } + rcu_read_unlock(); + return 0; +} + static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd) { struct inode *inode = dentry->d_inode; - struct task_struct *task = proc_task(inode); - int fd = proc_type(inode) - PROC_TID_FD_DIR; + struct task_struct *task = get_proc_task(inode); + int fd = proc_fd(inode); struct files_struct *files; - files = get_files_struct(task); - if (files) { - rcu_read_lock(); - if (fcheck_files(files, fd)) { + if (task) { + files = get_files_struct(task); + if (files) { + rcu_read_lock(); + if (fcheck_files(files, fd)) { + rcu_read_unlock(); + put_files_struct(files); + if (task_dumpable(task)) { + inode->i_uid = task->euid; + inode->i_gid = task->egid; + } else { + inode->i_uid = 0; + inode->i_gid = 0; + } + security_task_to_inode(task, inode); + put_task_struct(task); + return 1; + } rcu_read_unlock(); put_files_struct(files); - if (task_dumpable(task)) { - inode->i_uid = task->euid; - inode->i_gid = task->egid; - } else { - inode->i_uid = 0; - inode->i_gid = 0; - } - security_task_to_inode(task, inode); - return 1; } - rcu_read_unlock(); - put_files_struct(files); + put_task_struct(task); } d_drop(dentry); return 0; } -static void pid_base_iput(struct dentry *dentry, struct inode *inode) -{ - struct task_struct *task = proc_task(inode); - spin_lock(&task->proc_lock); - if (task->proc_dentry == dentry) - task->proc_dentry = NULL; - spin_unlock(&task->proc_lock); - iput(inode); -} - static int pid_delete_dentry(struct dentry * dentry) { /* Is the task we represent dead? * If so, then don't put the dentry on the lru list, * kill it immediately. */ - return !pid_alive(proc_task(dentry->d_inode)); + return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first; } static struct dentry_operations tid_fd_dentry_operations = @@ -1474,13 +1424,6 @@ static struct dentry_operations pid_dentry_operations = .d_delete = pid_delete_dentry, }; -static struct dentry_operations pid_base_dentry_operations = -{ - .d_revalidate = pid_revalidate, - .d_iput = pid_base_iput, - .d_delete = pid_delete_dentry, -}; - /* Lookups */ static unsigned name_to_int(struct dentry *dentry) @@ -1508,22 +1451,24 @@ out: /* SMP-safe */ static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd) { - struct task_struct *task = proc_task(dir); + struct task_struct *task = get_proc_task(dir); unsigned fd = name_to_int(dentry); + struct dentry *result = ERR_PTR(-ENOENT); struct file * file; struct files_struct * files; struct inode *inode; struct proc_inode *ei; + if (!task) + goto out_no_task; if (fd == ~0U) goto out; - if (!pid_alive(task)) - goto out; inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd); if (!inode) goto out; ei = PROC_I(inode); + ei->fd = fd; files = get_files_struct(task); if (!files) goto out_unlock; @@ -1548,19 +1493,25 @@ static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, ei->op.proc_get_link = proc_fd_link; dentry->d_op = &tid_fd_dentry_operations; d_add(dentry, inode); - return NULL; + /* Close the race of the process dying before we return the dentry */ + if (tid_fd_revalidate(dentry, NULL)) + result = NULL; +out: + put_task_struct(task); +out_no_task: + return result; out_unlock2: spin_unlock(&files->file_lock); put_files_struct(files); out_unlock: iput(inode); -out: - return ERR_PTR(-ENOENT); + goto out; } static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir); static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd); +static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat); static struct file_operations proc_fd_operations = { .read = generic_read_dir, @@ -1577,12 +1528,11 @@ static struct file_operations proc_task_operations = { */ static struct inode_operations proc_fd_inode_operations = { .lookup = proc_lookupfd, - .permission = proc_permission, }; static struct inode_operations proc_task_inode_operations = { .lookup = proc_task_lookup, - .permission = proc_task_permission, + .getattr = proc_task_getattr, }; #ifdef CONFIG_SECURITY @@ -1592,12 +1542,17 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf, struct inode * inode = file->f_dentry->d_inode; unsigned long page; ssize_t length; - struct task_struct *task = proc_task(inode); + struct task_struct *task = get_proc_task(inode); + + length = -ESRCH; + if (!task) + goto out_no_task; if (count > PAGE_SIZE) count = PAGE_SIZE; + length = -ENOMEM; if (!(page = __get_free_page(GFP_KERNEL))) - return -ENOMEM; + goto out; length = security_getprocattr(task, (char*)file->f_dentry->d_name.name, @@ -1605,6 +1560,9 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf, if (length >= 0) length = simple_read_from_buffer(buf, count, ppos, (char *)page, length); free_page(page); +out: + put_task_struct(task); +out_no_task: return length; } @@ -1614,26 +1572,36 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf, struct inode * inode = file->f_dentry->d_inode; char *page; ssize_t length; - struct task_struct *task = proc_task(inode); + struct task_struct *task = get_proc_task(inode); + length = -ESRCH; + if (!task) + goto out_no_task; if (count > PAGE_SIZE) count = PAGE_SIZE; - if (*ppos != 0) { - /* No partial writes. */ - return -EINVAL; - } + + /* No partial writes. */ + length = -EINVAL; + if (*ppos != 0) + goto out; + + length = -ENOMEM; page = (char*)__get_free_page(GFP_USER); if (!page) - return -ENOMEM; + goto out; + length = -EFAULT; if (copy_from_user(page, buf, count)) - goto out; + goto out_free; length = security_setprocattr(task, (char*)file->f_dentry->d_name.name, (void*)page, count); -out: +out_free: free_page((unsigned long) page); +out: + put_task_struct(task); +out_no_task: return length; } @@ -1648,24 +1616,22 @@ static struct file_operations proc_tgid_attr_operations; static struct inode_operations proc_tgid_attr_inode_operations; #endif -static int get_tid_list(int index, unsigned int *tids, struct inode *dir); - /* SMP-safe */ static struct dentry *proc_pident_lookup(struct inode *dir, struct dentry *dentry, struct pid_entry *ents) { struct inode *inode; - int error; - struct task_struct *task = proc_task(dir); + struct dentry *error; + struct task_struct *task = get_proc_task(dir); struct pid_entry *p; struct proc_inode *ei; - error = -ENOENT; + error = ERR_PTR(-ENOENT); inode = NULL; - if (!pid_alive(task)) - goto out; + if (!task) + goto out_no_task; for (p = ents; p->name; p++) { if (p->len != dentry->d_name.len) @@ -1676,7 +1642,7 @@ static struct dentry *proc_pident_lookup(struct inode *dir, if (!p->name) goto out; - error = -EINVAL; + error = ERR_PTR(-EINVAL); inode = proc_pid_make_inode(dir->i_sb, task, p->type); if (!inode) goto out; @@ -1689,7 +1655,7 @@ static struct dentry *proc_pident_lookup(struct inode *dir, */ switch(p->type) { case PROC_TGID_TASK: - inode->i_nlink = 2 + get_tid_list(2, NULL, dir); + inode->i_nlink = 2; inode->i_op = &proc_task_inode_operations; inode->i_fop = &proc_task_operations; break; @@ -1759,7 +1725,6 @@ static struct dentry *proc_pident_lookup(struct inode *dir, #endif case PROC_TID_MEM: case PROC_TGID_MEM: - inode->i_op = &proc_mem_inode_operations; inode->i_fop = &proc_mem_operations; break; #ifdef CONFIG_SECCOMP @@ -1801,6 +1766,10 @@ static struct dentry *proc_pident_lookup(struct inode *dir, case PROC_TGID_ATTR_EXEC: case PROC_TID_ATTR_FSCREATE: case PROC_TGID_ATTR_FSCREATE: + case PROC_TID_ATTR_KEYCREATE: + case PROC_TGID_ATTR_KEYCREATE: + case PROC_TID_ATTR_SOCKCREATE: + case PROC_TGID_ATTR_SOCKCREATE: inode->i_fop = &proc_pid_attr_operations; break; #endif @@ -1842,14 +1811,18 @@ static struct dentry *proc_pident_lookup(struct inode *dir, default: printk("procfs: impossible type (%d)",p->type); iput(inode); - return ERR_PTR(-EINVAL); + error = ERR_PTR(-EINVAL); + goto out; } dentry->d_op = &pid_dentry_operations; d_add(dentry, inode); - return NULL; - + /* Close the race of the process dying before we return the dentry */ + if (pid_revalidate(dentry, NULL)) + error = NULL; out: - return ERR_PTR(error); + put_task_struct(task); +out_no_task: + return error; } static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){ @@ -1872,10 +1845,12 @@ static struct file_operations proc_tid_base_operations = { static struct inode_operations proc_tgid_base_inode_operations = { .lookup = proc_tgid_base_lookup, + .getattr = pid_getattr, }; static struct inode_operations proc_tid_base_inode_operations = { .lookup = proc_tid_base_lookup, + .getattr = pid_getattr, }; #ifdef CONFIG_SECURITY @@ -1917,10 +1892,12 @@ static struct dentry *proc_tid_attr_lookup(struct inode *dir, static struct inode_operations proc_tgid_attr_inode_operations = { .lookup = proc_tgid_attr_lookup, + .getattr = pid_getattr, }; static struct inode_operations proc_tid_attr_inode_operations = { .lookup = proc_tid_attr_lookup, + .getattr = pid_getattr, }; #endif @@ -1930,14 +1907,14 @@ static struct inode_operations proc_tid_attr_inode_operations = { static int proc_self_readlink(struct dentry *dentry, char __user *buffer, int buflen) { - char tmp[30]; + char tmp[PROC_NUMBUF]; sprintf(tmp, "%d", current->tgid); return vfs_readlink(dentry,buffer,buflen,tmp); } static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd) { - char tmp[30]; + char tmp[PROC_NUMBUF]; sprintf(tmp, "%d", current->tgid); return ERR_PTR(vfs_follow_link(nd,tmp)); } @@ -1948,67 +1925,80 @@ static struct inode_operations proc_self_inode_operations = { }; /** - * proc_pid_unhash - Unhash /proc/@pid entry from the dcache. - * @p: task that should be flushed. + * proc_flush_task - Remove dcache entries for @task from the /proc dcache. + * + * @task: task that should be flushed. + * + * Looks in the dcache for + * /proc/@pid + * /proc/@tgid/task/@pid + * if either directory is present flushes it and all of it'ts children + * from the dcache. * - * Drops the /proc/@pid dcache entry from the hash chains. + * It is safe and reasonable to cache /proc entries for a task until + * that task exits. After that they just clog up the dcache with + * useless entries, possibly causing useful dcache entries to be + * flushed instead. This routine is proved to flush those useless + * dcache entries at process exit time. * - * Dropping /proc/@pid entries and detach_pid must be synchroneous, - * otherwise e.g. /proc/@pid/exe might point to the wrong executable, - * if the pid value is immediately reused. This is enforced by - * - caller must acquire spin_lock(p->proc_lock) - * - must be called before detach_pid() - * - proc_pid_lookup acquires proc_lock, and checks that - * the target is not dead by looking at the attach count - * of PIDTYPE_PID. + * NOTE: This routine is just an optimization so it does not guarantee + * that no dcache entries will exist at process exit time it + * just makes it very unlikely that any will persist. */ - -struct dentry *proc_pid_unhash(struct task_struct *p) +void proc_flush_task(struct task_struct *task) { - struct dentry *proc_dentry; + struct dentry *dentry, *leader, *dir; + char buf[PROC_NUMBUF]; + struct qstr name; + + name.name = buf; + name.len = snprintf(buf, sizeof(buf), "%d", task->pid); + dentry = d_hash_and_lookup(proc_mnt->mnt_root, &name); + if (dentry) { + shrink_dcache_parent(dentry); + d_drop(dentry); + dput(dentry); + } - proc_dentry = p->proc_dentry; - if (proc_dentry != NULL) { + if (thread_group_leader(task)) + goto out; - spin_lock(&dcache_lock); - spin_lock(&proc_dentry->d_lock); - if (!d_unhashed(proc_dentry)) { - dget_locked(proc_dentry); - __d_drop(proc_dentry); - spin_unlock(&proc_dentry->d_lock); - } else { - spin_unlock(&proc_dentry->d_lock); - proc_dentry = NULL; - } - spin_unlock(&dcache_lock); - } - return proc_dentry; -} + name.name = buf; + name.len = snprintf(buf, sizeof(buf), "%d", task->tgid); + leader = d_hash_and_lookup(proc_mnt->mnt_root, &name); + if (!leader) + goto out; -/** - * proc_pid_flush - recover memory used by stale /proc/@pid/x entries - * @proc_dentry: directoy to prune. - * - * Shrink the /proc directory that was used by the just killed thread. - */ - -void proc_pid_flush(struct dentry *proc_dentry) -{ - might_sleep(); - if(proc_dentry != NULL) { - shrink_dcache_parent(proc_dentry); - dput(proc_dentry); + name.name = "task"; + name.len = strlen(name.name); + dir = d_hash_and_lookup(leader, &name); + if (!dir) + goto out_put_leader; + + name.name = buf; + name.len = snprintf(buf, sizeof(buf), "%d", task->pid); + dentry = d_hash_and_lookup(dir, &name); + if (dentry) { + shrink_dcache_parent(dentry); + d_drop(dentry); + dput(dentry); } + + dput(dir); +out_put_leader: + dput(leader); +out: + return; } /* SMP-safe */ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) { + struct dentry *result = ERR_PTR(-ENOENT); struct task_struct *task; struct inode *inode; struct proc_inode *ei; unsigned tgid; - int died; if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) { inode = new_inode(dir->i_sb); @@ -2029,21 +2019,18 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct if (tgid == ~0U) goto out; - read_lock(&tasklist_lock); + rcu_read_lock(); task = find_task_by_pid(tgid); if (task) get_task_struct(task); - read_unlock(&tasklist_lock); + rcu_read_unlock(); if (!task) goto out; inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO); + if (!inode) + goto out_put_task; - - if (!inode) { - put_task_struct(task); - goto out; - } inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO; inode->i_op = &proc_tgid_base_inode_operations; inode->i_fop = &proc_tgid_base_operations; @@ -2054,45 +2041,40 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct inode->i_nlink = 4; #endif - dentry->d_op = &pid_base_dentry_operations; + dentry->d_op = &pid_dentry_operations; - died = 0; d_add(dentry, inode); - spin_lock(&task->proc_lock); - task->proc_dentry = dentry; - if (!pid_alive(task)) { - dentry = proc_pid_unhash(task); - died = 1; - } - spin_unlock(&task->proc_lock); + /* Close the race of the process dying before we return the dentry */ + if (pid_revalidate(dentry, NULL)) + result = NULL; +out_put_task: put_task_struct(task); - if (died) { - proc_pid_flush(dentry); - goto out; - } - return NULL; out: - return ERR_PTR(-ENOENT); + return result; } /* SMP-safe */ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) { + struct dentry *result = ERR_PTR(-ENOENT); struct task_struct *task; - struct task_struct *leader = proc_task(dir); + struct task_struct *leader = get_proc_task(dir); struct inode *inode; unsigned tid; + if (!leader) + goto out_no_task; + tid = name_to_int(dentry); if (tid == ~0U) goto out; - read_lock(&tasklist_lock); + rcu_read_lock(); task = find_task_by_pid(tid); if (task) get_task_struct(task); - read_unlock(&tasklist_lock); + rcu_read_unlock(); if (!task) goto out; if (leader->tgid != task->tgid) @@ -2113,101 +2095,95 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry inode->i_nlink = 3; #endif - dentry->d_op = &pid_base_dentry_operations; + dentry->d_op = &pid_dentry_operations; d_add(dentry, inode); + /* Close the race of the process dying before we return the dentry */ + if (pid_revalidate(dentry, NULL)) + result = NULL; - put_task_struct(task); - return NULL; out_drop_task: put_task_struct(task); out: - return ERR_PTR(-ENOENT); + put_task_struct(leader); +out_no_task: + return result; } -#define PROC_NUMBUF 10 -#define PROC_MAXPIDS 20 - /* - * Get a few tgid's to return for filldir - we need to hold the - * tasklist lock while doing this, and we must release it before - * we actually do the filldir itself, so we use a temp buffer.. + * Find the first tgid to return to user space. + * + * Usually this is just whatever follows &init_task, but if the users + * buffer was too small to hold the full list or there was a seek into + * the middle of the directory we have more work to do. + * + * In the case of a short read we start with find_task_by_pid. + * + * In the case of a seek we start with &init_task and walk nr + * threads past it. */ -static int get_tgid_list(int index, unsigned long version, unsigned int *tgids) -{ - struct task_struct *p; - int nr_tgids = 0; - - index--; - read_lock(&tasklist_lock); - p = NULL; - if (version) { - p = find_task_by_pid(version); - if (p && !thread_group_leader(p)) - p = NULL; +static struct task_struct *first_tgid(int tgid, unsigned int nr) +{ + struct task_struct *pos; + rcu_read_lock(); + if (tgid && nr) { + pos = find_task_by_pid(tgid); + if (pos && thread_group_leader(pos)) + goto found; } + /* If nr exceeds the number of processes get out quickly */ + pos = NULL; + if (nr && nr >= nr_processes()) + goto done; - if (p) - index = 0; - else - p = next_task(&init_task); - - for ( ; p != &init_task; p = next_task(p)) { - int tgid = p->pid; - if (!pid_alive(p)) - continue; - if (--index >= 0) - continue; - tgids[nr_tgids] = tgid; - nr_tgids++; - if (nr_tgids >= PROC_MAXPIDS) - break; + /* If we haven't found our starting place yet start with + * the init_task and walk nr tasks forward. + */ + for (pos = next_task(&init_task); nr > 0; --nr) { + pos = next_task(pos); + if (pos == &init_task) { + pos = NULL; + goto done; + } } - read_unlock(&tasklist_lock); - return nr_tgids; +found: + get_task_struct(pos); +done: + rcu_read_unlock(); + return pos; } /* - * Get a few tid's to return for filldir - we need to hold the - * tasklist lock while doing this, and we must release it before - * we actually do the filldir itself, so we use a temp buffer.. + * Find the next task in the task list. + * Return NULL if we loop or there is any error. + * + * The reference to the input task_struct is released. */ -static int get_tid_list(int index, unsigned int *tids, struct inode *dir) -{ - struct task_struct *leader_task = proc_task(dir); - struct task_struct *task = leader_task; - int nr_tids = 0; - - index -= 2; - read_lock(&tasklist_lock); - /* - * The starting point task (leader_task) might be an already - * unlinked task, which cannot be used to access the task-list - * via next_thread(). - */ - if (pid_alive(task)) do { - int tid = task->pid; - - if (--index >= 0) - continue; - if (tids != NULL) - tids[nr_tids] = tid; - nr_tids++; - if (nr_tids >= PROC_MAXPIDS) - break; - } while ((task = next_thread(task)) != leader_task); - read_unlock(&tasklist_lock); - return nr_tids; +static struct task_struct *next_tgid(struct task_struct *start) +{ + struct task_struct *pos; + rcu_read_lock(); + pos = start; + if (pid_alive(start)) + pos = next_task(start); + if (pid_alive(pos) && (pos != &init_task)) { + get_task_struct(pos); + goto done; + } + pos = NULL; +done: + rcu_read_unlock(); + put_task_struct(start); + return pos; } /* for the /proc/ directory itself, after non-process stuff has been done */ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir) { - unsigned int tgid_array[PROC_MAXPIDS]; char buf[PROC_NUMBUF]; unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY; - unsigned int nr_tgids, i; - int next_tgid; + struct task_struct *task; + int tgid; if (!nr) { ino_t ino = fake_ino(0,PROC_TGID_INO); @@ -2216,63 +2192,116 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir) filp->f_pos++; nr++; } + nr -= 1; /* f_version caches the tgid value that the last readdir call couldn't * return. lseek aka telldir automagically resets f_version to 0. */ - next_tgid = filp->f_version; + tgid = filp->f_version; filp->f_version = 0; - for (;;) { - nr_tgids = get_tgid_list(nr, next_tgid, tgid_array); - if (!nr_tgids) { - /* no more entries ! */ + for (task = first_tgid(tgid, nr); + task; + task = next_tgid(task), filp->f_pos++) { + int len; + ino_t ino; + tgid = task->pid; + len = snprintf(buf, sizeof(buf), "%d", tgid); + ino = fake_ino(tgid, PROC_TGID_INO); + if (filldir(dirent, buf, len, filp->f_pos, ino, DT_DIR) < 0) { + /* returning this tgid failed, save it as the first + * pid for the next readir call */ + filp->f_version = tgid; + put_task_struct(task); break; } - next_tgid = 0; + } + return 0; +} - /* do not use the last found pid, reserve it for next_tgid */ - if (nr_tgids == PROC_MAXPIDS) { - nr_tgids--; - next_tgid = tgid_array[nr_tgids]; - } +/* + * Find the first tid of a thread group to return to user space. + * + * Usually this is just the thread group leader, but if the users + * buffer was too small or there was a seek into the middle of the + * directory we have more work todo. + * + * In the case of a short read we start with find_task_by_pid. + * + * In the case of a seek we start with the leader and walk nr + * threads past it. + */ +static struct task_struct *first_tid(struct task_struct *leader, + int tid, int nr) +{ + struct task_struct *pos; - for (i=0;i<nr_tgids;i++) { - int tgid = tgid_array[i]; - ino_t ino = fake_ino(tgid,PROC_TGID_INO); - unsigned long j = PROC_NUMBUF; + rcu_read_lock(); + /* Attempt to start with the pid of a thread */ + if (tid && (nr > 0)) { + pos = find_task_by_pid(tid); + if (pos && (pos->group_leader == leader)) + goto found; + } - do - buf[--j] = '0' + (tgid % 10); - while ((tgid /= 10) != 0); + /* If nr exceeds the number of threads there is nothing todo */ + pos = NULL; + if (nr && nr >= get_nr_threads(leader)) + goto out; - if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) { - /* returning this tgid failed, save it as the first - * pid for the next readir call */ - filp->f_version = tgid_array[i]; - goto out; - } - filp->f_pos++; - nr++; + /* If we haven't found our starting place yet start + * with the leader and walk nr threads forward. + */ + for (pos = leader; nr > 0; --nr) { + pos = next_thread(pos); + if (pos == leader) { + pos = NULL; + goto out; } } +found: + get_task_struct(pos); out: - return 0; + rcu_read_unlock(); + return pos; +} + +/* + * Find the next thread in the thread list. + * Return NULL if there is an error or no next thread. + * + * The reference to the input task_struct is released. + */ +static struct task_struct *next_tid(struct task_struct *start) +{ + struct task_struct *pos = NULL; + rcu_read_lock(); + if (pid_alive(start)) { + pos = next_thread(start); + if (thread_group_leader(pos)) + pos = NULL; + else + get_task_struct(pos); + } + rcu_read_unlock(); + put_task_struct(start); + return pos; } /* for the /proc/TGID/task/ directories */ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir) { - unsigned int tid_array[PROC_MAXPIDS]; char buf[PROC_NUMBUF]; - unsigned int nr_tids, i; struct dentry *dentry = filp->f_dentry; struct inode *inode = dentry->d_inode; + struct task_struct *leader = get_proc_task(inode); + struct task_struct *task; int retval = -ENOENT; ino_t ino; + int tid; unsigned long pos = filp->f_pos; /* avoiding "long long" filp->f_pos */ - if (!pid_alive(proc_task(inode))) - goto out; + if (!leader) + goto out_no_task; retval = 0; switch (pos) { @@ -2290,24 +2319,45 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi /* fall through */ } - nr_tids = get_tid_list(pos, tid_array, inode); - inode->i_nlink = pos + nr_tids; - - for (i = 0; i < nr_tids; i++) { - unsigned long j = PROC_NUMBUF; - int tid = tid_array[i]; - - ino = fake_ino(tid,PROC_TID_INO); - - do - buf[--j] = '0' + (tid % 10); - while ((tid /= 10) != 0); - - if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0) + /* f_version caches the tgid value that the last readdir call couldn't + * return. lseek aka telldir automagically resets f_version to 0. + */ + tid = filp->f_version; + filp->f_version = 0; + for (task = first_tid(leader, tid, pos - 2); + task; + task = next_tid(task), pos++) { + int len; + tid = task->pid; + len = snprintf(buf, sizeof(buf), "%d", tid); + ino = fake_ino(tid, PROC_TID_INO); + if (filldir(dirent, buf, len, pos, ino, DT_DIR < 0)) { + /* returning this tgid failed, save it as the first + * pid for the next readir call */ + filp->f_version = tid; + put_task_struct(task); break; - pos++; + } } out: filp->f_pos = pos; + put_task_struct(leader); +out_no_task: return retval; } + +static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) +{ + struct inode *inode = dentry->d_inode; + struct task_struct *p = get_proc_task(inode); + generic_fillattr(inode, stat); + + if (p) { + rcu_read_lock(); + stat->nlink += get_nr_threads(p); + rcu_read_unlock(); + put_task_struct(p); + } + + return 0; +} |