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-rw-r--r--ipc/shm.c1237
1 files changed, 1237 insertions, 0 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
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index 00000000..406c5b20
--- /dev/null
+++ b/ipc/shm.c
@@ -0,0 +1,1237 @@
+/*
+ * linux/ipc/shm.c
+ * Copyright (C) 1992, 1993 Krishna Balasubramanian
+ * Many improvements/fixes by Bruno Haible.
+ * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
+ * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
+ *
+ * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
+ * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
+ * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
+ * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
+ * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
+ * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
+ * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
+ *
+ * support for audit of ipc object properties and permission changes
+ * Dustin Kirkland <dustin.kirkland@us.ibm.com>
+ *
+ * namespaces support
+ * OpenVZ, SWsoft Inc.
+ * Pavel Emelianov <xemul@openvz.org>
+ */
+
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/shm.h>
+#include <linux/init.h>
+#include <linux/file.h>
+#include <linux/mman.h>
+#include <linux/shmem_fs.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/audit.h>
+#include <linux/capability.h>
+#include <linux/ptrace.h>
+#include <linux/seq_file.h>
+#include <linux/rwsem.h>
+#include <linux/nsproxy.h>
+#include <linux/mount.h>
+#include <linux/ipc_namespace.h>
+
+#include <asm/uaccess.h>
+
+#include "util.h"
+
+struct shm_file_data {
+ int id;
+ struct ipc_namespace *ns;
+ struct file *file;
+ const struct vm_operations_struct *vm_ops;
+};
+
+#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
+
+static const struct file_operations shm_file_operations;
+static const struct vm_operations_struct shm_vm_ops;
+
+#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
+
+#define shm_unlock(shp) \
+ ipc_unlock(&(shp)->shm_perm)
+
+static int newseg(struct ipc_namespace *, struct ipc_params *);
+static void shm_open(struct vm_area_struct *vma);
+static void shm_close(struct vm_area_struct *vma);
+static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
+#ifdef CONFIG_PROC_FS
+static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
+#endif
+
+void shm_init_ns(struct ipc_namespace *ns)
+{
+ ns->shm_ctlmax = SHMMAX;
+ ns->shm_ctlall = SHMALL;
+ ns->shm_ctlmni = SHMMNI;
+ ns->shm_rmid_forced = 0;
+ ns->shm_tot = 0;
+ ipc_init_ids(&shm_ids(ns));
+}
+
+/*
+ * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
+ * Only shm_ids.rw_mutex remains locked on exit.
+ */
+static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
+{
+ struct shmid_kernel *shp;
+ shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+ if (shp->shm_nattch){
+ shp->shm_perm.mode |= SHM_DEST;
+ /* Do not find it any more */
+ shp->shm_perm.key = IPC_PRIVATE;
+ shm_unlock(shp);
+ } else
+ shm_destroy(ns, shp);
+}
+
+#ifdef CONFIG_IPC_NS
+void shm_exit_ns(struct ipc_namespace *ns)
+{
+ free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
+ idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
+}
+#endif
+
+static int __init ipc_ns_init(void)
+{
+ shm_init_ns(&init_ipc_ns);
+ return 0;
+}
+
+pure_initcall(ipc_ns_init);
+
+void __init shm_init (void)
+{
+ ipc_init_proc_interface("sysvipc/shm",
+#if BITS_PER_LONG <= 32
+ " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
+#else
+ " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
+#endif
+ IPC_SHM_IDS, sysvipc_shm_proc_show);
+}
+
+/*
+ * shm_lock_(check_) routines are called in the paths where the rw_mutex
+ * is not necessarily held.
+ */
+static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
+{
+ struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
+
+ if (IS_ERR(ipcp))
+ return (struct shmid_kernel *)ipcp;
+
+ return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
+{
+ rcu_read_lock();
+ spin_lock(&ipcp->shm_perm.lock);
+}
+
+static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
+ int id)
+{
+ struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
+
+ if (IS_ERR(ipcp))
+ return (struct shmid_kernel *)ipcp;
+
+ return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
+{
+ ipc_rmid(&shm_ids(ns), &s->shm_perm);
+}
+
+
+/* This is called by fork, once for every shm attach. */
+static void shm_open(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+ struct shmid_kernel *shp;
+
+ shp = shm_lock(sfd->ns, sfd->id);
+ BUG_ON(IS_ERR(shp));
+ shp->shm_atim = get_seconds();
+ shp->shm_lprid = task_tgid_vnr(current);
+ shp->shm_nattch++;
+ shm_unlock(shp);
+}
+
+/*
+ * shm_destroy - free the struct shmid_kernel
+ *
+ * @ns: namespace
+ * @shp: struct to free
+ *
+ * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
+ * but returns with shp unlocked and freed.
+ */
+static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
+{
+ ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ shm_rmid(ns, shp);
+ shm_unlock(shp);
+ if (!is_file_hugepages(shp->shm_file))
+ shmem_lock(shp->shm_file, 0, shp->mlock_user);
+ else if (shp->mlock_user)
+ user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
+ shp->mlock_user);
+ fput (shp->shm_file);
+ security_shm_free(shp);
+ ipc_rcu_putref(shp);
+}
+
+/*
+ * shm_may_destroy - identifies whether shm segment should be destroyed now
+ *
+ * Returns true if and only if there are no active users of the segment and
+ * one of the following is true:
+ *
+ * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
+ *
+ * 2) sysctl kernel.shm_rmid_forced is set to 1.
+ */
+static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
+{
+ return (shp->shm_nattch == 0) &&
+ (ns->shm_rmid_forced ||
+ (shp->shm_perm.mode & SHM_DEST));
+}
+
+/*
+ * remove the attach descriptor vma.
+ * free memory for segment if it is marked destroyed.
+ * The descriptor has already been removed from the current->mm->mmap list
+ * and will later be kfree()d.
+ */
+static void shm_close(struct vm_area_struct *vma)
+{
+ struct file * file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+ struct shmid_kernel *shp;
+ struct ipc_namespace *ns = sfd->ns;
+
+ down_write(&shm_ids(ns).rw_mutex);
+ /* remove from the list of attaches of the shm segment */
+ shp = shm_lock(ns, sfd->id);
+ BUG_ON(IS_ERR(shp));
+ shp->shm_lprid = task_tgid_vnr(current);
+ shp->shm_dtim = get_seconds();
+ shp->shm_nattch--;
+ if (shm_may_destroy(ns, shp))
+ shm_destroy(ns, shp);
+ else
+ shm_unlock(shp);
+ up_write(&shm_ids(ns).rw_mutex);
+}
+
+/* Called with ns->shm_ids(ns).rw_mutex locked */
+static int shm_try_destroy_current(int id, void *p, void *data)
+{
+ struct ipc_namespace *ns = data;
+ struct kern_ipc_perm *ipcp = p;
+ struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+ if (shp->shm_creator != current)
+ return 0;
+
+ /*
+ * Mark it as orphaned to destroy the segment when
+ * kernel.shm_rmid_forced is changed.
+ * It is noop if the following shm_may_destroy() returns true.
+ */
+ shp->shm_creator = NULL;
+
+ /*
+ * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
+ * is not set, it shouldn't be deleted here.
+ */
+ if (!ns->shm_rmid_forced)
+ return 0;
+
+ if (shm_may_destroy(ns, shp)) {
+ shm_lock_by_ptr(shp);
+ shm_destroy(ns, shp);
+ }
+ return 0;
+}
+
+/* Called with ns->shm_ids(ns).rw_mutex locked */
+static int shm_try_destroy_orphaned(int id, void *p, void *data)
+{
+ struct ipc_namespace *ns = data;
+ struct kern_ipc_perm *ipcp = p;
+ struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+ /*
+ * We want to destroy segments without users and with already
+ * exit'ed originating process.
+ *
+ * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
+ */
+ if (shp->shm_creator != NULL)
+ return 0;
+
+ if (shm_may_destroy(ns, shp)) {
+ shm_lock_by_ptr(shp);
+ shm_destroy(ns, shp);
+ }
+ return 0;
+}
+
+void shm_destroy_orphaned(struct ipc_namespace *ns)
+{
+ down_write(&shm_ids(ns).rw_mutex);
+ if (shm_ids(ns).in_use)
+ idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
+ up_write(&shm_ids(ns).rw_mutex);
+}
+
+
+void exit_shm(struct task_struct *task)
+{
+ struct ipc_namespace *ns = task->nsproxy->ipc_ns;
+
+ if (shm_ids(ns).in_use == 0)
+ return;
+
+ /* Destroy all already created segments, but not mapped yet */
+ down_write(&shm_ids(ns).rw_mutex);
+ if (shm_ids(ns).in_use)
+ idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
+ up_write(&shm_ids(ns).rw_mutex);
+}
+
+static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+
+ return sfd->vm_ops->fault(vma, vmf);
+}
+
+#ifdef CONFIG_NUMA
+static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+ int err = 0;
+ if (sfd->vm_ops->set_policy)
+ err = sfd->vm_ops->set_policy(vma, new);
+ return err;
+}
+
+static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+ struct mempolicy *pol = NULL;
+
+ if (sfd->vm_ops->get_policy)
+ pol = sfd->vm_ops->get_policy(vma, addr);
+ else if (vma->vm_policy)
+ pol = vma->vm_policy;
+
+ return pol;
+}
+#endif
+
+static int shm_mmap(struct file * file, struct vm_area_struct * vma)
+{
+ struct shm_file_data *sfd = shm_file_data(file);
+ int ret;
+
+ ret = sfd->file->f_op->mmap(sfd->file, vma);
+ if (ret != 0)
+ return ret;
+ sfd->vm_ops = vma->vm_ops;
+#ifdef CONFIG_MMU
+ BUG_ON(!sfd->vm_ops->fault);
+#endif
+ vma->vm_ops = &shm_vm_ops;
+ shm_open(vma);
+
+ return ret;
+}
+
+static int shm_release(struct inode *ino, struct file *file)
+{
+ struct shm_file_data *sfd = shm_file_data(file);
+
+ put_ipc_ns(sfd->ns);
+ shm_file_data(file) = NULL;
+ kfree(sfd);
+ return 0;
+}
+
+static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ struct shm_file_data *sfd = shm_file_data(file);
+
+ if (!sfd->file->f_op->fsync)
+ return -EINVAL;
+ return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
+}
+
+static unsigned long shm_get_unmapped_area(struct file *file,
+ unsigned long addr, unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ struct shm_file_data *sfd = shm_file_data(file);
+ return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
+ pgoff, flags);
+}
+
+static const struct file_operations shm_file_operations = {
+ .mmap = shm_mmap,
+ .fsync = shm_fsync,
+ .release = shm_release,
+#ifndef CONFIG_MMU
+ .get_unmapped_area = shm_get_unmapped_area,
+#endif
+ .llseek = noop_llseek,
+};
+
+static const struct file_operations shm_file_operations_huge = {
+ .mmap = shm_mmap,
+ .fsync = shm_fsync,
+ .release = shm_release,
+ .get_unmapped_area = shm_get_unmapped_area,
+ .llseek = noop_llseek,
+};
+
+int is_file_shm_hugepages(struct file *file)
+{
+ return file->f_op == &shm_file_operations_huge;
+}
+
+static const struct vm_operations_struct shm_vm_ops = {
+ .open = shm_open, /* callback for a new vm-area open */
+ .close = shm_close, /* callback for when the vm-area is released */
+ .fault = shm_fault,
+#if defined(CONFIG_NUMA)
+ .set_policy = shm_set_policy,
+ .get_policy = shm_get_policy,
+#endif
+};
+
+/**
+ * newseg - Create a new shared memory segment
+ * @ns: namespace
+ * @params: ptr to the structure that contains key, size and shmflg
+ *
+ * Called with shm_ids.rw_mutex held as a writer.
+ */
+
+static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
+{
+ key_t key = params->key;
+ int shmflg = params->flg;
+ size_t size = params->u.size;
+ int error;
+ struct shmid_kernel *shp;
+ int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
+ struct file * file;
+ char name[13];
+ int id;
+ vm_flags_t acctflag = 0;
+
+ if (size < SHMMIN || size > ns->shm_ctlmax)
+ return -EINVAL;
+
+ if (ns->shm_tot + numpages > ns->shm_ctlall)
+ return -ENOSPC;
+
+ shp = ipc_rcu_alloc(sizeof(*shp));
+ if (!shp)
+ return -ENOMEM;
+
+ shp->shm_perm.key = key;
+ shp->shm_perm.mode = (shmflg & S_IRWXUGO);
+ shp->mlock_user = NULL;
+
+ shp->shm_perm.security = NULL;
+ error = security_shm_alloc(shp);
+ if (error) {
+ ipc_rcu_putref(shp);
+ return error;
+ }
+
+ sprintf (name, "SYSV%08x", key);
+ if (shmflg & SHM_HUGETLB) {
+ /* hugetlb_file_setup applies strict accounting */
+ if (shmflg & SHM_NORESERVE)
+ acctflag = VM_NORESERVE;
+ file = hugetlb_file_setup(name, 0, size, acctflag,
+ &shp->mlock_user, HUGETLB_SHMFS_INODE);
+ } else {
+ /*
+ * Do not allow no accounting for OVERCOMMIT_NEVER, even
+ * if it's asked for.
+ */
+ if ((shmflg & SHM_NORESERVE) &&
+ sysctl_overcommit_memory != OVERCOMMIT_NEVER)
+ acctflag = VM_NORESERVE;
+ file = shmem_file_setup(name, size, acctflag);
+ }
+ error = PTR_ERR(file);
+ if (IS_ERR(file))
+ goto no_file;
+
+ id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
+ if (id < 0) {
+ error = id;
+ goto no_id;
+ }
+
+ shp->shm_cprid = task_tgid_vnr(current);
+ shp->shm_lprid = 0;
+ shp->shm_atim = shp->shm_dtim = 0;
+ shp->shm_ctim = get_seconds();
+ shp->shm_segsz = size;
+ shp->shm_nattch = 0;
+ shp->shm_file = file;
+ shp->shm_creator = current;
+ /*
+ * shmid gets reported as "inode#" in /proc/pid/maps.
+ * proc-ps tools use this. Changing this will break them.
+ */
+ file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
+
+ ns->shm_tot += numpages;
+ error = shp->shm_perm.id;
+ shm_unlock(shp);
+ return error;
+
+no_id:
+ if (is_file_hugepages(file) && shp->mlock_user)
+ user_shm_unlock(size, shp->mlock_user);
+ fput(file);
+no_file:
+ security_shm_free(shp);
+ ipc_rcu_putref(shp);
+ return error;
+}
+
+/*
+ * Called with shm_ids.rw_mutex and ipcp locked.
+ */
+static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
+{
+ struct shmid_kernel *shp;
+
+ shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+ return security_shm_associate(shp, shmflg);
+}
+
+/*
+ * Called with shm_ids.rw_mutex and ipcp locked.
+ */
+static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
+ struct ipc_params *params)
+{
+ struct shmid_kernel *shp;
+
+ shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+ if (shp->shm_segsz < params->u.size)
+ return -EINVAL;
+
+ return 0;
+}
+
+SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
+{
+ struct ipc_namespace *ns;
+ struct ipc_ops shm_ops;
+ struct ipc_params shm_params;
+
+ ns = current->nsproxy->ipc_ns;
+
+ shm_ops.getnew = newseg;
+ shm_ops.associate = shm_security;
+ shm_ops.more_checks = shm_more_checks;
+
+ shm_params.key = key;
+ shm_params.flg = shmflg;
+ shm_params.u.size = size;
+
+ return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
+}
+
+static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
+{
+ switch(version) {
+ case IPC_64:
+ return copy_to_user(buf, in, sizeof(*in));
+ case IPC_OLD:
+ {
+ struct shmid_ds out;
+
+ memset(&out, 0, sizeof(out));
+ ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
+ out.shm_segsz = in->shm_segsz;
+ out.shm_atime = in->shm_atime;
+ out.shm_dtime = in->shm_dtime;
+ out.shm_ctime = in->shm_ctime;
+ out.shm_cpid = in->shm_cpid;
+ out.shm_lpid = in->shm_lpid;
+ out.shm_nattch = in->shm_nattch;
+
+ return copy_to_user(buf, &out, sizeof(out));
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static inline unsigned long
+copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
+{
+ switch(version) {
+ case IPC_64:
+ if (copy_from_user(out, buf, sizeof(*out)))
+ return -EFAULT;
+ return 0;
+ case IPC_OLD:
+ {
+ struct shmid_ds tbuf_old;
+
+ if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
+ return -EFAULT;
+
+ out->shm_perm.uid = tbuf_old.shm_perm.uid;
+ out->shm_perm.gid = tbuf_old.shm_perm.gid;
+ out->shm_perm.mode = tbuf_old.shm_perm.mode;
+
+ return 0;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
+{
+ switch(version) {
+ case IPC_64:
+ return copy_to_user(buf, in, sizeof(*in));
+ case IPC_OLD:
+ {
+ struct shminfo out;
+
+ if(in->shmmax > INT_MAX)
+ out.shmmax = INT_MAX;
+ else
+ out.shmmax = (int)in->shmmax;
+
+ out.shmmin = in->shmmin;
+ out.shmmni = in->shmmni;
+ out.shmseg = in->shmseg;
+ out.shmall = in->shmall;
+
+ return copy_to_user(buf, &out, sizeof(out));
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+/*
+ * Calculate and add used RSS and swap pages of a shm.
+ * Called with shm_ids.rw_mutex held as a reader
+ */
+static void shm_add_rss_swap(struct shmid_kernel *shp,
+ unsigned long *rss_add, unsigned long *swp_add)
+{
+ struct inode *inode;
+
+ inode = shp->shm_file->f_path.dentry->d_inode;
+
+ if (is_file_hugepages(shp->shm_file)) {
+ struct address_space *mapping = inode->i_mapping;
+ struct hstate *h = hstate_file(shp->shm_file);
+ *rss_add += pages_per_huge_page(h) * mapping->nrpages;
+ } else {
+#ifdef CONFIG_SHMEM
+ struct shmem_inode_info *info = SHMEM_I(inode);
+ spin_lock(&info->lock);
+ *rss_add += inode->i_mapping->nrpages;
+ *swp_add += info->swapped;
+ spin_unlock(&info->lock);
+#else
+ *rss_add += inode->i_mapping->nrpages;
+#endif
+ }
+}
+
+/*
+ * Called with shm_ids.rw_mutex held as a reader
+ */
+static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
+ unsigned long *swp)
+{
+ int next_id;
+ int total, in_use;
+
+ *rss = 0;
+ *swp = 0;
+
+ in_use = shm_ids(ns).in_use;
+
+ for (total = 0, next_id = 0; total < in_use; next_id++) {
+ struct kern_ipc_perm *ipc;
+ struct shmid_kernel *shp;
+
+ ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
+ if (ipc == NULL)
+ continue;
+ shp = container_of(ipc, struct shmid_kernel, shm_perm);
+
+ shm_add_rss_swap(shp, rss, swp);
+
+ total++;
+ }
+}
+
+/*
+ * This function handles some shmctl commands which require the rw_mutex
+ * to be held in write mode.
+ * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ */
+static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
+ struct shmid_ds __user *buf, int version)
+{
+ struct kern_ipc_perm *ipcp;
+ struct shmid64_ds shmid64;
+ struct shmid_kernel *shp;
+ int err;
+
+ if (cmd == IPC_SET) {
+ if (copy_shmid_from_user(&shmid64, buf, version))
+ return -EFAULT;
+ }
+
+ ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
+ &shmid64.shm_perm, 0);
+ if (IS_ERR(ipcp))
+ return PTR_ERR(ipcp);
+
+ shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+ err = security_shm_shmctl(shp, cmd);
+ if (err)
+ goto out_unlock;
+ switch (cmd) {
+ case IPC_RMID:
+ do_shm_rmid(ns, ipcp);
+ goto out_up;
+ case IPC_SET:
+ ipc_update_perm(&shmid64.shm_perm, ipcp);
+ shp->shm_ctim = get_seconds();
+ break;
+ default:
+ err = -EINVAL;
+ }
+out_unlock:
+ shm_unlock(shp);
+out_up:
+ up_write(&shm_ids(ns).rw_mutex);
+ return err;
+}
+
+SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
+{
+ struct shmid_kernel *shp;
+ int err, version;
+ struct ipc_namespace *ns;
+
+ if (cmd < 0 || shmid < 0) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ version = ipc_parse_version(&cmd);
+ ns = current->nsproxy->ipc_ns;
+
+ switch (cmd) { /* replace with proc interface ? */
+ case IPC_INFO:
+ {
+ struct shminfo64 shminfo;
+
+ err = security_shm_shmctl(NULL, cmd);
+ if (err)
+ return err;
+
+ memset(&shminfo, 0, sizeof(shminfo));
+ shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
+ shminfo.shmmax = ns->shm_ctlmax;
+ shminfo.shmall = ns->shm_ctlall;
+
+ shminfo.shmmin = SHMMIN;
+ if(copy_shminfo_to_user (buf, &shminfo, version))
+ return -EFAULT;
+
+ down_read(&shm_ids(ns).rw_mutex);
+ err = ipc_get_maxid(&shm_ids(ns));
+ up_read(&shm_ids(ns).rw_mutex);
+
+ if(err<0)
+ err = 0;
+ goto out;
+ }
+ case SHM_INFO:
+ {
+ struct shm_info shm_info;
+
+ err = security_shm_shmctl(NULL, cmd);
+ if (err)
+ return err;
+
+ memset(&shm_info, 0, sizeof(shm_info));
+ down_read(&shm_ids(ns).rw_mutex);
+ shm_info.used_ids = shm_ids(ns).in_use;
+ shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
+ shm_info.shm_tot = ns->shm_tot;
+ shm_info.swap_attempts = 0;
+ shm_info.swap_successes = 0;
+ err = ipc_get_maxid(&shm_ids(ns));
+ up_read(&shm_ids(ns).rw_mutex);
+ if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
+ err = -EFAULT;
+ goto out;
+ }
+
+ err = err < 0 ? 0 : err;
+ goto out;
+ }
+ case SHM_STAT:
+ case IPC_STAT:
+ {
+ struct shmid64_ds tbuf;
+ int result;
+
+ if (cmd == SHM_STAT) {
+ shp = shm_lock(ns, shmid);
+ if (IS_ERR(shp)) {
+ err = PTR_ERR(shp);
+ goto out;
+ }
+ result = shp->shm_perm.id;
+ } else {
+ shp = shm_lock_check(ns, shmid);
+ if (IS_ERR(shp)) {
+ err = PTR_ERR(shp);
+ goto out;
+ }
+ result = 0;
+ }
+ err = -EACCES;
+ if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
+ goto out_unlock;
+ err = security_shm_shmctl(shp, cmd);
+ if (err)
+ goto out_unlock;
+ memset(&tbuf, 0, sizeof(tbuf));
+ kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
+ tbuf.shm_segsz = shp->shm_segsz;
+ tbuf.shm_atime = shp->shm_atim;
+ tbuf.shm_dtime = shp->shm_dtim;
+ tbuf.shm_ctime = shp->shm_ctim;
+ tbuf.shm_cpid = shp->shm_cprid;
+ tbuf.shm_lpid = shp->shm_lprid;
+ tbuf.shm_nattch = shp->shm_nattch;
+ shm_unlock(shp);
+ if(copy_shmid_to_user (buf, &tbuf, version))
+ err = -EFAULT;
+ else
+ err = result;
+ goto out;
+ }
+ case SHM_LOCK:
+ case SHM_UNLOCK:
+ {
+ struct file *shm_file;
+
+ shp = shm_lock_check(ns, shmid);
+ if (IS_ERR(shp)) {
+ err = PTR_ERR(shp);
+ goto out;
+ }
+
+ audit_ipc_obj(&(shp->shm_perm));
+
+ if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
+ uid_t euid = current_euid();
+ err = -EPERM;
+ if (euid != shp->shm_perm.uid &&
+ euid != shp->shm_perm.cuid)
+ goto out_unlock;
+ if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
+ goto out_unlock;
+ }
+
+ err = security_shm_shmctl(shp, cmd);
+ if (err)
+ goto out_unlock;
+
+ shm_file = shp->shm_file;
+ if (is_file_hugepages(shm_file))
+ goto out_unlock;
+
+ if (cmd == SHM_LOCK) {
+ struct user_struct *user = current_user();
+ err = shmem_lock(shm_file, 1, user);
+ if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
+ shp->shm_perm.mode |= SHM_LOCKED;
+ shp->mlock_user = user;
+ }
+ goto out_unlock;
+ }
+
+ /* SHM_UNLOCK */
+ if (!(shp->shm_perm.mode & SHM_LOCKED))
+ goto out_unlock;
+ shmem_lock(shm_file, 0, shp->mlock_user);
+ shp->shm_perm.mode &= ~SHM_LOCKED;
+ shp->mlock_user = NULL;
+ get_file(shm_file);
+ shm_unlock(shp);
+ shmem_unlock_mapping(shm_file->f_mapping);
+ fput(shm_file);
+ goto out;
+ }
+ case IPC_RMID:
+ case IPC_SET:
+ err = shmctl_down(ns, shmid, cmd, buf, version);
+ return err;
+ default:
+ return -EINVAL;
+ }
+
+out_unlock:
+ shm_unlock(shp);
+out:
+ return err;
+}
+
+/*
+ * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
+ *
+ * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
+ * "raddr" thing points to kernel space, and there has to be a wrapper around
+ * this.
+ */
+long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
+{
+ struct shmid_kernel *shp;
+ unsigned long addr;
+ unsigned long size;
+ struct file * file;
+ int err;
+ unsigned long flags;
+ unsigned long prot;
+ int acc_mode;
+ unsigned long user_addr;
+ struct ipc_namespace *ns;
+ struct shm_file_data *sfd;
+ struct path path;
+ fmode_t f_mode;
+
+ err = -EINVAL;
+ if (shmid < 0)
+ goto out;
+ else if ((addr = (ulong)shmaddr)) {
+ if (addr & (SHMLBA-1)) {
+ if (shmflg & SHM_RND)
+ addr &= ~(SHMLBA-1); /* round down */
+ else
+#ifndef __ARCH_FORCE_SHMLBA
+ if (addr & ~PAGE_MASK)
+#endif
+ goto out;
+ }
+ flags = MAP_SHARED | MAP_FIXED;
+ } else {
+ if ((shmflg & SHM_REMAP))
+ goto out;
+
+ flags = MAP_SHARED;
+ }
+
+ if (shmflg & SHM_RDONLY) {
+ prot = PROT_READ;
+ acc_mode = S_IRUGO;
+ f_mode = FMODE_READ;
+ } else {
+ prot = PROT_READ | PROT_WRITE;
+ acc_mode = S_IRUGO | S_IWUGO;
+ f_mode = FMODE_READ | FMODE_WRITE;
+ }
+ if (shmflg & SHM_EXEC) {
+ prot |= PROT_EXEC;
+ acc_mode |= S_IXUGO;
+ }
+
+ /*
+ * We cannot rely on the fs check since SYSV IPC does have an
+ * additional creator id...
+ */
+ ns = current->nsproxy->ipc_ns;
+ shp = shm_lock_check(ns, shmid);
+ if (IS_ERR(shp)) {
+ err = PTR_ERR(shp);
+ goto out;
+ }
+
+ err = -EACCES;
+ if (ipcperms(ns, &shp->shm_perm, acc_mode))
+ goto out_unlock;
+
+ err = security_shm_shmat(shp, shmaddr, shmflg);
+ if (err)
+ goto out_unlock;
+
+ path = shp->shm_file->f_path;
+ path_get(&path);
+ shp->shm_nattch++;
+ size = i_size_read(path.dentry->d_inode);
+ shm_unlock(shp);
+
+ err = -ENOMEM;
+ sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
+ if (!sfd)
+ goto out_put_dentry;
+
+ file = alloc_file(&path, f_mode,
+ is_file_hugepages(shp->shm_file) ?
+ &shm_file_operations_huge :
+ &shm_file_operations);
+ if (!file)
+ goto out_free;
+
+ file->private_data = sfd;
+ file->f_mapping = shp->shm_file->f_mapping;
+ sfd->id = shp->shm_perm.id;
+ sfd->ns = get_ipc_ns(ns);
+ sfd->file = shp->shm_file;
+ sfd->vm_ops = NULL;
+
+ down_write(&current->mm->mmap_sem);
+ if (addr && !(shmflg & SHM_REMAP)) {
+ err = -EINVAL;
+ if (find_vma_intersection(current->mm, addr, addr + size))
+ goto invalid;
+ /*
+ * If shm segment goes below stack, make sure there is some
+ * space left for the stack to grow (at least 4 pages).
+ */
+ if (addr < current->mm->start_stack &&
+ addr > current->mm->start_stack - size - PAGE_SIZE * 5)
+ goto invalid;
+ }
+
+ user_addr = do_mmap (file, addr, size, prot, flags, 0);
+ *raddr = user_addr;
+ err = 0;
+ if (IS_ERR_VALUE(user_addr))
+ err = (long)user_addr;
+invalid:
+ up_write(&current->mm->mmap_sem);
+
+ fput(file);
+
+out_nattch:
+ down_write(&shm_ids(ns).rw_mutex);
+ shp = shm_lock(ns, shmid);
+ BUG_ON(IS_ERR(shp));
+ shp->shm_nattch--;
+ if (shm_may_destroy(ns, shp))
+ shm_destroy(ns, shp);
+ else
+ shm_unlock(shp);
+ up_write(&shm_ids(ns).rw_mutex);
+
+out:
+ return err;
+
+out_unlock:
+ shm_unlock(shp);
+ goto out;
+
+out_free:
+ kfree(sfd);
+out_put_dentry:
+ path_put(&path);
+ goto out_nattch;
+}
+
+SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
+{
+ unsigned long ret;
+ long err;
+
+ err = do_shmat(shmid, shmaddr, shmflg, &ret);
+ if (err)
+ return err;
+ force_successful_syscall_return();
+ return (long)ret;
+}
+
+/*
+ * detach and kill segment if marked destroyed.
+ * The work is done in shm_close.
+ */
+SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long addr = (unsigned long)shmaddr;
+ int retval = -EINVAL;
+#ifdef CONFIG_MMU
+ loff_t size = 0;
+ struct vm_area_struct *next;
+#endif
+
+ if (addr & ~PAGE_MASK)
+ return retval;
+
+ down_write(&mm->mmap_sem);
+
+ /*
+ * This function tries to be smart and unmap shm segments that
+ * were modified by partial mlock or munmap calls:
+ * - It first determines the size of the shm segment that should be
+ * unmapped: It searches for a vma that is backed by shm and that
+ * started at address shmaddr. It records it's size and then unmaps
+ * it.
+ * - Then it unmaps all shm vmas that started at shmaddr and that
+ * are within the initially determined size.
+ * Errors from do_munmap are ignored: the function only fails if
+ * it's called with invalid parameters or if it's called to unmap
+ * a part of a vma. Both calls in this function are for full vmas,
+ * the parameters are directly copied from the vma itself and always
+ * valid - therefore do_munmap cannot fail. (famous last words?)
+ */
+ /*
+ * If it had been mremap()'d, the starting address would not
+ * match the usual checks anyway. So assume all vma's are
+ * above the starting address given.
+ */
+ vma = find_vma(mm, addr);
+
+#ifdef CONFIG_MMU
+ while (vma) {
+ next = vma->vm_next;
+
+ /*
+ * Check if the starting address would match, i.e. it's
+ * a fragment created by mprotect() and/or munmap(), or it
+ * otherwise it starts at this address with no hassles.
+ */
+ if ((vma->vm_ops == &shm_vm_ops) &&
+ (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
+
+
+ size = vma->vm_file->f_path.dentry->d_inode->i_size;
+ do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
+ /*
+ * We discovered the size of the shm segment, so
+ * break out of here and fall through to the next
+ * loop that uses the size information to stop
+ * searching for matching vma's.
+ */
+ retval = 0;
+ vma = next;
+ break;
+ }
+ vma = next;
+ }
+
+ /*
+ * We need look no further than the maximum address a fragment
+ * could possibly have landed at. Also cast things to loff_t to
+ * prevent overflows and make comparisons vs. equal-width types.
+ */
+ size = PAGE_ALIGN(size);
+ while (vma && (loff_t)(vma->vm_end - addr) <= size) {
+ next = vma->vm_next;
+
+ /* finding a matching vma now does not alter retval */
+ if ((vma->vm_ops == &shm_vm_ops) &&
+ (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
+
+ do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
+ vma = next;
+ }
+
+#else /* CONFIG_MMU */
+ /* under NOMMU conditions, the exact address to be destroyed must be
+ * given */
+ retval = -EINVAL;
+ if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
+ do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
+ retval = 0;
+ }
+
+#endif
+
+ up_write(&mm->mmap_sem);
+ return retval;
+}
+
+#ifdef CONFIG_PROC_FS
+static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
+{
+ struct shmid_kernel *shp = it;
+ unsigned long rss = 0, swp = 0;
+
+ shm_add_rss_swap(shp, &rss, &swp);
+
+#if BITS_PER_LONG <= 32
+#define SIZE_SPEC "%10lu"
+#else
+#define SIZE_SPEC "%21lu"
+#endif
+
+ return seq_printf(s,
+ "%10d %10d %4o " SIZE_SPEC " %5u %5u "
+ "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
+ SIZE_SPEC " " SIZE_SPEC "\n",
+ shp->shm_perm.key,
+ shp->shm_perm.id,
+ shp->shm_perm.mode,
+ shp->shm_segsz,
+ shp->shm_cprid,
+ shp->shm_lprid,
+ shp->shm_nattch,
+ shp->shm_perm.uid,
+ shp->shm_perm.gid,
+ shp->shm_perm.cuid,
+ shp->shm_perm.cgid,
+ shp->shm_atim,
+ shp->shm_dtim,
+ shp->shm_ctim,
+ rss * PAGE_SIZE,
+ swp * PAGE_SIZE);
+}
+#endif
generated by cgit (git 2.34.1) at 2024-12-20 14:27:46 +0000