+
+#ifdef CONFIG_PROC_FS
+static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
+{
+ struct ipc_proc_iface *iface = s->private;
+ struct kern_ipc_perm *ipc = it;
+ loff_t p;
+ struct ipc_ids *ids;
+
+ ids = current->nsproxy->ipc_ns->ids[iface->ids];
+
+ /* If we had an ipc id locked before, unlock it */
+ if (ipc && ipc != SEQ_START_TOKEN)
+ ipc_unlock(ipc);
+
+ /*
+ * p = *pos - 1 (because id 0 starts at position 1)
+ * + 1 (because we increment the position by one)
+ */
+ for (p = *pos; p <= ids->max_id; p++) {
+ if ((ipc = ipc_lock(ids, p)) != NULL) {
+ *pos = p + 1;
+ return ipc;
+ }
+ }
+
+ /* Out of range - return NULL to terminate iteration */
+ return NULL;
+}
+
+/*
+ * File positions: pos 0 -> header, pos n -> ipc id + 1.
+ * SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START.
+ */
+static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
+{
+ struct ipc_proc_iface *iface = s->private;
+ struct kern_ipc_perm *ipc;
+ loff_t p;
+ struct ipc_ids *ids;
+
+ ids = current->nsproxy->ipc_ns->ids[iface->ids];
+
+ /*
+ * Take the lock - this will be released by the corresponding
+ * call to stop().
+ */
+ mutex_lock(&ids->mutex);
+
+ /* pos < 0 is invalid */
+ if (*pos < 0)
+ return NULL;
+
+ /* pos == 0 means header */
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ /* Find the (pos-1)th ipc */
+ for (p = *pos - 1; p <= ids->max_id; p++) {
+ if ((ipc = ipc_lock(ids, p)) != NULL) {
+ *pos = p + 1;
+ return ipc;
+ }
+ }
+ return NULL;
+}
+
+static void sysvipc_proc_stop(struct seq_file *s, void *it)
+{
+ struct kern_ipc_perm *ipc = it;
+ struct ipc_proc_iface *iface = s->private;
+ struct ipc_ids *ids;
+
+ /* If we had a locked segment, release it */
+ if (ipc && ipc != SEQ_START_TOKEN)
+ ipc_unlock(ipc);
+
+ ids = current->nsproxy->ipc_ns->ids[iface->ids];
+ /* Release the lock we took in start() */
+ mutex_unlock(&ids->mutex);
+}
+
+static int sysvipc_proc_show(struct seq_file *s, void *it)
+{
+ struct ipc_proc_iface *iface = s->private;
+
+ if (it == SEQ_START_TOKEN)
+ return seq_puts(s, iface->header);
+
+ return iface->show(s, it);
+}
+
+static struct seq_operations sysvipc_proc_seqops = {
+ .start = sysvipc_proc_start,
+ .stop = sysvipc_proc_stop,
+ .next = sysvipc_proc_next,
+ .show = sysvipc_proc_show,
+};
+
+static int sysvipc_proc_open(struct inode *inode, struct file *file) {
+ int ret;
+ struct seq_file *seq;
+
+ ret = seq_open(file, &sysvipc_proc_seqops);
+ if (!ret) {
+ seq = file->private_data;
+ seq->private = PDE(inode)->data;
+ }
+ return ret;
+}
+
+static struct file_operations sysvipc_proc_fops = {
+ .open = sysvipc_proc_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+#endif /* CONFIG_PROC_FS */