[RFC V2 PATCH 21/25] net/netpolicy: set per task policy by proc
From: <hidden>
Date: 2016-08-04 19:15:24
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), proc filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Kan Liang <redacted> Users may not want to change the source code to add per task net polic support. Or they may want to change a running task's net policy. prctl does not work for both cases. This patch adds an interface in /proc, which can be used to set and retrieve policy of already running tasks. User can write the policy name into /proc/$PID/net_policy to set per task net policy. Signed-off-by: Kan Liang <redacted> --- fs/proc/base.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a11eb71..7679785 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c@@ -91,6 +91,8 @@ #include <asm/hardwall.h> #endif #include <trace/events/oom.h> +#include <linux/netpolicy.h> +#include <linux/ctype.h> #include "internal.h" #include "fd.h"
@@ -2807,6 +2809,65 @@ static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns, return err; } +#ifdef CONFIG_NETPOLICY +static int proc_net_policy_show(struct seq_file *m, void *v) +{ + struct inode *inode = m->private; + struct task_struct *task = get_proc_task(inode); + + if (is_net_policy_valid(task->task_netpolicy.policy)) + seq_printf(m, "%s\n", policy_name[task->task_netpolicy.policy]); + + return 0; +} + +static int proc_net_policy_open(struct inode *inode, struct file *file) +{ + return single_open(file, proc_net_policy_show, inode); +} + +static ssize_t proc_net_policy_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(file); + struct task_struct *task = get_proc_task(inode); + char name[POLICY_NAME_LEN_MAX]; + int i, ret; + + if (count >= POLICY_NAME_LEN_MAX) + return -EINVAL; + + if (copy_from_user(name, buf, count)) + return -EINVAL; + + for (i = 0; i < count - 1; i++) + name[i] = toupper(name[i]); + name[POLICY_NAME_LEN_MAX - 1] = 0; + + for (i = 0; i < NET_POLICY_MAX; i++) { + if (!strncmp(name, policy_name[i], strlen(policy_name[i]))) { + ret = netpolicy_register(&task->task_netpolicy, i); + if (ret) + return ret; + break; + } + } + + if (i == NET_POLICY_MAX) + return -EINVAL; + + return count; +} + +static const struct file_operations proc_net_policy_operations = { + .open = proc_net_policy_open, + .write = proc_net_policy_write, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; +#endif /* CONFIG_NETPOLICY */ + /* * Thread groups */
@@ -2906,6 +2967,9 @@ static const struct pid_entry tgid_base_stuff[] = { REG("timers", S_IRUGO, proc_timers_operations), #endif REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations), +#if IS_ENABLED(CONFIG_NETPOLICY) + REG("net_policy", S_IRUSR|S_IWUSR, proc_net_policy_operations), +#endif }; static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
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2.5.5