From 675c3596ff32c040d1dd2e28dd57e83e634b9f60 Mon Sep 17 00:00:00 2001 From: Juntong Deng Date: Mon, 14 Oct 2024 10:21:08 +0100 Subject: [PATCH] bpf: Add bpf_task_from_vpid() kfunc bpf_task_from_pid() that currently exists looks up the struct task_struct corresponding to the pid in the root pid namespace (init_pid_ns). This patch adds bpf_task_from_vpid() which looks up the struct task_struct corresponding to vpid in the pid namespace of the current process. This is useful for getting information about other processes in the same pid namespace. Signed-off-by: Juntong Deng Link: https://lore.kernel.org/r/AM6PR03MB5848E50DA58F79CDE65433C399442@AM6PR03MB5848.eurprd03.prod.outlook.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index aaaefefdf692..073e6f04f4d7 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2521,6 +2521,25 @@ __bpf_kfunc struct task_struct *bpf_task_from_pid(s32 pid) return p; } +/** + * bpf_task_from_vpid - Find a struct task_struct from its vpid by looking it up + * in the pid namespace of the current task. If a task is returned, it must + * either be stored in a map, or released with bpf_task_release(). + * @vpid: The vpid of the task being looked up. + */ +__bpf_kfunc struct task_struct *bpf_task_from_vpid(s32 vpid) +{ + struct task_struct *p; + + rcu_read_lock(); + p = find_task_by_vpid(vpid); + if (p) + p = bpf_task_acquire(p); + rcu_read_unlock(); + + return p; +} + /** * bpf_dynptr_slice() - Obtain a read-only pointer to the dynptr data. * @p: The dynptr whose data slice to retrieve @@ -3034,6 +3053,7 @@ BTF_ID_FLAGS(func, bpf_task_under_cgroup, KF_RCU) BTF_ID_FLAGS(func, bpf_task_get_cgroup1, KF_ACQUIRE | KF_RCU | KF_RET_NULL) #endif BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_task_from_vpid, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_throw) BTF_KFUNCS_END(generic_btf_ids) -- 2.50.1