From 04a8682a71becdb639ec9c0d82b315a2baef7a5d Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Tue, 12 Nov 2019 01:27:16 +0000 Subject: fs/proc: Introduce /proc/pid/timens_offsets API to set time namespace offsets for children processes, i.e.: echo "$clockid $offset_sec $offset_nsec" > /proc/self/timens_offsets Co-developed-by: Dmitry Safonov Signed-off-by: Andrei Vagin Signed-off-by: Dmitry Safonov Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20191112012724.250792-28-dima@arista.com --- fs/proc/base.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) (limited to 'fs/proc') diff --git a/fs/proc/base.c b/fs/proc/base.c index ebea9501afb8..5adc6390ac3a 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -94,6 +94,7 @@ #include #include #include +#include #include #include "internal.h" #include "fd.h" @@ -1533,6 +1534,96 @@ static const struct file_operations proc_pid_sched_autogroup_operations = { #endif /* CONFIG_SCHED_AUTOGROUP */ +#ifdef CONFIG_TIME_NS +static int timens_offsets_show(struct seq_file *m, void *v) +{ + struct task_struct *p; + + p = get_proc_task(file_inode(m->file)); + if (!p) + return -ESRCH; + proc_timens_show_offsets(p, m); + + put_task_struct(p); + + return 0; +} + +static ssize_t timens_offsets_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(file); + struct proc_timens_offset offsets[2]; + char *kbuf = NULL, *pos, *next_line; + struct task_struct *p; + int ret, noffsets; + + /* Only allow < page size writes at the beginning of the file */ + if ((*ppos != 0) || (count >= PAGE_SIZE)) + return -EINVAL; + + /* Slurp in the user data */ + kbuf = memdup_user_nul(buf, count); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + /* Parse the user data */ + ret = -EINVAL; + noffsets = 0; + for (pos = kbuf; pos; pos = next_line) { + struct proc_timens_offset *off = &offsets[noffsets]; + int err; + + /* Find the end of line and ensure we don't look past it */ + next_line = strchr(pos, '\n'); + if (next_line) { + *next_line = '\0'; + next_line++; + if (*next_line == '\0') + next_line = NULL; + } + + err = sscanf(pos, "%u %lld %lu", &off->clockid, + &off->val.tv_sec, &off->val.tv_nsec); + if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC) + goto out; + noffsets++; + if (noffsets == ARRAY_SIZE(offsets)) { + if (next_line) + count = next_line - kbuf; + break; + } + } + + ret = -ESRCH; + p = get_proc_task(inode); + if (!p) + goto out; + ret = proc_timens_set_offset(file, p, offsets, noffsets); + put_task_struct(p); + if (ret) + goto out; + + ret = count; +out: + kfree(kbuf); + return ret; +} + +static int timens_offsets_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, timens_offsets_show, inode); +} + +static const struct file_operations proc_timens_offsets_operations = { + .open = timens_offsets_open, + .read = seq_read, + .write = timens_offsets_write, + .llseek = seq_lseek, + .release = single_release, +}; +#endif /* CONFIG_TIME_NS */ + static ssize_t comm_write(struct file *file, const char __user *buf, size_t count, loff_t *offset) { @@ -3015,6 +3106,9 @@ static const struct pid_entry tgid_base_stuff[] = { #endif #ifdef CONFIG_SCHED_AUTOGROUP REG("autogroup", S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations), +#endif +#ifdef CONFIG_TIME_NS + REG("timens_offsets", S_IRUGO|S_IWUSR, proc_timens_offsets_operations), #endif REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations), #ifdef CONFIG_HAVE_ARCH_TRACEHOOK -- cgit v1.2.3-59-g8ed1b