On Thu, Apr 14, 2016 at 2:08 PM, Richard W.M. Jones <rjo...@redhat.com> wrote: > It's not possible to read the process umask without also modifying it, > which is what umask(2) does. A library cannot read umask safely, > especially if the main program might be multithreaded. > > Add a new status line ("Umask") in /proc/<PID>/status. It contains > the file mode creation mask (umask) in octal. It is only shown for > tasks which have task->fs. > > This patch is adapted from one originally written by Pierre Carrier. > > Signed-off-by: Richard W.M. Jones <rjo...@redhat.com>
Acked-by: Konstantin Khlebnikov <koc...@gmail.com> > --- > Documentation/filesystems/proc.txt | 1 + > fs/proc/array.c | 20 +++++++++++++++++++- > 2 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/Documentation/filesystems/proc.txt > b/Documentation/filesystems/proc.txt > index 7f5607a..e8d0075 100644 > --- a/Documentation/filesystems/proc.txt > +++ b/Documentation/filesystems/proc.txt > @@ -225,6 +225,7 @@ Table 1-2: Contents of the status files (as of 4.1) > TracerPid PID of process tracing this process (0 if not) > Uid Real, effective, saved set, and file system > UIDs > Gid Real, effective, saved set, and file system > GIDs > + Umask file mode creation mask > FDSize number of file descriptor slots currently > allocated > Groups supplementary group list > NStgid descendant namespace thread group ID hierarchy > diff --git a/fs/proc/array.c b/fs/proc/array.c > index b6c00ce..88c7de1 100644 > --- a/fs/proc/array.c > +++ b/fs/proc/array.c > @@ -83,6 +83,7 @@ > #include <linux/tracehook.h> > #include <linux/string_helpers.h> > #include <linux/user_namespace.h> > +#include <linux/fs_struct.h> > > #include <asm/pgtable.h> > #include <asm/processor.h> > @@ -139,12 +140,25 @@ static inline const char *get_task_state(struct > task_struct *tsk) > return task_state_array[fls(state)]; > } > > +static inline int get_task_umask(struct task_struct *tsk) > +{ > + struct fs_struct *fs; > + int umask = -ENOENT; > + > + task_lock(tsk); > + fs = tsk->fs; > + if (fs) > + umask = fs->umask; > + task_unlock(tsk); > + return umask; > +} > + > static inline void task_state(struct seq_file *m, struct pid_namespace *ns, > struct pid *pid, struct task_struct *p) > { > struct user_namespace *user_ns = seq_user_ns(m); > struct group_info *group_info; > - int g; > + int g, umask; > struct task_struct *tracer; > const struct cred *cred; > pid_t ppid, tpid = 0, tgid, ngid; > @@ -162,6 +176,10 @@ static inline void task_state(struct seq_file *m, struct > pid_namespace *ns, > ngid = task_numa_group_id(p); > cred = get_task_cred(p); > > + umask = get_task_umask(p); > + if (umask >= 0) > + seq_printf(m, "Umask:\t%#04o\n", umask); > + > task_lock(p); > if (p->files) > max_fds = files_fdtable(p->files)->max_fds; > -- > 2.7.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html