Add procstat_getumask function to retrieve a process umask.

MFC after:	1 month

lib/libprocstat/Symbol.map

@@ -20,6 +20,7 @@ FBSD_1.3 {
 	procstat_freevmmap;
 	procstat_get_shm_info;
 	procstat_getgroups;
+	procstat_getumask;
 	procstat_getvmmap;
 	procstat_open_core;
 };

lib/libprocstat/core.c

@@ -171,6 +171,10 @@ procstat_core_get(struct procstat_core *core, enum psc_type type, void *buf,
 		n_type = NT_PROCSTAT_GROUPS;
 		structsize = sizeof(gid_t);
 		break;
+	case PSC_TYPE_UMASK:
+		n_type = NT_PROCSTAT_UMASK;
+		structsize = sizeof(u_short);
+		break;
 	default:
 		warnx("unknown core stat type: %d", type);
 		return (NULL);

lib/libprocstat/core.h

@@ -34,6 +34,7 @@ enum psc_type {
 	PSC_TYPE_FILES,
 	PSC_TYPE_VMMAP,
 	PSC_TYPE_GROUPS,
+	PSC_TYPE_UMASK,
 };
 
 struct procstat_core;

lib/libprocstat/libprocstat.3

@@ -35,6 +35,7 @@
 .Nm procstat_getfiles ,
 .Nm procstat_getgroups ,
 .Nm procstat_getprocs ,
+.Nm procstat_getumask ,
 .Nm procstat_getvmmap ,
 .Nm procstat_freefiles ,
 .Nm procstat_freegroups ,
@@ -126,6 +127,12 @@
 .Fa "int arg"
 .Fa "unsigned int *count"
 .Fc
+.Ft "int"
+.Fo procstat_getumask
+.Fa "struct procstat *procstat"
+.Fa "struct kinfo_proc *kp"
+.Fa "unsigned short *maskp"
+.Fc
 .Ft "struct kinfo_vmentry *"
 .Fo procstat_getvmmap
 .Fa "struct procstat *procstat"
@@ -254,6 +261,14 @@ The caller is responsible to free the allocated memory with a subsequent
 function call.
 .Pp
 The
+.Fn procstat_getumask
+function gets a pointer to the
+.Vt procstat
+structure, a pointer to
+.Vt kinfo_proc
+structure, and returns the process umask in the 3rd reference parameter.
+.Pp
+The
 .Fn procstat_getvmmap
 function gets a pointer to the
 .Vt procstat

lib/libprocstat/libprocstat.c

@@ -135,6 +135,9 @@ static int	procstat_get_vnode_info_sysctl(struct filestat *fst,
 static gid_t	*procstat_getgroups_core(struct procstat_core *core,
     unsigned int *count);
 static gid_t	*procstat_getgroups_sysctl(pid_t pid, unsigned int *count);
+static int	procstat_getumask_core(struct procstat_core *core,
+    unsigned short *maskp);
+static int	procstat_getumask_sysctl(pid_t pid, unsigned short *maskp);
 static int	vntype2psfsttype(int type);
 
 void
@@ -1655,3 +1658,57 @@ procstat_freegroups(struct procstat *procstat __unused, gid_t *groups)
 
 	free(groups);
 }
+
+static int
+procstat_getumask_sysctl(pid_t pid, unsigned short *maskp)
+{
+	int error;
+	int mib[4];
+	size_t len;
+
+	mib[0] = CTL_KERN;
+	mib[1] = KERN_PROC;
+	mib[2] = KERN_PROC_UMASK;
+	mib[3] = pid;
+	len = sizeof(*maskp);
+	error = sysctl(mib, 4, maskp, &len, NULL, 0);
+	if (error != 0 && errno != ESRCH)
+		warn("sysctl: kern.proc.umask: %d", pid);
+	return (error);
+}
+
+static int
+procstat_getumask_core(struct procstat_core *core, unsigned short *maskp)
+{
+	size_t len;
+	unsigned short *buf;
+
+	buf = procstat_core_get(core, PSC_TYPE_UMASK, NULL, &len);
+	if (buf == NULL)
+		return (-1);
+	if (len < sizeof(*maskp)) {
+		free(buf);
+		return (-1);
+	}
+	*maskp = *buf;
+	free(buf);
+	return (0);
+}
+
+int
+procstat_getumask(struct procstat *procstat, struct kinfo_proc *kp,
+    unsigned short *maskp)
+{
+	switch(procstat->type) {
+	case PROCSTAT_KVM:
+		warnx("kvm method is not supported");
+		return (-1);
+	case PROCSTAT_SYSCTL:
+		return (procstat_getumask_sysctl(kp->ki_pid, maskp));
+	case PROCSTAT_CORE:
+		return (procstat_getumask_core(procstat->core, maskp));
+	default:
+		warnx("unknown access method: %d", procstat->type);
+		return (-1);
+	}
+}

lib/libprocstat/libprocstat.h

@@ -168,6 +168,8 @@ int	procstat_get_vnode_info(struct procstat *procstat, struct filestat *fst,
     struct vnstat *vn, char *errbuf);
 gid_t	*procstat_getgroups(struct procstat *procstat, struct kinfo_proc *kp,
     unsigned int *count);
+int	procstat_getumask(struct procstat *procstat, struct kinfo_proc *kp,
+    unsigned short* umask);
 struct kinfo_vmentry	*procstat_getvmmap(struct procstat *procstat,
     struct kinfo_proc *kp, unsigned int *count);
 struct procstat	*procstat_open_core(const char *filename);