uml: code tidying under arch/um/os-Linux

This patch contains varied fixes and improvements for some files under
arch/um/os-Linux/, such as a typo fix in a perror message, a missing
argument fix for a printf, some constifying for pointers and so on.

[ jdike - made sigprocmask failure return -errno instead of -1 ]

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 6f0d1c7..82e5aea 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -137,24 +137,24 @@
 extern int os_mode_fd(int fd, int mode);
 
 extern int os_seek_file(int fd, unsigned long long offset);
-extern int os_open_file(char *file, struct openflags flags, int mode);
+extern int os_open_file(const char *file, struct openflags flags, int mode);
 extern int os_read_file(int fd, void *buf, int len);
 extern int os_write_file(int fd, const void *buf, int count);
-extern int os_file_size(char *file, unsigned long long *size_out);
-extern int os_file_modtime(char *file, unsigned long *modtime);
+extern int os_file_size(const char *file, unsigned long long *size_out);
+extern int os_file_modtime(const char *file, unsigned long *modtime);
 extern int os_pipe(int *fd, int stream, int close_on_exec);
 extern int os_set_fd_async(int fd, int owner);
 extern int os_clear_fd_async(int fd);
 extern int os_set_fd_block(int fd, int blocking);
 extern int os_accept_connection(int fd);
-extern int os_create_unix_socket(char *file, int len, int close_on_exec);
+extern int os_create_unix_socket(const char *file, int len, int close_on_exec);
 extern int os_shutdown_socket(int fd, int r, int w);
 extern void os_close_file(int fd);
 extern int os_rcv_fd(int fd, int *helper_pid_out);
 extern int create_unix_socket(char *file, int len, int close_on_exec);
-extern int os_connect_socket(char *name);
+extern int os_connect_socket(const char *name);
 extern int os_file_type(char *file);
-extern int os_file_mode(char *file, struct openflags *mode_out);
+extern int os_file_mode(const char *file, struct openflags *mode_out);
 extern int os_lock_file(int fd, int excl);
 extern void os_flush_stdout(void);
 extern int os_stat_filesystem(char *path, long *bsize_out,