[LTP] [PATCH RFC 1/2] lib: add SAFE_READ_PROC_STATUS macro

[Li Wang <liwang@redhat.com>]

To parse /proc/PID/status files, for example:
    SAFE_READ_PROC_STATUS(pid, "VmSwap:");

Signed-off-by: Li Wang <liwang@redhat.com>
Cc: Petr Vorel <pvorel@suse.cz>
Cc: Alexander Egorenkov <egorenar@linux.ibm.com>
---
 include/tst_safe_file_ops.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/tst_safe_file_ops.h b/include/tst_safe_file_ops.h
index 894c16123..7a4076c4c 100644
--- a/include/tst_safe_file_ops.h
+++ b/include/tst_safe_file_ops.h
@@ -25,6 +25,14 @@
                         &tst_rval); \
         tst_rval;})
 
+#define SAFE_READ_PROC_STATUS(pid, item) \
+       ({long tst_rval_; \
+        char tst_path_[128]; \
+        sprintf(tst_path_, "/proc/%d/status", pid); \
+        SAFE_FILE_LINES_SCANF(tst_path_, item " %ld", \
+                        &tst_rval_); \
+        tst_rval_;})
+
 #define FILE_PRINTF(path, fmt, ...) \
 	file_printf(__FILE__, __LINE__, \
 		    (path), (fmt), ## __VA_ARGS__)
-- 
2.21.3