lib: add strtol into utility library

The utility library is for functions which are shared in commands,
but that does not belong to libproc-ng.  The first function is a
wrapper for strtol that performs error checking, and exists if such
happen.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

Makefile.am

@@ -3,6 +3,7 @@ AM_CPPFLAGS = -include $(top_builddir)/config.h -I$(top_srcdir)/include
 ACLOCAL_AMFLAGS = -I m4
 SUBDIRS = \
 	include \
+	lib \
 	po \
 	proc \
 	ps \

configure.ac

@@ -188,6 +188,7 @@ AC_SUBST(DEJAGNU)
 AC_CONFIG_FILES([
 	Makefile
 	include/Makefile
+	lib/Makefile
 	po/Makefile.in
 	proc/Makefile
 	proc/libprocfs.pc

include/strutils.h

@@ -0,0 +1,6 @@
+#ifndef PROCPS_NG_STRUTILS
+#define PROCPS_NG_STRUTILS
+
+extern long strtol_or_err(const char *str, const char *errmesg);
+
+#endif

lib/.gitignore

@@ -0,0 +1 @@
+test_strutils

lib/Makefile.am

@@ -0,0 +1,7 @@
+AM_CPPFLAGS = -include $(top_builddir)/config.h -I$(top_srcdir)/include
+
+AM_CPPFLAGS += -DTEST_PROGRAM
+
+noinst_PROGRAMS = test_strutils
+
+test_strutils_SOURCES = strutils.c

lib/strutils.c

@@ -0,0 +1,34 @@
+#include <stdlib.h>
+
+#include "c.h"
+#include "strutils.h"
+
+/*
+ * same as strtol(3) but exit on failure instead of returning crap
+ */
+long strtol_or_err(const char *str, const char *errmesg)
+{
+	long num;
+	char *end = NULL;
+
+	if (str == NULL || *str == '\0')
+		goto err;
+	errno = 0;
+	num = strtol(str, &end, 10);
+	if (errno || str == end || (end && *end))
+		goto err;
+
+	return num;
+ err:
+	if (errno)
+		err(EXIT_FAILURE, "%s: '%s'", errmesg, str);
+	else
+		errx(EXIT_FAILURE, "%s: '%s'", errmesg, str);
+}
+
+#ifdef TEST_PROGRAM
+int main(int argc, char *argv[])
+{
+	return EXIT_FAILURE;
+}
+#endif				/* TEST_PROGRAM */