lib,path: move path access functions from lscpu into lib/path.c

A couple of these functions already have been copied to chcpu.c,
so it makes sense to move these functions into an own file.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

lib/path.c

@@ -0,0 +1,191 @@
+/*
+ * Simple functions to access files.
+ *
+ * Taken from lscpu.c
+ *
+ * Copyright (C) 2008 Cai Qian <qcai@redhat.com>
+ * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "cpuset.h"
+#include "path.h"
+#include "nls.h"
+#include "c.h"
+
+static size_t prefixlen;
+static char pathbuf[PATH_MAX];
+
+static const char *
+path_vcreate(const char *path, va_list ap)
+{
+	if (prefixlen)
+		vsnprintf(pathbuf + prefixlen,
+			  sizeof(pathbuf) - prefixlen, path, ap);
+	else
+		vsnprintf(pathbuf, sizeof(pathbuf), path, ap);
+	return pathbuf;
+}
+
+static FILE *
+path_vfopen(const char *mode, int exit_on_error, const char *path, va_list ap)
+{
+	FILE *f;
+	const char *p = path_vcreate(path, ap);
+
+	f = fopen(p, mode);
+	if (!f && exit_on_error)
+		err(EXIT_FAILURE, _("error: cannot open %s"), p);
+	return f;
+}
+
+FILE *
+path_fopen(const char *mode, int exit_on_error, const char *path, ...)
+{
+	FILE *fd;
+	va_list ap;
+
+	va_start(ap, path);
+	fd = path_vfopen(mode, exit_on_error, path, ap);
+	va_end(ap);
+
+	return fd;
+}
+
+void
+path_getstr(char *result, size_t len, const char *path, ...)
+{
+	FILE *fd;
+	va_list ap;
+
+	va_start(ap, path);
+	fd = path_vfopen("r", 1, path, ap);
+	va_end(ap);
+
+	if (!fgets(result, len, fd))
+		err(EXIT_FAILURE, _("failed to read: %s"), pathbuf);
+	fclose(fd);
+
+	len = strlen(result);
+	if (result[len - 1] == '\n')
+		result[len - 1] = '\0';
+}
+
+int
+path_getnum(const char *path, ...)
+{
+	FILE *fd;
+	va_list ap;
+	int result;
+
+	va_start(ap, path);
+	fd = path_vfopen("r", 1, path, ap);
+	va_end(ap);
+
+	if (fscanf(fd, "%d", &result) != 1) {
+		if (ferror(fd))
+			err(EXIT_FAILURE, _("failed to read: %s"), pathbuf);
+		else
+			errx(EXIT_FAILURE, _("parse error: %s"), pathbuf);
+	}
+	fclose(fd);
+	return result;
+}
+
+int
+path_exist(const char *path, ...)
+{
+	va_list ap;
+	const char *p;
+
+	va_start(ap, path);
+	p = path_vcreate(path, ap);
+	va_end(ap);
+
+	return access(p, F_OK) == 0;
+}
+
+static cpu_set_t *
+path_cpuparse(int maxcpus, int islist, const char *path, va_list ap)
+{
+	FILE *fd;
+	cpu_set_t *set;
+	size_t setsize, len = maxcpus * 7;
+	char buf[len];
+
+	fd = path_vfopen("r", 1, path, ap);
+
+	if (!fgets(buf, len, fd))
+		err(EXIT_FAILURE, _("failed to read: %s"), pathbuf);
+	fclose(fd);
+
+	len = strlen(buf);
+	if (buf[len - 1] == '\n')
+		buf[len - 1] = '\0';
+
+	set = cpuset_alloc(maxcpus, &setsize, NULL);
+	if (!set)
+		err(EXIT_FAILURE, _("failed to callocate cpu set"));
+
+	if (islist) {
+		if (cpulist_parse(buf, set, setsize, 0))
+			errx(EXIT_FAILURE, _("failed to parse CPU list %s"), buf);
+	} else {
+		if (cpumask_parse(buf, set, setsize))
+			errx(EXIT_FAILURE, _("failed to parse CPU mask %s"), buf);
+	}
+	return set;
+}
+
+cpu_set_t *
+path_cpuset(int maxcpus, const char *path, ...)
+{
+	va_list ap;
+	cpu_set_t *set;
+
+	va_start(ap, path);
+	set = path_cpuparse(maxcpus, 0, path, ap);
+	va_end(ap);
+
+	return set;
+}
+
+cpu_set_t *
+path_cpulist(int maxcpus, const char *path, ...)
+{
+	va_list ap;
+	cpu_set_t *set;
+
+	va_start(ap, path);
+	set = path_cpuparse(maxcpus, 1, path, ap);
+	va_end(ap);
+
+	return set;
+}
+
+void
+path_setprefix(const char *prefix)
+{
+	prefixlen = strlen(prefix);
+	strncpy(pathbuf, prefix, sizeof(pathbuf));
+	pathbuf[sizeof(pathbuf) - 1] = '\0';
+}