[dpdk-dev] [PATCH 2/5] eal: extract function eal_parse_sysfs_valuef

[Shreyansh Jain <shreyansh.jain@nxp.com>]

From: Jan Viktorin <viktorin@rehivetech.com>

From: Jan Viktorin <viktorin@rehivetech.com>

The eal_parse_sysfs_value function accepts a filename however, such
interface introduces race-conditions to the code. Introduce the
variant of this function that accepts an already opened file instead of
a filename.

Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
---
 lib/librte_eal/common/eal_filesystem.h |  5 +++++
 lib/librte_eal/linuxapp/eal/eal.c      | 36 +++++++++++++++++++++++-----------
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/lib/librte_eal/common/eal_filesystem.h b/lib/librte_eal/common/eal_filesystem.h
index fdb4a70..7875454 100644
--- a/lib/librte_eal/common/eal_filesystem.h
+++ b/lib/librte_eal/common/eal_filesystem.h
@@ -43,6 +43,7 @@
 /** Path of rte config file. */
 #define RUNTIME_CONFIG_FMT "%s/.%s_config"
 
+#include <stdio.h>
 #include <stdint.h>
 #include <limits.h>
 #include <unistd.h>
@@ -115,4 +116,8 @@ eal_get_hugefile_temp_path(char *buffer, size_t buflen, const char *hugedir, int
  * Used to read information from files on /sys */
 int eal_parse_sysfs_value(const char *filename, unsigned long *val);
 
+/** Function to read a single numeric value from a file on the filesystem.
+ * Used to read information from files on /sys */
+int eal_parse_sysfs_valuef(FILE *f, unsigned long *val);
+
 #endif /* EAL_FILESYSTEM_H */
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index d5b81a3..f912e4e 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -126,13 +126,30 @@ rte_eal_get_configuration(void)
 	return &rte_config;
 }
 
+int
+eal_parse_sysfs_valuef(FILE *f, unsigned long *val)
+{
+	char buf[BUFSIZ];
+	char *end = NULL;
+
+	RTE_VERIFY(f != NULL);
+
+	if (fgets(buf, sizeof(buf), f) == NULL)
+		return -1;
+
+	*val = strtoul(buf, &end, 0);
+	if ((buf[0] == '\0') || (end == NULL) || (*end != '\n'))
+		return -2;
+
+	return 0;
+}
+
 /* parse a sysfs (or other) file containing one integer value */
 int
 eal_parse_sysfs_value(const char *filename, unsigned long *val)
 {
+	int ret;
 	FILE *f;
-	char buf[BUFSIZ];
-	char *end = NULL;
 
 	if ((f = fopen(filename, "r")) == NULL) {
 		RTE_LOG(ERR, EAL, "%s(): cannot open sysfs value %s\n",
@@ -140,21 +157,18 @@ eal_parse_sysfs_value(const char *filename, unsigned long *val)
 		return -1;
 	}
 
-	if (fgets(buf, sizeof(buf), f) == NULL) {
+	ret = eal_parse_sysfs_valuef(f, val);
+	if (ret == -1) {
 		RTE_LOG(ERR, EAL, "%s(): cannot read sysfs value %s\n",
-			__func__, filename);
-		fclose(f);
-		return -1;
+				__func__, filename);
 	}
-	*val = strtoul(buf, &end, 0);
-	if ((buf[0] == '\0') || (end == NULL) || (*end != '\n')) {
+	else if (ret < 0) {
 		RTE_LOG(ERR, EAL, "%s(): cannot parse sysfs value %s\n",
 				__func__, filename);
-		fclose(f);
-		return -1;
 	}
+
 	fclose(f);
-	return 0;
+	return ret;
 }
 
 
-- 
2.7.4