From 15d9095122c0d4f9a4dab05fb0e84d84c624e1b4 Mon Sep 17 00:00:00 2001
From: PA4WDH
Date: Sat, 20 May 2023 17:17:43 +0200
Subject: Translate POC to C code

---
 sysfs.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 sysfs.c

(limited to 'sysfs.c')

diff --git a/sysfs.c b/sysfs.c
new file mode 100644
index 0000000..e31aef2
--- /dev/null
+++ b/sysfs.c
@@ -0,0 +1,83 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include "debug.h"
+
+int sysfs_read_str(char *sysfs_file,char *buf,size_t bufsize)
+{
+ int sysfs_handle;
+ size_t datalen;
+
+ DEBUG1_SYSFS("Reading sysfs file %s\n",sysfs_file);
+
+// Open the file
+ sysfs_handle=open(sysfs_file,O_RDONLY);
+ DEBUG2_SYSFS("Open returned %d\n",sysfs_handle);
+ if (sysfs_handle<0) return -1;
+
+// Read the content of the file
+ datalen=read(sysfs_handle,buf,bufsize);
+ HEXDUMP2_SYSFS(buf,datalen);
+ close(sysfs_handle);
+ buf[datalen]=0;
+
+// Strip newline
+ if (buf[datalen-1]=='\n')
+ {
+  DEBUG2_SYSFS("Newline stripped\n");
+  datalen--;
+  buf[datalen]=0;
+ }
+
+ return datalen;
+}
+
+long int sysfs_read_long_int(char *sysfs_file)
+{
+ char buf[255];
+ int datalen;
+
+// Read data
+ datalen=sysfs_read_str(sysfs_file,buf,sizeof(buf));
+ if (datalen<0) return 0;
+
+// Convert to long int
+ return strtoll((char*)&buf,NULL,10);
+}
+
+int sysfs_write_str(char *sysfs_file,char *value,int checkdelay)
+{
+ int sysfs_handle;
+ size_t len;
+ char buf[255];
+
+ DEBUG1_SYSFS("Writing %s to sysfs file %s\n",value,sysfs_file);
+
+// Open the file
+ sysfs_handle=open(sysfs_file,O_WRONLY);
+ DEBUG2_SYSFS("Open returned %d\n",sysfs_handle);
+ if (sysfs_handle<0) return -1;
+
+// Write the data
+ len=write(sysfs_handle,value,strlen(value));
+ close(sysfs_handle);
+ DEBUG2_SYSFS("Written %zd bytes\n",len);
+
+// What if instructed to
+ if (checkdelay>0) usleep(checkdelay*1000);
+
+// Validate we actually set what we want to set
+ sysfs_read_str(sysfs_file,buf,sizeof(buf));
+ DEBUG2_SYSFS("Content is now %s\n",buf);
+
+ if (strncmp(value,buf,255)!=0)
+ {
+  DEBUG2_SYSFS("Set failed\n");
+  return -1;
+ }
+ DEBUG2_SYSFS("Set successfull\n");
+
+ return 0;
+}
-- 
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