X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=panel-plugin%2Fhdaps.c;h=776477d0bddf26901902ce59c15ee4ac74e8b2bb;hb=ab31414f32e0c386fb8d3926e805395a701fe6a3;hp=de1476f3199076e0e1791b26ad5c77ffc5f0dc94;hpb=63eef27ea56fc385cf1eb7af33211e697b384c3e;p=xfce4-hdaps.git

diff --git a/panel-plugin/hdaps.c b/panel-plugin/hdaps.c
index de1476f..776477d 100644
--- a/panel-plugin/hdaps.c
+++ b/panel-plugin/hdaps.c
@@ -1,3 +1,24 @@
+/*
+ * xfce4-hdaps, an XFCE4 panel plugin for the HDAPS system.
+ *
+ * Copyright (C) 2019 Michael Orlitzky
+ *
+ *   http://michael.orlitzky.com/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details:
+ *
+ *   https://www.gnu.org/licenses/agpl-3.0.html
+ *
+ */
+
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
@@ -6,8 +27,9 @@
 #include <sys/types.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
 #include "hdaps.h"
 
 /* The most space we expect to need when reading in
@@ -20,6 +42,7 @@
 #define SYSFS_BLOCK_DEVICE_DIR "/sys/block/"
 
 
+
 static int hdaps_device_exists(const char* device) {
   /* Determine whether or not a device (file) exists and has an
      unload_heads entry in sysfs. */
@@ -29,19 +52,25 @@ static int hdaps_device_exists(const char* device) {
 }
 
 
+
 int get_hdaps_device_list(char list[MAX_HDAPS_DEVICES][FILENAME_MAX]) {
+  /* Gets a list of devices which support HDAPS.
+   * We start by getting every device in the sysfs
+   * block device directory, and then eliminate those
+   * which don't have an unload_heads entry.
+   */
   int list_idx = 0;
   DIR *dp;
   struct dirent *ep;
 
   dp = opendir(SYSFS_BLOCK_DEVICE_DIR);
-  
+
   if (dp != NULL) {
     while ((ep = readdir(dp)) && list_idx < MAX_HDAPS_DEVICES) {
       /* This next test covers "." and ".." too. */
       if (hdaps_device_exists(ep->d_name)) {
-	strncpy(list[list_idx], ep->d_name, FILENAME_MAX);
-	list_idx++;
+        strncpy(list[list_idx], ep->d_name, FILENAME_MAX);
+        list_idx++;
       }
     }
 
@@ -52,38 +81,46 @@ int get_hdaps_device_list(char list[MAX_HDAPS_DEVICES][FILENAME_MAX]) {
 }
 
 
+
 int slurp_file(const char* filename, char* buf, int max_bytes) {
   /* This function just reads the contents of filename
-   * into buf. It is slightly stolen from the hdapsd project.
+   * into buf, and returns the number of bytes read.
    */
-  
+  if (filename == NULL || buf == NULL) {
+    /* HDAPS_SUPER_BAD_ERROR */
+    return HDAPS_ERROR;
+  }
+
+
   /* Return an error value by default. */
-  int ret = HDAPS_ERROR;
+  int bytes_read = HDAPS_ERROR;
+
   int fd = open(filename, O_RDONLY);
 
-  if (filename == NULL || buf == NULL) {
-    return ret;
-  }
-  
   if (fd < 0) {
+    /* open() didn't work. Report the error, and bail. */
     fprintf(stderr, "open(%s): %s\n", filename, strerror(errno));
-    return fd;
-  }	
+    return HDAPS_ERROR;
+  }
 
-  ret = read(fd, buf, max_bytes-1);
-  
-  if (ret < 0) {
+  bytes_read = read(fd, buf, max_bytes-1);
+
+  if (bytes_read < 0) {
+    /* Why did we read fewer than 0 bytes? */
     fprintf(stderr, "read(%s): %s\n", filename, strerror(errno));
   }
   else {
-    buf[ret] = 0; /* Null-terminate buf. */
+    /* Null-terminate buf if read() worked. */
+    buf[bytes_read] = 0;
   }
 
+
   if (close(fd)) {
+    /* Oh hey we should be able to close the file, too. */
     fprintf(stderr, "close(%s): %s\n", filename, strerror(errno));
   }
-  
-  return ret;
+
+  return bytes_read;
 }
 
 
@@ -92,17 +129,20 @@ int slurp_file(const char* filename, char* buf, int max_bytes) {
 int parse_int_from_file(const char* filename) {
   /* Read an integer from a file. We expect the file
      to contain an integer (although in string form). */
-  
-  char buf[MAX_FILE_CONTENTS_SIZE];
-  int ret = slurp_file(filename, buf, sizeof(buf));
 
-  if (ret < 0) {
-    /* Why did we read fewer than 0 bytes? */
-    return ret;
+  char buf[MAX_FILE_CONTENTS_SIZE];
+  int bytes_read = slurp_file(filename, buf, sizeof(buf));
+
+  if (bytes_read <= 0) {
+    /* We can't parse what doesn't exist. Note that
+     * reading "0" from a file should result in reading
+     * at least 1 byte.
+     */
+    return HDAPS_ERROR;
   }
   else {
     /* If we read more than 0 bytes, hopefully we can
-       count on atoi to succeed. */
+     * count on atoi to succeed. */
     return atoi(buf);
   }
 }