added available frequencies split into strings and some fopen checks

src/homemade_speedstep.c

@@ -1,4 +1,6 @@
 #include <stdio.h>
+#include <stdlib.h>
+
 #define CURGOV "/sys/devices/system/cpu/cpufreq/policy0/scaling_governor"
 #define FREQS "/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies"
 #define MAXSPDPATH "/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq"
@@ -59,35 +61,104 @@ int stringlength(char string[]){
   return i;
 }
 
+int splitstr(char** dest, char line[], int index1, int index2){
+  int offset = index1;
+  while (line[index1] != ' ' && index1 < stringlength(line)){
+    index1++;
+  }
+  char* p = malloc(sizeof (char)*index1);
+  int i;
+  for(i = 0; i < index1 - offset; i++){
+    p[i] = line[i + offset];
+  }
+  p[i] = '\0';
+  dest[index2] = p;
+  return index1 + 1;
+}
+
+int countblanks(char line[]){
+  int i = 0;
+  int j = 0;
+  while(line[i] != '\0'){
+    if (line[i] == ' '){
+      j++;
+    }
+    i++;
+  }
+  return j;
+}
+
 int main(int argc, char** argv){
+  /* check for no arguments or help */
   if (argc == 1 || comparestrings(argv[1], "-h") == 0
       || comparestrings(argv[1], "--help") == 0){
-    printf("usage: homemade_speedstep <max temp> <min temp>\n");
+    fprintf(stderr, "usage: homemade_speedstep <max temp> <min temp>\n");
-    printf("       homemade_speedstep [-h | --help]\n");
+    fprintf(stderr, "       homemade_speedstep [-h | --help]\n");
-    printf("       -h | --help   prints out this help message\n");
+    fprintf(stderr, "       -h | --help   prints out this help message\n");
     return 0;
   }
+  /* check for correct ammount of arguments */
   if (argc != 3){
-    printf("error: wrong ammount of arguments given\n");
+    fprintf(stderr, "error: wrong ammount of arguments given\n");
-    printf("       see homemade_speedstep --help\n");
+    fprintf(stderr, "       see homemade_speedstep --help\n");
     return 1;
   }
-  int maxtemp = stringtoint(argv[1], stringlength(argv[1]));
+  /* set maxtemp and mintemp TODO: check for integer and difference */
-  int mintemp = stringtoint(argv[2], stringlength(argv[2]));
+  const int maxtemp = stringtoint(argv[1], stringlength(argv[1]));
-  char gov[20];
+  const int mintemp = stringtoint(argv[2], stringlength(argv[2]));
+  /* try to open scaling_current_governor, exit on fail */
   FILE* govfile = fopen(CURGOV, "r");
-  getfilec(govfile, gov);
+  if (govfile == NULL){
-  if (comparestrings(gov, "userspace\n") != 0){
+    fprintf(stderr, "error: couldn't open scaling_current_governor\n");
-    printf("error: userspace governor not set\n");
+    fprintf(stderr, "       check that you have support for cpufreq\n");
-    fclose(govfile);
+    fprintf(stderr, "       and the userspace governor in your kernel\n");
+    fprintf(stderr, "       also check that you're running this program\n");
+    fprintf(stderr, "       as root\n");
     return 2;
   }
+  /* assign content of govfile to a temporary char array */
+  char* gov = malloc(sizeof(char) * 20);
+  getfilec(govfile, gov);
+  /* check content of scaling_current_governor and exit on failure */
+  if (comparestrings(gov, "userspace\n") != 0){
+    fprintf(stderr, "error: userspace governor not set\n");
+    /* free memory and close file */
+    free(gov);
+    fclose(govfile);
+    return 3;
+  }
+  /* free memory and close file */
+  free(gov);
+  fclose(govfile);
+  /* try to open scaling_available_frequencies, exit on fail */
   FILE *freqsfile = fopen(FREQS, "r");
+  if (freqsfile == NULL){
+    fprintf(stderr, "error: couldn't open scaling_available_frequencies\n");
+    fprintf(stderr, "       check that you have support for cpufreq\n");
+    fprintf(stderr, "       in your kernel and that the program is\n");
+    fprintf(stderr, "       running as root\n");
+    return 4;
+  }
+  /* assign content of freqsfile to a temporary char array */
+  char* freqsfilec = malloc(sizeof(char) * 200);
+  getfilec(freqsfile, freqsfilec);
+  int stepc = countblanks(freqsfilec);
+  /* create a char ** array with pointers to freq steps */
+  char ** steps = malloc(sizeof(char*) * stepc);
+  int index = 0;
+  int i;
+  for(i = 0; i < stepc; i++){
+    index = splitstr(steps, freqsfilec, index, i);
+  }
+  /* free memory and close file */
+  free(freqsfilec);
+  fclose(freqsfile);
+  /* from here onwards an infinite while loop should start */
+  /* cleanup for graceful exit */
+  free(steps);
   FILE* curmaxfile = fopen(MAXSPDPATH, "r");
   FILE* setspeedfile = fopen(SETSPDPATH, "r");
   FILE* curtempfile = fopen(CURTEMPPATH, "r");
-  fclose(govfile);
-  fclose(freqsfile);
   fclose(curmaxfile);
   fclose(setspeedfile);
   fclose(curtempfile);