initial commit

Author: Fabian Holler

c/getusage.c

@@ -0,0 +1,82 @@
+//Last modified: 17/10/11 18:52:02(CEST) by Fabian Holler
+#include <stdlib.h> 
+#include <sys/types.h>
+#include <stdio.h>
+#include <strings.h>
+#include <unistd.h>
+
+struct pstat{
+    long unsigned int utime_ticks;
+    long int cutime_ticks;
+    long unsigned int stime_ticks;
+    long int cstime_ticks;
+    long unsigned int vsize; // virtual memory size in bytes
+    long unsigned int rss; //Resident  Set  Size in bytes
+
+    long unsigned int cpu_total_time;
+};
+
+/*
+ * read /proc data into the passed struct pstat
+ * returns 0 on success, -1 on error
+*/
+int get_usage(const pid_t pid, struct pstat* result){
+    //convert  pid to string
+    char pid_s[20];
+    snprintf(pid_s, sizeof(pid_s), "%d", pid);
+    char stat_filepath[30] = "/proc/";
+    strncat(stat_filepath, pid_s, sizeof(stat_filepath) - strlen(stat_filepath) -1);
+    strncat(stat_filepath, "/stat", sizeof(stat_filepath) - strlen(stat_filepath) -1);
+
+    //open /proc/pid/stat
+    FILE *fpstat = fopen(stat_filepath, "r");
+    if(fpstat == NULL){
+        printf("FOPEN ERROR pid stat %s:\n", stat_filepath);
+        return -1;
+    }
+
+    //open /proc/stat
+    FILE *fstat = fopen("/proc/stat", "r");
+    if(fstat == NULL){
+        printf("FOPEN ERROR");
+        fclose(fstat);
+        return -1;
+    }
+    bzero(result, sizeof(struct pstat));
+
+    //read values from /proc/pid/stat
+    long int rss;
+    if(fscanf(fpstat, "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %lu %lu %ld %ld %*d %*d %*d %*d %*u %lu %ld", &result->utime_ticks, &result->stime_ticks, &result->cutime_ticks, &result->cstime_ticks, &result->vsize, &rss) == EOF){
+        fclose(fpstat);
+        fclose(fstat);
+        return -1;
+    }
+    fclose(fpstat);
+    result->rss = rss * getpagesize();
+
+    //read+calc cpu total time from /proc/stat, on linux 2.6.35-23 x86_64 the cpu row has 10values could differ on different architectures :/
+    long unsigned int cpu_time[10];
+    bzero(cpu_time, sizeof(cpu_time));
+    if(fscanf(fstat, "%*s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu", &cpu_time[0], &cpu_time[1], &cpu_time[2], &cpu_time[3], &cpu_time[4], &cpu_time[5], &cpu_time[6], &cpu_time[7], &cpu_time[8], &cpu_time[9]) == EOF){
+        fclose(fstat);
+        return -1;
+    }
+    fclose(fstat);
+
+    for(int i=0; i < 10;i++){
+        result->cpu_total_time += cpu_time[i];
+    }
+
+    return 0;
+}
+
+/*
+* calculates the actual CPU usage(cur_usage - last_usage) in percent
+* cur_usage, last_usage: both last measured get_usage() results
+* ucpu_usage, scpu_usage: result parameters: user and sys cpu usage in %
+*/
+void calc_cpu_usage(const struct pstat* cur_usage, const struct pstat* last_usage, float* ucpu_usage, float* scpu_usage){
+    *ucpu_usage = 100 * ((((cur_usage->utime_ticks + cur_usage->cutime_ticks) - (last_usage->utime_ticks + last_usage->cutime_ticks))) / (float)((cur_usage->cpu_total_time - last_usage->cpu_total_time)));
+    *scpu_usage = 100 * ((((cur_usage->stime_ticks + cur_usage->cstime_ticks) - (last_usage->stime_ticks + last_usage->cstime_ticks))) / (float)((cur_usage->cpu_total_time - last_usage->cpu_total_time)));
+}
+

c/print_bytes.c

@@ -0,0 +1,11 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+void print_bytes(void* buf, size_t len){
+    for(unsigned int i = 0;i < len; i++){
+        if(len != 0)
+            printf(":");
+        printf("%02x", *((uint8_t*) ((char*) buf + i)));
+    }
+    printf("\n");
+}