process_info.c

#include <dirent.h>
#include <ctype.h>
#include <string.h>
#include <ncurses.h>


int row=3,col=5;

void get_pid_info(const char * pid) {
    char path[256];
    long rss;
    FILE *fp;

    // status file
    snprintf(path, sizeof(path), "/proc/%s/status", pid);
    fp = fopen(path, "r");
    if (!fp) return;

    char line[256];
    char name[256] = "Unknown";
    while (fgets(line, sizeof(line), fp)) {
        if (strncmp(line, "Name:", 5) == 0) sscanf(line, "Name:\t%s", name);
        if (strncmp(line, "VmRSS:", 6) == 0) sscanf(line, "VmRSS:\t%ld", &rss);
    }
    fclose(fp);

    //display
    mvprintw(row++, col,"%-8s %-20s %ld KB", pid, name, rss);
}

void get_process_info() {
    //open proc directory
    DIR *dir = opendir("/proc");

    if (dir == NULL) {
        perror("opendir");
        return;
    }

    /*
    struct dirent {
        ino_t          d_ino;       // Inode number (the file's unique ID)
        off_t          d_off;       // Not an offset you'd usually use
        unsigned short d_reclen;    // Length of this record
        unsigned char  d_type;      // Type of file (DT_REG for file, DT_DIR for folder)
        char           d_name[256]; // The actual filename
    };
    */

    mvprintw(row++,col,"%-8s %-20s %s", "PID", "NAME", "MEMORY (RSS)");
    mvprintw(row++,col,"------------------------------------------");

    struct dirent *entry;

    while ((entry= readdir(dir)) ) {
        // select only processes 
        if (isdigit(entry->d_name[0]))
            get_pid_info(entry->d_name);
    }

    closedir(dir);

}