/*
 * log.c
 *
 * Copyright (C) 2009-2012 Intel Coproration
 *
 * Authors:
 *   Auke Kok <auke-jan.h.kok@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */

#define _GNU_SOURCE 1
#include <unistd.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <string.h>
#include <dirent.h>
#include <fcntl.h>
#include <time.h>


#include "bootchart.h"
#include "util.h"

/*
 * Alloc a static 4k buffer for stdio - primarily used to increase
 * PSS buffering from the default 1k stdin buffer to reduce
 * read() overhead.
 */
static char smaps_buf[4096];
DIR *proc;


double gettime_ns(void)
{
        struct timespec n;

        clock_gettime(CLOCK_MONOTONIC, &n);

        return (n.tv_sec + (n.tv_nsec / 1000000000.0));
}


void log_uptime(void)
{
        FILE *f;
        char str[32];
        double uptime;

        f = fopen("/proc/uptime", "r");
        if (!f)
                return;
        if (!fscanf(f, "%s %*s", str)) {
                fclose(f);
                return;
        }
        fclose(f);
        uptime = strtod(str, NULL);

        log_start = gettime_ns();

        /* start graph at kernel boot time */
        if (relative)
                graph_start = log_start;
        else
                graph_start = log_start - uptime;
}


static char *bufgetline(char *buf)
{
        char *c;

        if (!buf)
                return NULL;

        c = strchr(buf, '\n');
        if (c)
                c++;
        return c;
}


void log_sample(int sample)
{
        static int vmstat;
        static int schedstat;
        FILE *st;
        char buf[4095];
        char key[256];
        char val[256];
        char rt[256];
        char wt[256];
        char *m;
        int c;
        int p;
        int mod;
        static int e_fd;
        ssize_t s;
        ssize_t n;
        struct dirent *ent;

        if (!vmstat) {
                /* block stuff */
                vmstat = open("/proc/vmstat", O_RDONLY);
                if (vmstat == -1) {
                        perror("open /proc/vmstat");
                        exit (EXIT_FAILURE);
                }
        }

        n = pread(vmstat, buf, sizeof(buf) - 1, 0);
        if (n <= 0) {
                close(vmstat);
                return;
        }
        buf[n] = '\0';

        m = buf;
        while (m) {
                if (sscanf(m, "%s %s", key, val) < 2)
                        goto vmstat_next;
                if (streq(key, "pgpgin"))
                        blockstat[sample].bi = atoi(val);
                if (streq(key, "pgpgout")) {
                        blockstat[sample].bo = atoi(val);
                        break;
                }
vmstat_next:
                m = bufgetline(m);
                if (!m)
                        break;
        }

        if (!schedstat) {
                /* overall CPU utilization */
                schedstat = open("/proc/schedstat", O_RDONLY);
                if (schedstat == -1) {
                        perror("open /proc/schedstat");
                        exit (EXIT_FAILURE);
                }
        }

        n = pread(schedstat, buf, sizeof(buf) - 1, 0);
        if (n <= 0) {
                close(schedstat);
                return;
        }
        buf[n] = '\0';

        m = buf;
        while (m) {
                if (sscanf(m, "%s %*s %*s %*s %*s %*s %*s %s %s", key, rt, wt) < 3)
                        goto schedstat_next;

                if (strstr(key, "cpu")) {
                        c = atoi((const char*)(key+3));
                        if (c > MAXCPUS)
                                /* Oops, we only have room for MAXCPUS data */
                                break;
                        cpustat[c].sample[sample].runtime = atoll(rt);
                        cpustat[c].sample[sample].waittime = atoll(wt);

                        if (c == cpus)
                                cpus = c + 1;
                }
schedstat_next:
                m = bufgetline(m);
                if (!m)
                        break;
        }

        if (entropy) {
                if (!e_fd) {
                        e_fd = open("/proc/sys/kernel/random/entropy_avail", O_RDONLY);
                }

                if (e_fd) {
                        n = pread(e_fd, buf, sizeof(buf) - 1, 0);
                        if (n > 0) {
                                buf[n] = '\0';
                                entropy_avail[sample] = atoi(buf);
                        }
                }
        }

        /* all the per-process stuff goes here */
        if (!proc) {
                /* find all processes */
                proc = opendir("/proc");
                if (!proc)
                        return;
        } else {
                rewinddir(proc);
        }

        while ((ent = readdir(proc)) != NULL) {
                char filename[PATH_MAX];
                int pid;
                struct ps_struct *ps;

                if ((ent->d_name[0] < '0') || (ent->d_name[0] > '9'))
                        continue;

                pid = atoi(ent->d_name);

                if (pid >= MAXPIDS)
                        continue;

                ps = ps_first;
                while (ps->next_ps) {
                        ps = ps->next_ps;
                        if (ps->pid == pid)
                                break;
                }

                /* end of our LL? then append a new record */
                if (ps->pid != pid) {
                        char t[32];
                        struct ps_struct *parent;

                        ps->next_ps = calloc(1, sizeof(struct ps_struct));
                        if (!ps->next_ps) {
                                perror("calloc(ps_struct)");
                                exit (EXIT_FAILURE);
                        }
                        ps = ps->next_ps;
                        ps->pid = pid;

                        ps->sample = calloc(len + 1, sizeof(struct ps_sched_struct));
                        if (!ps->sample) {
                                perror("calloc(ps_struct)");
                                exit (EXIT_FAILURE);
                        }

                        pscount++;

                        /* mark our first sample */
                        ps->first = sample;

                        /* get name, start time */
                        if (!ps->sched) {
                                sprintf(filename, "/proc/%d/sched", pid);
                                ps->sched = open(filename, O_RDONLY);
                                if (ps->sched == -1)
                                        continue;
                        }

                        s = pread(ps->sched, buf, sizeof(buf) - 1, 0);
                        if (s <= 0) {
                                close(ps->sched);
                                continue;
                        }
                        buf[s] = '\0';

                        if (!sscanf(buf, "%s %*s %*s", key))
                                continue;

                        strncpy(ps->name, key, 16);
                        /* discard line 2 */
                        m = bufgetline(buf);
                        if (!m)
                                continue;

                        m = bufgetline(m);
                        if (!m)
                                continue;

                        if (!sscanf(m, "%*s %*s %s", t))
                                continue;

                        ps->starttime = strtod(t, NULL) / 1000.0;

                        /* ppid */
                        sprintf(filename, "/proc/%d/stat", pid);
                        st = fopen(filename, "r");
                        if (!st)
                                continue;
                        if (!fscanf(st, "%*s %*s %*s %i", &p)) {
                                fclose(st);
                                continue;
                        }
                        fclose(st);
                        ps->ppid = p;

                        /*
                         * setup child pointers
                         *
                         * these are used to paint the tree coherently later
                         * each parent has a LL of children, and a LL of siblings
                         */
                        if (pid == 1)
                                continue; /* nothing to do for init atm */

                        /* kthreadd has ppid=0, which breaks our tree ordering */
                        if (ps->ppid == 0)
                                ps->ppid = 1;

                        parent = ps_first;
                        while ((parent->next_ps && parent->pid != ps->ppid))
                                parent = parent->next_ps;

                        if ((!parent) || (parent->pid != ps->ppid)) {
                                /* orphan */
                                ps->ppid = 1;
                                parent = ps_first->next_ps;
                        }

                        ps->parent = parent;

                        if (!parent->children) {
                                /* it's the first child */
                                parent->children = ps;
                        } else {
                                /* walk all children and append */
                                struct ps_struct *children;
                                children = parent->children;
                                while (children->next)
                                        children = children->next;
                                children->next = ps;
                        }
                }

                /* else -> found pid, append data in ps */

                /* below here is all continuous logging parts - we get here on every
                 * iteration */

                /* rt, wt */
                if (!ps->schedstat) {
                        sprintf(filename, "/proc/%d/schedstat", pid);
                        ps->schedstat = open(filename, O_RDONLY);
                        if (ps->schedstat == -1)
                                continue;
                }
                s = pread(ps->schedstat, buf, sizeof(buf) - 1, 0);
                if (s <= 0) {
                        /* clean up our file descriptors - assume that the process exited */
                        close(ps->schedstat);
                        if (ps->sched)
                                close(ps->sched);
                        //if (ps->smaps)
                        //        fclose(ps->smaps);
                        continue;
                }
                buf[s] = '\0';

                if (!sscanf(buf, "%s %s %*s", rt, wt))
                        continue;

                ps->last = sample;
                ps->sample[sample].runtime = atoll(rt);
                ps->sample[sample].waittime = atoll(wt);

                ps->total = (ps->sample[ps->last].runtime
                                 - ps->sample[ps->first].runtime)
                                 / 1000000000.0;

                if (!pss)
                        goto catch_rename;
                /* Pss */
                if (!ps->smaps) {
                        sprintf(filename, "/proc/%d/smaps", pid);
                        ps->smaps = fopen(filename, "r");
                        if (!ps->smaps)
                                continue;
                        setvbuf(ps->smaps, smaps_buf, _IOFBF, sizeof(smaps_buf));
                } else {
                        rewind(ps->smaps);
                }

                while (1) {
                        int pss_kb;

                        /* skip one line, this contains the object mapped */
                        if (fgets(buf, sizeof(buf), ps->smaps) == NULL)
                                break;
                        /* then there's a 28 char 14 line block */
                        if (fread(buf, 1, 28 * 14, ps->smaps) != 28 * 14)
                                break;

                        pss_kb = atoi(&buf[61]);
                        ps->sample[sample].pss += pss_kb;
                }

                if (ps->sample[sample].pss > ps->pss_max)
                        ps->pss_max = ps->sample[sample].pss;

catch_rename:
                /* catch process rename, try to randomize time */
                mod = (hz < 4.0) ? 4.0 : (hz / 4.0);
                if (((samples - ps->first) + pid) % (int)(mod) == 0) {

                        /* re-fetch name */
                        /* get name, start time */
                        if (!ps->sched) {
                                sprintf(filename, "/proc/%d/sched", pid);
                                ps->sched = open(filename, O_RDONLY);
                                if (ps->sched == -1)
                                        continue;
                        }
                        s = pread(ps->sched, buf, sizeof(buf) - 1, 0);
                        if (s <= 0) {
                                /* clean up file descriptors */
                                close(ps->sched);
                                if (ps->schedstat)
                                        close(ps->schedstat);
                                //if (ps->smaps)
                                //        fclose(ps->smaps);
                                continue;
                        }
                        buf[s] = '\0';

                        if (!sscanf(buf, "%s %*s %*s", key))
                                continue;

                        strncpy(ps->name, key, 16);
                }
        }
}
