source: MondoRescue/branches/3.3/mindi-busybox/procps/top.c@ 3837

/* vi: set sw=4 ts=4: */
/*
 * A tiny 'top' utility.
 *
 * This is written specifically for the linux /proc/<PID>/stat(m)
 * files format.
 *
 * This reads the PIDs of all processes and their status and shows
 * the status of processes (first ones that fit to screen) at given
 * intervals.
 *
 * NOTES:
 * - At startup this changes to /proc, all the reads are then
 *   relative to that.
 *
 * (C) Eero Tamminen <oak at welho dot com>
 *
 * Rewritten by Vladimir Oleynik (C) 2002 <dzo@simtreas.ru>
 *
 * Sept 2008: Vineet Gupta <vineet.gupta@arc.com>
 * Added Support for reporting SMP Information
 * - CPU where process was last seen running
 *   (to see effect of sched_setaffinity() etc)
 * - CPU time split (idle/IO/wait etc) per CPU
 *
 * Copyright (c) 1992 Branko Lankester
 * Copyright (c) 1992 Roger Binns
 * Copyright (C) 1994-1996 Charles L. Blake.
 * Copyright (C) 1992-1998 Michael K. Johnson
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
/* How to snapshot /proc for debugging top problems:
 * for f in /proc/[0-9]*""/stat; do
 *         n=${f#/proc/}
 *         n=${n%/stat}_stat
 *         cp $f $n
 * done
 * cp /proc/stat /proc/meminfo /proc/loadavg .
 * top -bn1 >top.out
 *
 * ...and how to run top on it on another machine:
 * rm -rf proc; mkdir proc
 * for f in [0-9]*_stat; do
 *         p=${f%_stat}
 *         mkdir -p proc/$p
 *         cp $f proc/$p/stat
 * done
 * cp stat meminfo loadavg proc
 * chroot . ./top -bn1 >top1.out
 */

//config:config TOP
//config:   bool "top"
//config:   default y
//config:   help
//config:     The top program provides a dynamic real-time view of a running
//config:     system.
//config:
//config:config FEATURE_TOP_CPU_USAGE_PERCENTAGE
//config:   bool "Show CPU per-process usage percentage"
//config:   default y
//config:   depends on TOP
//config:   help
//config:     Make top display CPU usage for each process.
//config:     This adds about 2k.
//config:
//config:config FEATURE_TOP_CPU_GLOBAL_PERCENTS
//config:   bool "Show CPU global usage percentage"
//config:   default y
//config:   depends on FEATURE_TOP_CPU_USAGE_PERCENTAGE
//config:   help
//config:     Makes top display "CPU: NN% usr NN% sys..." line.
//config:     This adds about 0.5k.
//config:
//config:config FEATURE_TOP_SMP_CPU
//config:   bool "SMP CPU usage display ('c' key)"
//config:   default y
//config:   depends on FEATURE_TOP_CPU_GLOBAL_PERCENTS
//config:   help
//config:     Allow 'c' key to switch between individual/cumulative CPU stats
//config:     This adds about 0.5k.
//config:
//config:config FEATURE_TOP_DECIMALS
//config:   bool "Show 1/10th of a percent in CPU/mem statistics"
//config:   default y
//config:   depends on FEATURE_TOP_CPU_USAGE_PERCENTAGE
//config:   help
//config:     Show 1/10th of a percent in CPU/mem statistics.
//config:     This adds about 0.3k.
//config:
//config:config FEATURE_TOP_SMP_PROCESS
//config:   bool "Show CPU process runs on ('j' field)"
//config:   default y
//config:   depends on TOP
//config:   help
//config:     Show CPU where process was last found running on.
//config:     This is the 'j' field.
//config:
//config:config FEATURE_TOPMEM
//config:   bool "Topmem command ('s' key)"
//config:   default y
//config:   depends on TOP
//config:   help
//config:     Enable 's' in top (gives lots of memory info).

#include "libbb.h"
#include "common_bufsiz.h"


typedef struct top_status_t {
    unsigned long vsz;
#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
    unsigned long ticks;
    unsigned pcpu; /* delta of ticks */
#endif
    unsigned pid, ppid;
    unsigned uid;
    char state[4];
    char comm[COMM_LEN];
#if ENABLE_FEATURE_TOP_SMP_PROCESS
    int last_seen_on_cpu;
#endif
} top_status_t;

typedef struct jiffy_counts_t {
    /* Linux 2.4.x has only first four */
    unsigned long long usr, nic, sys, idle;
    unsigned long long iowait, irq, softirq, steal;
    unsigned long long total;
    unsigned long long busy;
} jiffy_counts_t;

/* This structure stores some critical information from one frame to
   the next. Used for finding deltas. */
typedef struct save_hist {
    unsigned long ticks;
    pid_t pid;
} save_hist;

typedef int (*cmp_funcp)(top_status_t *P, top_status_t *Q);


enum { SORT_DEPTH = 3 };


struct globals {
    top_status_t *top;
    int ntop;
    smallint inverted;
#if ENABLE_FEATURE_TOPMEM
    smallint sort_field;
#endif
#if ENABLE_FEATURE_TOP_SMP_CPU
    smallint smp_cpu_info; /* one/many cpu info lines? */
#endif
    unsigned lines;  /* screen height */
#if ENABLE_FEATURE_USE_TERMIOS
    struct termios initial_settings;
    int scroll_ofs;
#define G_scroll_ofs G.scroll_ofs
#else
#define G_scroll_ofs 0
#endif
#if !ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
    cmp_funcp sort_function[1];
#else
    cmp_funcp sort_function[SORT_DEPTH];
    struct save_hist *prev_hist;
    int prev_hist_count;
    jiffy_counts_t cur_jif, prev_jif;
    /* int hist_iterations; */
    unsigned total_pcpu;
    /* unsigned long total_vsz; */
#endif
#if ENABLE_FEATURE_TOP_SMP_CPU
    /* Per CPU samples: current and last */
    jiffy_counts_t *cpu_jif, *cpu_prev_jif;
    int num_cpus;
#endif
#if ENABLE_FEATURE_USE_TERMIOS
    char kbd_input[KEYCODE_BUFFER_SIZE];
#endif
    char line_buf[80];
}; //FIX_ALIASING; - large code growth
enum { LINE_BUF_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line_buf) };
#define G (*(struct globals*)bb_common_bufsiz1)
#define top              (G.top               )
#define ntop             (G.ntop              )
#define sort_field       (G.sort_field        )
#define inverted         (G.inverted          )
#define smp_cpu_info     (G.smp_cpu_info      )
#define initial_settings (G.initial_settings  )
#define sort_function    (G.sort_function     )
#define prev_hist        (G.prev_hist         )
#define prev_hist_count  (G.prev_hist_count   )
#define cur_jif          (G.cur_jif           )
#define prev_jif         (G.prev_jif          )
#define cpu_jif          (G.cpu_jif           )
#define cpu_prev_jif     (G.cpu_prev_jif      )
#define num_cpus         (G.num_cpus          )
#define total_pcpu       (G.total_pcpu        )
#define line_buf         (G.line_buf          )
#define INIT_G() do { \
    setup_common_bufsiz(); \
    BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
    BUILD_BUG_ON(LINE_BUF_SIZE <= 80); \
} while (0)

enum {
    OPT_d = (1 << 0),
    OPT_n = (1 << 1),
    OPT_b = (1 << 2),
    OPT_m = (1 << 3),
    OPT_EOF = (1 << 4), /* pseudo: "we saw EOF in stdin" */
};
#define OPT_BATCH_MODE (option_mask32 & OPT_b)


#if ENABLE_FEATURE_USE_TERMIOS
static int pid_sort(top_status_t *P, top_status_t *Q)
{
    /* Buggy wrt pids with high bit set */
    /* (linux pids are in [1..2^15-1]) */
    return (Q->pid - P->pid);
}
#endif

static int mem_sort(top_status_t *P, top_status_t *Q)
{
    /* We want to avoid unsigned->signed and truncation errors */
    if (Q->vsz < P->vsz) return -1;
    return Q->vsz != P->vsz; /* 0 if ==, 1 if > */
}


#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE

static int pcpu_sort(top_status_t *P, top_status_t *Q)
{
    /* Buggy wrt ticks with high bit set */
    /* Affects only processes for which ticks overflow */
    return (int)Q->pcpu - (int)P->pcpu;
}

static int time_sort(top_status_t *P, top_status_t *Q)
{
    /* We want to avoid unsigned->signed and truncation errors */
    if (Q->ticks < P->ticks) return -1;
    return Q->ticks != P->ticks; /* 0 if ==, 1 if > */
}

static int mult_lvl_cmp(void* a, void* b)
{
    int i, cmp_val;

    for (i = 0; i < SORT_DEPTH; i++) {
        cmp_val = (*sort_function[i])(a, b);
        if (cmp_val != 0)
            break;
    }
    return inverted ? -cmp_val : cmp_val;
}

static NOINLINE int read_cpu_jiffy(FILE *fp, jiffy_counts_t *p_jif)
{
#if !ENABLE_FEATURE_TOP_SMP_CPU
    static const char fmt[] ALIGN1 = "cpu %llu %llu %llu %llu %llu %llu %llu %llu";
#else
    static const char fmt[] ALIGN1 = "cp%*s %llu %llu %llu %llu %llu %llu %llu %llu";
#endif
    int ret;

    if (!fgets(line_buf, LINE_BUF_SIZE, fp) || line_buf[0] != 'c' /* not "cpu" */)
        return 0;
    ret = sscanf(line_buf, fmt,
            &p_jif->usr, &p_jif->nic, &p_jif->sys, &p_jif->idle,
            &p_jif->iowait, &p_jif->irq, &p_jif->softirq,
            &p_jif->steal);
    if (ret >= 4) {
        p_jif->total = p_jif->usr + p_jif->nic + p_jif->sys + p_jif->idle
            + p_jif->iowait + p_jif->irq + p_jif->softirq + p_jif->steal;
        /* procps 2.x does not count iowait as busy time */
        p_jif->busy = p_jif->total - p_jif->idle - p_jif->iowait;
    }

    return ret;
}

static void get_jiffy_counts(void)
{
    FILE* fp = xfopen_for_read("stat");

    /* We need to parse cumulative counts even if SMP CPU display is on,
     * they are used to calculate per process CPU% */
    prev_jif = cur_jif;
    if (read_cpu_jiffy(fp, &cur_jif) < 4)
        bb_error_msg_and_die("can't read '%s'", "/proc/stat");

#if !ENABLE_FEATURE_TOP_SMP_CPU
    fclose(fp);
    return;
#else
    if (!smp_cpu_info) {
        fclose(fp);
        return;
    }

    if (!num_cpus) {
        /* First time here. How many CPUs?
         * There will be at least 1 /proc/stat line with cpu%d
         */
        while (1) {
            cpu_jif = xrealloc_vector(cpu_jif, 1, num_cpus);
            if (read_cpu_jiffy(fp, &cpu_jif[num_cpus]) <= 4)
                break;
            num_cpus++;
        }
        if (num_cpus == 0) /* /proc/stat with only "cpu ..." line?! */
            smp_cpu_info = 0;

        cpu_prev_jif = xzalloc(sizeof(cpu_prev_jif[0]) * num_cpus);

        /* Otherwise the first per cpu display shows all 100% idles */
        usleep(50000);
    } else { /* Non first time invocation */
        jiffy_counts_t *tmp;
        int i;

        /* First switch the sample pointers: no need to copy */
        tmp = cpu_prev_jif;
        cpu_prev_jif = cpu_jif;
        cpu_jif = tmp;

        /* Get the new samples */
        for (i = 0; i < num_cpus; i++)
            read_cpu_jiffy(fp, &cpu_jif[i]);
    }
#endif
    fclose(fp);
}

static void do_stats(void)
{
    top_status_t *cur;
    pid_t pid;
    int i, last_i, n;
    struct save_hist *new_hist;

    get_jiffy_counts();
    total_pcpu = 0;
    /* total_vsz = 0; */
    new_hist = xmalloc(sizeof(new_hist[0]) * ntop);
    /*
     * Make a pass through the data to get stats.
     */
    /* hist_iterations = 0; */
    i = 0;
    for (n = 0; n < ntop; n++) {
        cur = top + n;

        /*
         * Calculate time in cur process.  Time is sum of user time
         * and system time
         */
        pid = cur->pid;
        new_hist[n].ticks = cur->ticks;
        new_hist[n].pid = pid;

        /* find matching entry from previous pass */
        cur->pcpu = 0;
        /* do not start at index 0, continue at last used one
         * (brought hist_iterations from ~14000 down to 172) */
        last_i = i;
        if (prev_hist_count) do {
            if (prev_hist[i].pid == pid) {
                cur->pcpu = cur->ticks - prev_hist[i].ticks;
                total_pcpu += cur->pcpu;
                break;
            }
            i = (i+1) % prev_hist_count;
            /* hist_iterations++; */
        } while (i != last_i);
        /* total_vsz += cur->vsz; */
    }

    /*
     * Save cur frame's information.
     */
    free(prev_hist);
    prev_hist = new_hist;
    prev_hist_count = ntop;
}

#endif /* FEATURE_TOP_CPU_USAGE_PERCENTAGE */

#if ENABLE_FEATURE_TOP_CPU_GLOBAL_PERCENTS && ENABLE_FEATURE_TOP_DECIMALS
/* formats 7 char string (8 with terminating NUL) */
static char *fmt_100percent_8(char pbuf[8], unsigned value, unsigned total)
{
    unsigned t;
    if (value >= total) { /* 100% ? */
        strcpy(pbuf, "  100% ");
        return pbuf;
    }
    /* else generate " [N/space]N.N% " string */
    value = 1000 * value / total;
    t = value / 100;
    value = value % 100;
    pbuf[0] = ' ';
    pbuf[1] = t ? t + '0' : ' ';
    pbuf[2] = '0' + (value / 10);
    pbuf[3] = '.';
    pbuf[4] = '0' + (value % 10);
    pbuf[5] = '%';
    pbuf[6] = ' ';
    pbuf[7] = '\0';
    return pbuf;
}
#endif

#if ENABLE_FEATURE_TOP_CPU_GLOBAL_PERCENTS
static void display_cpus(int scr_width, char *scrbuf, int *lines_rem_p)
{
    /*
     * xxx% = (cur_jif.xxx - prev_jif.xxx) / (cur_jif.total - prev_jif.total) * 100%
     */
    unsigned total_diff;
    jiffy_counts_t *p_jif, *p_prev_jif;
    int i;
# if ENABLE_FEATURE_TOP_SMP_CPU
    int n_cpu_lines;
# endif

    /* using (unsigned) casts to make operations cheaper */
# define  CALC_TOTAL_DIFF do { \
    total_diff = (unsigned)(p_jif->total - p_prev_jif->total); \
    if (total_diff == 0) total_diff = 1; \
} while (0)

# if ENABLE_FEATURE_TOP_DECIMALS
#  define CALC_STAT(xxx) char xxx[8]
#  define SHOW_STAT(xxx) fmt_100percent_8(xxx, (unsigned)(p_jif->xxx - p_prev_jif->xxx), total_diff)
#  define FMT "%s"
# else
#  define CALC_STAT(xxx) unsigned xxx = 100 * (unsigned)(p_jif->xxx - p_prev_jif->xxx) / total_diff
#  define SHOW_STAT(xxx) xxx
#  define FMT "%4u%% "
# endif

# if !ENABLE_FEATURE_TOP_SMP_CPU
    {
        i = 1;
        p_jif = &cur_jif;
        p_prev_jif = &prev_jif;
# else
    /* Loop thru CPU(s) */
    n_cpu_lines = smp_cpu_info ? num_cpus : 1;
    if (n_cpu_lines > *lines_rem_p)
        n_cpu_lines = *lines_rem_p;

    for (i = 0; i < n_cpu_lines; i++) {
        p_jif = &cpu_jif[i];
        p_prev_jif = &cpu_prev_jif[i];
# endif
        CALC_TOTAL_DIFF;

        { /* Need a block: CALC_STAT are declarations */
            CALC_STAT(usr);
            CALC_STAT(sys);
            CALC_STAT(nic);
            CALC_STAT(idle);
            CALC_STAT(iowait);
            CALC_STAT(irq);
            CALC_STAT(softirq);
            /*CALC_STAT(steal);*/

            snprintf(scrbuf, scr_width,
                /* Barely fits in 79 chars when in "decimals" mode. */
# if ENABLE_FEATURE_TOP_SMP_CPU
                "CPU%s:"FMT"usr"FMT"sys"FMT"nic"FMT"idle"FMT"io"FMT"irq"FMT"sirq",
                (smp_cpu_info ? utoa(i) : ""),
# else
                "CPU:"FMT"usr"FMT"sys"FMT"nic"FMT"idle"FMT"io"FMT"irq"FMT"sirq",
# endif
                SHOW_STAT(usr), SHOW_STAT(sys), SHOW_STAT(nic), SHOW_STAT(idle),
                SHOW_STAT(iowait), SHOW_STAT(irq), SHOW_STAT(softirq)
                /*, SHOW_STAT(steal) - what is this 'steal' thing? */
                /* I doubt anyone wants to know it */
            );
            puts(scrbuf);
        }
    }
# undef SHOW_STAT
# undef CALC_STAT
# undef FMT
    *lines_rem_p -= i;
}
#else  /* !ENABLE_FEATURE_TOP_CPU_GLOBAL_PERCENTS */
# define display_cpus(scr_width, scrbuf, lines_rem) ((void)0)
#endif

enum {
    MI_MEMTOTAL,
    MI_MEMFREE,
    MI_MEMSHARED,
    MI_SHMEM,
    MI_BUFFERS,
    MI_CACHED,
    MI_SWAPTOTAL,
    MI_SWAPFREE,
    MI_DIRTY,
    MI_WRITEBACK,
    MI_ANONPAGES,
    MI_MAPPED,
    MI_SLAB,
    MI_MAX
};

static void parse_meminfo(unsigned long meminfo[MI_MAX])
{
    static const char fields[] ALIGN1 =
        "MemTotal\0"
        "MemFree\0"
        "MemShared\0"
        "Shmem\0"
        "Buffers\0"
        "Cached\0"
        "SwapTotal\0"
        "SwapFree\0"
        "Dirty\0"
        "Writeback\0"
        "AnonPages\0"
        "Mapped\0"
        "Slab\0";
    char buf[60]; /* actual lines we expect are ~30 chars or less */
    FILE *f;
    int i;

    memset(meminfo, 0, sizeof(meminfo[0]) * MI_MAX);
    f = xfopen_for_read("meminfo");
    while (fgets(buf, sizeof(buf), f) != NULL) {
        char *c = strchr(buf, ':');
        if (!c)
            continue;
        *c = '\0';
        i = index_in_strings(fields, buf);
        if (i >= 0)
            meminfo[i] = strtoul(c+1, NULL, 10);
    }
    fclose(f);
}

static unsigned long display_header(int scr_width, int *lines_rem_p)
{
    char scrbuf[100]; /* [80] was a bit too low on 8Gb ram box */
    char *buf;
    unsigned long meminfo[MI_MAX];

    parse_meminfo(meminfo);

    /* Output memory info */
    if (scr_width > (int)sizeof(scrbuf))
        scr_width = sizeof(scrbuf);
    snprintf(scrbuf, scr_width,
        "Mem: %luK used, %luK free, %luK shrd, %luK buff, %luK cached",
        meminfo[MI_MEMTOTAL] - meminfo[MI_MEMFREE],
        meminfo[MI_MEMFREE],
        meminfo[MI_MEMSHARED] + meminfo[MI_SHMEM],
        meminfo[MI_BUFFERS],
        meminfo[MI_CACHED]);
    /* Go to top & clear to the end of screen */
    printf(OPT_BATCH_MODE ? "%s\n" : "\033[H\033[J%s\n", scrbuf);
    (*lines_rem_p)--;

    /* Display CPU time split as percentage of total time.
     * This displays either a cumulative line or one line per CPU.
     */
    display_cpus(scr_width, scrbuf, lines_rem_p);

    /* Read load average as a string */
    buf = stpcpy(scrbuf, "Load average: ");
    open_read_close("loadavg", buf, sizeof(scrbuf) - sizeof("Load average: "));
    scrbuf[scr_width - 1] = '\0';
    strchrnul(buf, '\n')[0] = '\0';
    puts(scrbuf);
    (*lines_rem_p)--;

    return meminfo[MI_MEMTOTAL];
}

static NOINLINE void display_process_list(int lines_rem, int scr_width)
{
    enum {
        BITS_PER_INT = sizeof(int) * 8
    };

    top_status_t *s;
    char vsz_str_buf[8];
    unsigned long total_memory = display_header(scr_width, &lines_rem); /* or use total_vsz? */
    /* xxx_shift and xxx_scale variables allow us to replace
     * expensive divides with multiply and shift */
    unsigned pmem_shift, pmem_scale, pmem_half;
#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
    unsigned tmp_unsigned;
    unsigned pcpu_shift, pcpu_scale, pcpu_half;
    unsigned busy_jifs;
#endif

    /* what info of the processes is shown */
    printf(OPT_BATCH_MODE ? "%.*s" : "\033[7m%.*s\033[0m", scr_width,
        "  PID  PPID USER     STAT   VSZ %VSZ"
        IF_FEATURE_TOP_SMP_PROCESS(" CPU")
        IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE(" %CPU")
        " COMMAND");
    lines_rem--;

#if ENABLE_FEATURE_TOP_DECIMALS
# define UPSCALE 1000
# define CALC_STAT(name, val) div_t name = div((val), 10)
# define SHOW_STAT(name) name.quot, '0'+name.rem
# define FMT "%3u.%c"
#else
# define UPSCALE 100
# define CALC_STAT(name, val) unsigned name = (val)
# define SHOW_STAT(name) name
# define FMT "%4u%%"
#endif
    /*
     * %VSZ = s->vsz/MemTotal
     */
    pmem_shift = BITS_PER_INT-11;
    pmem_scale = UPSCALE*(1U<<(BITS_PER_INT-11)) / total_memory;
    /* s->vsz is in kb. we want (s->vsz * pmem_scale) to never overflow */
    while (pmem_scale >= 512) {
        pmem_scale /= 4;
        pmem_shift -= 2;
    }
    pmem_half = (1U << pmem_shift) / (ENABLE_FEATURE_TOP_DECIMALS ? 20 : 2);
#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
    busy_jifs = cur_jif.busy - prev_jif.busy;
    /* This happens if there were lots of short-lived processes
     * between two top updates (e.g. compilation) */
    if (total_pcpu < busy_jifs) total_pcpu = busy_jifs;

    /*
     * CPU% = s->pcpu/sum(s->pcpu) * busy_cpu_ticks/total_cpu_ticks
     * (pcpu is delta of sys+user time between samples)
     */
    /* (cur_jif.xxx - prev_jif.xxx) and s->pcpu are
     * in 0..~64000 range (HZ*update_interval).
     * we assume that unsigned is at least 32-bit.
     */
    pcpu_shift = 6;
    pcpu_scale = UPSCALE*64 * (uint16_t)busy_jifs;
    if (pcpu_scale == 0)
        pcpu_scale = 1;
    while (pcpu_scale < (1U << (BITS_PER_INT-2))) {
        pcpu_scale *= 4;
        pcpu_shift += 2;
    }
    tmp_unsigned = (uint16_t)(cur_jif.total - prev_jif.total) * total_pcpu;
    if (tmp_unsigned != 0)
        pcpu_scale /= tmp_unsigned;
    /* we want (s->pcpu * pcpu_scale) to never overflow */
    while (pcpu_scale >= 1024) {
        pcpu_scale /= 4;
        pcpu_shift -= 2;
    }
    pcpu_half = (1U << pcpu_shift) / (ENABLE_FEATURE_TOP_DECIMALS ? 20 : 2);
    /* printf(" pmem_scale=%u pcpu_scale=%u ", pmem_scale, pcpu_scale); */
#endif

    /* Ok, all preliminary data is ready, go through the list */
    scr_width += 2; /* account for leading '\n' and trailing NUL */
    if (lines_rem > ntop - G_scroll_ofs)
        lines_rem = ntop - G_scroll_ofs;
    s = top + G_scroll_ofs;
    while (--lines_rem >= 0) {
        unsigned col;
        CALC_STAT(pmem, (s->vsz*pmem_scale + pmem_half) >> pmem_shift);
#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
        CALC_STAT(pcpu, (s->pcpu*pcpu_scale + pcpu_half) >> pcpu_shift);
#endif

        if (s->vsz >= 100000)
            sprintf(vsz_str_buf, "%6ldm", s->vsz/1024);
        else
            sprintf(vsz_str_buf, "%7lu", s->vsz);
        /* PID PPID USER STAT VSZ %VSZ [%CPU] COMMAND */
        col = snprintf(line_buf, scr_width,
                "\n" "%5u%6u %-8.8s %s%s" FMT
                IF_FEATURE_TOP_SMP_PROCESS(" %3d")
                IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE(FMT)
                " ",
                s->pid, s->ppid, get_cached_username(s->uid),
                s->state, vsz_str_buf,
                SHOW_STAT(pmem)
                IF_FEATURE_TOP_SMP_PROCESS(, s->last_seen_on_cpu)
                IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE(, SHOW_STAT(pcpu))
        );
        if ((int)(col + 1) < scr_width)
            read_cmdline(line_buf + col, scr_width - col, s->pid, s->comm);
        fputs(line_buf, stdout);
        /* printf(" %d/%d %lld/%lld", s->pcpu, total_pcpu,
            cur_jif.busy - prev_jif.busy, cur_jif.total - prev_jif.total); */
        s++;
    }
    /* printf(" %d", hist_iterations); */
    bb_putchar(OPT_BATCH_MODE ? '\n' : '\r');
    fflush_all();
}
#undef UPSCALE
#undef SHOW_STAT
#undef CALC_STAT
#undef FMT

static void clearmems(void)
{
    clear_username_cache();
    free(top);
    top = NULL;
}

#if ENABLE_FEATURE_USE_TERMIOS

static void reset_term(void)
{
    if (!OPT_BATCH_MODE)
        tcsetattr_stdin_TCSANOW(&initial_settings);
    if (ENABLE_FEATURE_CLEAN_UP) {
        clearmems();
# if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
        free(prev_hist);
# endif
    }
}

static void sig_catcher(int sig)
{
    reset_term();
    kill_myself_with_sig(sig);
}

#endif /* FEATURE_USE_TERMIOS */

/*
 * TOPMEM support
 */

typedef unsigned long mem_t;

typedef struct topmem_status_t {
    unsigned pid;
    char comm[COMM_LEN];
    /* vsz doesn't count /dev/xxx mappings except /dev/zero */
    mem_t vsz     ;
    mem_t vszrw   ;
    mem_t rss     ;
    mem_t rss_sh  ;
    mem_t dirty   ;
    mem_t dirty_sh;
    mem_t stack   ;
} topmem_status_t;

enum { NUM_SORT_FIELD = 7 };

#define topmem ((topmem_status_t*)top)

#if ENABLE_FEATURE_TOPMEM

static int topmem_sort(char *a, char *b)
{
    int n;
    mem_t l, r;

    n = offsetof(topmem_status_t, vsz) + (sort_field * sizeof(mem_t));
    l = *(mem_t*)(a + n);
    r = *(mem_t*)(b + n);
    if (l == r) {
        l = ((topmem_status_t*)a)->dirty;
        r = ((topmem_status_t*)b)->dirty;
    }
    /* We want to avoid unsigned->signed and truncation errors */
    /* l>r: -1, l=r: 0, l<r: 1 */
    n = (l > r) ? -1 : (l != r);
    return inverted ? -n : n;
}

/* display header info (meminfo / loadavg) */
static void display_topmem_header(int scr_width, int *lines_rem_p)
{
    unsigned long meminfo[MI_MAX];

    parse_meminfo(meminfo);

    snprintf(line_buf, LINE_BUF_SIZE,
        "Mem total:%lu anon:%lu map:%lu free:%lu",
        meminfo[MI_MEMTOTAL],
        meminfo[MI_ANONPAGES],
        meminfo[MI_MAPPED],
        meminfo[MI_MEMFREE]);
    printf(OPT_BATCH_MODE ? "%.*s\n" : "\033[H\033[J%.*s\n", scr_width, line_buf);

    snprintf(line_buf, LINE_BUF_SIZE,
        " slab:%lu buf:%lu cache:%lu dirty:%lu write:%lu",
        meminfo[MI_SLAB],
        meminfo[MI_BUFFERS],
        meminfo[MI_CACHED],
        meminfo[MI_DIRTY],
        meminfo[MI_WRITEBACK]);
    printf("%.*s\n", scr_width, line_buf);

    snprintf(line_buf, LINE_BUF_SIZE,
        "Swap total:%lu free:%lu", // TODO: % used?
        meminfo[MI_SWAPTOTAL],
        meminfo[MI_SWAPFREE]);
    printf("%.*s\n", scr_width, line_buf);

    (*lines_rem_p) -= 3;
}

static void ulltoa6_and_space(unsigned long long ul, char buf[6])
{
    /* see http://en.wikipedia.org/wiki/Tera */
    smart_ulltoa5(ul, buf, " mgtpezy")[0] = ' ';
}

static NOINLINE void display_topmem_process_list(int lines_rem, int scr_width)
{
#define HDR_STR "  PID   VSZ VSZRW   RSS (SHR) DIRTY (SHR) STACK"
#define MIN_WIDTH sizeof(HDR_STR)
    const topmem_status_t *s = topmem + G_scroll_ofs;
    char *cp, ch;

    display_topmem_header(scr_width, &lines_rem);

    strcpy(line_buf, HDR_STR " COMMAND");
    /* Mark the ^FIELD^ we sort by */
    cp = &line_buf[5 + sort_field * 6];
    ch = "^_"[inverted];
    cp[6] = ch;
    do *cp++ = ch; while (*cp == ' ');

    printf(OPT_BATCH_MODE ? "%.*s" : "\e[7m%.*s\e[0m", scr_width, line_buf);
    lines_rem--;

    if (lines_rem > ntop - G_scroll_ofs)
        lines_rem = ntop - G_scroll_ofs;
    while (--lines_rem >= 0) {
        /* PID VSZ VSZRW RSS (SHR) DIRTY (SHR) COMMAND */
        ulltoa6_and_space(s->pid     , &line_buf[0*6]);
        ulltoa6_and_space(s->vsz     , &line_buf[1*6]);
        ulltoa6_and_space(s->vszrw   , &line_buf[2*6]);
        ulltoa6_and_space(s->rss     , &line_buf[3*6]);
        ulltoa6_and_space(s->rss_sh  , &line_buf[4*6]);
        ulltoa6_and_space(s->dirty   , &line_buf[5*6]);
        ulltoa6_and_space(s->dirty_sh, &line_buf[6*6]);
        ulltoa6_and_space(s->stack   , &line_buf[7*6]);
        line_buf[8*6] = '\0';
        if (scr_width > (int)MIN_WIDTH) {
            read_cmdline(&line_buf[8*6], scr_width - MIN_WIDTH, s->pid, s->comm);
        }
        printf("\n""%.*s", scr_width, line_buf);
        s++;
    }
    bb_putchar(OPT_BATCH_MODE ? '\n' : '\r');
    fflush_all();
#undef HDR_STR
#undef MIN_WIDTH
}

#else
void display_topmem_process_list(int lines_rem, int scr_width);
int topmem_sort(char *a, char *b);
#endif /* TOPMEM */

/*
 * end TOPMEM support
 */

enum {
    TOP_MASK = 0
        | PSSCAN_PID
        | PSSCAN_PPID
        | PSSCAN_VSZ
        | PSSCAN_STIME
        | PSSCAN_UTIME
        | PSSCAN_STATE
        | PSSCAN_COMM
        | PSSCAN_CPU
        | PSSCAN_UIDGID,
    TOPMEM_MASK = 0
        | PSSCAN_PID
        | PSSCAN_SMAPS
        | PSSCAN_COMM,
    EXIT_MASK = (unsigned)-1,
};

#if ENABLE_FEATURE_USE_TERMIOS
static unsigned handle_input(unsigned scan_mask, unsigned interval)
{
    if (option_mask32 & OPT_EOF) {
        /* EOF on stdin ("top </dev/null") */
        sleep(interval);
        return scan_mask;
    }

    while (1) {
        int32_t c;

        c = read_key(STDIN_FILENO, G.kbd_input, interval * 1000);
        if (c == -1 && errno != EAGAIN) {
            /* error/EOF */
            option_mask32 |= OPT_EOF;
            break;
        }
        interval = 0;

        if (c == initial_settings.c_cc[VINTR])
            return EXIT_MASK;
        if (c == initial_settings.c_cc[VEOF])
            return EXIT_MASK;

        if (c == KEYCODE_UP) {
            G_scroll_ofs--;
            goto normalize_ofs;
        }
        if (c == KEYCODE_DOWN) {
            G_scroll_ofs++;
            goto normalize_ofs;
        }
        if (c == KEYCODE_HOME) {
            G_scroll_ofs = 0;
            break;
        }
        if (c == KEYCODE_END) {
            G_scroll_ofs = ntop - G.lines / 2;
            goto normalize_ofs;
        }
        if (c == KEYCODE_PAGEUP) {
            G_scroll_ofs -= G.lines / 2;
            goto normalize_ofs;
        }
        if (c == KEYCODE_PAGEDOWN) {
            G_scroll_ofs += G.lines / 2;
 normalize_ofs:
            if (G_scroll_ofs >= ntop)
                G_scroll_ofs = ntop - 1;
            if (G_scroll_ofs < 0)
                G_scroll_ofs = 0;
            break;
        }

        c |= 0x20; /* lowercase */
        if (c == 'q')
            return EXIT_MASK;

        if (c == 'n') {
            IF_FEATURE_TOPMEM(scan_mask = TOP_MASK;)
            sort_function[0] = pid_sort;
            continue;
        }
        if (c == 'm') {
            IF_FEATURE_TOPMEM(scan_mask = TOP_MASK;)
            sort_function[0] = mem_sort;
# if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
            sort_function[1] = pcpu_sort;
            sort_function[2] = time_sort;
# endif
            continue;
        }
# if ENABLE_FEATURE_SHOW_THREADS
        if (c == 'h'
        IF_FEATURE_TOPMEM(&& scan_mask != TOPMEM_MASK)
        ) {
            scan_mask ^= PSSCAN_TASKS;
            continue;
        }
# endif
# if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
        if (c == 'p') {
            IF_FEATURE_TOPMEM(scan_mask = TOP_MASK;)
            sort_function[0] = pcpu_sort;
            sort_function[1] = mem_sort;
            sort_function[2] = time_sort;
            continue;
        }
        if (c == 't') {
            IF_FEATURE_TOPMEM(scan_mask = TOP_MASK;)
            sort_function[0] = time_sort;
            sort_function[1] = mem_sort;
            sort_function[2] = pcpu_sort;
            continue;
        }
#  if ENABLE_FEATURE_TOPMEM
        if (c == 's') {
            scan_mask = TOPMEM_MASK;
            free(prev_hist);
            prev_hist = NULL;
            prev_hist_count = 0;
            sort_field = (sort_field + 1) % NUM_SORT_FIELD;
            continue;
        }
#  endif
        if (c == 'r') {
            inverted ^= 1;
            continue;
        }
#  if ENABLE_FEATURE_TOP_SMP_CPU
        /* procps-2.0.18 uses 'C', 3.2.7 uses '1' */
        if (c == 'c' || c == '1') {
            /* User wants to toggle per cpu <> aggregate */
            if (smp_cpu_info) {
                free(cpu_prev_jif);
                free(cpu_jif);
                cpu_jif = &cur_jif;
                cpu_prev_jif = &prev_jif;
            } else {
                /* Prepare for xrealloc() */
                cpu_jif = cpu_prev_jif = NULL;
            }
            num_cpus = 0;
            smp_cpu_info = !smp_cpu_info;
            get_jiffy_counts();
            continue;
        }
#  endif
# endif
        break; /* unknown key -> force refresh */
    }

    return scan_mask;
}
#endif

//usage:#if ENABLE_FEATURE_SHOW_THREADS || ENABLE_FEATURE_TOP_SMP_CPU
//usage:# define IF_SHOW_THREADS_OR_TOP_SMP(...) __VA_ARGS__
//usage:#else
//usage:# define IF_SHOW_THREADS_OR_TOP_SMP(...)
//usage:#endif
//usage:#define top_trivial_usage
//usage:       "[-b] [-nCOUNT] [-dSECONDS]" IF_FEATURE_TOPMEM(" [-m]")
//usage:#define top_full_usage "\n\n"
//usage:       "Provide a view of process activity in real time."
//usage:   "\n""Read the status of all processes from /proc each SECONDS"
//usage:   "\n""and display a screenful of them."
//usage:   "\n""Keys:"
//usage:   "\n""    N/M"
//usage:                IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE("/P")
//usage:                IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE("/T")
//usage:           ": " IF_FEATURE_TOPMEM("show CPU usage, ") "sort by pid/mem"
//usage:                IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE("/cpu")
//usage:                IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE("/time")
//usage:    IF_FEATURE_TOPMEM(
//usage:   "\n""    S: show memory"
//usage:    )
//usage:   "\n""    R: reverse sort"
//usage:    IF_SHOW_THREADS_OR_TOP_SMP(
//usage:   "\n""    "
//usage:                IF_FEATURE_SHOW_THREADS("H: toggle threads")
//usage:                IF_FEATURE_SHOW_THREADS(IF_FEATURE_TOP_SMP_CPU(", "))
//usage:                IF_FEATURE_TOP_SMP_CPU("1: toggle SMP")
//usage:    )
//usage:   "\n""    Q,^C: exit"
//usage:   "\n"
//usage:   "\n""Options:"
//usage:   "\n""    -b  Batch mode"
//usage:   "\n""    -n N    Exit after N iterations"
//usage:   "\n""    -d N    Delay between updates"
//usage:    IF_FEATURE_TOPMEM(
//usage:   "\n""    -m  Same as 's' key"
//usage:    )

/* Interactive testing:
 * echo sss | ./busybox top
 * - shows memory screen
 * echo sss | ./busybox top -bn1 >mem
 * - saves memory screen - the *whole* list, not first NROWS processes!
 * echo .m.s.s.s.s.s.s.q | ./busybox top -b >z
 * - saves several different screens, and exits
 *
 * TODO: -i STRING param as a better alternative?
 */

int top_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int top_main(int argc UNUSED_PARAM, char **argv)
{
    int iterations;
    unsigned col;
    unsigned interval;
    char *str_interval, *str_iterations;
    unsigned scan_mask = TOP_MASK;
#if ENABLE_FEATURE_USE_TERMIOS
    struct termios new_settings;
#endif

    INIT_G();

    interval = 5; /* default update interval is 5 seconds */
    iterations = 0; /* infinite */
#if ENABLE_FEATURE_TOP_SMP_CPU
    /*num_cpus = 0;*/
    /*smp_cpu_info = 0;*/  /* to start with show aggregate */
    cpu_jif = &cur_jif;
    cpu_prev_jif = &prev_jif;
#endif

    /* all args are options; -n NUM */
    opt_complementary = "-"; /* options can be specified w/o dash */
    col = getopt32(argv, "d:n:b"IF_FEATURE_TOPMEM("m"), &str_interval, &str_iterations);
#if ENABLE_FEATURE_TOPMEM
    if (col & OPT_m) /* -m (busybox specific) */
        scan_mask = TOPMEM_MASK;
#endif
    if (col & OPT_d) {
        /* work around for "-d 1" -> "-d -1" done by getopt32
         * (opt_complementary == "-" does this) */
        if (str_interval[0] == '-')
            str_interval++;
        /* Need to limit it to not overflow poll timeout */
        interval = xatou16(str_interval);
    }
    if (col & OPT_n) {
        if (str_iterations[0] == '-')
            str_iterations++;
        iterations = xatou(str_iterations);
    }

    /* change to /proc */
    xchdir("/proc");

#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
    sort_function[0] = pcpu_sort;
    sort_function[1] = mem_sort;
    sort_function[2] = time_sort;
#else
    sort_function[0] = mem_sort;
#endif

    if (OPT_BATCH_MODE) {
        option_mask32 |= OPT_EOF;
    }
#if ENABLE_FEATURE_USE_TERMIOS
    else {
        tcgetattr(0, (void *) &initial_settings);
        memcpy(&new_settings, &initial_settings, sizeof(new_settings));
        /* unbuffered input, turn off echo */
        new_settings.c_lflag &= ~(ISIG | ICANON | ECHO | ECHONL);
        tcsetattr_stdin_TCSANOW(&new_settings);
    }

    bb_signals(BB_FATAL_SIGS, sig_catcher);

    /* Eat initial input, if any */
    scan_mask = handle_input(scan_mask, 0);
#endif

    while (scan_mask != EXIT_MASK) {
        procps_status_t *p = NULL;

        if (OPT_BATCH_MODE) {
            G.lines = INT_MAX;
            col = LINE_BUF_SIZE - 2; /* +2 bytes for '\n', NUL */
        } else {
            G.lines = 24; /* default */
            col = 79;
#if ENABLE_FEATURE_USE_TERMIOS
            /* We output to stdout, we need size of stdout (not stdin)! */
            get_terminal_width_height(STDOUT_FILENO, &col, &G.lines);
            if (G.lines < 5 || col < 10) {
                sleep(interval);
                continue;
            }
#endif
            if (col > LINE_BUF_SIZE - 2)
                col = LINE_BUF_SIZE - 2;
        }

        /* read process IDs & status for all the processes */
        ntop = 0;
        while ((p = procps_scan(p, scan_mask)) != NULL) {
            int n;

            IF_FEATURE_TOPMEM(if (scan_mask != TOPMEM_MASK)) {
                n = ntop;
                top = xrealloc_vector(top, 6, ntop++);
                top[n].pid = p->pid;
                top[n].ppid = p->ppid;
                top[n].vsz = p->vsz;
#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
                top[n].ticks = p->stime + p->utime;
#endif
                top[n].uid = p->uid;
                strcpy(top[n].state, p->state);
                strcpy(top[n].comm, p->comm);
#if ENABLE_FEATURE_TOP_SMP_PROCESS
                top[n].last_seen_on_cpu = p->last_seen_on_cpu;
#endif
            }
#if ENABLE_FEATURE_TOPMEM
            else { /* TOPMEM */
                if (!(p->smaps.mapped_ro | p->smaps.mapped_rw))
                    continue; /* kernel threads are ignored */
                n = ntop;
                /* No bug here - top and topmem are the same */
                top = xrealloc_vector(topmem, 6, ntop++);
                strcpy(topmem[n].comm, p->comm);
                topmem[n].pid      = p->pid;
                topmem[n].vsz      = p->smaps.mapped_rw + p->smaps.mapped_ro;
                topmem[n].vszrw    = p->smaps.mapped_rw;
                topmem[n].rss_sh   = p->smaps.shared_clean + p->smaps.shared_dirty;
                topmem[n].rss      = p->smaps.private_clean + p->smaps.private_dirty + topmem[n].rss_sh;
                topmem[n].dirty    = p->smaps.private_dirty + p->smaps.shared_dirty;
                topmem[n].dirty_sh = p->smaps.shared_dirty;
                topmem[n].stack    = p->smaps.stack;
            }
#endif
        } /* end of "while we read /proc" */
        if (ntop == 0) {
            bb_error_msg("no process info in /proc");
            break;
        }

        IF_FEATURE_TOPMEM(if (scan_mask != TOPMEM_MASK)) {
#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
            if (!prev_hist_count) {
                do_stats();
                usleep(100000);
                clearmems();
                continue;
            }
            do_stats();
            /* TODO: we don't need to sort all 10000 processes, we need to find top 24! */
            qsort(top, ntop, sizeof(top_status_t), (void*)mult_lvl_cmp);
#else
            qsort(top, ntop, sizeof(top_status_t), (void*)(sort_function[0]));
#endif
            display_process_list(G.lines, col);
        }
#if ENABLE_FEATURE_TOPMEM
        else { /* TOPMEM */
            qsort(topmem, ntop, sizeof(topmem_status_t), (void*)topmem_sort);
            display_topmem_process_list(G.lines, col);
        }
#endif
        clearmems();
        if (iterations >= 0 && !--iterations)
            break;
#if !ENABLE_FEATURE_USE_TERMIOS
        sleep(interval);
#else
        scan_mask = handle_input(scan_mask, interval);
#endif
    } /* end of "while (not Q)" */

    bb_putchar('\n');
#if ENABLE_FEATURE_USE_TERMIOS
    reset_term();
#endif
    return EXIT_SUCCESS;
}