/*
 * Copyright (c) 1984 through 2008, William LeFebvre
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 * 
 *     * Neither the name of William LeFebvre nor the names of other
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

char *copyright =
    "Copyright (c) 1984 through 2008, William LeFebvre";

/*
 * Changes to other files that we can do at the same time:
 * screen.c:init_termcap: get rid of the "interactive" argument and have it
 *      pass back something meaningful (such as success/failure/error).
 */

#include "os.h"
#include <signal.h>
#include <setjmp.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>

#ifdef HAVE_SYS_UTSNAME_H
#include <sys/utsname.h>
#endif

#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif

/* definitions */
#ifndef STDIN_FILENO
#define STDIN_FILENO 0
#endif

/* determine which type of signal functions to use */
/* cant have sigaction without sigprocmask */
#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGPROCMASK)
#undef HAVE_SIGACTION
#endif
/* always use sigaction when it is available */
#ifdef HAVE_SIGACTION
#undef HAVE_SIGHOLD
#else
/* use sighold/sigrelse, otherwise use old fashioned BSD signals */
#if !defined(HAVE_SIGHOLD) || !defined(HAVE_SIGRELSE)
#define BSD_SIGNALS
#endif
#endif

/* if FD_SET and friends aren't present, then fake something up */
#ifndef FD_SET
typedef int fd_set;
#define FD_ZERO(x)     (*(x) = 0)
#define FD_SET(f, x)   (*(x) = 1<<f)
#endif

/* includes specific to top */

#include "top.h"
#include "machine.h"
#include "globalstate.h"
#include "commands.h"
#include "display.h"
#include "screen.h"
#include "boolean.h"
#include "username.h"
#include "utils.h"
#include "version.h"
#ifdef ENABLE_COLOR
#include "color.h"
#endif

/* definitions */
#define BUFFERSIZE 4096
#define JMP_RESUME 1
#define JMP_RESIZE 2

/* externs for getopt: */
extern int  optind;
extern char *optarg;

/* statics */
static char stdoutbuf[BUFFERSIZE];
static jmp_buf jmp_int;

/* globals */
char *myname = "top";

void
quit(int status)

{
    screen_end();
    chdir("/tmp");
    exit(status);
    /* NOTREACHED */
}

/*
 *  signal handlers
 */

void
set_signal(int sig, RETSIGTYPE (*handler)(int))

{
#ifdef HAVE_SIGACTION
    struct sigaction action;

    action.sa_handler = handler;
    action.sa_flags = 0;
    (void) sigaction(sig, &action, NULL);
#else
    (void) signal(sig, handler);
#endif
}

void
release_signal(int sig)

{
#ifdef HAVE_SIGACTION
    sigset_t set;
    sigemptyset(&set);
    sigaddset(&set, sig);
    sigprocmask(SIG_UNBLOCK, &set, NULL);
#endif

#ifdef HAVE_SIGHOLD
    sigrelse(sig);
#endif

#ifdef BSD_SIGNALS
    (void) sigsetmask(sigblock(0) & ~(sigmask(sig)));
#endif
}

RETSIGTYPE
sig_leave(int i)        /* exit under normal conditions -- INT handler */

{
    screen_end();
    exit(EX_OK);
}

RETSIGTYPE
sig_tstop(int i)        /* SIGTSTP handler */

{
    /* move to the lower left */
    screen_end();
    fflush(stdout);

    /* default the signal handler action */
    set_signal(SIGTSTP, SIG_DFL);

    /* unblock the TSTP signal */
    release_signal(SIGTSTP);

    /* send ourselves a TSTP to stop the process */
    (void) kill(0, SIGTSTP);

    /* reset the signal handler */
    set_signal(SIGTSTP, sig_tstop);

    /* reinit screen */
    screen_reinit();

    /* jump back to a known place in the main loop */
    longjmp(jmp_int, JMP_RESUME);

    /* NOTREACHED */
}

#ifdef SIGWINCH
RETSIGTYPE
sig_winch(int i)                /* SIGWINCH handler */

{
    /* reascertain the screen dimensions */
    screen_getsize();

    /* jump back to a known place in the main loop */
    longjmp(jmp_int, JMP_RESIZE);
}
#endif

#ifdef HAVE_SIGACTION
static sigset_t signalset;
#endif

void *
hold_signals()

{
#ifdef HAVE_SIGACTION
    sigemptyset(&signalset);
    sigaddset(&signalset, SIGINT);
    sigaddset(&signalset, SIGQUIT);
    sigaddset(&signalset, SIGTSTP);
#ifdef SIGWINCH
    sigaddset(&signalset, SIGWINCH);
#endif
    sigprocmask(SIG_BLOCK, &signalset, NULL);
    return (void *)(&signalset);
#endif

#ifdef HAVE_SIGHOLD
    sighold(SIGINT);
    sighold(SIGQUIT);
    sighold(SIGTSTP);
#ifdef SIGWINCH
    sighold(SIGWINCH);
    return NULL;
#endif
#endif

#ifdef BSD_SIGNALS
    int mask;
#ifdef SIGWINCH
    mask = sigblock(sigmask(SIGINT) | sigmask(SIGQUIT) |
                    sigmask(SIGTSTP) | sigmask(SIGWINCH));
#else
    mask = sigblock(sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTSTP));
    return (void *)mask;
#endif
#endif

}

void
set_signals()

{
    (void) set_signal(SIGINT, sig_leave);
    (void) set_signal(SIGQUIT, sig_leave);
    (void) set_signal(SIGTSTP, sig_tstop);
#ifdef SIGWINCH
    (void) set_signal(SIGWINCH, sig_winch);
#endif
}

void
release_signals(void *parm)

{
#ifdef HAVE_SIGACTION
    sigprocmask(SIG_UNBLOCK, (sigset_t *)parm, NULL);
#endif

#ifdef HAVE_SIGHOLD
    sigrelse(SIGINT);
    sigrelse(SIGQUIT);
    sigrelse(SIGTSTP);
#ifdef SIGWINCH
    sigrelse(SIGWINCH);
#endif
#endif

#ifdef BSD_SIGNALS
    (void) sigsetmask((int)parm);
#endif
}

/*
 * void do_arguments(globalstate *gstate, int ac, char **av)
 *
 * Arguments processing.  gstate points to the global state,
 * ac and av are the arguments to process.  This can be called
 * multiple times with different sets of arguments.
 */

#ifdef HAVE_GETOPT_LONG
static struct option longopts[] = {
    { "color", no_argument, NULL, 'C' },
    { "debug", no_argument, NULL, 'D' },
    { "system-procs", no_argument, NULL, 'S' },
    { "idle-procs", no_argument, NULL, 'I' },
    { "tag-names", no_argument, NULL, 'T' },
    { "all", no_argument, NULL, 'a' },
    { "batch", no_argument, NULL, 'b' },
    { "full-commands", no_argument, NULL, 'c' },
    { "interactive", no_argument, NULL, 'i' },
    { "quick", no_argument, NULL, 'q' },
    { "threads", no_argument, NULL, 't' },
    { "uids", no_argument, NULL, 'u' },
    { "version", no_argument, NULL, 'v' },
    { "delay", required_argument, NULL, 's' },
    { "displays", required_argument, NULL, 'd' },
    { "user", required_argument, NULL, 'U' },
    { "sort-order", required_argument, NULL, 'o' },
    { "display-mode", required_argument, NULL, 'm' },
    { NULL, 0, NULL, 0 },
};
#endif


void
do_arguments(globalstate *gstate, int ac, char **av)

{
    int i;

    /* this appears to keep getopt happy */
    optind = 1;

#ifdef HAVE_GETOPT_LONG
    while ((i = getopt_long(ac, av, "CDSIMTabcinqtuvs:d:U:o:m:", longopts, NULL)) != -1)
#else
    while ((i = getopt(ac, av, "CDSIMTabcinqtuvs:d:U:o:m:")) != EOF)
#endif
    {
        switch(i)
        {
#ifdef ENABLE_COLOR
        case 'C':
            gstate->use_color = !gstate->use_color;
            break;
#endif

        case 'D':
            debug_set(1);
            break;

        case 'v':
            fprintf(stderr, "%s: version %s\n", myname, version_string());
            exit(EX_OK);
            break;

        case 'b':
        case 'n':
            gstate->interactive = No;
            break;

        case 'a':
            gstate->displays = Infinity;
            gstate->topn = Infinity;
            break;

        case 'i':
            gstate->interactive = Yes;
            break;

        case 'o':
            gstate->order_name = optarg;
            break;

        case 'd':
            i = atoiwi(optarg);
            if (i == Invalid || i == 0)
            {
                message_error(" Bad display count");
            }
            else
            {
                gstate->displays = i;
            }
            break;

        case 's':
            i = atoi(optarg);
            if (i < 0 || (i == 0 && getuid() != 0))
            {
                message_error(" Bad seconds delay");
            }
            else
            {
                gstate->delay = i;
            }
            break;

        case 'u':
            gstate->show_usernames = !gstate->show_usernames;
            break;

        case 'U':
            i = userid(optarg);
            if (i == -1)
            {
                message_error(" Unknown user '%s'", optarg);
            }
            else
            {
                gstate->pselect.uid = i;
            }
            break;

        case 'm':
            i = atoi(optarg);
            gstate->pselect.mode = i;
            break;

        case 'S':
            gstate->pselect.system = !gstate->pselect.system;
            break;

        case 'I':
            gstate->pselect.idle = !gstate->pselect.idle;
            break;

        case 'M':
            enable_ncpus = 1;
            break;


#ifdef ENABLE_COLOR
        case 'T':
            gstate->show_tags = 1;
            break;
#endif

        case 'c':
            gstate->pselect.fullcmd = !gstate->pselect.fullcmd;
            break;

        case 't':
            gstate->pselect.threads = !gstate->pselect.threads;
            break;

        case 'q':               /* be quick about it */
            /* only allow this if user is really root */
            if (getuid() == 0)
            {
                /* be very un-nice! */
                (void) nice(-20);
            }
            else
            {
                message_error(" Option -q can only be used by root");
            }
            break;

        default:
            fprintf(stderr, "\
Top version %s\n\
Usage: %s [-ISTabcinqu] [-d x] [-s x] [-o field] [-U username] [number]\n",
                    version_string(), myname);
            exit(EX_USAGE);
        }
    }

    /* get count of top processes to display */
    if (optind < ac && *av[optind])
    {
        if ((i = atoiwi(av[optind])) == Invalid)
        {
            message_error(" Process count not a number");
        }
        else
        {
            gstate->topn = i;
        }
    }
}

void
do_display(globalstate *gstate)

{
    int active_procs;
    int i;
    time_t curr_time;
    caddr_t processes;
    struct system_info system_info;
    char *hdr;

    /* get the time */
    time_mark(&(gstate->now));
    curr_time = (time_t)(gstate->now.tv_sec);

    /* get the current stats */
    get_system_info(&system_info);

    /* get the current processes */
    processes = get_process_info(&system_info, &(gstate->pselect), gstate->order_index);

    /* determine number of processes to actually display */
    if (gstate->topn > 0)
    {
        /* this number will be the smallest of:  active processes,
           number user requested, number current screen accomodates */
        active_procs = system_info.P_ACTIVE;
        if (active_procs > gstate->topn)
        {
            active_procs = gstate->topn;
        }
        if (active_procs > gstate->max_topn)
        {
            active_procs = gstate->max_topn;
        }
    }
    else
    {
        /* dont show any */
        active_procs = 0;
    }

    hdr = gstate->header_text;

    /* full screen or update? */
    if (gstate->fulldraw)
    {
        struct timespec uts;

        clock_gettime(CLOCK_UPTIME, &uts);
        display_clear();
        i_loadave(system_info.last_pid, system_info.load_avg);
        i_uptime(uts.tv_sec);
        i_timeofday(&curr_time);
        i_procstates(system_info.p_total, system_info.procstates, gstate->pselect.threads);
        if (gstate->show_cpustates)
        {
            i_cpustates(system_info.cpustates);
        }
        else
        {
            if (smart_terminal)
            {
                z_cpustates();
            }
            gstate->show_cpustates = Yes;
        }
        i_kernel(system_info.kernel);
        i_memory(system_info.memory);
        i_swap(system_info.swap);
        i_message(&(gstate->now));
        i_header(hdr);
        for (i = 0; i < active_procs; i++)
        {
            i_process(i, format_next_process(processes, gstate->get_userid));
        }
        i_endscreen();
        if (gstate->smart_terminal)
        {
            gstate->fulldraw = No;
        }
    }
    else
    {
        struct timespec uts;

        clock_gettime(CLOCK_UPTIME, &uts);
        u_loadave(system_info.last_pid, system_info.load_avg);
        u_uptime(uts.tv_sec);
        i_timeofday(&curr_time);
        u_procstates(system_info.p_total, system_info.procstates, gstate->pselect.threads);
        u_cpustates(system_info.cpustates);
        u_kernel(system_info.kernel);
        u_memory(system_info.memory);
        u_swap(system_info.swap);
        u_message(&(gstate->now));
        u_header(hdr);
        for (i = 0; i < active_procs; i++)
        {
            u_process(i, format_next_process(processes, gstate->get_userid));
        }
        u_endscreen();
    }
}

#ifdef DEBUG
void
timeval_xdprint(char *s, struct timeval tv)

{
    xdprintf("%s %d.%06d\n", s, tv.tv_sec, tv.tv_usec);
}
#endif

void
do_wait(globalstate *gstate)

{
    struct timeval wait;

    wait.tv_sec = gstate->delay;
    wait.tv_usec = 0;
    select(0, NULL, NULL, NULL, &wait);
}

void
do_command(globalstate *gstate)

{
    int status;
    struct timeval wait = {0, 0};
    struct timeval now;
    fd_set readfds;
    unsigned char ch;

    /* calculate new refresh time */
    gstate->refresh = gstate->now;
    gstate->refresh.tv_sec += gstate->delay;
    time_get(&now);

    /* loop waiting for time to expire */
    do {
        /* calculate time to wait */
        if (gstate->delay > 0)
        {
            wait = gstate->refresh;
            wait.tv_usec -= now.tv_usec;
            if (wait.tv_usec < 0)
            {
                wait.tv_usec += 1000000;
                wait.tv_sec--;
            }
            wait.tv_sec -= now.tv_sec;
        }

        /* set up arguments for select on stdin (0) */
        FD_ZERO(&readfds);
        FD_SET(STDIN_FILENO, &readfds);

        /* wait for something to read or time out */
        if (select(32, &readfds, NULL, NULL, &wait) > 0)
        {
            /* read it */
            if (read(STDIN_FILENO, &ch, 1) != 1)
            {
                /* read error */
                message_error(" Read error on stdin");
                quit(EX_DATAERR);
                /*NOTREACHED*/
            }

            /* mark pending messages as old */
            message_mark();

            /* dispatch */
            status = command_process(gstate, (int)ch);
            switch(status)
            {
            case CMD_ERROR:
                quit(EX_SOFTWARE);
                /*NOTREACHED*/
                
            case CMD_REFRESH:
                return;

            case CMD_UNKNOWN:
                message_error(" Unknown command");
                break;

            case CMD_NA:
                message_error(" Command not available");
            }
        }

        /* get new time */
        time_get(&now);
    } while (timercmp(&now, &(gstate->refresh), < ));
}

void
do_minidisplay(globalstate *gstate)

{
    int real_delay;
    struct system_info si;

    /* save the real delay and substitute 1 second */
    real_delay = gstate->delay;
    gstate->delay = 1;

    /* wait 1 second for a command */
    time_mark(&(gstate->now));
    do_command(gstate);

    /* do a mini update that only updates the cpustates */
    get_system_info(&si);
    u_cpustates(si.cpustates);

    /* restore the delay time */
    gstate->delay = real_delay;

    /* done */
    i_endscreen();
}

int
main(int argc, char *argv[])

{
    char *env_top;
    char **preset_argv;
    int preset_argc = 0;
    void *mask;
    int need_mini = 1;

    struct statics statics;
    globalstate *gstate;

    /* get our name */
    if (argc > 0)
    {
        if ((myname = strrchr(argv[0], '/')) == NULL)
        {
            myname = argv[0];
        }
        else
        {
            myname++;
        }
    }

    /* binary compatibility check */
#ifdef HAVE_UNAME
    {
        struct utsname uts;

        if (uname(&uts) == 0)
        {
            if (strcmp(uts.machine, UNAME_HARDWARE) != 0)
            {
                fprintf(stderr, "%s: incompatible hardware platform\n",
                        myname);
                exit(EX_UNAVAILABLE);
            }
        }
    }
#endif

    /* initialization */
    gstate = (globalstate *)calloc(1, sizeof(globalstate));
    gstate->statics = &statics;
    time_mark(NULL);

    /* preset defaults for various options */
    gstate->show_usernames = Yes;
    gstate->topn = DEFAULT_TOPN;
    gstate->delay = DEFAULT_DELAY;
    gstate->fulldraw = Yes;
    gstate->use_color = Yes;
    gstate->interactive = Maybe;

    /* preset defaults for process selection */
    gstate->pselect.idle = Yes;
    gstate->pselect.system = No;
    gstate->pselect.fullcmd = No;
    gstate->pselect.command = NULL;
    gstate->pselect.uid = -1;
    gstate->pselect.mode = 0;

    /* use a large buffer for stdout */
#ifdef HAVE_SETVBUF
    setvbuf(stdout, stdoutbuf, _IOFBF, BUFFERSIZE);
#else
#ifdef HAVE_SETBUFFER
    setbuffer(stdout, stdoutbuf, BUFFERSIZE);
#endif
#endif

    /* get preset options from the environment */
    if ((env_top = getenv("TOP")) != NULL)
    {
        preset_argv = argparse(env_top, &preset_argc);
        preset_argv[0] = myname;
        do_arguments(gstate, preset_argc, preset_argv);
    }

    /* process arguments */
    do_arguments(gstate, argc, argv);

#ifdef ENABLE_COLOR
    /* If colour has been turned on read in the settings. */
    env_top = getenv("TOPCOLOURS");
    if (!env_top)
    {
        env_top = getenv("TOPCOLORS");
    }
    /* must do something about error messages */
    color_env_parse(env_top);
    color_activate(gstate->use_color);
#endif

    /* in order to support forward compatability, we have to ensure that
       the entire statics structure is set to a known value before we call
       machine_init.  This way fields that a module does not know about
       will retain their default values */
    memzero((void *)&statics, sizeof(statics));

    /* call the platform-specific init */
    if (machine_init(&statics) == -1)
    {
        exit(EX_SOFTWARE);
    }

    /* create a helper list of sort order names */
    gstate->order_namelist = string_list(statics.order_names);

    /* look up chosen sorting order */
    if (gstate->order_name != NULL)
    {
        int i;

        if (statics.order_names == NULL)
        {
            message_error(" This platform does not support arbitrary ordering");
        }
        else if ((i = string_index(gstate->order_name,
                                   statics.order_names)) == -1)
        {
            message_error(" Sort order `%s' not recognized", gstate->order_name);
            message_error(" Recognized sort orders: %s", gstate->order_namelist);
        }
        else
        {
            gstate->order_index = i;
        }
    }

    /* initialize extensions */
    init_username();

    /* initialize termcap */
    gstate->smart_terminal = screen_readtermcap(gstate->interactive);

    /* determine interactive state */
    if (gstate->interactive == Maybe)
    {
        gstate->interactive = smart_terminal;
    }

    /* if displays were not specified, choose an appropriate default */
    if (gstate->displays == 0)
    {
        gstate->displays = gstate->smart_terminal ? Infinity: 1;
    }

    /* we don't need a mini display when delay is less than 2
       seconds or when we are not on a smart terminal */
    if (gstate->delay <= 1 || !smart_terminal)
    {
        need_mini = 0;
    }

    /* set constants for username/uid display */
    if (gstate->show_usernames)
    {
        gstate->header_text = format_header("USERNAME");
        gstate->get_userid = username;
    }
    else
    {
        gstate->header_text = format_header("   UID  ");
        gstate->get_userid = itoa7;
    }
    gstate->pselect.usernames = gstate->show_usernames;

    /* initialize display */
    if ((gstate->max_topn = display_init(&statics)) == -1)
    {
        fprintf(stderr, "%s: can't allocate sufficient memory\n", myname);
        exit(EX_OSERR);
    }

    /* check for infinity and for overflowed screen */
    if (gstate->topn == Infinity)
    {
        gstate->topn = INT_MAX;
    }
    else if (gstate->topn > gstate->max_topn)
    {
#if 0
        message_error(" This terminal can only display %d processes",
                      gstate->max_topn);
#endif
    }

#ifdef ENABLE_COLOR
    /* producing a list of color tags is easy */
    if (gstate->show_tags)
    {
        color_dump(stdout);
        exit(EX_OK);
    }
#endif

    /* hold all signals while we initialize the screen */
    mask = hold_signals();
    screen_init();

    /* set the signal handlers */
    set_signals();

    /* longjmp re-entry point */
    /* set the jump buffer for long jumps out of signal handlers */
    if (setjmp(jmp_int) != 0)
    {
        /* this is where we end up after processing sigwinch or sigtstp */

        /* tell display to resize its buffers, and get the new length */
        if ((gstate->max_topn = display_resize()) == -1)
        {
            /* thats bad */
            quit(EX_OSERR);
            /*NOTREACHED*/
        }

        /* set up for a full redraw, and get the current line count */
        gstate->fulldraw = Yes;

        /* safe to release the signals now */
        release_signals(mask);
    }
    else
    {
        /* release the signals */
        release_signals(mask);

        /* some systems require a warmup */
        /* always do a warmup for batch mode */
        if (gstate->interactive == 0 || statics.flags.warmup)
        {
            struct system_info system_info;
            struct timeval timeout;

            time_mark(&(gstate->now));
            get_system_info(&system_info);
            (void)get_process_info(&system_info, &gstate->pselect, 0);
            timeout.tv_sec = 1;
            timeout.tv_usec = 0;
            select(0, NULL, NULL, NULL, &timeout);

            /* if we've warmed up, then we can show good states too */
            gstate->show_cpustates = Yes;
            need_mini = 0;
        }
    }

    /* main loop */
    while ((gstate->displays == -1) || (--gstate->displays > 0))
    {
        do_display(gstate);
        if (gstate->interactive)
        {
            if (need_mini)
            {
                do_minidisplay(gstate);
                need_mini = 0;
            }
            do_command(gstate);
        }
        else
        {
            do_wait(gstate);
        }
    }

    /* do one last display */
    do_display(gstate);

    quit(EX_OK);
    /* NOTREACHED */
    return 1; /* Keep compiler quiet. */
}