/* $OpenBSD$ */

/*
* Copyright (c) 2009 Nicholas Marriott <[email protected]>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/stat.h>
#include <sys/sysctl.h>

#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "tmux.h"

#define is_runnable(p) \
       ((p)->p_stat == LSRUN || (p)->p_stat == SIDL)
#define is_stopped(p) \
       ((p)->p_stat == SSTOP || (p)->p_stat == SZOMB)

struct kinfo_proc2      *cmp_procs(struct kinfo_proc2 *, struct kinfo_proc2 *);

struct kinfo_proc2 *
cmp_procs(struct kinfo_proc2 *p1, struct kinfo_proc2 *p2)
{
       if (is_runnable(p1) && !is_runnable(p2))
               return (p1);
       if (!is_runnable(p1) && is_runnable(p2))
               return (p2);

       if (is_stopped(p1) && !is_stopped(p2))
               return (p1);
       if (!is_stopped(p1) && is_stopped(p2))
               return (p2);

       if (p1->p_estcpu > p2->p_estcpu)
               return (p1);
       if (p1->p_estcpu < p2->p_estcpu)
               return (p2);

       if (p1->p_slptime < p2->p_slptime)
               return (p1);
       if (p1->p_slptime > p2->p_slptime)
               return (p2);

       if (p1->p_pid > p2->p_pid)
               return (p1);
       return (p2);
}

char *
osdep_get_name(int fd, __unused char *tty)
{
       int              mib[6];
       struct stat      sb;
       size_t           len, i;
       struct kinfo_proc2 *buf, *newbuf, *bestp;
       char            *name;

       if (stat(tty, &sb) == -1)
               return (NULL);
       if ((mib[3] = tcgetpgrp(fd)) == -1)
               return (NULL);

       buf = NULL;
       len = sizeof bestp;

       mib[0] = CTL_KERN;
       mib[1] = KERN_PROC2;
       mib[2] = KERN_PROC_PGRP;
       mib[4] = sizeof *buf;

retry:
       mib[5] = 0;

       if (sysctl(mib, __arraycount(mib), NULL, &len, NULL, 0) == -1)
               return (NULL);

       if ((newbuf = realloc(buf, len)) == NULL)
               goto error;
       buf = newbuf;

       mib[5] = len / (sizeof *buf);
       if (sysctl(mib, __arraycount(mib), buf, &len, NULL, 0) == -1) {
               if (errno == ENOMEM)
                       goto retry;
               goto error;
       }

       bestp = NULL;
       for (i = 0; i < len / (sizeof *buf); i++) {
               if (buf[i].p_tdev != sb.st_rdev)
                       continue;
               if (bestp == NULL)
                       bestp = &buf[i];
               else
                       bestp = cmp_procs(&buf[i], bestp);
       }

       name = NULL;
       if (bestp != NULL)
               name = strdup(bestp->p_comm);

       free(buf);
       return (name);

error:
       free(buf);
       return (NULL);
}

char *
osdep_get_cwd(int fd)
{
       static char     target[PATH_MAX + 1];
       pid_t           pgrp;
#ifdef KERN_PROC_CWD
       int             mib[4];
       size_t          len;
#else
       char            *path;
       ssize_t         n;
#endif

       if ((pgrp = tcgetpgrp(fd)) == -1)
               return (NULL);

#ifdef KERN_PROC_CWD
       mib[0] = CTL_KERN;
       mib[1] = KERN_PROC_ARGS;
       mib[2] = pgrp;
       mib[3] = KERN_PROC_CWD;
       len = sizeof(target);
       if (sysctl(mib, __arraycount(mib), target, &len, NULL, 0) == 0)
               return (target);
#else
       xasprintf(&path, "/proc/%lld/cwd", (long long) pgrp);
       n = readlink(path, target, sizeof(target) - 1);
       free(path);
       if (n > 0) {
               target[n] = '\0';
               return (target);
       }
#endif

       return (NULL);
}

struct event_base *
osdep_event_init(void)
{
       return (event_init());
}