text: /* ps.c - show process list
   *
   * Copyright 2015 Rob Landley <rob@landley.net>
   *
   * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ps.html
   * And http://kernel.org/doc/Documentation/filesystems/proc.txt Table 1-4
   * And linux kernel source fs/proc/array.c function do_task_stat()
   *
   * Deviations from posix: no -n because /proc/self/wchan exists; we use -n to
   * mean "show numeric users and groups" instead.
   * Posix says default output should have field named "TTY" but if you "-o tty"
   * the same field should be called "TT" which is _INSANE_ and I'm not doing it.
   * Similarly -f outputs USER but calls it UID (we call it USER).
   * It also says that -o "args" and "comm" should behave differently but use
   * the same title, which is not the same title as the default output. (No.)
   * Select by session id is -s not -g. Posix doesn't say truncated fields
   * should end with "+" but it's pretty common behavior.
   *
   * Posix defines -o ADDR as "The address of the process" but the process
   * start address is a constant on any elf system with mmu. The procps ADDR
   * field always prints "-" with an alignment of 1, which is why it has 11
   * characters left for "cmd" in in 80 column "ps -l" mode. On x86-64 you
   * need 12 chars, leaving nothing for cmd: I.E. posix 2008 ps -l mode can't
   * be sanely implemented on 64 bit Linux systems. In procps there's ps -y
   * which changes -l by removing the "F" column and swapping RSS for ADDR,
   * leaving 9 chars for cmd, so we're using that as our -l output.
   *
   * Added a bunch of new -o fields posix doesn't mention, and we don't
   * label "ps -o command,args,comm" as "COMMAND COMMAND COMMAND". We don't
   * output argv[0] unmodified for -o comm or -o args (but procps violates
   * posix for -o comm anyway, it's stat[2] not argv[0]).
   *
   * Note: iotop is STAYROOT so it can read other process's /proc/$PID/io
   *       files (why they're not globally readable when the rest of proc
   *       data is...?) and get a global I/O picture. Normal top is NOT,
   *       even though you can -o AIO there, to give sysadmins the option
   *       to reduce security exposure.)
   *
   * TODO: ps aux (att & bsd style "ps -ax" vs "ps ax" behavior difference)
   * TODO: switch -fl to -y
   * TODO: thread support /proc/$d/task/%d/stat (and -o stat has "l")
   * TODO: iotop: Window size change: respond immediately. Why not padding
   *       at right edge? (Not adjusting to screen size at all? Header wraps?)
   * TODO: top: thread support and SMP
   * TODO: pgrep -f only searches the amount of cmdline that fits in toybuf.
  
  USE_PS(NEWTOY(ps, "k(sort)*P(ppid)*aAdeflMno*O*p(pid)*s*t*Tu*U*g*G*wZ[!ol][+Ae][!oO]", TOYFLAG_BIN|TOYFLAG_LOCALE))
  // stayroot because iotop needs root to read other process' proc/$$/io
  // TOP and IOTOP have a large common option block used for common processing,
  // the default values are different but the flags are in the same order.
  USE_TOP(NEWTOY(top, ">0O*" "Hk*o*p*u*s#<1d%<100=3000m#n#<1bq[!oO]", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_LOCALE))
  USE_IOTOP(NEWTOY(iotop, ">0AaKO" "Hk*o*p*u*s#<1=7d%<100=3000m#n#<1bq", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT|TOYFLAG_LOCALE))
  USE_PGREP(NEWTOY(pgrep, "?cld:u*U*t*s*P*g*G*fnovxL:[-no]", TOYFLAG_USR|TOYFLAG_BIN))
  USE_PKILL(NEWTOY(pkill,    "?Vu*U*t*s*P*g*G*fnovxl:[-no]", TOYFLAG_USR|TOYFLAG_BIN))
  
  config PS
    bool "ps"
    default y
    help
      usage: ps [-AadefLlnwZ] [-gG GROUP,] [-k FIELD,] [-o FIELD,] [-p PID,] [-t TTY,] [-uU USER,]
  
      List processes.
  
      Which processes to show (-gGuUpPt selections may be comma separated lists):
  
      -A  All					-a  Has terminal not session leader
      -d  All but session leaders		-e  Synonym for -A
      -g  In GROUPs				-G  In real GROUPs (before sgid)
      -p  PIDs (--pid)			-P  Parent PIDs (--ppid)
      -s  In session IDs			-t  Attached to selected TTYs
      -T  Show threads also			-u  Owned by selected USERs
      -U  Real USERs (before suid)
  
      Output modifiers:
  
      -k  Sort FIELDs (-FIELD to reverse)	-M  Measure/pad future field widths
      -n  Show numeric USER and GROUP		-w  Wide output (don't truncate fields)
  
      Which FIELDs to show. (-o HELP for list, default = -o PID,TTY,TIME,CMD)
  
      -f  Full listing (-o USER:12=UID,PID,PPID,C,STIME,TTY,TIME,ARGS=CMD)
      -l  Long listing (-o F,S,UID,PID,PPID,C,PRI,NI,ADDR,SZ,WCHAN,TTY,TIME,CMD)
      -o  Output FIELDs instead of defaults, each with optional :size and =title
      -O  Add FIELDS to defaults
      -Z  Include LABEL
  
  config TOP
    bool "top"
    default y
    help
      usage: top [-Hbq] [-k FIELD,] [-o FIELD,] [-s SORT] [-n NUMBER] [-m LINES] [-d SECONDS] [-p PID,] [-u USER,]
  
      Show process activity in real time.
  
      -H	Show threads
      -k	Fallback sort FIELDS (default -S,-%CPU,-ETIME,-PID)
      -o	Show FIELDS (def PID,USER,PR,NI,VIRT,RES,SHR,S,%CPU,%MEM,TIME+,CMDLINE)
      -O	Add FIELDS (replacing PR,NI,VIRT,RES,SHR,S from default)
      -s	Sort by field number (1-X, default 9)
      -b	Batch mode (no tty)
      -d	Delay SECONDS between each cycle (default 3)
      -m	Maximum number of tasks to show
      -n	Exit after NUMBER iterations
      -p	Show these PIDs
      -u	Show these USERs
      -q	Quiet (no header lines)
  
      Cursor LEFT/RIGHT to change sort, UP/DOWN move list, space to force
      update, R to reverse sort, Q to exit.
  
  # Requires CONFIG_IRQ_TIME_ACCOUNTING in the kernel for /proc/$$/io
  config IOTOP
    bool "iotop"
    default y
    help
      usage: iotop [-AaKObq] [-n NUMBER] [-d SECONDS] [-p PID,] [-u USER,]
  
      Rank processes by I/O.
  
      -A	All I/O, not just disk
      -a	Accumulated I/O (not percentage)
      -H	Show threads
      -K	Kilobytes
      -k	Fallback sort FIELDS (default -[D]IO,-ETIME,-PID)
      -m	Maximum number of tasks to show
      -O	Only show processes doing I/O
      -o	Show FIELDS (default PID,PR,USER,[D]READ,[D]WRITE,SWAP,[D]IO,COMM)
      -s	Sort by field number (0-X, default 6)
      -b	Batch mode (no tty)
      -d	Delay SECONDS between each cycle (default 3)
      -n	Exit after NUMBER iterations
      -p	Show these PIDs
      -u	Show these USERs
      -q	Quiet (no header lines)
  
      Cursor LEFT/RIGHT to change sort, UP/DOWN move list, space to force
      update, R to reverse sort, Q to exit.
  
  config PGREP
    bool "pgrep"
    default y
    help
      usage: pgrep [-clfnovx] [-d DELIM] [-L SIGNAL] [PATTERN] [-G GID,] [-g PGRP,] [-P PPID,] [-s SID,] [-t TERM,] [-U UID,] [-u EUID,]
  
      Search for process(es). PATTERN is an extended regular expression checked
      against command names.
  
      -c	Show only count of matches
      -d	Use DELIM instead of newline
      -L	Send SIGNAL instead of printing name
      -l	Show command name
      -f	Check full command line for PATTERN
      -G	Match real Group ID(s)
      -g	Match Process Group(s) (0 is current user)
      -n	Newest match only
      -o	Oldest match only
      -P	Match Parent Process ID(s)
      -s	Match Session ID(s) (0 for current)
      -t	Match Terminal(s)
      -U	Match real User ID(s)
      -u	Match effective User ID(s)
      -v	Negate the match
      -x	Match whole command (not substring)
  
  config PKILL
    bool "pkill"
    default y
    help
      usage: pkill [-fnovx] [-SIGNAL|-l SIGNAL] [PATTERN] [-G GID,] [-g PGRP,] [-P PPID,] [-s SID,] [-t TERM,] [-U UID,] [-u EUID,]
  
      -l	Send SIGNAL (default SIGTERM)
      -V	Verbose
      -f	Check full command line for PATTERN
      -G	Match real Group ID(s)
      -g	Match Process Group(s) (0 is current user)
      -n	Newest match only
      -o	Oldest match only
      -P	Match Parent Process ID(s)
      -s	Match Session ID(s) (0 for current)
      -t	Match Terminal(s)
      -U	Match real User ID(s)
      -u	Match effective User ID(s)
      -v	Negate the match
      -x	Match whole command (not substring)
  */
  
  #define FOR_ps
  #include "toys.h"
  
  GLOBALS(
    union {
      struct {
        struct arg_list *G, *g, *U, *u, *t, *s, *p, *O, *o, *P, *k;
      } ps;
      struct {
        long n, m, d, s;
        struct arg_list *u, *p, *o, *k, *O;
      } top;
      struct {
        char *L;
        struct arg_list *G, *g, *P, *s, *t, *U, *u;
        char *d;
  
        void *regexes, *snapshot;
        int signal;
        pid_t self, match;
      } pgrep;
    };
  
    struct ptr_len gg, GG, pp, PP, ss, tt, uu, UU;
    struct dirtree *threadparent;
    unsigned width, height;
    dev_t tty;
    void *fields, *kfields;
    long long ticks, bits, time;
    int kcount, forcek, sortpos;
    int (*match_process)(long long *slot);
    void (*show_process)(void *tb);
  )
  
  // Linked list of -o fields selected for display, in order, with :len and =title
  
  struct ofields {
    struct ofields *next, *prev;
    short which, len, reverse;
    char *title;
  };
  
  /* The function get_ps() reads all the data about one process, saving it in
   * toybox as a struct procpid. Simple ps calls then pass toybuf directly to
   * show_ps(), but features like sorting append a copy to a linked list
   * for further processing once all processes have been read.
   *
   * struct procpid contains a slot[] array of 64 bit values, with the following
   * data at each position in the array. Most is read from /proc/$PID/stat (see
   * https://kernel.org/doc/Documentation/filesystems/proc.txt table 1-4) but
   * we replace several fields with don't use with other data. */
  
  enum {
   SLOT_pid,      /*process id*/            SLOT_ppid,      // parent process id
   SLOT_pgrp,     /*process group*/         SLOT_sid,       // session id
   SLOT_ttynr,    /*tty the process uses*/  SLOT_ttypgrp,   // pgrp of the tty
   SLOT_flags,    /*task flags*/            SLOT_minflt,    // minor faults
   SLOT_cminflt,  /*minor faults+child*/    SLOT_majflt,    // major faults
   SLOT_cmajflt,  /*major faults+child*/    SLOT_utime,     // user+kernel jiffies
   SLOT_stime,    /*kernel mode jiffies*/   SLOT_cutime,    // utime+child utime
   SLOT_cstime,   /*stime+child*/           SLOT_priority,  // priority level
   SLOT_nice,     /*nice level*/            SLOT_numthreads,// thread count
   SLOT_vmlck,    /*locked memory*/         SLOT_starttime, // jiffies after boot
   SLOT_vsize,    /*virtual memory size*/   SLOT_rss,       // resident set size
   SLOT_rsslim,   /*limit in bytes on rss*/ SLOT_startcode, // code segment addr
   SLOT_endcode,  /*code segment address*/  SLOT_startstack,// stack address
   SLOT_esp,      /*task stack pointer*/    SLOT_eip,       // instruction pointer
   SLOT_iobytes,  /*All I/O bytes*/         SLOT_diobytes,  // disk I/O bytes
   SLOT_utime2,   /*relative utime (top)*/  SLOT_uid,       // user id
   SLOT_ruid,     /*real user id*/          SLOT_gid,       // group id
   SLOT_rgid,     /*real group id*/         SLOT_exitsig,   // sent to parent
   SLOT_taskcpu,  /*CPU running on*/        SLOT_rtprio,    // realtime priority
   SLOT_policy,   /*man sched_setscheduler*/SLOT_blkioticks,// IO wait time
   SLOT_gtime,    /*guest jiffies of task*/ SLOT_cgtime,    // gtime+child
   SLOT_startbss, /*data/bss address*/      SLOT_endbss,    // end addr data+bss
  // end of /proc/$PID/stat fields
   SLOT_upticks,  /*uptime-starttime*/      SLOT_argv0len,  // argv[0] length
   SLOT_uptime,   /*sysinfo.uptime*/        SLOT_totalram,  // sysinfo.totalram
   SLOT_vsz,      /*Virtual mem Size*/      SLOT_shr,       // Shared memory
   SLOT_pcy,      /*Android sched pol*/     SLOT_rchar,     // All bytes read
   SLOT_wchar,    /*All bytes written*/     SLOT_rbytes,    // Disk bytes read
   SLOT_wbytes,   /*Disk bytes written*/    SLOT_swap,      // Swap pages used
   SLOT_bits,     /*32 or 64*/              SLOT_tid,       // Thread ID
   SLOT_tcount,   /*Thread count*/
  
   SLOT_count /* Size of array */
  };
  
  /* In addition to slot[], carevup contains 6 string fields to display
     command name, tty device, selinux label... They're stored one after the
     other in str[] (separated by null terminators), and offset[] contains the
     starting position of each string after the first (which is always 0). */
  
  // Data layout in toybuf
  struct procpid {
    long long slot[SLOT_count]; // data (see enum above)
    unsigned short offset[6];   // offset of fields in str[] (skip CMD, always 0)
    char state;
    char str[];                 // CMD, TTY, WCHAN, LABEL, COMM, ARGS, NAME
  };
  
  /* The typos[] array lists all the types understood by "ps -o", I.E all the
   * columns ps and top know how to display. Each entry has:
   *
   * name: the column name, displayed at top and used to select column with -o
   *
   * width: the display width. Fields are padded to this width when displaying
   *        to a terminal (negative means right justified). Strings are truncated
   *        to fit, numerical fields are padded but not truncated (although
   *        the display code reclaims unused padding from later fields to try to
   *        get the overflow back).
   *
   * slot: which slot[] out of procpid. Negative means it's a string field.
   *       value|XX requests extra display/sort processing.
   *
   * The TAGGED_ARRAY plumbing produces an enum of indexes, the "tag" is the
   * first string argument and the prefix is the first argument to TAGGED_ARRAY
   * so in this case "NAME" becomes PS_NAME which is the offset into typos[]
   * for that entry, and also _PS_NAME (the bit position, 1<<PS_NAME).
   * We record active columns in TT.bits, ala:
   *
   *   if (TT.bits & _PS_NAME) printf("-o included PS_NAME");
   */
  
  #define XX 64 // force string representation for sorting, etc
  
  // TODO: Android uses -30 for LABEL, but ideally it would auto-size.
  // TODO: ideally, PID and PPID would auto-size too.
  struct typography {
    char *name, *help;
    signed char width, slot;
  } static const typos[] = TAGGED_ARRAY(PS,
    // Numbers. (What's in slot[] is what's displayed, sorted numerically.)
    {"PID", "Process ID", 6, SLOT_pid},
    {"PPID", "Parent Process ID", 6, SLOT_ppid},
    {"PRI", "Priority (dynamic 0 to 139)", 3, SLOT_priority},
    {"NI", "Niceness (static 19 to -20)", 3, SLOT_nice},
    {"ADDR", "Instruction pointer", 4+sizeof(long), SLOT_eip},
    {"SZ", "4k pages to swap out", 5, SLOT_vsize},
    {"RSS", "Resident Set Size (DRAM pages)", 6, SLOT_rss},
    {"PGID", "Process Group ID", 5, SLOT_pgrp},
    {"VSZ", "Virtual memory size (1k units)", 7, SLOT_vsize},
    {"MAJFL", "Major page faults", 6, SLOT_majflt},
    {"MINFL", "Minor page faults", 6, SLOT_minflt},
    {"PR", "Prio Reversed (dyn 39-0, RT)", 2, SLOT_priority},
    {"PSR", "Processor last executed on", 3, SLOT_taskcpu},
    {"RTPRIO", "Realtime priority", 6, SLOT_rtprio},
    {"SCH", "Scheduling policy (0=other, 1=fifo, 2=rr, 3=batch, 4=iso, 5=idle)",
     3, SLOT_policy},
    {"CPU", "Which processor running on", 3, SLOT_taskcpu},
    {"TID", "Thread ID", 5, SLOT_tid},
    {"TCNT", "Thread count", 4, SLOT_tcount},
    {"BIT", "32 or 64", 3, SLOT_bits},
  
    // String fields (-1 is procpid->str, rest are str+offset[1-slot])
    {"TTY", "Controlling terminal", -8, -2},
    {"WCHAN", "Wait location in kernel", -6, -3},
    {"LABEL", "Security label", -30, -4},
    {"COMM", "EXE filename (/proc/PID/exe)", -27, -5},
    {"NAME", "Process name (PID's argv[0])", -27, -7},
    {"COMMAND", "EXE path (/proc/PID/exe)", -27, -5},
    {"CMDLINE", "Command line (argv[])", -27, -6},
    {"ARGS", "CMDLINE minus initial path", -27, -6},
    {"CMD", "Thread name (/proc/TID/stat:2)", -15, -1},
  
    // user/group (may call getpwuid() or similar)
    {"UID", "User id", 5, SLOT_uid},
    {"USER", "User name", -12, XX|SLOT_uid},
    {"RUID", "Real (before suid) user ID", 4, SLOT_ruid},
    {"RUSER", "Real (before suid) user name", -8, XX|SLOT_ruid},
    {"GID", "Group ID", 8, SLOT_gid},
    {"GROUP", "Group name", -8, XX|SLOT_gid},
    {"RGID", "Real (before sgid) Group ID", 4, SLOT_rgid},
    {"RGROUP", "Real (before sgid) group name", -8, XX|SLOT_rgid},
  
    // clock displays (00:00:00)
    {"TIME", "CPU time consumed", 8, SLOT_utime},
    {"ELAPSED", "Elapsed time since PID start", 11, SLOT_starttime},
    {"TIME+", "CPU time (high precision)", 9, SLOT_utime},
  
    // Percentage displays (fixed point, one decimal digit. 123 -> 12.3)
    {"C", "Total %CPU used since start", 1, SLOT_utime2},
    {"%VSZ", "VSZ as % of physical memory", 5, SLOT_vsize},
    {"%MEM", "RSS as % of physical memory", 5, SLOT_rss},
    {"%CPU", "Percentage of CPU time used", 4, SLOT_utime2},
  
    // human_readable (function human_readable() in lib, 1.23M, 1.4G, etc)
    {"VIRT", "Virtual memory size", 4, SLOT_vsz},
    {"RES", "Short RSS", 4, SLOT_rss},
    {"SHR", "Shared memory", 4, SLOT_shr},
    {"READ", "Data read", 6, SLOT_rchar},
    {"WRITE", "Data written", 6, SLOT_wchar},
    {"IO", "Data I/O", 6, SLOT_iobytes},
    {"DREAD", "Data read from disk", 6, SLOT_rbytes},
    {"DWRITE", "Data written to disk", 6, SLOT_wbytes},
    {"SWAP", "Swap I/O", 6, SLOT_swap},
    {"DIO", "Disk I/O", 6, SLOT_diobytes},
  
    // Misc (special cases)
    {"STIME", "Start time (ISO 8601)", 5, SLOT_starttime},
    {"F", "Flags 1=FORKNOEXEC 4=SUPERPRIV", 1, XX|SLOT_flags},
    {"S", "Process state:\n"
     "\t  R (running) S (sleeping) D (device I/O) T (stopped)  t (trace stop)\n"
     "\t  X (dead)    Z (zombie)   P (parked)     I (idle)\n"
     "\t  Also between Linux 2.6.33 and 3.13:\n"
     "\t  x (dead)    K (wakekill) W (waking)\n",
     -1, XX},
    {"STAT", "Process state (S) plus:\n"
     "\t  < high priority          N low priority L locked memory\n"
     "\t  s session leader         + foreground   l multithreaded",
     -5, XX},
    {"PCY", "Android scheduling policy", 3, XX|SLOT_pcy},
  );
  
  // Show sorted "-o help" text for fields listed in toybuf[len]
  static void help_fields(int len, int multi)
  {
    int i, j, k, left = 0;
    struct typography *t;
  
    // Quick and dirty sort of toybuf[] entries (see TODO below)
    for (j = len; j--; ) {
      k = -1;
  
      for (i=0; i<j; i++) {
        if (strcmp(typos[toybuf[i]].name, typos[toybuf[i+1]].name)>0) {
          k = toybuf[i];
          toybuf[i] = toybuf[i+1];
          toybuf[i+1] = k;
        }
      }
      if (k == -1) break;
    }
  
    // Display loop
    for (i = j = 0; i<len; i++, j++) {
      t = (void *)(typos+toybuf[i]);
      if (strlen(t->help)>30) {
        if (multi) printf("  %-8s%s\n", t->name, t->help);
        else j--;
      } else if (!multi) {
        left = !(j&1);
        printf("  %-8s%*s%c"+2*!left, t->name, -30*left, t->help, 10+22*left);
      }
    }
    if (!multi && left) xputc('\n');
  }
  
  // Print help text for each -o field, with categories.
  static void help_help(void)
  {
    int i, jump = PS_CMD+1-PS_COMM;
  
    // TODO: sort the array of -o types so they're already alphabetical and
    // don't need sorting here. A regex to find everything that currently cares
    // about symbol order might be: "which *[><]=* *PS"
  
    // First show the half-dozen variants of command line display.
  
    printf("Command line field types:\n\n");
    for (i = 0; i<jump; i++) toybuf[i] = PS_COMM+i;
    help_fields(jump, 0);
  
    // Show the rest of the -o types, starting with the ones that don't columnize
  
    printf("\nProcess attribute field types:\n\n");
    for (i = 0; i<ARRAY_LEN(typos)-jump; i++) toybuf[i] = i+(i>=PS_COMM)*jump;
    help_fields(ARRAY_LEN(typos)-jump, 1);
    help_fields(ARRAY_LEN(typos)-jump, 0);
  
    xexit();
  }
  
  // process match filter for top/ps/pgrep: Return 0 to discard, nonzero to keep
  static int shared_match_process(long long *slot)
  {
    struct ptr_len match[] = {
      {&TT.gg, SLOT_gid}, {&TT.GG, SLOT_rgid}, {&TT.pp, SLOT_pid},
      {&TT.PP, SLOT_ppid}, {&TT.ss, SLOT_sid}, {&TT.tt, SLOT_ttynr},
      {&TT.uu, SLOT_uid}, {&TT.UU, SLOT_ruid}
    };
    int i, j;
    long *ll = 0;
  
    // Do we have -g -G -p -P -s -t -u -U options selecting processes?
    for (i = 0; i < ARRAY_LEN(match); i++) {
      struct ptr_len *mm = match[i].ptr;
  
      if (mm->len) {
        ll = mm->ptr;
        for (j = 0; j<mm->len; j++) if (ll[j] == slot[match[i].len]) return 1;
      }
    }
  
    return ll ? 0 : -1;
  }
  
  // process match filter for ps: Return 0 to discard, nonzero to keep
  static int ps_match_process(long long *slot)
  {
    int i = shared_match_process(slot);
  
    if (i>0) return 1;
    // If we had selections and didn't match them, don't display
    if (!i) return 0;
  
    // Filter implicit categories for other display types
    if ((FLAG(a)||FLAG(d)) && slot[SLOT_sid]==*slot) return 0;
    if (FLAG(a) && !slot[SLOT_ttynr]) return 0;
    if (!(FLAG(a)||FLAG(d)||FLAG(A)||FLAG(e)) && TT.tty!=slot[SLOT_ttynr])
      return 0;
  
    return 1;
  }
  
  // Generate display string (260 bytes at end of toybuf) from struct ofield
  static char *string_field(struct procpid *tb, struct ofields *field)
  {
    char *buf = toybuf+sizeof(toybuf)-260, *out = buf, *s;
    int which = field->which, sl = typos[which].slot;
    long long *slot = tb->slot, ll = (sl >= 0) ? slot[sl&(XX-1)] : 0;
  
    // numbers, mostly from /proc/$PID/stat
    if (which <= PS_BIT) {
      char *fmt = "%lld";
  
      if (which==PS_PRI) ll = 39-ll;
      if (which==PS_ADDR) fmt = "%llx";
      else if (which==PS_SZ) ll >>= 12;
      else if (which==PS_RSS) ll <<= 2;
      else if (which==PS_VSZ) ll >>= 10;
      else if (which==PS_PR && ll<-9) fmt="RT";
      else if ((which==PS_RTPRIO || which==PS_BIT) && ll == 0) fmt="-";
      sprintf(out, fmt, ll);
  
    // String fields
    } else if (sl < 0) {
      out = tb->str;
      sl *= -1;
      // First string slot has offset 0, others are offset[-slot-2]
      if (--sl) out += tb->offset[--sl];
      if (which==PS_ARGS || which==PS_COMM) {
        int i;
  
        s = out;
        for (i = 0; (which==PS_ARGS) ? i < slot[SLOT_argv0len] : out[i]; i++)
          if (out[i] == '/') s = out+i+1;
        out = s;
      }
      if (which>=PS_COMM && !*out) sprintf(out = buf, "[%s]", tb->str);
  
    // user/group
    } else if (which <= PS_RGROUP) {
      sprintf(out, "%lld", ll);
      if (sl&XX) {
        if (which > PS_RUSER) {
          struct group *gr = bufgetgrgid(ll);
  
          if (gr) out = gr->gr_name;
        } else {
          struct passwd *pw = bufgetpwuid(ll);
  
          if (pw) out = pw->pw_name;
        }
      }
  
    // Clock displays
    } else if (which <= PS_TIME_) {
      int unit = 60, pad = 2, j = TT.ticks; 
      time_t seconds;
  
      if (which!=PS_TIME_) unit *= 60*24;
      else pad = 0;
      // top adjusts slot[SLOT_upticks], we want original meaning.
      if (which==PS_ELAPSED) ll = (slot[SLOT_uptime]*j)-slot[SLOT_starttime];
      seconds = ll/j;
  
      // Output days-hours:mins:secs, skipping non-required fields with zero
      // TIME has 3 required fields, ETIME has 2. (Posix!) TIME+ is from top
      for (s = 0, j = 2*(which==PS_TIME_); j<4; j++) {
        if (!s && (seconds>unit || j == 1+(which!=PS_TIME))) s = out;
        if (s) {
          s += sprintf(s, j ? "%0*ld": "%*ld", pad, (long)(seconds/unit));
          pad = 2;
          if ((*s = "-::"[j])) s++;
        }
        seconds %= unit;
        unit /= j ? 60 : 24;
      }
      if (which==PS_TIME_ && s-out<8)
        sprintf(s, ".%02lld", (100*(ll%TT.ticks))/TT.ticks);
  
    // Percentage displays
    } else if (which <= PS__CPU) {
      ll = slot[sl&(XX-1)]*1000;
      if (which==PS__VSZ || which==PS__MEM)
        ll /= slot[SLOT_totalram]/((which==PS__VSZ) ? 1024 : 4096);
      else if (slot[SLOT_upticks]) ll /= slot[SLOT_upticks];
      sl = ll;
      if (which==PS_C) sl += 5;
      sprintf(out, "%d", sl/10);
      if (which!=PS_C && sl<1000) sprintf(out+strlen(out), ".%d", sl%10);
  
    // Human readable
    } else if (which <= PS_DIO) {
      int i = abs(field->len);
  
      if (i<4) i = 4;
      s = out;
      if ((ll = slot[typos[which].slot])<0) {
        ll = -ll;
        *s++ = '-';
        if (i>4) i--;
      }
      if (which <= PS_SHR) ll *= sysconf(_SC_PAGESIZE);
      if (TT.forcek) sprintf(out, "%lldk", ll/1024);
      else human_readable_long(s, ll, i-1, 0);
  
    // Posix doesn't specify what flags should say. Man page says
    // 1 for PF_FORKNOEXEC and 4 for PF_SUPERPRIV from linux/sched.h
    } else if (which==PS_F) sprintf(out, "%llo", (slot[SLOT_flags]>>6)&5);
    else if (which==PS_S || which==PS_STAT) {
      s = out;
      *s++ = tb->state;
      if (which==PS_STAT) {
        // TODO l = multithreaded
        if (slot[SLOT_nice]<0) *s++ = '<';
        else if (slot[SLOT_nice]>0) *s++ = 'N';
        if (slot[SLOT_sid]==*slot) *s++ = 's';
        if (slot[SLOT_vmlck]) *s++ = 'L';
        if (slot[SLOT_ttypgrp]==*slot) *s++ = '+';
      } 
      *s = 0;
    } else if (which==PS_STIME) {
      time_t t = time(0)-slot[SLOT_uptime]+slot[SLOT_starttime]/TT.ticks;
  
      // Padding behavior's a bit odd: default field size is just hh:mm.
      // Increasing stime:size reveals more data at left until full,
      // so move start address so yyyy-mm-dd hh:mm revealed on left at :16,
      // then add :ss on right for :19.
      strftime(out, 260, "%F %T", localtime(&t));
      out = out+strlen(out)-3-abs(field->len);
      if (out<buf) out = buf;
  
    } else if (which==PS_PCY) sprintf(out, "%.2s", get_sched_policy_name(ll));
    else if (CFG_TOYBOX_DEBUG) error_exit("bad which %d", which);
  
    return out;
  }
  
  // Display process data that get_ps() read from /proc, formatting via TT.fields
  static void show_ps(void *p)
  {
    struct procpid *tb = p;
    struct ofields *field;
    int pad, len, width = TT.width, abslen, sign, olen, extra = 0;
  
    // Loop through fields to display
    for (field = TT.fields; field; field = field->next) {
      char *out = string_field(tb, field);
  
      // Output the field, appropriately padded
  
      // Minimum one space between each field
      if (width<2) break;
      if (field != TT.fields) {
        putchar(' ');
        width--;
      }
  
      // Don't truncate number fields, but try to reclaim extra offset from later
      // fields that can naturally be shorter
      abslen = abs(field->len);
      sign = field->len<0 ? -1 : 1;
      olen = (TT.tty) ? utf8len(out) : strlen(out);
      if ((field->which<=PS_BIT || FLAG(w)) && olen>abslen) {
        // overflow but remember by how much
        extra += olen-abslen;
        abslen = olen;
      } else if (extra && olen<abslen) {
        int unused = abslen-olen;
  
        // If later fields have slack space, take back overflow
        if (unused>extra) unused = extra;
        abslen -= unused;
        extra -= unused;
      }
      if (abslen>width) abslen = width;
      len = pad = abslen;
      pad *= sign;
  
      // If last field is left justified, no trailing spaces.
      if (!field->next && sign<0) {
        pad = -1;
        len = width;
      }
  
      // If we truncated a left-justified field, show + instead of last char
      if (olen>len && len>1 && sign<0) {
        width--;
        len--;
        if (field->next) pad++;
        abslen = 0;
      }
  
      if (TT.tty) width -= draw_trim(out, pad, len);
      else width -= printf("%*.*s", pad, len, out);
      if (!abslen) putchar('+');
      if (!width) break;
    }
    putchar(TT.time ? '\r' : '\n');
  }
  
  // dirtree callback: read data about a process, then display or store it.
  // Fills toybuf with struct procpid and either DIRTREE_SAVEs a copy to ->extra
  // (in -k mode) or calls show_ps directly on toybuf (for low memory systems).
  static int get_ps(struct dirtree *new)
  {
    struct {
      char *name;     // Path under /proc/$PID directory
      long long bits; // Only fetch extra data if an -o field is displaying it
    } fetch[] = {
      // sources for procpid->offset[] data
      {"fd/", _PS_TTY}, {"wchan", _PS_WCHAN}, {"attr/current", _PS_LABEL},
      {"exe", _PS_COMMAND|_PS_COMM}, {"cmdline", _PS_CMDLINE|_PS_ARGS|_PS_NAME},
      {"", _PS_NAME}
    };
    struct procpid *tb = (void *)toybuf;
    long long *slot = tb->slot;
    char *name, *s, *buf = tb->str, *end = 0;
    struct sysinfo si;
    int i, j, fd;
    off_t len;
  
    // Recurse one level into /proc children, skip non-numeric entries
    if (!new->parent)
      return DIRTREE_RECURSE|DIRTREE_SHUTUP|DIRTREE_PROC
        |(DIRTREE_SAVE*(TT.threadparent||!TT.show_process));
  
    // Grab PID and figure out if we're a thread or a process
    memset(slot, 0, sizeof(tb->slot));
    slot[SLOT_tid] = *slot = atol(new->name);
    if (TT.threadparent && TT.threadparent->extra) {
      struct procpid *tb2 = (struct procpid *)TT.threadparent->extra;
  
      *slot = *tb2->slot;
      // Parent also shows up as a thread, but we need to reread task/stat fields
      // to get non-collated info for just parent thread (vs whole process).
      if (*slot == slot[SLOT_tid]) slot = tb2->slot;
    }
    fd = dirtree_parentfd(new);
  
    // Read /proc/$PID/stat into half of toybuf.
    len = 2048;
    sprintf(buf, "%lld/stat", slot[SLOT_tid]);
    if (!readfileat(fd, buf, buf, &len)) return 0;
  
    // parse oddball fields: the first field is same as new->name (skip it)
    // and the second and third (name and state) are the only non-numeric fields.
    // Name has (parentheses) around it, and can have embedded ')' so match
    // _last_ ')' (VFS limits filenames to 255 bytes max, sanity check that).
    // TODO: kernel task struct actually limits name to 16 chars?
    if (!(name = strchr(buf, '('))) return 0;
    for (s = ++name; *s; s++) if (*s == ')') end = s;
    if (!end || end-name>255) return 0;
    if (1>sscanf(s = end, ") %c%n", &tb->state, &i)) return 0;
  
    // All remaining fields should be numeric, parse them into slot[] array
    // (skipping first 3 stat fields and first slot[], both were handled above)
    // yes this means the alignment's off: stat[4] becomes slot[1]
    for (j = SLOT_ppid; j<SLOT_upticks; j++)
      if (1>sscanf(s += i, " %lld%n", slot+j, &i)) break;
  
    // Now we've read the data, move status and name right after slot[] array,
    // and convert low chars to ? for non-tty display while we're at it.
    for (i = 0; i<end-name; i++)
      if ((tb->str[i] = name[i]) < ' ')
        if (!TT.tty) tb->str[i] = '?';
    buf = tb->str+i;
    *buf++ = 0;
    len = sizeof(toybuf)-(buf-toybuf);
  
    // Overwrite useless/obsolete stat fields with more interesting data.
  
    // save uid, ruid, gid, gid, and rgid int slots 31-34 (we don't use sigcatch
    // or numeric wchan, and the remaining two are always zero), and vmlck into
    // 18 (which is "obsolete, always 0" from stat)
    slot[SLOT_uid] = new->st.st_uid;
    slot[SLOT_gid] = new->st.st_gid;
  
    // TIME and TIME+ use combined value, ksort needs 'em added.
    slot[SLOT_utime] += slot[SLOT_stime];
    slot[SLOT_utime2] = slot[SLOT_utime];
  
    // Do we need to read "status"?
    if ((TT.bits&(_PS_RGROUP|_PS_RUSER|_PS_STAT|_PS_RUID|_PS_RGID|_PS_SWAP
                 |_PS_IO|_PS_DIO)) || TT.GG.len || TT.UU.len)
    {
      off_t temp = len;
  
      sprintf(buf, "%lld/status", slot[SLOT_tid]);
      if (!readfileat(fd, buf, buf, &temp)) *buf = 0;
      s = strafter(buf, "\nUid:");
      slot[SLOT_ruid] = s ? atol(s) : new->st.st_uid;
      s = strafter(buf, "\nGid:");
      slot[SLOT_rgid] = s ? atol(s) : new->st.st_gid;
      if ((s = strafter(buf, "\nVmLck:"))) slot[SLOT_vmlck] = atoll(s)*1024;
      if ((s = strafter(buf, "\nVmSwap:"))) slot[SLOT_swap] = atoll(s)*1024;
    }
  
    // Do we need to read "io"?
    if (TT.bits&(_PS_READ|_PS_WRITE|_PS_DREAD|_PS_DWRITE|_PS_IO|_PS_DIO)) {
      off_t temp = len;
  
      sprintf(buf, "%lld/io", slot[SLOT_tid]);
      if (!readfileat(fd, buf, buf, &temp)) *buf = 0;
      if ((s = strafter(buf, "rchar:"))) slot[SLOT_rchar] = atoll(s);
      if ((s = strafter(buf, "wchar:"))) slot[SLOT_wchar] = atoll(s);
      if ((s = strafter(buf, "read_bytes:"))) slot[SLOT_rbytes] = atoll(s);
      if ((s = strafter(buf, "write_bytes:"))) slot[SLOT_wbytes] = atoll(s);
      slot[SLOT_iobytes] = slot[SLOT_rchar]+slot[SLOT_wchar]+slot[SLOT_swap];
      slot[SLOT_diobytes] = slot[SLOT_rbytes]+slot[SLOT_wbytes]+slot[SLOT_swap];
    }
  
    // If we were updating thread parent with its own task info, we're done.
    if (slot != tb->slot) return 0;
  
    // We now know enough to skip processes we don't care about.
    if (TT.match_process && !TT.match_process(slot)) return 0;
  
    // /proc data is generated as it's read, so for maximum accuracy on slow
    // systems (or ps | more) we re-fetch uptime as we fetch each /proc line.
    sysinfo(&si);
    slot[SLOT_uptime] = si.uptime;
    slot[SLOT_totalram] = si.totalram;
    slot[SLOT_upticks] = slot[SLOT_uptime]*TT.ticks - slot[SLOT_starttime];
  
    // Do we need to read "statm"?
    if (TT.bits&(_PS_VIRT|_PS_SHR)) {
      off_t temp = len;
  
      sprintf(buf, "%lld/statm", slot[SLOT_tid]);
      if (!readfileat(fd, buf, buf, &temp)) *buf = 0;
  
      // Skip redundant RSS field, we got it from stat.
      slot[SLOT_vsz] = slot[SLOT_shr] = 0;
      sscanf(buf, "%lld %*d %lld", &slot[SLOT_vsz], &slot[SLOT_shr]);
    }
  
    // Do we need to read "exe"?
    if (TT.bits&_PS_BIT) {
      off_t temp = 6;
  
      sprintf(buf, "%lld/exe", slot[SLOT_tid]);
      if (readfileat(fd, buf, buf, &temp) && !memcmp(buf, "\177ELF", 4)) {
        if (buf[4] == 1) slot[SLOT_bits] = 32;
        else if (buf[4] == 2) slot[SLOT_bits] = 64;
      }
    }
  
    // Do we need Android scheduling policy?
    if (TT.bits&_PS_PCY)
      get_sched_policy(slot[SLOT_tid], (void *)&slot[SLOT_pcy]);
  
    // Done using buf[] (tb->str) as scratch space, now read string data,
    // saving consective null terminated strings. (Save starting offsets into
    // str->offset to avoid strlen() loop to find relevant string.)
  
    // Fetch string data while parentfd still available, appending to buf.
    // (There's well over 3k of toybuf left. We could dynamically malloc, but
    // it'd almost never get used, querying length of a proc file is awkward,
    // fixed buffer is nommu friendly... Wait for somebody to complain. :)
  
    // The fetch[] array at the start of the function says what file to read
    // and what -o display field outputs it (to skip the ones we don't need).
  
    slot[SLOT_argv0len] = 0;
    for (j = 0; j<ARRAY_LEN(fetch); j++) {
      tb->offset[j] = buf-(tb->str);
      if (!(TT.bits&fetch[j].bits)) {
        *buf++ = 0;
        continue;
      }
  
      // Determine available space: reserve 256 bytes (guaranteed minimum) for
      // each string we haven't checked yet, tb->str starts after the numeric
      // arrays in struct procpid, and we reserve 260 bytes scratch space at the
      // end of toybuf for output conversion in string_field(). Other than that,
      // each use all available space, and future strings that don't use their
      // guaranteed minimum add to the pool.
      len = sizeof(toybuf)-256*(ARRAY_LEN(fetch)-j)-(buf-toybuf)-260;
      sprintf(buf, "%lld/%s", slot[SLOT_tid], fetch[j].name);
  
      // For exe (j==3) readlink() instead of reading file's contents
      // for -o NAME (j==5) copy data from threadparent (PID) into thread (TID).
      if (j==3 || j==5) {
        struct procpid *ptb = 0;
        int k;
  
        // Thread doesn't have exe or argv[0], so use parent's
        if (TT.threadparent && TT.threadparent->extra)
          ptb = (void *)TT.threadparent->extra;
  
        if (j==3 && !ptb) len = readlinkat0(fd, buf, buf, len);
        else {
          if (j==3) i = strlen(s = ptb->str+ptb->offset[3]);
          else {
            if (!ptb || slot[SLOT_argv0len]) ptb = tb;
            i = ptb->slot[SLOT_argv0len];
            s = ptb->str+ptb->offset[4];
            while (-1!=(k = stridx(s, '/')) && k<i) {
              s += k+1;
              i -= k+1;
            }
          }
          if (i<len) len = i;
          memcpy(buf, s, len);
          buf[len] = 0;
        }
  
      // Turning stat's SLOT_ttynr into a string is an outright heuristic ordeal.
      } else if (!j) {
        int rdev = slot[SLOT_ttynr];
        struct stat st;
  
        // Call no tty "?" rather than "0:0".
        strcpy(buf, "?");
        if (rdev) {
          // Can we readlink() our way to a name?
          for (i = 0; i<3; i++) {
            sprintf(buf, "%lld/fd/%i", slot[SLOT_tid], i);
            if (!fstatat(fd, buf, &st, 0) && S_ISCHR(st.st_mode)
              && st.st_rdev == rdev && (len = readlinkat0(fd, buf, buf, len)))
                break;
          }
  
          // Couldn't find it, try all the tty drivers.
          if (i == 3) {
            FILE *fp = fopen("/proc/tty/drivers", "r");
            int tty_major = 0, maj = dev_major(rdev), min = dev_minor(rdev);
  
            if (fp) {
              while (fscanf(fp, "%*s %256s %d %*s %*s", buf, &tty_major) == 2) {
                // TODO: we could parse the minor range too.
                if (tty_major == maj) {
                  len = strlen(buf);
                  len += sprintf(buf+len, "%d", min);
                  if (!stat(buf, &st) && S_ISCHR(st.st_mode) && st.st_rdev==rdev)
                    break;
                }
                tty_major = 0;
              }
              fclose(fp);
            }
  
            // Really couldn't find it, so just show major:minor.
            if (!tty_major) len = sprintf(buf, "%d:%d", maj, min);
          }
  
          s = buf;
          if (strstart(&s, "/dev/")) memmove(buf, s, len -= 4);
        }
  
      // For the rest, the data we want is in a file we can just read.
      } else {
        int temp = 0;
  
        // When command has no arguments, don't space over the NUL
        if (readfileat(fd, buf, buf, &len) && len>0) {
  
          // Trim trailing whitespace and NUL bytes
          while (len)
            if (!buf[len-1] || isspace(buf[len-1])) buf[--len] = 0;
            else break;
  
          // Turn NUL to space, other low ascii to ? (in non-tty mode), except
          // cmdline has a trailing NUL that we don't want to turn to space.
          for (i=0; i<len-1; i++) {
            char c = buf[i];
  
            if (!c) {
              if (!temp) temp = i;
              c = ' ';
            } else if (!TT.tty && c<' ') c = '?';
            buf[i] = c;
          }
        } else *buf = len = 0;
  
        // Store end of argv[0] so ARGS and CMDLINE can differ.
        // We do it for each file string slot but last is cmdline, which sticks.
        slot[SLOT_argv0len] = temp ? temp : len;  // Position of _first_ NUL
      }
  
      // Each case above calculated/retained len, so we don't need to re-strlen.
      buf += len+1;
    }
  
    // Record that we saw another process, and display/return now if appropriate
    TT.kcount++;
    if (TT.show_process && !TT.threadparent) {
      TT.show_process(tb);
  
      return 0;
    }
  
    // We're retaining data (probably to sort it), save copy in list.
    s = xmalloc(buf-toybuf);
    new->extra = (long)s;
    memcpy(s, toybuf, buf-toybuf);
  
    return DIRTREE_SAVE;
  }
  
  // wrapper for get_ps() that also collects threads under each processes
  static int get_threads(struct dirtree *new)
  {
    struct dirtree *dt;
    struct procpid *tb;
    unsigned pid, kcount;
  
    if (!new->parent) return get_ps(new);
    pid = atol(new->name);
  
    TT.threadparent = new;
    if (!get_ps(new)) {
      // it exited out from under us
      TT.threadparent = 0;
  
      return 0;
    }
  
    // Recurse down into tasks, retaining thread groups.
    // Disable show_process at least until we can calculate tcount
    kcount = TT.kcount;
    sprintf(toybuf, "/proc/%u/task", pid);
    new->child = dirtree_flagread(toybuf, DIRTREE_SHUTUP|DIRTREE_PROC, get_ps);
    if (new->child == DIRTREE_ABORTVAL) new->child = 0;
    TT.threadparent = 0;
    kcount = TT.kcount-kcount+1;
    tb = (void *)new->extra;
    tb->slot[SLOT_tcount] = kcount;
  
    // Fill out tid and thread count for each entry in group (if it didn't exit
    // out from under us again; asynchronous reads of unlocked data are fun!)
    if (new->child) for (dt = new->child->child; dt; dt = dt->next) {
      tb = (void *)dt->extra;
      tb->slot[SLOT_pid] = pid;
      tb->slot[SLOT_tcount] = kcount;
    }
  
    // Save or display
    if (!TT.show_process) return DIRTREE_SAVE;
    TT.show_process((void *)new->extra);
    if ((dt = new->child)) {
      new->child = 0;
      while (dt->child) {
        new = dt->child->next;
        TT.show_process((void *)dt->child->extra);
        free(dt->child);
        dt->child = new;
      }
      free(dt);
    }
  
    return 0;
  }
  
  // Parse one FIELD argument (with optional =name :width) into struct ofields
  static char *parse_ko(void *data, char *type, int length)
  {
    struct ofields *field;
    char *width, *title, *end, *s;
    int i, j, k;
  
    // Caller's WOULD_EXIT catches -o help and prints help
    if (length==4 && !strncasecmp(type, "HELP", length)) xexit();
  
    // Get title, length of title, type, end of type, and display width
  
    // Chip off =name to display
    if ((end = strchr(type, '=')) && length>(end-type)) {
      title = end+1;
      length -= (end-type)+1;
    } else {
      end = type+length;
      title = 0;
    }
  
    // Chip off :width to display
    if ((width = strchr(type, ':')) && width<end) {
      if (!title) length = width-type;
    } else width = 0;
  
    // Allocate structure plus extra space to append a copy of title data
    // (this way it's same lifetime, freeing struct automatically frees title)
    field = xzalloc(sizeof(struct ofields)+(length+1)*!!title);
    if (title) {
      memcpy(field->title = (char *)(field+1), title, length);
      field->title[field->len = length] = 0;
    }
  
    if (width) {
      field->len = strtol(++width, &title, 10);
      if (!isdigit(*width) || title != end) return title;
      end = --width;
    }
  
    // Find type
    field->reverse = 1;
    if (*type == '-') field->reverse = -1;
    else if (*type != '+') type--;
    type++;
    for (i = 0; i<ARRAY_LEN(typos); i++) {
      field->which = i;
      for (j = 0; j<2; j++) {
        if (!j) s = typos[i].name;
        // posix requires alternate names for some fields
        else if (-1==(k = stridx((char []){PS_NI, PS_SCH, PS_ELAPSED, PS__CPU,
          PS_VSZ, PS_USER, 0}, i))) continue;
        else
          s = ((char *[]){"NICE", "SCHED", "ETIME", "PCPU", "VSIZE", "UNAME"})[k];
  
        if (!strncasecmp(type, s, end-type) && strlen(s)==end-type) break;
      }
      if (j!=2) break;
    }
    if (i==ARRAY_LEN(typos)) return type;
    if (!field->title) field->title = typos[field->which].name;
    if (!field->len) field->len = typos[field->which].width;
    else if (typos[field->which].width<0) field->len *= -1;
    dlist_add_nomalloc(data, (void *)field);
  
    return 0;
  }
  
  // Write FIELD list into display header string (truncating at blen),
  // and return bitfield of which FIELDs are used.
  static long long get_headers(struct ofields *field, char *buf, int blen)
  {
    long long bits = 0;
    int len = 0;
  
    for (; field; field = field->next) {
      len += snprintf(buf+len, blen-len, " %*s"+!bits, field->len,
        field->title);
      bits |= 1LL<<field->which;
    }
  
    return bits;
  }
  
  // Parse command line options -p -s -t -u -U -g -G
  static char *parse_rest(void *data, char *str, int len)
  {
    struct ptr_len *pl = (struct ptr_len *)data;
    long *ll = pl->ptr;
    char *end;
    int num = 0;
  
    // Allocate next chunk of data
    if (!(15&pl->len))
      ll = pl->ptr = xrealloc(pl->ptr, sizeof(long)*(pl->len+16));
  
    // Parse numerical input
    if (isdigit(*str)) {
      ll[pl->len] = xstrtol(str, &end, 10);
      if (end==(len+str)) num++;
      // For pkill, -s 0 represents pkill's session id.
      if (pl==&TT.ss && ll[pl->len]==0) ll[pl->len] = getsid(0);
    }
  
    if (pl==&TT.pp || pl==&TT.ss) {
      if (num && ll[pl->len]>0) {
        pl->len++;
  
        return 0;
      }
    } else if (pl==&TT.tt) {
      // -t pts = 12,pts/12 tty = /dev/tty2,tty2,S0
      if (!num) {
        if (strstart(&str, strcpy(toybuf, "/dev/"))) len -= 5;
        if (strstart(&str, "pts/")) {
          len -= 4;
          num++;
        } else if (strstart(&str, "tty")) len -= 3;
      }
      if (len<256 && (!(end = strchr(str, '/')) || end-str>len)) {
        struct stat st;
  
        end = toybuf + sprintf(toybuf, "/dev/%s", num ? "pts/" : "tty");
        memcpy(end, str, len);
        end[len] = 0;
        xstat(toybuf, &st);
        ll[pl->len++] = st.st_rdev;
  
        return 0;
      }
    } else if (len<255) {
      char name[256];
  
      if (num) {
        pl->len++;
  
        return 0;
      }
  
      memcpy(name, str, len);
      name[len] = 0;
      if (pl==&TT.gg || pl==&TT.GG) {
        struct group *gr = getgrnam(name);
        if (gr) {
          ll[pl->len++] = gr->gr_gid;
  
          return 0;
        }
      } else if (pl==&TT.uu || pl==&TT.UU) {
        struct passwd *pw = getpwnam(name);
        if (pw) {
          ll[pl->len++] = pw->pw_uid;
  
          return 0;
        }
      }
    }
  
    // Return error
    return str;
  }
  
  // sort processes by FIELD(s) listed in option -k
  static int ksort(void *aa, void *bb)
  {
    struct ofields *field;
    struct procpid *ta = *(struct procpid **)aa, *tb = *(struct procpid **)bb;
    int ret = 0, slot;
  
    for (field = TT.kfields; field && !ret; field = field->next) {
      slot = typos[field->which].slot;
  
      // Can we do numeric sort?
      if (!(slot&XX)) {
        if (ta->slot[slot]<tb->slot[slot]) ret = -1;
        if (ta->slot[slot]>tb->slot[slot]) ret = 1;
      }
  
      // fallback to string sort
      if (!ret) {
        memccpy(toybuf, string_field(ta, field), 0, 2048);
        toybuf[2048] = 0;
        ret = strcmp(toybuf, string_field(tb, field));
      }
      ret *= field->reverse;
    }
  
    return ret;
  }
  
  // Collect ->extra field from leaf nodes DIRTREE_SAVEd by get_ps() into array
  // (recursion because tree from get_thread() isn't flat list of siblings)
  static struct procpid **collate_leaves(struct procpid **tb, struct dirtree *dt) 
  {
    while (dt) {
      struct dirtree *next = dt->next;
  
      if (dt->extra) *(tb++) = (void *)dt->extra;
      if (dt->child) tb = collate_leaves(tb, dt->child);
      free(dt);
      dt = next;
    }
  
    return tb;
  }
  
  // Allocate struct procpid array of length count and populate it with ->extra
  // fields from dirtree leaf nodes. (top diffs old & new array to show changes)
  static struct procpid **collate(int count, struct dirtree *dt)
  {
    struct procpid **tbsort = xmalloc(count*sizeof(struct procpid *));
  
    collate_leaves(tbsort, dt);
  
    return tbsort;
  } 
  
  // parse command line arguments (ala -k -o) with a comma separated FIELD list
  static void default_ko(char *s, void *fields, char *err, struct arg_list *arg)
  {
    struct arg_list def;
    int x;
  
    memset(&def, 0, sizeof(struct arg_list));
    def.arg = s;
    WOULD_EXIT(x, comma_args(arg ? arg : &def, fields, err, parse_ko));
    if (x) help_help();
  }
  
  void ps_main(void)
  {
    char **arg;
    struct dirtree *dt;
    char *not_o;
    int i;
  
    TT.ticks = sysconf(_SC_CLK_TCK); // units for starttime/uptime
  
    if (-1 != (i = tty_fd())) {
      struct stat st;
  
      if (!fstat(i, &st)) TT.tty = st.st_rdev;
    }
  
    // If we can't query terminal size pad to 80 but do -w
    TT.width = 80;
    if (!isatty(1) || !terminal_size(&TT.width, 0)) toys.optflags |= FLAG_w;
    if (FLAG(w)) TT.width = 99999;
  
    // parse command line options other than -o
    comma_args(TT.ps.P, &TT.PP, "bad -P", parse_rest);
    comma_args(TT.ps.p, &TT.pp, "bad -p", parse_rest);
    comma_args(TT.ps.t, &TT.tt, "bad -t", parse_rest);
    comma_args(TT.ps.s, &TT.ss, "bad -s", parse_rest);
    comma_args(TT.ps.u, &TT.uu, "bad -u", parse_rest);
    comma_args(TT.ps.U, &TT.UU, "bad -U", parse_rest);
    comma_args(TT.ps.g, &TT.gg, "bad -g", parse_rest);
    comma_args(TT.ps.G, &TT.GG, "bad -G", parse_rest);
    comma_args(TT.ps.k, &TT.kfields, "bad -k", parse_ko);
    dlist_terminate(TT.kfields);
  
    // It's undocumented, but traditionally extra arguments are extra -p args
    for (arg = toys.optargs; *arg; arg++)
      if (parse_rest(&TT.pp, *arg, strlen(*arg))) error_exit("bad %s", *arg);
  
    // Figure out which fields to display
    not_o = "%sTTY,TIME,CMD";
    if (FLAG(f))
      sprintf(not_o = toybuf+128,
        "USER:12=UID,%%sPPID,%s,STIME,TTY,TIME,ARGS=CMD", FLAG(T) ? "TCNT" :"C");
    else if (FLAG(l))
      not_o = "F,S,UID,%sPPID,C,PRI,NI,BIT,SZ,WCHAN,TTY,TIME,CMD";
    else if (CFG_TOYBOX_ON_ANDROID)
      sprintf(not_o = toybuf+128,
              "USER,%%sPPID,VSIZE,RSS,WCHAN:10,ADDR:10,S,%s",
              FLAG(T) ? "CMD" : "NAME");
    sprintf(toybuf, not_o, FLAG(T) ? "PID,TID," : "PID,");
  
    // Init TT.fields. This only uses toybuf if TT.ps.o is NULL
    if (FLAG(Z)) default_ko("LABEL", &TT.fields, 0, 0);
    default_ko(toybuf, &TT.fields, "bad -o", TT.ps.o);
  
    if (TT.ps.O) {
      if (TT.fields) TT.fields = ((struct ofields *)TT.fields)->prev;
      comma_args(TT.ps.O, &TT.fields, "bad -O", parse_ko);
      if (TT.fields) TT.fields = ((struct ofields *)TT.fields)->next;
    }
    dlist_terminate(TT.fields);
  
    // -f and -n change the meaning of some fields
    if (FLAG(f)||FLAG(n)) {
      struct ofields *field;
  
      for (field = TT.fields; field; field = field->next) {
        if (FLAG(n) && field->which>=PS_UID
          && field->which<=PS_RGROUP && (typos[field->which].slot&XX))
            field->which--;
      }
    }
  
    // Calculate seen fields bit array, and if we aren't deferring printing
    // print headers now (for low memory/nommu systems).
    TT.bits = get_headers(TT.fields, toybuf, sizeof(toybuf));
    if (!FLAG(M)) printf("%.*s\n", TT.width, toybuf);
    if (!(FLAG(k)||FLAG(M))) TT.show_process = show_ps;
    TT.match_process = ps_match_process;
    dt = dirtree_flagread("/proc", DIRTREE_SHUTUP|DIRTREE_PROC,
      (FLAG(T) || (TT.bits&(_PS_TID|_PS_TCNT)))
        ? get_threads : get_ps);
  
    if ((dt != DIRTREE_ABORTVAL) && (FLAG(k)||FLAG(M))) {
      struct procpid **tbsort = collate(TT.kcount, dt);
  
      if (FLAG(M)) {
        for (i = 0; i<TT.kcount; i++) {
          struct ofields *field;
  
          for (field = TT.fields; field; field = field->next) {
            int len = strlen(string_field(tbsort[i], field));
  
            if (abs(field->len)<len) field->len = (field->len<0) ? -len : len;
          }
        }
  
        // Now that we've recalculated field widths, re-pad headers again
        get_headers(TT.fields, toybuf, sizeof(toybuf));
        printf("%.*s\n", TT.width, toybuf);
      }
  
      if (FLAG(k)) qsort(tbsort, TT.kcount, sizeof(void *), (void *)ksort);
      for (i = 0; i<TT.kcount; i++) {
        show_ps(tbsort[i]);
        free(tbsort[i]);
      }
      if (CFG_TOYBOX_FREE) free(tbsort);
    }
  
    if (CFG_TOYBOX_FREE) {
      free(TT.gg.ptr);
      free(TT.GG.ptr);
      free(TT.pp.ptr);
      free(TT.PP.ptr);
      free(TT.ss.ptr);
      free(TT.tt.ptr);
      free(TT.uu.ptr);
      free(TT.UU.ptr);
      llist_traverse(TT.fields, free);
    }
  }
  
  #define CLEANUP_ps
  #define FOR_top
  #include "generated/flags.h"
  
  // select which of the -o fields to sort by
  static void setsort(int pos)
  {
    struct ofields *field, *field2;
    int i = 0;
  
    if (pos<0) pos = 0;
  
    for (field = TT.fields; field; field = field->next) {
      if ((TT.sortpos = i++)<pos && field->next) continue;
      field2 = TT.kfields;
      field2->which = field->which;
      field2->len = field->len;
      break;
    }
  }
  
  // If we have both, adjust slot[deltas[]] to be relative to previous
  // measurement rather than process start. Stomping old.data is fine
  // because we free it after displaying.
  static int merge_deltas(long long *oslot, long long *nslot, int milis)
  {
    char deltas[] = {SLOT_utime2, SLOT_iobytes, SLOT_diobytes, SLOT_rchar,
                     SLOT_wchar, SLOT_rbytes, SLOT_wbytes, SLOT_swap};
    int i;
  
    for (i = 0; i<ARRAY_LEN(deltas); i++)
      oslot[deltas[i]] = nslot[deltas[i]] - oslot[deltas[i]];
    oslot[SLOT_upticks] = (milis*TT.ticks)/1000;
  
    return 1;
  }
  
  static int header_line(int line, int rev)
  {
    if (!line) return 0;
  
    if (FLAG(b)) puts(toybuf);
    else {
      printf("%s%-*.*s%s\r\n", rev?"\033[7m":"", rev?TT.width:0, TT.width, toybuf,
        rev?"\033[0m":"");
    }
  
    return line-1;
  }
  
  static void top_cursor_cleanup(void)
  {
    tty_esc("?25h");
  }
  
  static void top_common(
    int (*filter)(long long *oslot, long long *nslot, int milis))
  {
    long long timeout = 0, now, stats[16];
    struct proclist {
      struct procpid **tb;
      int count;
      long long whence;
    } plist[2], *plold, *plnew, old, new, mix;
    char scratch[16], *pos, *cpufields[] = {"user", "nice", "sys", "idle",
      "iow", "irq", "sirq", "host"};
    unsigned tock = 0;
    int i, lines, topoff = 0, done = 0;
    char stdout_buf[BUFSIZ];
  
    if (!TT.fields) perror_exit("no -o");
  
    // Avoid flicker and hide the cursor in interactive mode.
    if (!FLAG(b)) {
      setbuf(stdout, stdout_buf);
      sigatexit(top_cursor_cleanup);
      tty_esc("?25l");
    }
  
    toys.signal = SIGWINCH;
    TT.bits = get_headers(TT.fields, toybuf, sizeof(toybuf));
    *scratch = 0;
    memset(plist, 0, sizeof(plist));
    memset(stats, 0, sizeof(stats));
    do {
      struct dirtree *dt;
      int recalc = 1;
  
      plold = plist+(tock++&1);
      plnew = plist+(tock&1);
      plnew->whence = millitime();
      dt = dirtree_flagread("/proc", DIRTREE_SHUTUP|DIRTREE_PROC,
        (FLAG(H) || (TT.bits&(_PS_TID|_PS_TCNT))) ? get_threads : get_ps);
      if (dt == DIRTREE_ABORTVAL) error_exit("no /proc");
      plnew->tb = collate(plnew->count = TT.kcount, dt);
      TT.kcount = 0;
  
      if (readfile("/proc/stat", pos = toybuf, sizeof(toybuf))) {
        long long *st = stats+8*(tock&1);
  
        // user nice system idle iowait irq softirq host
        sscanf(pos, "cpu %lld %lld %lld %lld %lld %lld %lld %lld",
          st, st+1, st+2, st+3, st+4, st+5, st+6, st+7);
      }
  
      // First time, wait a quarter of a second to collect a little delta data.
      if (!plold->tb) {
        msleep(250);
        continue;
      }
  
      // Collate old and new into "mix", depends on /proc read in pid sort order
      old = *plold;
      new = *plnew;
      mix.tb = xmalloc((old.count+new.count)*sizeof(struct procpid));
      mix.count = 0;
  
      while (old.count || new.count) {
        struct procpid *otb = old.count ? *old.tb : 0,
                       *ntb = new.count ? *new.tb : 0;
  
        // If we just have old for this process, it exited. Discard it.
        if (old.count && (!new.count || *otb->slot < *ntb->slot)) {
          old.tb++;
          old.count--;
  
          continue;
        }
  
        // If we just have new, use it verbatim
        if (!old.count || *otb->slot > *ntb->slot) mix.tb[mix.count] = ntb;
        else {
          // Keep or discard
          if (filter(otb->slot, ntb->slot, new.whence-old.whence)) {
            mix.tb[mix.count] = otb;
            mix.count++;
          }
          old.tb++;
          old.count--;
        }
        new.tb++;
        new.count--;
      }
  
      // Don't re-fetch data if it's not time yet, just re-display existing data.
      for (;;) {
        char was, is;
  
        if (recalc) {
          qsort(mix.tb, mix.count, sizeof(struct procpid *), (void *)ksort);
          if (!FLAG(b)) {
            printf("\033[H\033[J");
            if (toys.signal) {
              toys.signal = 0;
              terminal_probesize(&TT.width, &TT.height);
            }
          }
          if (TT.top.m) TT.height = TT.top.m+5;
          lines = TT.height;
        }
        if (recalc && !FLAG(q)) {
          // Display "top" header.
          if (*toys.which->name == 't') {
            struct ofields field;
            char hr[4][32];
            long long ll, up = 0;
            long run[6];
            int j;
  
            // Count running, sleeping, stopped, zombie processes.
            // The kernel has more states (and different sets in different
            // versions), so we need to map them. (R)unning and (Z)ombie are
            // easy enough, and since "stopped" is rare (just T and t as of
            // Linux 4.20), we assume everything else is "sleeping".
            field.which = PS_S;
            memset(run, 0, sizeof(run));
            for (i = 0; i<mix.count; i++)
              run[1+stridx("RTtZ", *string_field(mix.tb[i], &field))]++;
            sprintf(toybuf,
              "%ss: %d total, %3ld running, %3ld sleeping, %3ld stopped, "
              "%3ld zombie", FLAG(H)?"Thread":"Task", mix.count, run[1], run[0],
              run[2]+run[3], run[4]);
            lines = header_line(lines, 0);
  
            if (readfile("/proc/meminfo", toybuf+256, sizeof(toybuf)-256)) {
              for (i = 0; i<6; i++) {
                j = i%3;
                pos = strafter(toybuf+256, (char *[]){"MemTotal:","\nMemFree:",
                      "\nBuffers:","\nSwapTotal:","\nSwapFree:","\nCached:"}[i]);
                human_readable_long(hr[j+!!j], 1024*(run[i] = pos?atol(pos):0),
                  8, 0);
                if (j==1) human_readable_long(hr[1], 1024*(run[i-1]-run[i]), 8,0);
                else if (j==2) {
                  sprintf(toybuf, (i<3)
                    ? "  Mem: %9s total, %9s used, %9s free, %9s buffers"
                    : " Swap: %9s total, %9s used, %9s free, %9s cached",
                    hr[0], hr[1], hr[2], hr[3]);
                  lines = header_line(lines, 0);
                }
              }
            }
  
            pos = toybuf;
            i = sysconf(_SC_NPROCESSORS_CONF);
            pos += sprintf(pos, "%d%%cpu", i*100);
            j = 4+(i>10);
  
            // If a processor goes idle it's powered down and its idle ticks don't
            // advance, so calculate idle time as potential time - used.
            if (mix.count) up = mix.tb[0]->slot[SLOT_upticks];
            if (!up) up = 1;
            now = up*i;
            ll = stats[3] = stats[11] = 0;
            for (i = 0; i<8; i++) ll += stats[i]-stats[i+8];
            stats[3] = now - llabs(ll);
  
            for (i = 0; i<8; i++) {
              ll = (llabs(stats[i]-stats[i+8])*1000)/up;
              pos += sprintf(pos, "% *lld%%%s", j, (ll+5)/10, cpufields[i]);
            }
            lines = header_line(lines, 0);
          } else {
            struct ofields *field;
            struct procpid tb;
  
            memset(&tb, 0, sizeof(struct procpid));
            pos = stpcpy(toybuf, "Totals:");
            for (field = TT.fields; field; field = field->next) {
              long long ll, bits = 0;
              int slot = typos[field->which].slot&(XX-1);
  
              if (field->which<PS_C || field->which>PS_DIO) continue;
              ll = 1LL<<field->which;
              if (bits&ll) continue;
              bits |= ll;
              for (i=0; i<mix.count; i++)
                tb.slot[slot] += mix.tb[i]->slot[slot];
              pos += snprintf(pos, sizeof(toybuf)/2-(pos-toybuf),
                " %s: %*s,", typos[field->which].name,
                field->len, string_field(&tb, field));
            }
            *--pos = 0;
            lines = header_line(lines, 0);
          }
  
          get_headers(TT.fields, pos = toybuf, sizeof(toybuf));
          for (i = 0, is = ' '; *pos; pos++) {
            was = is;
            is = *pos;
            if (isspace(was) && !isspace(is) && i++==TT.sortpos && pos!=toybuf)
              pos[-1] = '[';
            if (!isspace(was) && isspace(is) && i==TT.sortpos+1) *pos = ']';
          }
          if (FLAG(b)) while (isspace(*(pos-1))) --pos;
          *pos = 0;
          lines = header_line(lines, 1);
        }
        if (!recalc && !FLAG(b))
          printf("\033[%dH\033[J", 1+TT.height-lines);
        recalc = 1;
  
        for (i = 0; i<lines && i+topoff<mix.count; i++) {
          // Running processes are shown in bold.
          int bold = !FLAG(b) && mix.tb[i+topoff]->state == 'R';
  
          if (!FLAG(b) && i) putchar('\n');
          if (bold) printf("\033[1m");
          show_ps(mix.tb[i+topoff]);
          if (bold) printf("\033[m");
        }
  
        if (TT.top.n && !--TT.top.n) {
          done++;
          break;
        }
  
        now = millitime();
        if (timeout<=now) timeout = new.whence+TT.top.d;
        if (timeout<=now || timeout>now+TT.top.d) timeout = now+TT.top.d;
  
        // In batch mode, we ignore the keyboard.
        if (FLAG(b)) {
          msleep(timeout-now);
          // Make an obvious gap between datasets.
          xputs("\n\n");
          break;
        } else fflush(stdout);
  
        i = scan_key_getsize(scratch, timeout-now, &TT.width, &TT.height);
        if (i==-1 || i==3 || toupper(i)=='Q') {
          done++;
          break;
        }
        if (i==-2) break;
        if (i==-3) continue;
  
        // Flush unknown escape sequences.
        if (i==27) while (0<scan_key_getsize(scratch, 0, &TT.width, &TT.height));
        else if (i=='\r' || i==' ') {
          timeout = 0;
          break;
        } else if (toupper(i)=='R')
          ((struct ofields *)TT.kfields)->reverse *= -1;
        else {
          i -= 256;
          if (i == KEY_LEFT) setsort(TT.sortpos-1);
          else if (i == KEY_RIGHT) setsort(TT.sortpos+1);
          // KEY_UP is 0, so at end of strchr
          else if (strchr((char []){KEY_DOWN,KEY_PGUP,KEY_PGDN,KEY_UP}, i)) {
            recalc = 0;
  
            if (i == KEY_UP) topoff--;
            else if (i == KEY_DOWN) topoff++;
            else if (i == KEY_PGDN) topoff += lines;
            else if (i == KEY_PGUP) topoff -= lines;
            if (topoff<0) topoff = 0; 
            if (topoff>mix.count) topoff = mix.count;
          }
        }
        continue;
      }
  
      free(mix.tb);
      for (i=0; i<plold->count; i++) free(plold->tb[i]);
      free(plold->tb);
    } while (!done);
  
    if (!FLAG(b)) tty_reset();
  }
  
  static void top_setup(char *defo, char *defk)
  {
    TT.ticks = sysconf(_SC_CLK_TCK); // units for starttime/uptime
    TT.tty = tty_fd() != -1;
  
    // Are we doing "batch" output or interactive?
    if (FLAG(b)) TT.width = TT.height = 99999;
    else {
      // Grab starting time, make terminal raw, switch off cursor,
      // set signal handler to put terminal/cursor back to normal at exit.
      TT.time = millitime();
      start_redraw(&TT.width, &TT.height);
    }
  
    comma_args(TT.top.u, &TT.uu, "bad -u", parse_rest);
    comma_args(TT.top.p, &TT.pp, "bad -p", parse_rest);
    TT.match_process = shared_match_process;
  
    default_ko(defo, &TT.fields, "bad -o", TT.top.o);
    dlist_terminate(TT.fields);
  
    // First (dummy) sort field is overwritten by setsort()
    default_ko("-S", &TT.kfields, 0, 0);
    default_ko(defk, &TT.kfields, "bad -k", TT.top.k);
    dlist_terminate(TT.kfields);
    setsort(TT.top.s-1);
  }
  
  void top_main(void)
  {
    sprintf(toybuf, "%cID,USER,%s%%CPU,%%MEM,TIME+,%s", FLAG(H) ? 'T' : 'P',
      TT.top.O ? "" : "PR,NI,VIRT,RES,SHR,S,",
      FLAG(H) ? "CMD:15=THREAD,NAME=PROCESS" : "ARGS");
    if (!TT.top.s) TT.top.s = TT.top.O ? 3 : 9;
    top_setup(toybuf, "-%CPU,-ETIME,-PID");
    if (TT.top.O) {
      struct ofields *field = TT.fields;
  
      field = field->next->next;
      comma_args(TT.top.O, &field, "bad -O", parse_ko);
    }
  
    top_common(merge_deltas);
  }
  
  #define CLEANUP_top
  #define FOR_iotop
  #include "generated/flags.h"
  
  // Compare old and new proces lists to measure changes
  static int iotop_filter(long long *oslot, long long *nslot, int milis)
  {
    // Current I/O, or accumulated since process start?
    if (!FLAG(a)) merge_deltas(oslot, nslot, milis);
    else oslot[SLOT_upticks] = ((millitime()-TT.time)*TT.ticks)/1000;
  
    return !FLAG(O)||oslot[SLOT_iobytes+!FLAG(A)];
  }
  
  void iotop_main(void)
  {
    char *s1 = 0, *s2 = 0, *d = "D"+!!FLAG(A);
  
    if (FLAG(K)) TT.forcek++;
  
    top_setup(s1 = xmprintf("PID,PR,USER,%sREAD,%sWRITE,SWAP,%sIO,COMM",d,d,d),
      s2 = xmprintf("-%sIO,-ETIME,-PID",d));
    free(s1);
    free(s2);
    top_common(iotop_filter);
  }
  
  // pkill's plumbing wraps pgrep's and thus mostly takes place in pgrep's flag
  // context, so force pgrep's flags on even when building pkill standalone.
  // (All the pgrep/pkill functions drop out when building ps standalone.)
  #define FORCE_FLAGS
  #define CLEANUP_iotop
  #define FOR_pgrep
  #include "generated/flags.h"
  
  struct regex_list {
    struct regex_list *next;
    regex_t reg;
  };
  
  static void do_pgk(struct procpid *tb)
  {
    if (TT.pgrep.signal) {
      if (kill(*tb->slot, TT.pgrep.signal)) {
        char *s = num_to_sig(TT.pgrep.signal);
  
        if (!s) sprintf(s = toybuf, "%d", TT.pgrep.signal);
        perror_msg("%s->%lld", s, *tb->slot);
      }
    }
    if (!FLAG(c) && (!TT.pgrep.signal || TT.tty)) {
      printf("%lld", *tb->slot);
      if (FLAG(l))
        printf(" %s", tb->str+tb->offset[4]*!!FLAG(f));
      
      printf("%s", TT.pgrep.d ? TT.pgrep.d : "\n");
    }
  }
  
  static void match_pgrep(void *p)
  {
    struct procpid *tb = p;
    regmatch_t match;
    struct regex_list *reg;
    char *name = tb->str+tb->offset[4]*!!FLAG(f);
  
    // Never match ourselves.
    if (TT.pgrep.self == *tb->slot) return;
  
    if (TT.pgrep.regexes) {
      for (reg = TT.pgrep.regexes; reg; reg = reg->next) {
        if (regexec(&reg->reg, name, 1, &match, 0)) continue;
        if (FLAG(x))
          if (match.rm_so || match.rm_eo!=strlen(name)) continue;
        break;
      }
      if (!FLAG(v) == !reg) return;
    }
  
    // pgrep should return success if there's a match.
    toys.exitval = 0;
  
    // Repurpose a field for -c count.
    TT.sortpos++;
    if (FLAG(n)||FLAG(o)) {
      long long ll = tb->slot[SLOT_starttime];
  
      if (FLAG(o)) ll *= -1;
      if (TT.time && TT.time>ll) return;
      TT.time = ll;
      free(TT.pgrep.snapshot);
      TT.pgrep.snapshot = xmemdup(toybuf, (name+strlen(name)+1)-toybuf);
    } else do_pgk(tb);
  }
  
  static int pgrep_match_process(long long *slot)
  {
    return !FLAG(v) == !!shared_match_process(slot);
  }
  
  void pgrep_main(void)
  {
    char **arg;
    struct regex_list *reg;
  
    TT.pgrep.self = getpid();
  
    // No signal names start with "L", so no need for "L: " in optstr.
    if (TT.pgrep.L && 1>(TT.pgrep.signal = sig_to_num(TT.pgrep.L)))
      error_exit("bad -L '%s'", TT.pgrep.L);
  
    comma_args(TT.pgrep.G, &TT.GG, "bad -G", parse_rest);
    comma_args(TT.pgrep.g, &TT.gg, "bad -g", parse_rest);
    comma_args(TT.pgrep.P, &TT.PP, "bad -P", parse_rest);
    comma_args(TT.pgrep.s, &TT.ss, "bad -s", parse_rest);
    comma_args(TT.pgrep.t, &TT.tt, "bad -t", parse_rest);
    comma_args(TT.pgrep.U, &TT.UU, "bad -U", parse_rest);
    comma_args(TT.pgrep.u, &TT.uu, "bad -u", parse_rest);
  
    if ((toys.optflags&(FLAG_x|FLAG_f)) ||
        !(toys.optflags&(FLAG_G|FLAG_g|FLAG_P|FLAG_s|FLAG_t|FLAG_U|FLAG_u)))
      if (!toys.optc) help_exit("No PATTERN");
  
    if (FLAG(f)) TT.bits |= _PS_CMDLINE;
    for (arg = toys.optargs; *arg; arg++) {
      reg = xmalloc(sizeof(struct regex_list));
      xregcomp(&reg->reg, *arg, REG_EXTENDED);
      reg->next = TT.pgrep.regexes;
      TT.pgrep.regexes = reg;
    }
    TT.match_process = pgrep_match_process;
    TT.show_process = match_pgrep;
  
    // pgrep should return failure if there are no matches.
    toys.exitval = 1;
  
    dirtree_flagread("/proc", DIRTREE_SHUTUP|DIRTREE_PROC, get_ps);
    if (FLAG(c)) printf("%d\n", TT.sortpos);
    if (TT.pgrep.snapshot) {
      do_pgk(TT.pgrep.snapshot);
      if (CFG_TOYBOX_FREE) free(TT.pgrep.snapshot);
    }
    if (TT.pgrep.d) xputc('\n');
  }
  
  #define CLEANUP_pgrep
  #define FOR_pkill
  #include "generated/flags.h"
  
  void pkill_main(void)
  {
    char **args = toys.optargs;
  
    if (!FLAG(l) && *args && **args=='-') TT.pgrep.L = *(args++)+1;
    if (!TT.pgrep.L) TT.pgrep.signal = SIGTERM;
    if (FLAG(V)) TT.tty = 1;
    pgrep_main();
  }
  