source: trunk/third/top/commands.c @ 9084

/*
 *  Top users/processes display for Unix
 *  Version 3
 *
 *  This program may be freely redistributed,
 *  but this entire comment MUST remain intact.
 *
 *  Copyright (c) 1984, 1989, William LeFebvre, Rice University
 *  Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University
 */

/*
 *  This file contains the routines that implement some of the interactive
 *  mode commands.  Note that some of the commands are implemented in-line
 *  in "main".  This is necessary because they change the global state of
 *  "top" (i.e.:  changing the number of processes to display).
 */

#include "os.h"
#include <ctype.h>
#include <signal.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/resource.h>

#include "sigdesc.h"            /* generated automatically */
#include "boolean.h"
#include "utils.h"

extern int  errno;

extern char *copyright;

/* imported from screen.c */
extern int overstrike;

int err_compar();
char *err_string();

/*
 *  show_help() - display the help screen; invoked in response to
 *              either 'h' or '?'.
 */

show_help()

{
    printf("Top version %s, %s\n", version_string(), copyright);
    fputs("\n\n\
A top users display for Unix\n\
\n\
These single-character commands are available:\n\
\n\
^L      - redraw screen\n\
q       - quit\n\
h or ?  - help; show this text\n", stdout);

    /* not all commands are availalbe with overstrike terminals */
    if (overstrike)
    {
        fputs("\n\
Other commands are also available, but this terminal is not\n\
sophisticated enough to handle those commands gracefully.\n\n", stdout);
    }
    else
    {
        fputs("\
d       - change number of displays to show\n\
e       - list errors generated by last \"kill\" or \"renice\" command\n\
i       - toggle the displaying of idle processes\n\
I       - same as 'i'\n\
k       - kill processes; send a signal to a list of processes\n\
n or #  - change number of processes to display\n", stdout);
#ifdef ORDER
        fputs("\
o       - specify sort order (size, res, cpu, time)\n", stdout);
#endif
        fputs("\
r       - renice a process\n\
s       - change number of seconds to delay between updates\n\
u       - display processes for only one user (+ selects all users)\n\
\n\
\n", stdout);
    }
}

/*
 *  Utility routines that help with some of the commands.
 */

char *next_field(str)

register char *str;

{
    if ((str = strchr(str, ' ')) == NULL)
    {
        return(NULL);
    }
    *str = '\0';
    while (*++str == ' ') /* loop */;

    /* if there is nothing left of the string, return NULL */
    /* This fix is dedicated to Greg Earle */
    return(*str == '\0' ? NULL : str);
}

scanint(str, intp)

char *str;
int  *intp;

{
    register int val = 0;
    register char ch;

    /* if there is nothing left of the string, flag it as an error */
    /* This fix is dedicated to Greg Earle */
    if (*str == '\0')
    {
        return(-1);
    }

    while ((ch = *str++) != '\0')
    {
        if (isdigit(ch))
        {
            val = val * 10 + (ch - '0');
        }
        else if (isspace(ch))
        {
            break;
        }
        else
        {
            return(-1);
        }
    }
    *intp = val;
    return(0);
}

/*
 *  Some of the commands make system calls that could generate errors.
 *  These errors are collected up in an array of structures for later
 *  contemplation and display.  Such routines return a string containing an
 *  error message, or NULL if no errors occurred.  The next few routines are
 *  for manipulating and displaying these errors.  We need an upper limit on
 *  the number of errors, so we arbitrarily choose 20.
 */

#define ERRMAX 20

struct errs             /* structure for a system-call error */
{
    int  errno;         /* value of errno (that is, the actual error) */
    char *arg;          /* argument that caused the error */
};

static struct errs errs[ERRMAX];
static int errcnt;
static char *err_toomany = " too many errors occurred";
static char *err_listem = 
        " Many errors occurred.  Press `e' to display the list of errors.";

/* These macros get used to reset and log the errors */
#define ERR_RESET   errcnt = 0
#define ERROR(p, e) if (errcnt >= ERRMAX) \
                    { \
                        return(err_toomany); \
                    } \
                    else \
                    { \
                        errs[errcnt].arg = (p); \
                        errs[errcnt++].errno = (e); \
                    }

/*
 *  err_string() - return an appropriate error string.  This is what the
 *      command will return for displaying.  If no errors were logged, then
 *      return NULL.  The maximum length of the error string is defined by
 *      "STRMAX".
 */

#define STRMAX 80

char *err_string()

{
    register struct errs *errp;
    register int  cnt = 0;
    register int  first = Yes;
    register int  currerr = -1;
    int stringlen;              /* characters still available in "string" */
    static char string[STRMAX];

    /* if there are no errors, return NULL */
    if (errcnt == 0)
    {
        return(NULL);
    }

    /* sort the errors */
    qsort((char *)errs, errcnt, sizeof(struct errs), err_compar);

    /* need a space at the front of the error string */
    string[0] = ' ';
    string[1] = '\0';
    stringlen = STRMAX - 2;

    /* loop thru the sorted list, building an error string */
    while (cnt < errcnt)
    {
        errp = &(errs[cnt++]);
        if (errp->errno != currerr)
        {
            if (currerr != -1)
            {
                if ((stringlen = str_adderr(string, stringlen, currerr)) < 2)
                {
                    return(err_listem);
                }
                (void) strcat(string, "; ");      /* we know there's more */
            }
            currerr = errp->errno;
            first = Yes;
        }
        if ((stringlen = str_addarg(string, stringlen, errp->arg, first)) ==0)
        {
            return(err_listem);
        }
        first = No;
    }

    /* add final message */
    stringlen = str_adderr(string, stringlen, currerr);

    /* return the error string */
    return(stringlen == 0 ? err_listem : string);
}

/*
 *  str_adderr(str, len, err) - add an explanation of error "err" to
 *      the string "str".
 */

str_adderr(str, len, err)

char *str;
int len;
int err;

{
    register char *msg;
    register int  msglen;

    msg = err == 0 ? "Not a number" : errmsg(err);
    msglen = strlen(msg) + 2;
    if (len <= msglen)
    {
        return(0);
    }
    (void) strcat(str, ": ");
    (void) strcat(str, msg);
    return(len - msglen);
}

/*
 *  str_addarg(str, len, arg, first) - add the string argument "arg" to
 *      the string "str".  This is the first in the group when "first"
 *      is set (indicating that a comma should NOT be added to the front).
 */

str_addarg(str, len, arg, first)

char *str;
int  len;
char *arg;
int  first;

{
    register int arglen;

    arglen = strlen(arg);
    if (!first)
    {
        arglen += 2;
    }
    if (len <= arglen)
    {
        return(0);
    }
    if (!first)
    {
        (void) strcat(str, ", ");
    }
    (void) strcat(str, arg);
    return(len - arglen);
}

/*
 *  err_compar(p1, p2) - comparison routine used by "qsort"
 *      for sorting errors.
 */

err_compar(p1, p2)

register struct errs *p1, *p2;

{
    register int result;

    if ((result = p1->errno - p2->errno) == 0)
    {
        return(strcmp(p1->arg, p2->arg));
    }
    return(result);
}

/*
 *  error_count() - return the number of errors currently logged.
 */

error_count()

{
    return(errcnt);
}

/*
 *  show_errors() - display on stdout the current log of errors.
 */

show_errors()

{
    register int cnt = 0;
    register struct errs *errp = errs;

    printf("%d error%s:\n\n", errcnt, errcnt == 1 ? "" : "s");
    while (cnt++ < errcnt)
    {
        printf("%5s: %s\n", errp->arg,
            errp->errno == 0 ? "Not a number" : errmsg(errp->errno));
        errp++;
    }
}

/*
 *  kill_procs(str) - send signals to processes, much like the "kill"
 *              command does; invoked in response to 'k'.
 */

char *kill_procs(str)

char *str;

{
    register char *nptr;
    int signum = SIGTERM;       /* default */
    int procnum;
    struct sigdesc *sigp;
    int uid;

    /* reset error array */
    ERR_RESET;

    /* remember our uid */
    uid = getuid();

    /* skip over leading white space */
    while (isspace(*str)) str++;

    if (str[0] == '-')
    {
        /* explicit signal specified */
        if ((nptr = next_field(str)) == NULL)
        {
            return(" kill: no processes specified");
        }

        if (isdigit(str[1]))
        {
            (void) scanint(str + 1, &signum);
            if (signum <= 0 || signum >= NSIG)
            {
                return(" invalid signal number");
            }
        }
        else 
        {
            /* translate the name into a number */
            for (sigp = sigdesc; sigp->name != NULL; sigp++)
            {
                if (strcmp(sigp->name, str + 1) == 0)
                {
                    signum = sigp->number;
                    break;
                }
            }

            /* was it ever found */
            if (sigp->name == NULL)
            {
                return(" bad signal name");
            }
        }
        /* put the new pointer in place */
        str = nptr;
    }

    /* loop thru the string, killing processes */
    do
    {
        if (scanint(str, &procnum) == -1)
        {
            ERROR(str, 0);
        }
        else
        {
            /* check process owner if we're not root */
            if (uid && (uid != proc_owner(procnum)))
            {
                ERROR(str, EACCES);
            }
            /* go in for the kill */
            else if (kill(procnum, signum) == -1)
            {
                /* chalk up an error */
                ERROR(str, errno);
            }
        }
    } while ((str = next_field(str)) != NULL);

    /* return appropriate error string */
    return(err_string());
}

/*
 *  renice_procs(str) - change the "nice" of processes, much like the
 *              "renice" command does; invoked in response to 'r'.
 */

char *renice_procs(str)

char *str;

{
    register char negate;
    int prio;
    int procnum;
    int uid;

    ERR_RESET;
    uid = getuid();

    /* allow for negative priority values */
    if ((negate = (*str == '-')) != 0)
    {
        /* move past the minus sign */
        str++;
    }

    /* use procnum as a temporary holding place and get the number */
    procnum = scanint(str, &prio);

    /* negate if necessary */
    if (negate)
    {
        prio = -prio;
    }

#if defined(PRIO_MIN) && defined(PRIO_MAX)
    /* check for validity */
    if (procnum == -1 || prio < PRIO_MIN || prio > PRIO_MAX)
    {
        return(" bad priority value");
    }
#endif

    /* move to the first process number */
    if ((str = next_field(str)) == NULL)
    {
        return(" no processes specified");
    }

    /* loop thru the process numbers, renicing each one */
    do
    {
        if (scanint(str, &procnum) == -1)
        {
            ERROR(str, 0);
        }

        /* check process owner if we're not root */
        else if (uid && (uid != proc_owner(procnum)))
        {
            ERROR(str, EACCES);
        }
        else if (setpriority(PRIO_PROCESS, procnum, prio) == -1)
        {
            ERROR(str, errno);
        }
    } while ((str = next_field(str)) != NULL);

    /* return appropriate error string */
    return(err_string());
}