root-tail/root-tail.c

/*
 * Copyright 2001 by Marco d'Itri <md@linux.it>
 *
 * Original version by Mike Baker, then maintained by pcg@goof.com.
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */

#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <time.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <locale.h>
#if HAS_REGEX
#include <regex.h>
#endif
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xutil.h>

/* data structures */
struct logfile_entry {
    char *fname;         /* name of file                                */
    char *desc;          /* alternative description                     */
    char *buf;           /* text read but not yet displayed             */
    FILE *fp;            /* FILE struct associated with file            */
    ino_t inode;         /* inode of the file opened                    */
    off_t last_size;     /* file size at the last check                 */
    unsigned long color; /* color to be used for printing               */
    int partial;         /* true if the last line isn't complete        */
    int lastpartial;     /* true if the previous output wasn't complete */
    int index;           /* index into linematrix of a partial line     */
    struct logfile_entry *next;
};

struct linematrix {
    char *line;
    unsigned long color;
};


/* global variables */
int width = STD_WIDTH, listlen = STD_HEIGHT;
int win_x = LOC_X, win_y = LOC_Y;
int w = -1, h = -1, font_width, font_height, font_descent;
int do_reopen;
struct timeval interval = { 3, 0 };     /* see Knuth */
XFontSet fontset;

/* command line options */
int opt_noinitial, opt_shade, opt_frame, opt_reverse, opt_nofilename,
    opt_whole, opt_update, geom_mask, reload = 0;
const char *command = NULL,
    *fontname = USE_FONT, *dispname = NULL, *def_color = DEF_COLOR,
    *continuation = "[+]";

struct logfile_entry *loglist = NULL, *loglist_tail = NULL;

Display *disp;
Window root;
GC WinGC;

#if HAS_REGEX
struct re_list {
    regex_t from;
    const char *to;
    struct re_list *next;
};
struct re_list *re_head, *re_tail;
#endif


/* prototypes */
void list_files(int);
void force_reopen(int);
void force_refresh(int);
void blank_window(int);

void InitWindow(void);
unsigned long GetColor(const char *);
void redraw(void);
void refresh(struct linematrix *, int, int);

void transform_line(char *s);
int lineinput(struct logfile_entry *);
void reopen(void);
void check_open_files(void);
FILE *openlog(struct logfile_entry *);
void main_loop(void);

void display_version(void);
void display_help(char *);
void install_signal(int, void (*)(int));
void *xstrdup(const char *);
void *xmalloc(size_t);
int daemonize(void);

/* signal handlers */
void list_files(int dummy)
{
    struct logfile_entry *e;

    fprintf(stderr, "Files opened:\n");
    for (e = loglist; e; e = e->next)
        fprintf(stderr, "\t%s (%s)\n", e->fname, e->desc);
}

void force_reopen(int dummy)
{
    do_reopen = 1;
}

void force_refresh(int dummy)
{
    XClearArea(disp, root, win_x, win_y, w, h + font_descent + 2, False);
    redraw();
}

void blank_window(int dummy)
{
    XClearArea(disp, root, win_x, win_y, w, h + font_descent + 2, False);
    XFlush(disp);
    exit(0);
}

/* X related functions */
unsigned long GetColor(const char *ColorName)
{
    XColor Color;
    XWindowAttributes Attributes;

    XGetWindowAttributes(disp, root, &Attributes);
    Color.pixel = 0;

    if (!XParseColor(disp, Attributes.colormap, ColorName, &Color))
        fprintf(stderr, "can't parse %s\n", ColorName);
    else if (!XAllocColor(disp, Attributes.colormap, &Color))
        fprintf(stderr, "can't allocate %s\n", ColorName);

    return Color.pixel;
}

static Window root_window (Display *display, int screen_number)
{
  Atom __SWM_VROOT = XInternAtom (display, "__SWM_VROOT", False);
  Window real_root_window = RootWindow (display, screen_number);

  if (root) /* root window set via option */
    return root;

  if (__SWM_VROOT != None)
    {
      Window unused, *windows;
      unsigned int count;

      if (XQueryTree (display, real_root_window, &unused, &unused, &windows,
                      &count))
        {
          int i;

          for (i = 0; i < count; i++)
            {
              Atom type;
              int format;
              unsigned long nitems, bytes_after_return;
              unsigned char *virtual_root_window;

              if (XGetWindowProperty (display, windows[i], __SWM_VROOT,
                                      0, 1, False, XA_WINDOW, &type, &format,
                                      &nitems, &bytes_after_return,
                                      &virtual_root_window)
                  == Success)
                {
                  if (type != None)
                    {
                      if (type == XA_WINDOW)
                        {
                          XFree (windows);
                          return (Window)virtual_root_window;
                        }
                      else
                        fprintf (stderr, "__SWM_VROOT property type mismatch");
                    }
                }
              else
                fprintf (stderr,
                         "failed to get __SWM_VROOT property on window 0x%lx",
                         windows[i]);
            }

          if (count)
            XFree (windows);
        }
      else
        fprintf (stderr, "Can't query tree on root window 0x%lx",
                 real_root_window);
    }
  else
    /* This shouldn't happen. The Xlib documentation is wrong BTW. */
    fprintf (stderr, "Can't intern atom __SWM_VROOT");

  return real_root_window;
}

void InitWindow(void)
{
    XGCValues gcv;
    Font font;
    unsigned long gcm;
    XFontStruct *info;
    int screen, ScreenWidth, ScreenHeight;

    if (!(disp = XOpenDisplay(dispname))) {
        fprintf(stderr, "Can't open display %s.\n", dispname);
        exit(1);
    }
    screen = DefaultScreen(disp);
    ScreenHeight = DisplayHeight(disp, screen);
    ScreenWidth = DisplayWidth(disp, screen);

    root = root_window (disp, screen);

    gcm = GCBackground;
    gcv.graphics_exposures = True;
    WinGC = XCreateGC(disp, root, gcm, &gcv);
    XMapWindow(disp, root);
    XSetForeground(disp, WinGC, GetColor(DEF_COLOR));

    font = XLoadFont(disp, fontname);
    XSetFont(disp, WinGC, font);
    info = XQueryFont(disp, font);
    font_width = info->max_bounds.width;
    font_descent = info->max_bounds.descent;
    font_height = info->max_bounds.ascent + font_descent;

    w = width * font_width;
    h = listlen * font_height;

    if (geom_mask & XNegative)
        win_x = win_x + ScreenWidth - w;
    if (geom_mask & YNegative)
        win_y = win_y + ScreenHeight - h;

    XSelectInput(disp, root, ExposureMask|FocusChangeMask);
}

char *
detabificate (char *s)
{
  char * out;
  int i, j;

  out = malloc (8 * strlen (s) + 1);

  for(i = 0, j = 0; s[i]; i++)
    {
      if (s[i] == '\t')
        do
          out[j++] = ' ';
        while (j % 8);
      else
        out[j++] = s[i];
    }

  out[j] = '\0';
  return out;
}

/*
 * redraw does a complete redraw, rather than an update (i.e. the area
 * gets cleared first)
 * the rest is handled by regular refresh()'es
 */
void redraw(void)
{
    XClearArea(disp, root, win_x, win_y, w, h + font_descent + 2, True);
}

/* Just redraw everything without clearing (i.e. after an EXPOSE event) */
void refresh(struct linematrix *lines, int miny, int maxy)
{
    int lin;
    int offset = (listlen + 1) * font_height;
    unsigned long black_color = GetColor("black");

    miny -= win_y + font_height;
    maxy -= win_y - font_height;

    for (lin = listlen; lin--;)
      {
        char *temp;

        offset -= font_height;

        if (offset < miny || offset > maxy)
          continue;

#define LIN ((opt_reverse)?(listlen-lin-1):(lin))
        temp = detabificate (lines[LIN].line);

        if (opt_shade)
          {
            XSetForeground (disp, WinGC, black_color);
#if 0
            XmbDrawString (disp, root, fontset, WinGC, win_x + 2, win_y + offset + 2,
                           temp, strlen (temp));
#endif
            XDrawString (disp, root, WinGC, win_x + 2, win_y + offset + 2,
                         temp, strlen (temp));
          }

        XSetForeground (disp, WinGC, lines[LIN].color);
#if 0
        XmbDrawString (disp, root, fontset, WinGC, win_x, win_y + offset,
                       temp, strlen (temp));
#endif
        XDrawString (disp, root, WinGC, win_x, win_y + offset,
                     temp, strlen (temp));
        free (temp);
    }

    if (opt_frame) {
        int bot_y = win_y + h + font_descent + 2;

        XDrawLine(disp, root, WinGC, win_x, win_y, win_x + w, win_y);
        XDrawLine(disp, root, WinGC, win_x + w, win_y, win_x + w, bot_y);
        XDrawLine(disp, root, WinGC, win_x + w, bot_y, win_x, bot_y);
        XDrawLine(disp, root, WinGC, win_x, bot_y, win_x, win_y);
    }
}

#if HAS_REGEX
void transform_line(char *s)
{
#ifdef I_AM_Md
    int i;
    if (1) {
        for (i = 16; s[i]; i++)
            s[i] = s[i + 11];
    }
    s[i + 1] = '\0';
#endif

    if (transformre) {
        int i;
        regmatch_t matched[16];

        i = regexec(&transformre, string, 16, matched, 0);
        if (i == 0) {                   /* matched */
        }
    }
}
#endif


/*
 * This routine should read 'width' characters and not more. However,
 * we really want to read width + 1 characters if the last char is a '\n',
 * which we should remove afterwards. So, read width+1 chars and ungetc
 * the last character if it's not a newline. This means 'string' must be
 * width + 2 wide!
 */
int lineinput(struct logfile_entry *logfile)
{
  char *string = logfile->buf;
  int slen = width + 2;
  FILE *f = logfile->fp;

  int len = strlen(string);
  int partial = logfile->partial;

    do {
        if (fgets(string + len, slen - len, f) == NULL) /* EOF or Error */
            return 0;

        len = strlen(string);
    } while (len == 0);

    logfile->partial = 0;

    /* if the string ends in a newline, delete the newline */
    if (string[len - 1] == '\n')
        string[len - 1] = '\0';                 /* erase newline */
    /* otherwise if we've read one too many characters, un-read the last one and delete it */
    else if (len >= slen - 1) {
        ungetc(string[len - 1], f);
        string[len - 1] = '\0';
    } else if (opt_whole)
        return 0;
    else
        logfile->partial = 1;

#if HAS_REGEX
    transform_line(string);
#endif
    logfile->lastpartial = partial;
    return len;
}

/* input: reads file->fname
 * output: fills file->fp, file->inode
 * returns file->fp
 * in case of error, file->fp is NULL
 */
FILE *openlog(struct logfile_entry *file)
{
    struct stat stats;

    if ((file->fp = fopen(file->fname, "r")) == NULL) {
        file->fp = NULL;
        return NULL;
    }

    fstat(fileno(file->fp), &stats);
    if (S_ISFIFO(stats.st_mode)) {
        if (fcntl(fileno(file->fp), F_SETFL, O_NONBLOCK) < 0)
            perror("fcntl"), exit(1);
        file->inode = 0;
    } else
        file->inode = stats.st_ino;

    if (opt_noinitial)
      fseek (file->fp, 0, SEEK_END);
    else if (stats.st_size > (listlen + 1) * width)
      fseek(file->fp, -((listlen + 2) * width), SEEK_END);

    file->last_size = stats.st_size;
    return file->fp;
}

void reopen(void)
{
    struct logfile_entry *e;

    for (e = loglist; e; e = e->next) {
        if (!e->inode)
            continue;                   /* skip stdin */

        if (e->fp)
            fclose(e->fp);
        /* if fp is NULL we will try again later */
        openlog(e);
    }

    do_reopen = 0;
}

void check_open_files(void)
{
    struct logfile_entry *e;
    struct stat stats;

    for (e = loglist; e; e = e->next) {
        if (!e->inode)
            continue;                           /* skip stdin */

        if (stat(e->fname, &stats) < 0) {       /* file missing? */
            sleep(1);
            if (e->fp)
                fclose(e->fp);
            if (openlog(e) == NULL)
                break;
        }

        if (stats.st_ino != e->inode)   {       /* file renamed? */
            if (e->fp)
                fclose(e->fp);
            if (openlog(e) == NULL)
                break;
        }

        if (stats.st_size < e->last_size) {     /* file truncated? */
            fseek(e->fp, 0, SEEK_SET);
            e->last_size = stats.st_size;
        }
    }
}

#define SCROLL_UP(lines, listlen)                               \
{                                                               \
    int cur_line;                                               \
    struct logfile_entry *current;                              \
    for (cur_line = 0; cur_line < (listlen - 1); cur_line++) {  \
        strcpy(lines[cur_line].line, lines[cur_line + 1].line); \
        lines[cur_line].color = lines[cur_line + 1].color;      \
    }                                                           \
    for (current = loglist; current; current = current->next)   \
        if (current->partial && current->index)                 \
            current->index--;                                   \
}

void main_loop(void)
{
    struct linematrix *lines = xmalloc(sizeof(struct linematrix) * listlen);
    int lin, miny, maxy;
    time_t lastreload;
    Region region = XCreateRegion();
    XEvent xev;
    struct logfile_entry *lastprinted = NULL;
    struct logfile_entry *current;

    maxy = 0;
    miny = win_y + h;
    lastreload = time(NULL);

    /* Initialize linematrix */
    for (lin = 0; lin < listlen; lin++) {
        lines[lin].line = xmalloc(width + 2);
        strcpy(lines[lin].line, "~");
        lines[lin].color = GetColor(def_color);
    }

    /* show the display full of empty lines ("~") in case the first
     * time around the loop doesn't produce any output, as it won't if
     * either (a) -noinitial is set or (b) all the files are currently
     * empty */
    redraw();

    for (;;) {
        int need_update = 0;

        /* read logs */
        for (current = loglist; current; current = current->next) {
            if (!current->fp)
                continue;               /* skip missing files */

            clearerr(current->fp);

            while (lineinput(current) != 0) {

                /* if we're trying to update old partial lines in
                 * place, and the last time this file was updated the
                 * output was partial, and that partial line is not
                 * too close to the top of the screen, then update
                 * that partial line */
                if (opt_update && current->lastpartial && current->index >= 3) {
                    int old_len = strlen(lines[current->index].line);
                    int new_len = strlen(current->buf);
                    int space_on_old_line = width - old_len;
                    strncat(lines[current->index].line, current->buf, width - old_len);
                    /* if we can't fit the whole update into the old
                     * partial line then we're going to have to print
                     * the rest of it at the bottom on the screen */
                    if (new_len > space_on_old_line) {
                        /* strcpy() doesn't like the strings to
                         * overlap in memory, but memmove() doesn't
                         * care */
                        memmove(current->buf,
                                current->buf + space_on_old_line,
                                new_len - space_on_old_line + 1);
                    } else {
                      need_update = 1;
                      strcpy(current->buf, "");
                      continue;
                    }
                }

                /* print filename if any, and if last line was from
                 * different file */
                if (!opt_nofilename &&
                    lastprinted != current &&
                    current->desc[0]) {
                    SCROLL_UP(lines, listlen);
                    sprintf(lines[listlen - 1].line, "[%s]", current->desc);
                    lines[listlen - 1].color = current->color;
                }

                /* if this is the same file we showed last, and the
                 * last time we showed it, it wasn't finished, then
                 * append to the last line shown */
                if (lastprinted == current && current->lastpartial) {
                    int old_len = strlen(lines[listlen - 1].line);
                    int new_len = strlen(current->buf);
                    strncat(lines[listlen - 1].line, current->buf, width - old_len);
                    /* if it doesn't all fit, then put the part that
                     * doesn't fit on a new line */
                    if (new_len > width - old_len) {
                        SCROLL_UP(lines, listlen);
                        strcpy(lines[listlen - 1].line, current->buf + width - old_len);
                    }
                /* show the 'continuation' string because we've got a
                 * continued partial line, but we weren't able to
                 * append it to the old displayed partial line */
                } else if (current->lastpartial) {
                    int old_len = strlen(continuation);
                    int new_len = strlen(current->buf);
                    SCROLL_UP(lines, listlen);
                    strcpy(lines[listlen - 1].line, continuation);
                    strncat(lines[listlen - 1].line, current->buf, width - old_len);
                    /* it might not fit, now that we've displayed the
                     * continuation string, so we may need to 'wrap' it */
                    if (new_len > width - old_len) {
                        SCROLL_UP(lines, listlen);
                        strcpy(lines[listlen - 1].line, current->buf + width - old_len);
                    }
                } else {
                  SCROLL_UP(lines, listlen);
                  strcpy(lines[listlen - 1].line, current->buf);
                }

                /* we've shown the line now.  clear the buffer for the next line */
                strcpy(current->buf, "");
                current->index = listlen - 1;
                lines[listlen - 1].color = current->color;

                lastprinted = current;
                need_update = 1;
            }
        }

        if (need_update)
            redraw();
        else {
            XFlush(disp);
            if (!XPending(disp)) {
                fd_set fdr;
                struct timeval to = interval;

                FD_ZERO(&fdr);
                FD_SET(ConnectionNumber(disp), &fdr);
                select(ConnectionNumber(disp) + 1, &fdr, 0, 0, &to);
            }
        }

        check_open_files();

        if (do_reopen)
            reopen();

        /* we ignore possible errors due to window resizing &c */
        while (XPending(disp)) {
            XNextEvent(disp, &xev);
            switch (xev.type) {
            case Expose:
                {
                    XRectangle r;

                    r.x = xev.xexpose.x;
                    r.y = xev.xexpose.y;
                    r.width = xev.xexpose.width;
                    r.height = xev.xexpose.height;
                    XUnionRectWithRegion(&r, region, region);
                    if (miny > r.y)
                        miny = r.y;
                    if (maxy < r.y + r.height)
                        maxy = r.y + r.height;
                }
                break;
            default:
#ifdef DEBUGMODE
                fprintf(stderr, "PANIC! Unknown event %d\n", xev.type);
#endif
                break;
            }
        }

        /* reload if requested */
        if (reload && lastreload + reload < time(NULL)) {
            if (command && command[0])
                system(command);

            reopen();
            lastreload = time(NULL);
        }

        if (!XEmptyRegion(region)) {
            XSetRegion(disp, WinGC, region);
            refresh(lines, miny, maxy);
            XDestroyRegion(region);
            region = XCreateRegion();
            maxy = 0;
            miny = win_y + h;
        }
    }
}


int main(int argc, char *argv[])
{
    int i;
    int opt_daemonize = 0;
    int opt_partial = 0, file_count = 0;
#if HAS_REGEX
    char *transform = NULL;
#endif

    setlocale (LC_CTYPE, ""); /* try to initialize the locale. */

    /* window needs to be initialized before colorlookups can be done */
    /* just a dummy to get the color lookups right */
    geom_mask = NoValue;
    InitWindow();

    for (i = 1; i < argc; i++) {
        const char *arg = argv[i];

        if (arg[0] == '-' && arg[1] != '\0' && arg[1] != ',') {
            if (arg[1] == '-')
              arg++;

            if (!strcmp(arg, "-?") ||
                !strcmp(arg, "-help") || !strcmp(arg, "-h"))
                display_help(argv[0]);
            else if (!strcmp(arg, "-V"))
                display_version();
            else if (!strcmp(arg, "-g") || !strcmp(arg, "-geometry"))
                geom_mask = XParseGeometry(argv[++i],
                        &win_x, &win_y, &width, &listlen);
            else if (!strcmp(arg, "-display"))
                dispname = argv[++i];
            else if (!strcmp(arg, "-cont"))
                continuation = argv[++i];
            else if (!strcmp(arg, "-font") || !strcmp(arg, "-fn"))
                fontname = argv[++i];
#if HAS_REGEX
            else if (!strcmp(arg, "-t"))
                transform = argv[++i];
#endif
            else if (!strcmp(arg, "-fork") || !strcmp(arg, "-f"))
                opt_daemonize = 1;
            else if (!strcmp(arg, "-reload")) {
                reload = atoi(argv[++i]);
                command = argv[++i];
            }
            else if (!strcmp(arg, "-shade"))
                opt_shade = 1;
            else if (!strcmp(arg, "-frame"))
                opt_frame = 1;
            else if (!strcmp(arg, "-no-filename"))
                opt_nofilename = 1;
            else if (!strcmp(arg, "-reverse"))
                opt_reverse = 1;
            else if (!strcmp(arg, "-whole"))
                opt_whole = 1;
            else if (!strcmp(arg, "-partial"))
                opt_partial = 1;
            else if (!strcmp(arg, "-update"))
                opt_update = opt_partial = 1;
            else if (!strcmp(arg, "-color"))
                def_color = argv[++i];
            else if (!strcmp(arg, "-noinitial"))
                opt_noinitial = 1;
            else if (!strcmp(arg, "-id"))
                root = atoi (argv[++i]);
            else if (!strcmp(arg, "-interval") || !strcmp(arg, "-i")) {
                double iv = atof(argv[++i]);

                interval.tv_sec = (int) iv;
                interval.tv_usec = (iv - interval.tv_sec) * 1e6;
            } else {
                fprintf(stderr, "Unknown option '%s'.\n"
                        "Try --help for more information.\n", arg);
                exit(1);
            }
        } else {                /* it must be a filename */
            struct logfile_entry *e;
            const char *fname, *desc, *fcolor = def_color;
            char *p;

            file_count++;

            /* this is not foolproof yet (',' in filenames are not allowed) */
            fname = desc = arg;
            if ((p = strchr(arg, ','))) {
                *p = '\0';
                fcolor = p + 1;

                if ((p = strchr(fcolor, ','))) {
                    *p = '\0';
                    desc = p + 1;
                }
            }

            e = xmalloc(sizeof(struct logfile_entry));
            if (arg[0] == '-' && arg[1] == '\0') {
                if ((e->fp = fdopen(0, "r")) == NULL)
                    perror("fdopen"), exit(1);
                if (fcntl(0, F_SETFL, O_NONBLOCK) < 0)
                    perror("fcntl"), exit(1);
                e->fname = NULL;
                e->inode = 0;
                e->desc = xstrdup("stdin");
            } else {
                int l;

                e->fname = xstrdup(fname);
                if (openlog(e) == NULL)
                    perror(fname), exit(1);

                l = strlen(desc);
                if (l > width - 2)              /* must account for [ ] */
                    l = width - 2;
                e->desc = xmalloc(l + 1);
                memcpy(e->desc, desc, l);
                *(e->desc + l) = '\0';
            }

            e->color = GetColor(fcolor);
            e->buf = xmalloc(width + 2);
            e->partial = 0;
            e->buf[0] = '\0';
            e->next = NULL;

            if (!loglist)
                loglist = e;
            if (loglist_tail)
                loglist_tail->next = e;
            loglist_tail = e;
        }
    }

    if (!loglist) {
        fprintf(stderr, "You did not specify any files to tail\n"
                "use %s --help for help\n", argv[0]);
        exit(1);
    }

    if (opt_partial && opt_whole) {
      fprintf(stderr, "Specify at most one of -partial and -whole\n");
      exit(1);
    }

    /* if we specifically requested to see partial lines then don't insist on whole lines */
    if (opt_partial) {
      opt_whole = 0;
    /* otherwise, if we've viewing multiple files, default to showing whole lines */
    } else if (file_count > 1) {
      opt_whole = 1;
    }

#if HAS_REGEX
    if (transform) {
        int i;

        transformre = xmalloc(sizeof(transformre));
        i = regcomp(&transformre, transform, REG_EXTENDED);
        if (i != 0) {
            char buf[512];

            regerror(i, &transformre, buf, sizeof(buf));
            fprintf(stderr, "Cannot compile regular expression: %s\n", buf);
        }
    }
#endif

    InitWindow();

    install_signal(SIGINT, blank_window);
    install_signal(SIGQUIT, blank_window);
    install_signal(SIGTERM, blank_window);
    install_signal(SIGHUP, force_reopen);
    install_signal(SIGUSR1, list_files);
    install_signal(SIGUSR2, force_refresh);

    if (opt_daemonize)
        daemonize();

    main_loop();

    exit(1);                    /* to make gcc -Wall stop complaining */
}

void install_signal(int sig, void (*handler)(int))
{
    struct sigaction action;

    action.sa_handler = handler;
    sigemptyset(&action.sa_mask);
    action.sa_flags = SA_RESTART;
    if (sigaction(sig, &action, NULL) < 0)
        fprintf(stderr, "sigaction(%d): %s\n", sig, strerror(errno)), exit(1);
}

void *xstrdup(const char *string)
{
    void *p;

    while ((p = strdup(string)) == NULL) {
        fprintf(stderr, "Memory exausted.");
        sleep(10);
    }
    return p;
}

void *xmalloc(size_t size)
{
    void *p;

    while ((p = malloc(size)) == NULL) {
        fprintf(stderr, "Memory exausted.");
        sleep(10);
    }
    return p;
}

void display_help(char *myname)
{
    printf("Usage: %s [options] file1[,color[,desc]] "
           "[file2[,color[,desc]] ...]\n", myname);
    printf(" -g | -geometry geometry   -g WIDTHxHEIGHT+X+Y\n"
            " -color    color           use color $color as default\n"
            " -reload sec command       reload after $sec and run command\n"
            " -id id                    window id to use instead of the root window\n"
            " -font FONTSPEC            (-fn) font to use\n"
            " -f | -fork                fork into background\n"
            " -reverse                  print new lines at the top\n"
            " -whole                    wait for \\n before showing a line\n"
            " -partial                  show lines even if they don't end with a \\n\n"
            " -update                   allow updates to old partial lines\n"
            " -cont                     string to prefix continued partial lines with\n"
            "                           defaults to \"[+]\"\n"
            " -shade                    add shading to font\n"
            " -noinitial                don't display the last file lines on\n"
            "                           startup\n"
            " -i | -interval seconds    interval between checks (fractional\n"
            "                           values o.k.). Default 3 seconds\n"
            " -V                        display version information and exit\n"
            "\n");
    printf("Example:\n%s -g 80x25+100+50 -font fixed /var/log/messages,green "
         "/var/log/secure,red,'ALERT'\n", myname);
    exit(0);
}

void display_version(void) {
    printf("root-tail version " VERSION "\n");
    exit(0);
}

int daemonize(void) {
    switch (fork()) {
    case -1:
        return -1;
    case 0:
        break;
    default:
        _exit(0);
    }

    if (setsid() == -1)
        return -1;

    return 0;
}
Revision:	1.10
Committed:	Fri Mar 26 12:11:05 2004 UTC (22 years, 5 months ago) by chris_moore
Content type:	text/plain
Branch:	MAIN
Changes since 1.9:	+7 -3 lines
Log Message:	- call redraw() before entering the main loop to ensure that at least something is displayed on the root window immediately