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lightning-sunbird  0.9+nobinonly
Defines | Functions | Variables
tail.c File Reference
#include "prio.h"
#include "prprf.h"
#include "prinit.h"
#include "prthread.h"
#include "prinrval.h"
#include "plerror.h"
#include "plgetopt.h"
#include <stdlib.h>

Go to the source code of this file.

Defines

#define BUFFER_SIZE   500

Functions

static void Help (void)
PRIntn main (PRIntn argc, char **argv)

Variables

static PRFileDescout = NULL
static PRFileDescerr = NULL

Define Documentation

#define BUFFER_SIZE   500

Definition at line 49 of file tail.c.


Function Documentation

static void Help ( void  ) [static]

Definition at line 53 of file tail.c.

{
    PR_fprintf(err, "Usage: tail [-n <n>] [-f] [-h] <filename>\n");
    PR_fprintf(err, "\t-t <n>      Dally time in milliseconds\n");
    PR_fprintf(err, "\t-n <n>      Number of bytes before <eof>\n");
    PR_fprintf(err, "\t-f          Follow the <eof>\n");
    PR_fprintf(err, "\t-h          This message and nothing else\n");
}  /* Help */
PRIntn main ( PRIntn  argc,
char **  argv 
)

Definition at line 62 of file tail.c.

{
       PRIntn rv = 0;
    PLOptStatus os;
       PRStatus status;
       PRFileDesc *file;
       PRFileInfo fileInfo;
       PRIntervalTime dally;
       char buffer[BUFFER_SIZE];
       PRBool follow = PR_FALSE;
       const char *filename = NULL;
       PRUint32 position = 0, seek = 0, time = 0;
    PLOptState *opt = PL_CreateOptState(argc, argv, "hfn:");

    out = PR_GetSpecialFD(PR_StandardOutput);
    err = PR_GetSpecialFD(PR_StandardError);

    while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
    {
        if (PL_OPT_BAD == os) continue;
        switch (opt->option)
        {
              case 0:  /* it's the filename */
                     filename = opt->value;
                     break;
        case 'n':  /* bytes before end of file */
            seek = atoi(opt->value);
            break;
        case 't':  /* dally time */
            time = atoi(opt->value);
            break;
        case 'f':  /* follow the end of file */
            follow = PR_TRUE;
            break;
        case 'h':  /* user wants some guidance */
            Help();  /* so give him an earful */
            return 2;  /* but not a lot else */
            break;
         default:
            break;
        }
    }
    PL_DestroyOptState(opt);

       if (0 == time) time = 1000;
       dally = PR_MillisecondsToInterval(time);

    if (NULL == filename)
    {
        (void)PR_fprintf(out, "Input file not specified\n");
        rv = 1; goto done;
    }
       file = PR_Open(filename, PR_RDONLY, 0);
       if (NULL == file)
       {
              PL_FPrintError(err, "File cannot be opened for reading");
              return 1;
       }

       status = PR_GetOpenFileInfo(file, &fileInfo);
       if (PR_FAILURE == status)
       {
              PL_FPrintError(err, "Cannot acquire status of file");
              rv = 1; goto done;
       }
       if (seek > 0)
       {
           if (seek > fileInfo.size) seek = 0;
              position = PR_Seek(file, (fileInfo.size - seek), PR_SEEK_SET);
              if (-1 == (PRInt32)position)
                     PL_FPrintError(err, "Cannot seek to starting position");
       }

       do
       {
              while (position < fileInfo.size)
              {
                     PRInt32 read, bytes = fileInfo.size - position;
                     if (bytes > sizeof(buffer)) bytes = sizeof(buffer);
                     read = PR_Read(file, buffer, bytes);
                     if (read != bytes)
                            PL_FPrintError(err, "Cannot read to eof");
                     position += read;
                     PR_Write(out, buffer, read);
              }

              if (follow)
              {
                     PR_Sleep(dally);
                     status = PR_GetOpenFileInfo(file, &fileInfo);
                     if (PR_FAILURE == status)
                     {
                            PL_FPrintError(err, "Cannot acquire status of file");
                            rv = 1; goto done;
                     }
              }
       } while (follow);

done:
       PR_Close(file);

       return rv;
}  /* main */

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Variable Documentation

PRFileDesc * err = NULL [static]

Definition at line 51 of file tail.c.

PRFileDesc* out = NULL [static]

Definition at line 51 of file tail.c.