git.maemo.org Git - monky/blob - src/tailhead.c

   1 /* -*- mode: c; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: t -*-
   2  * vim: ts=4 sw=4 noet ai cindent syntax=c
   3  *
   4  * Conky, a system monitor, based on torsmo
   5  *
   6  * Any original torsmo code is licensed under the BSD license
   7  *
   8  * All code written since the fork of torsmo is licensed under the GPL
   9  *
  10  * Please see COPYING for details
  11  *
  12  * Copyright (c) 2004, Hannu Saransaari and Lauri Hakkarainen
  13  * Copyright (c) 2005-2009 Brenden Matthews, Philip Kovacs, et. al.
  14  *      (see AUTHORS)
  15  * All rights reserved.
  16  *
  17  * This program is free software: you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation, either version 3 of the License, or
  20  * (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  28  *
  29  */
  30
  31 #define _GNU_SOURCE
  32 #include "common.h"
  33 #include "text_object.h"
  34 #include "logging.h"
  35 #include <sys/stat.h>
  36 #include <fcntl.h>
  37 #include <string.h>
  38 #include <unistd.h>
  39
  40 #define MAX_HEADTAIL_LINES 30
  41 #define DEFAULT_MAX_HEADTAIL_USES 2
  42
  43 struct headtail {
  44         int wantedlines;
  45         char *logfile;
  46         char *buffer;
  47         int current_use;
  48         int max_uses;
  49         int reported;
  50 };
  51
  52 static void tailstring(char *string, int endofstring, int wantedlines) {
  53         int i, linescounted = 0;
  54
  55         string[endofstring] = 0;
  56         if(endofstring > 0) {
  57                 if(string[endofstring-1] == '\n') {     //work with or without \n at end of file
  58                         string[endofstring-1] = 0;
  59                 }
  60                 for(i = endofstring - 1; i >= 0 && linescounted < wantedlines; i--) {
  61                         if(string[i] == '\n') {
  62                                 linescounted++;
  63                         }
  64                 }
  65                 if(i > 0) {
  66                         strfold(string, i+2);
  67                 }
  68         }
  69 }
  70
  71 void free_tailhead(struct text_object *obj)
  72 {
  73         struct headtail *ht = obj->data.opaque;
  74         if (!ht)
  75                 return;
  76         if (ht->logfile)
  77                 free(ht->logfile);
  78         if (ht->buffer)
  79                 free(ht->buffer);
  80         free(obj->data.opaque);
  81         obj->data.opaque = NULL;
  82 }
  83
  84 void init_tailhead(const char* type, const char* arg, struct text_object *obj, void* free_at_crash) {
  85         unsigned int args;
  86         struct headtail *ht;
  87
  88         ht = malloc(sizeof(struct headtail));
  89         memset(ht, 0, sizeof(struct headtail));
  90
  91         ht->logfile = malloc(DEFAULT_TEXT_BUFFER_SIZE);
  92         memset(ht->logfile, 0, DEFAULT_TEXT_BUFFER_SIZE);
  93
  94         ht->max_uses = DEFAULT_MAX_HEADTAIL_USES;
  95
  96         args = sscanf(arg, "%s %d %d", ht->logfile, &ht->wantedlines, &ht->max_uses);
  97         if (args < 2 || args > 3) {
  98                 free_tailhead(obj);
  99                 CRIT_ERR(obj, free_at_crash, "%s needs a file as 1st and a number of lines as 2nd argument", type);
 100         }
 101         if (ht->max_uses < 1) {
 102                 free_tailhead(obj);
 103                 CRIT_ERR(obj, free_at_crash, "invalid arg for %s, next_check must be larger than 0", type);
 104         }
 105         if (ht->wantedlines > 0 && ht->wantedlines <= MAX_HEADTAIL_LINES) {
 106                 to_real_path(ht->logfile, ht->logfile);
 107                 ht->buffer = NULL;
 108                 ht->current_use = 0;
 109         } else {
 110                 free_tailhead(obj);
 111                 CRIT_ERR(obj, free_at_crash, "invalid arg for %s, number of lines must be between 1 and %d", type, MAX_HEADTAIL_LINES);
 112         }
 113         obj->data.opaque = ht;
 114 }
 115
 116 void print_tailhead(const char* type, struct text_object *obj, char *p, int p_max_size) {
 117         int fd, i, endofstring = 0, linescounted = 0;
 118         FILE *fp;
 119         struct stat st;
 120         struct headtail *ht = obj->data.opaque;
 121
 122         if (!ht)
 123                 return;
 124
 125         //empty the buffer and reset the counter if we used it the max number of times
 126         if(ht->buffer && ht->current_use >= ht->max_uses - 1) {
 127                 free(ht->buffer);
 128                 ht->buffer = NULL;
 129                 ht->current_use = 0;
 130         }
 131         //use the buffer if possible
 132         if(ht->buffer) {
 133                 strcpy(p, ht->buffer);
 134                 ht->current_use++;
 135         }else{  //otherwise find the needed data
 136                 if(stat(ht->logfile, &st) == 0) {
 137                         if (S_ISFIFO(st.st_mode)) {
 138                                 fd = open_fifo(ht->logfile, &ht->reported);
 139                                 if(fd != -1) {
 140                                         if(strcmp(type, "head") == 0) {
 141                                                 for(i = 0; linescounted < ht->wantedlines; i++) {
 142                                                         read(fd, p + i, 1);
 143                                                         if(p[i] == '\n') {
 144                                                                 linescounted++;
 145                                                         }
 146                                                 }
 147                                                 p[i] = 0;
 148                                         } else if(strcmp(type, "tail") == 0) {
 149                                                 i = read(fd, p, p_max_size - 1);
 150                                                 tailstring(p, i, ht->wantedlines);
 151                                         } else {
 152                                                 CRIT_ERR(NULL, NULL, "If you are seeing this then there is a bug in the code, report it !");
 153                                         }
 154                                 }
 155                                 close(fd);
 156                         } else {
 157                                 fp = open_file(ht->logfile, &ht->reported);
 158                                 if(fp != NULL) {
 159                                         if(strcmp(type, "head") == 0) {
 160                                                 for(i = 0; i < ht->wantedlines; i++) {
 161                                                         fgets(p + endofstring, p_max_size - endofstring, fp);
 162                                                         endofstring = strlen(p);
 163                                                 }
 164                                         } else if(strcmp(type, "tail") == 0) {
 165                                                 fseek(fp, - p_max_size, SEEK_END);
 166                                                 i = fread(p, 1, p_max_size - 1, fp);
 167                                                 tailstring(p, i, ht->wantedlines);
 168                                         } else {
 169                                                 CRIT_ERR(NULL, NULL, "If you are seeing this then there is a bug in the code, report it !");
 170                                         }
 171                                         fclose(fp);
 172                                 }
 173                         }
 174                         ht->buffer = strdup(p);
 175                 } else {
 176                         CRIT_ERR(NULL, NULL, "$%s can't find information about %s", type, ht->logfile);
 177                 }
 178         }
 179         return;
 180 }