vcs.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 #include "text_object.h"
  32 #include "logging.h"
  33 #include <sys/stat.h>
  34 #include <fcntl.h>
  35 #include <unistd.h>
  36
  37 #define MAX_HEADTAIL_LINES 30
  38 #define DEFAULT_MAX_HEADTAIL_USES 2
  39
  40 struct headtail {
  41         int wantedlines;
  42         char *logfile;
  43         char *buffer;
  44         int current_use;
  45         int max_uses;
  46         int reported;
  47 };
  48
  49 static void tailstring(char *string, int endofstring, int wantedlines) {
  50         int i, linescounted = 0;
  51
  52         string[endofstring] = 0;
  53         if(endofstring > 0) {
  54                 if(string[endofstring-1] == '\n') {     //work with or without \n at end of file
  55                         string[endofstring-1] = 0;
  56                 }
  57                 for(i = endofstring - 1; i >= 0 && linescounted < wantedlines; i--) {
  58                         if(string[i] == '\n') {
  59                                 linescounted++;
  60                         }
  61                 }
  62                 if(i > 0) {
  63                         strfold(string, i+2);
  64                 }
  65         }
  66 }
  67
  68 void free_tailhead(struct text_object *obj)
  69 {
  70         struct headtail *ht = obj->data.opaque;
  71         if (!ht)
  72                 return;
  73         if (ht->logfile)
  74                 free(ht->logfile);
  75         if (ht->buffer)
  76                 free(ht->buffer);
  77         free(obj->data.opaque);
  78         obj->data.opaque = NULL;
  79 }
  80
  81 void init_tailhead(const char* type, const char* arg, struct text_object *obj, void* free_at_crash) {
  82         unsigned int args;
  83         struct headtail *ht;
  84
  85         ht = malloc(sizeof(struct headtail));
  86         memset(ht, 0, sizeof(struct headtail));
  87
  88         ht->logfile = malloc(DEFAULT_TEXT_BUFFER_SIZE);
  89         memset(ht->logfile, 0, DEFAULT_TEXT_BUFFER_SIZE);
  90
  91         ht->max_uses = DEFAULT_MAX_HEADTAIL_USES;
  92
  93         args = sscanf(arg, "%s %d %d", ht->logfile, &ht->wantedlines, &ht->max_uses);
  94         if (args < 2 || args > 3) {
  95                 free_tailhead(obj);
  96                 CRIT_ERR(obj, free_at_crash, "%s needs a file as 1st and a number of lines as 2nd argument", type);
  97         }
  98         if (ht->max_uses < 1) {
  99                 free_tailhead(obj);
 100                 CRIT_ERR(obj, free_at_crash, "invalid arg for %s, next_check must be larger than 0", type);
 101         }
 102         if (ht->wantedlines > 0 && ht->wantedlines <= MAX_HEADTAIL_LINES) {
 103                 to_real_path(ht->logfile, ht->logfile);
 104                 ht->buffer = NULL;
 105                 ht->current_use = 0;
 106         } else {
 107                 free_tailhead(obj);
 108                 CRIT_ERR(obj, free_at_crash, "invalid arg for %s, number of lines must be between 1 and %d", type, MAX_HEADTAIL_LINES);
 109         }
 110         obj->data.opaque = ht;
 111 }
 112
 113 void print_tailhead(const char* type, struct text_object *obj, char *p, int p_max_size) {
 114         int fd, i, endofstring = 0, linescounted = 0;
 115         FILE *fp;
 116         struct stat st;
 117         struct headtail *ht = obj->data.opaque;
 118
 119         if (!ht)
 120                 return;
 121
 122         //empty the buffer and reset the counter if we used it the max number of times
 123         if(ht->buffer && ht->current_use >= ht->max_uses - 1) {
 124                 free(ht->buffer);
 125                 ht->buffer = NULL;
 126                 ht->current_use = 0;
 127         }
 128         //use the buffer if possible
 129         if(ht->buffer) {
 130                 strcpy(p, ht->buffer);
 131                 ht->current_use++;
 132         }else{  //otherwise find the needed data
 133                 if(stat(ht->logfile, &st) == 0) {
 134                         if (S_ISFIFO(st.st_mode)) {
 135                                 fd = open_fifo(ht->logfile, &ht->reported);
 136                                 if(fd != -1) {
 137                                         if(strcmp(type, "head") == 0) {
 138                                                 for(i = 0; linescounted < ht->wantedlines; i++) {
 139                                                         read(fd, p + i, 1);
 140                                                         if(p[i] == '\n') {
 141                                                                 linescounted++;
 142                                                         }
 143                                                 }
 144                                                 p[i] = 0;
 145                                         } else if(strcmp(type, "tail") == 0) {
 146                                                 i = read(fd, p, p_max_size - 1);
 147                                                 tailstring(p, i, ht->wantedlines);
 148                                         } else {
 149                                                 CRIT_ERR(NULL, NULL, "If you are seeing this then there is a bug in the code, report it !");
 150                                         }
 151                                 }
 152                                 close(fd);
 153                         } else {
 154                                 fp = open_file(ht->logfile, &ht->reported);
 155                                 if(fp != NULL) {
 156                                         if(strcmp(type, "head") == 0) {
 157                                                 for(i = 0; i < ht->wantedlines; i++) {
 158                                                         fgets(p + endofstring, p_max_size - endofstring, fp);
 159                                                         endofstring = strlen(p);
 160                                                 }
 161                                         } else if(strcmp(type, "tail") == 0) {
 162                                                 fseek(fp, - p_max_size, SEEK_END);
 163                                                 i = fread(p, 1, p_max_size - 1, fp);
 164                                                 tailstring(p, i, ht->wantedlines);
 165                                         } else {
 166                                                 CRIT_ERR(NULL, NULL, "If you are seeing this then there is a bug in the code, report it !");
 167                                         }
 168                                         fclose(fp);
 169                                 }
 170                         }
 171                         ht->buffer = strdup(p);
 172                 } else {
 173                         CRIT_ERR(NULL, NULL, "$%s can't find information about %s", type, ht->logfile);
 174                 }
 175         }
 176         return;
 177 }