citadel/dynloader.c

   1 /*******************************************************
   2  *
   3  * Citadel Dynamic Loading Module
   4  * Written by Brian Costello
   5  * btx@calyx.net
   6  *
   7  ******************************************************/
   8
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <dlfcn.h>
  13 #include <sys/types.h>
  14 #include <dirent.h>
  15 #include <strings.h>
  16 #include <syslog.h>
  17 #include "dynloader.h"
  18
  19 symtab *global_symtab;
  20
  21 int DLoader_Exec_Cmd(char *cmdbuf)
  22 {
  23    symtab *t_sym;
  24    void *fcn_handle;
  25    char *dl_error;
  26    void (*cmd_ptr)(void *);
  27
  28    for (t_sym = global_symtab; ((t_sym) && (strncmp(t_sym->server_cmd, cmdbuf, strlen(t_sym->server_cmd))) ); t_sym=t_sym->next)
  29       ;
  30
  31    if (t_sym)
  32    {
  33       if (!(fcn_handle = dlopen(t_sym->module_path, RTLD_LAZY)))
  34       {
  35          dl_error = dlerror();
  36          syslog(LOG_NOTICE, "WARNING: module %s failed to load", t_sym->module_path);
  37          return(0);
  38       }
  39
  40       cmd_ptr = dlsym(fcn_handle, t_sym->fcn_name);
  41       if ((dl_error = dlerror()) != NULL)
  42       {
  43          syslog(LOG_NOTICE, "dlsym error: %s - %s", dl_error, t_sym->module_path);
  44          return(0);
  45       }
  46       (*cmd_ptr)(&cmdbuf[5]);
  47       dlclose(fcn_handle);
  48       if ((dl_error = dlerror()) != NULL)
  49       {
  50          syslog(LOG_NOTICE, "dlclose error: %s", dl_error);
  51          return(0);
  52       }
  53       return(1);
  54    }  /* If symbol found */
  55
  56    return(0);
  57 }
  58
  59 void add_symbol(char *fcn_name, char *server_cmd, char *info_msg, symtab **first_symtab)
  60 {
  61    symtab *new_symtab, *t_sym, *last_sym;
  62
  63    if (!(new_symtab = malloc(sizeof(symtab))))
  64    {
  65       perror("Malloc new symtab");
  66       exit(1);
  67    }
  68
  69    new_symtab->fcn_name = strdup(fcn_name);
  70    new_symtab->server_cmd = strdup(server_cmd);
  71    new_symtab->info_msg = strdup(info_msg);
  72    new_symtab->next = NULL;
  73
  74    if (!(*first_symtab))
  75       (*first_symtab) = new_symtab;
  76    else
  77    {
  78       last_sym = NULL;
  79       for (t_sym = (*first_symtab); (t_sym); t_sym = t_sym->next)
  80          last_sym = t_sym;
  81       last_sym->next = new_symtab;
  82    }
  83 }
  84
  85 void DLoader_Init(char *pathname, symtab **my_symtab)
  86 {
  87    void *fcn_handle;
  88    void (*h_init_fcn)(struct DLModule_Info *);
  89    void (*h_get_symtab)(symtab **);
  90    char *dl_error;
  91    char *filename;
  92    DIR *dir;
  93    struct dirent *dptr;
  94
  95    char pathbuf[512];
  96    struct DLModule_Info dl_info;
  97    symtab *stab = NULL;
  98    symtab *t_sym;
  99
 100    global_symtab = NULL;                        /* Global symbol table */
 101
 102    if ((dir = opendir(pathname))==NULL)
 103    {
 104       perror("opendir");
 105       exit(1);
 106    }
 107
 108    while ((dptr=readdir(dir))!= NULL)
 109    {
 110       if (dptr->d_name[0] == '.')
 111          continue;
 112
 113       filename = strdup(dptr->d_name);
 114       snprintf(pathbuf, 512, "%s/%s", pathname, filename);
 115       if (!(fcn_handle = dlopen(pathbuf, RTLD_LAZY)))
 116       {
 117          dl_error = dlerror();
 118          fprintf(stderr, "DLoader_Init dlopen failed (%s)", dl_error);
 119          continue;
 120       }
 121
 122       h_init_fcn = dlsym(fcn_handle, "Dynamic_Module_Init");
 123       if ((dl_error = dlerror()) != NULL)
 124       {
 125          fprintf(stderr,"DLoader_Init dlsym failed (%s)", dl_error);
 126          continue;
 127       }
 128
 129       (*h_init_fcn)(&dl_info);
 130
 131       printf("Loaded module %s v%d.%d\nBy %s (%s)\n", dl_info.module_name,
 132                                                      dl_info.major_version,
 133                                                      dl_info.minor_version,
 134                                                      dl_info.module_author,
 135                                                      dl_info.module_author_email);
 136
 137       h_get_symtab = dlsym(fcn_handle, "Get_Symtab");
 138       if ((dl_error = dlerror()) != NULL)
 139       {
 140          fprintf(stderr,"DLoader_Init dlsym failed for Get_Symtab (%s) on module %s", dl_error, dl_info.module_name);
 141          continue;
 142       }
 143
 144 /* Get the symbol table for the current module and link it on */
 145
 146       (*h_get_symtab)(&stab);
 147       if (!(*my_symtab))
 148       {
 149          (*my_symtab) = global_symtab = stab;
 150       }
 151       else
 152       {
 153          for (t_sym = (*my_symtab) ; t_sym->next; t_sym=t_sym->next);
 154             ;
 155          t_sym->next = stab;
 156       }
 157       for (t_sym = stab; t_sym; t_sym=t_sym->next)
 158          t_sym->module_path = (char *)strdup(pathbuf);
 159       dlclose(fcn_handle);
 160       if ((dl_error = dlerror()) != NULL)
 161       {
 162          fprintf(stderr,"DLoader_Init dlclose failed (%s)", dl_error);
 163          continue;
 164       }
 165
 166    }    /* While */
 167
 168 }
 169