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1 | /* This file is part of the Linux Trace Toolkit viewer |
2 | * Copyright (C) 2003-2004 Michel Dagenais |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify |
5 | * it under the terms of the GNU General Public License Version 2 as |
6 | * published by the Free Software Foundation; |
7 | * |
8 | * This program is distributed in the hope that it will be useful, |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
11 | * GNU General Public License for more details. |
12 | * |
13 | * You should have received a copy of the GNU General Public License |
14 | * along with this program; if not, write to the Free Software |
15 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
16 | * MA 02111-1307, USA. |
17 | */ |
18 | |
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19 | |
20 | /* module.c : Implementation of the module loading/unloading mechanism. |
21 | * |
22 | */ |
23 | |
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24 | #include <lttv/module.h> |
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25 | |
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26 | #define g_info(format...) g_log (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, format) |
27 | #define g_debug(format...) g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, format) |
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28 | |
29 | struct _LttvModule |
30 | { |
31 | GModule *module; |
32 | guint ref_count; |
33 | guint load_count; |
34 | GPtrArray *dependents; |
35 | }; |
36 | |
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37 | |
38 | /* Table of loaded modules and paths where to search for modules */ |
39 | |
40 | static GHashTable *modules = NULL; |
41 | |
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42 | static GPtrArray *modulesPaths = NULL; |
43 | |
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44 | static void lttv_module_unload_all(); |
45 | |
46 | |
47 | void lttv_module_init(int argc, char **argv) |
48 | { |
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49 | g_info("Init module.c"); |
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50 | modules = g_hash_table_new(g_str_hash, g_str_equal); |
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51 | modulesPaths = g_ptr_array_new(); |
52 | } |
53 | |
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54 | |
55 | void lttv_module_destroy() |
56 | { |
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57 | int i; |
58 | |
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59 | g_info("Destroy module.c"); |
60 | |
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61 | /* Unload all modules */ |
62 | lttv_module_unload_all(); |
63 | |
64 | /* Free the modules paths pointer array as well as the elements */ |
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65 | for(i = 0; i < modulesPaths->len ; i++) { |
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66 | g_free(modulesPaths->pdata[i]); |
67 | } |
68 | g_ptr_array_free(modulesPaths,TRUE) ; |
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69 | modulesPaths = NULL; |
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70 | |
71 | /* destroy the hash table */ |
72 | g_hash_table_destroy(modules) ; |
73 | modules = NULL; |
74 | } |
75 | |
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76 | |
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77 | /* Add a new pathname to the modules loading search path */ |
78 | |
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79 | void lttv_module_path_add(const char *name) |
80 | { |
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81 | g_info("Add module path %s", name); |
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82 | g_ptr_array_add(modulesPaths,(char*)g_strdup(name)); |
83 | } |
84 | |
85 | |
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86 | static LttvModule * |
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87 | module_load(const char *name, int argc, char **argv) |
88 | { |
89 | GModule *gm; |
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90 | |
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91 | LttvModule *m; |
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92 | |
93 | int i; |
94 | |
95 | char *pathname; |
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96 | |
97 | const char *module_name; |
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98 | |
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99 | LttvModuleInit init_function; |
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100 | |
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101 | g_info("Load module %s", name); |
102 | |
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103 | /* Try to find the module along all the user specified paths */ |
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104 | |
105 | for(i = 0 ; i < modulesPaths->len ; i++) { |
106 | pathname = g_module_build_path(modulesPaths->pdata[i],name); |
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107 | g_info("Try path %s", pathname); |
108 | gm = g_module_open(pathname,0); |
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109 | g_free(pathname); |
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110 | |
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111 | if(gm != NULL) break; |
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112 | g_info("Trial failed, %s", g_module_error()); |
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113 | } |
114 | |
115 | /* Try the default system path */ |
116 | |
117 | if(gm == NULL) { |
118 | pathname = g_module_build_path(NULL,name); |
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119 | g_info("Try default path"); |
120 | gm = g_module_open(pathname,0); |
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121 | g_free(pathname); |
122 | } |
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123 | |
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124 | /* Module cannot be found */ |
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125 | if(gm == NULL) { |
126 | g_info("Trial failed, %s", g_module_error()); |
127 | g_info("Failed to load %s", name); |
128 | return NULL; |
129 | } |
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130 | |
131 | /* Check if the module was already opened using the hopefully canonical name |
132 | returned by g_module_name. */ |
133 | |
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134 | module_name = g_module_name(gm); |
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135 | |
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136 | m = g_hash_table_lookup(modules, module_name); |
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137 | |
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138 | if(m == NULL) { |
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139 | g_info("Module %s (%s) loaded, call its init function", name, module_name); |
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140 | |
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141 | /* Module loaded for the first time. Insert it in the table and call the |
142 | init function if any. */ |
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143 | |
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144 | m = g_new(LttvModule, 1); |
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145 | m->module = gm; |
146 | m->ref_count = 0; |
147 | m->load_count = 0; |
148 | m->dependents = g_ptr_array_new(); |
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149 | g_hash_table_insert(modules, (gpointer)module_name, m); |
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150 | |
151 | if(!g_module_symbol(gm, "init", (gpointer)&init_function)) { |
152 | g_warning("module %s (%s) has no init function", name, pathname); |
153 | } |
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154 | else init_function(m, argc, argv); |
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155 | } |
156 | else { |
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157 | |
158 | /* Module was already opened, check that it really is the same and |
159 | undo the extra g_module_open */ |
160 | |
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161 | g_info("Module %s (%s) was already loaded, no need to call init function", |
162 | name, module_name); |
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163 | if(m->module != gm) g_error("Two gmodules with the same pathname"); |
164 | g_module_close(gm); |
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165 | } |
166 | |
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167 | m->ref_count++; |
168 | return m; |
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169 | } |
170 | |
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171 | |
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172 | LttvModule * |
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173 | lttv_module_load(const char *name, int argc, char **argv) |
174 | { |
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175 | g_info("Load module %s explicitly", name); |
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176 | LttvModule *m = module_load(name, argc, argv); |
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177 | if(m != NULL) m->load_count++; |
178 | return m; |
179 | } |
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180 | |
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181 | |
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182 | LttvModule * |
183 | lttv_module_require(LttvModule *m, const char *name, int argc, char **argv) |
184 | { |
185 | LttvModule *module; |
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186 | |
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187 | g_info("Load module %s, as %s is a dependent requiring it", name, |
188 | g_module_name(m->module)); |
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189 | module = module_load(name, argc, argv); |
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190 | if(module != NULL) g_ptr_array_add(module->dependents, m); |
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191 | return module; |
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192 | } |
193 | |
194 | |
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195 | static void module_unload(LttvModule *m) |
196 | { |
197 | LttvModuleDestroy destroy_function; |
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198 | |
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199 | char *pathname; |
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200 | |
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201 | guint i, len; |
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202 | |
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203 | /* Decrement the reference count */ |
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204 | |
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205 | g_info("Unload module %s", g_module_name(m->module)); |
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206 | m->ref_count--; |
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207 | if(m->ref_count > 0) { |
208 | g_info("Module usage count decremented to %d", m->ref_count); |
209 | return; |
210 | } |
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211 | /* We really have to unload the module, first unload its dependents */ |
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212 | |
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213 | len = m->dependents->len; |
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214 | g_info("Unload dependent modules"); |
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215 | |
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216 | for(i = 0 ; i < len ; i++) { |
217 | module_unload(m->dependents->pdata[i]); |
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218 | } |
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219 | |
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220 | if(len != m->dependents->len) g_error("dependents list modified"); |
221 | |
222 | /* Unload the module itself */ |
223 | |
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224 | g_info("Call the destroy function and unload the module"); |
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225 | if(!g_module_symbol(m->module, "destroy", (gpointer)&destroy_function)) { |
226 | g_warning("module (%s) has no destroy function", pathname); |
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227 | } |
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228 | else destroy_function(); |
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229 | |
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230 | g_hash_table_remove(modules, g_module_name(m->module)); |
231 | g_ptr_array_free(m->dependents, TRUE); |
232 | g_module_close(m->module); |
233 | g_free(m); |
234 | } |
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235 | |
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236 | |
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237 | void lttv_module_unload(LttvModule *m) |
238 | { |
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239 | g_info("Explicitly unload module %s", g_module_name(m->module)); |
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240 | if(m->load_count <= 0) { |
241 | g_error("more unload than load (%s)", g_module_name(m->module)); |
242 | return; |
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243 | } |
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244 | m->load_count--; |
245 | module_unload(m); |
246 | } |
247 | |
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248 | |
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249 | static void |
250 | list_modules(gpointer key, gpointer value, gpointer user_data) |
251 | { |
252 | g_ptr_array_add((GPtrArray *)user_data, value); |
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253 | } |
254 | |
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255 | |
256 | LttvModule ** |
257 | lttv_module_list(guint *nb) |
258 | { |
259 | GPtrArray *list = g_ptr_array_new(); |
260 | |
261 | LttvModule **array; |
262 | |
263 | g_hash_table_foreach(modules, list_modules, list); |
264 | *nb = list->len; |
265 | array = (LttvModule **)list->pdata; |
266 | g_ptr_array_free(list, FALSE); |
267 | return array; |
268 | } |
269 | |
270 | |
271 | LttvModule ** |
272 | lttv_module_info(LttvModule *m, const char **name, |
273 | guint *ref_count, guint *load_count, guint *nb_dependents) |
274 | { |
275 | guint i, len = m->dependents->len; |
276 | |
277 | LttvModule **array = g_new(LttvModule *, len); |
278 | |
279 | *name = g_module_name(m->module); |
280 | *ref_count = m->ref_count; |
281 | *load_count = m->load_count; |
282 | *nb_dependents = len; |
283 | for(i = 0 ; i < len ; i++) array[i] = m->dependents->pdata[i]; |
284 | return array; |
285 | } |
286 | |
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287 | char * |
288 | lttv_module_name(LttvModule *m) |
289 | { |
290 | return g_module_name(m->module); |
291 | } |
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292 | |
293 | static void |
294 | list_independent(gpointer key, gpointer value, gpointer user_data) |
295 | { |
296 | LttvModule *m = (LttvModule *)value; |
297 | |
298 | if(m->load_count > 0) g_ptr_array_add((GPtrArray *)user_data, m); |
299 | } |
300 | |
301 | |
302 | void |
303 | lttv_module_unload_all() |
304 | { |
305 | guint i; |
306 | |
307 | LttvModule *m; |
308 | |
309 | GPtrArray *independent_modules = g_ptr_array_new(); |
310 | |
311 | g_hash_table_foreach(modules, list_independent, independent_modules); |
312 | |
313 | for(i = 0 ; i < independent_modules->len ; i++) { |
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314 | m = (LttvModule *)independent_modules->pdata[i]; |
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315 | while(m->load_count > 0) lttv_module_unload(m); |
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316 | } |
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317 | |
318 | g_ptr_array_free(independent_modules, TRUE); |
319 | if(g_hash_table_size(modules) != 0) g_warning("cannot unload all modules"); |
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320 | } |