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