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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 | struct _LttvModule |
27 | { |
28 | GModule *module; |
29 | guint ref_count; |
30 | guint load_count; |
31 | GPtrArray *dependents; |
32 | }; |
33 | |
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34 | |
35 | /* Table of loaded modules and paths where to search for modules */ |
36 | |
37 | static GHashTable *modules = NULL; |
38 | |
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39 | static GPtrArray *modulesPaths = NULL; |
40 | |
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41 | static void lttv_module_unload_all(); |
42 | |
43 | |
44 | void lttv_module_init(int argc, char **argv) |
45 | { |
2a2fa4f0 |
46 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Init module.c"); |
eccb5352 |
47 | modules = g_hash_table_new(g_str_hash, g_str_equal); |
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48 | modulesPaths = g_ptr_array_new(); |
49 | } |
50 | |
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51 | |
52 | void lttv_module_destroy() |
53 | { |
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54 | int i; |
55 | |
2a2fa4f0 |
56 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Destroy module.c"); |
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57 | |
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58 | /* Unload all modules */ |
59 | lttv_module_unload_all(); |
60 | |
61 | /* Free the modules paths pointer array as well as the elements */ |
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62 | for(i = 0; i < modulesPaths->len ; i++) { |
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63 | g_free(modulesPaths->pdata[i]); |
64 | } |
65 | g_ptr_array_free(modulesPaths,TRUE) ; |
eccb5352 |
66 | modulesPaths = NULL; |
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67 | |
68 | /* destroy the hash table */ |
69 | g_hash_table_destroy(modules) ; |
70 | modules = NULL; |
71 | } |
72 | |
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73 | |
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74 | /* Add a new pathname to the modules loading search path */ |
75 | |
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76 | void lttv_module_path_add(const char *name) |
77 | { |
2a2fa4f0 |
78 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Add module path %s", name); |
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79 | g_ptr_array_add(modulesPaths,(char*)g_strdup(name)); |
80 | } |
81 | |
82 | |
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83 | static LttvModule * |
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84 | module_load(const char *name, int argc, char **argv) |
85 | { |
86 | GModule *gm; |
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87 | |
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88 | LttvModule *m; |
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89 | |
90 | int i; |
91 | |
92 | char *pathname; |
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93 | |
94 | const char *module_name; |
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95 | |
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96 | LttvModuleInit init_function; |
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97 | |
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98 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load module %s", name); |
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99 | |
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100 | /* Try to find the module along all the user specified paths */ |
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101 | |
102 | for(i = 0 ; i < modulesPaths->len ; i++) { |
103 | pathname = g_module_build_path(modulesPaths->pdata[i],name); |
2a2fa4f0 |
104 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, "Try path %s", pathname); |
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105 | gm = g_module_open(pathname,0); |
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106 | g_free(pathname); |
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107 | |
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108 | if(gm != NULL) break; |
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109 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,"Trial failed, %s",g_module_error()); |
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110 | } |
111 | |
112 | /* Try the default system path */ |
113 | |
114 | if(gm == NULL) { |
115 | pathname = g_module_build_path(NULL,name); |
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116 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, "Try default path"); |
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117 | gm = g_module_open(pathname,0); |
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118 | g_free(pathname); |
119 | } |
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120 | |
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121 | /* Module cannot be found */ |
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122 | if(gm == NULL) { |
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123 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,"Trial failed, %s",g_module_error()); |
124 | g_warning("Failed to load module %s", name); |
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125 | return NULL; |
126 | } |
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127 | |
128 | /* Check if the module was already opened using the hopefully canonical name |
129 | returned by g_module_name. */ |
130 | |
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131 | module_name = g_module_name(gm); |
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132 | |
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133 | m = g_hash_table_lookup(modules, module_name); |
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134 | |
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135 | if(m == NULL) { |
2a2fa4f0 |
136 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, |
137 | "Module %s (%s) loaded, call its init function", name, module_name); |
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138 | |
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139 | /* Module loaded for the first time. Insert it in the table and call the |
140 | init function if any. */ |
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141 | |
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142 | m = g_new(LttvModule, 1); |
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143 | m->module = gm; |
144 | m->ref_count = 0; |
145 | m->load_count = 0; |
146 | m->dependents = g_ptr_array_new(); |
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147 | g_hash_table_insert(modules, (gpointer)module_name, m); |
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148 | |
149 | if(!g_module_symbol(gm, "init", (gpointer)&init_function)) { |
150 | g_warning("module %s (%s) has no init function", name, pathname); |
151 | } |
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152 | else init_function(m, argc, argv); |
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153 | } |
154 | else { |
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155 | |
156 | /* Module was already opened, check that it really is the same and |
157 | undo the extra g_module_open */ |
158 | |
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159 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, |
160 | "Module %s (%s) was already loaded, no need to call init function", |
161 | name, module_name); |
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162 | if(m->module != gm) g_error("Two gmodules with the same pathname"); |
163 | g_module_close(gm); |
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164 | } |
165 | |
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166 | m->ref_count++; |
167 | return m; |
eccb5352 |
168 | } |
169 | |
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170 | |
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171 | LttvModule * |
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172 | lttv_module_load(const char *name, int argc, char **argv) |
173 | { |
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174 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Load module %s explicitly", name); |
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175 | LttvModule *m = module_load(name, argc, argv); |
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176 | if(m != NULL) m->load_count++; |
177 | return m; |
178 | } |
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179 | |
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180 | |
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181 | LttvModule * |
182 | lttv_module_require(LttvModule *m, const char *name, int argc, char **argv) |
183 | { |
184 | LttvModule *module; |
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185 | |
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186 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, |
187 | "Load module %s, as %s is a dependent requiring it", name, |
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188 | g_module_name(m->module)); |
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189 | module = module_load(name, argc, argv); |
dbb7bb09 |
190 | if(module != NULL) g_ptr_array_add(m->dependents, module); |
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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_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload module %s", |
206 | g_module_name(m->module)); |
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207 | m->ref_count--; |
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208 | if(m->ref_count > 0) { |
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209 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, |
210 | "Module usage count decremented to %d", m->ref_count); |
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211 | return; |
212 | } |
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213 | |
214 | /* We really have to unload the module. First destroy it. */ |
215 | |
216 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, |
217 | "Call the destroy function and unload the module"); |
218 | if(!g_module_symbol(m->module, "destroy", (gpointer)&destroy_function)) { |
219 | g_warning("module (%s) has no destroy function", pathname); |
220 | } |
221 | else destroy_function(); |
222 | |
223 | /* Then release the modules required by this module */ |
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224 | |
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225 | len = m->dependents->len; |
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226 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Unload dependent modules"); |
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227 | |
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228 | for(i = 0 ; i < len ; i++) { |
229 | module_unload(m->dependents->pdata[i]); |
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230 | } |
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231 | |
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232 | if(len != m->dependents->len) g_error("dependents list modified"); |
233 | |
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234 | /* Finally remove any trace of this module */ |
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235 | |
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236 | g_hash_table_remove(modules, g_module_name(m->module)); |
237 | g_ptr_array_free(m->dependents, TRUE); |
238 | g_module_close(m->module); |
239 | g_free(m); |
240 | } |
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241 | |
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242 | |
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243 | void lttv_module_unload(LttvModule *m) |
244 | { |
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245 | g_log(G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "Explicitly unload module %s", |
246 | g_module_name(m->module)); |
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247 | if(m->load_count <= 0) { |
248 | g_error("more unload than load (%s)", g_module_name(m->module)); |
249 | return; |
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250 | } |
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251 | m->load_count--; |
252 | module_unload(m); |
253 | } |
254 | |
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255 | |
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256 | static void |
257 | list_modules(gpointer key, gpointer value, gpointer user_data) |
258 | { |
259 | g_ptr_array_add((GPtrArray *)user_data, value); |
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260 | } |
261 | |
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262 | |
263 | LttvModule ** |
264 | lttv_module_list(guint *nb) |
265 | { |
266 | GPtrArray *list = g_ptr_array_new(); |
267 | |
268 | LttvModule **array; |
269 | |
270 | g_hash_table_foreach(modules, list_modules, list); |
271 | *nb = list->len; |
272 | array = (LttvModule **)list->pdata; |
273 | g_ptr_array_free(list, FALSE); |
274 | return array; |
275 | } |
276 | |
277 | |
278 | LttvModule ** |
279 | lttv_module_info(LttvModule *m, const char **name, |
280 | guint *ref_count, guint *load_count, guint *nb_dependents) |
281 | { |
282 | guint i, len = m->dependents->len; |
283 | |
284 | LttvModule **array = g_new(LttvModule *, len); |
285 | |
286 | *name = g_module_name(m->module); |
287 | *ref_count = m->ref_count; |
288 | *load_count = m->load_count; |
289 | *nb_dependents = len; |
290 | for(i = 0 ; i < len ; i++) array[i] = m->dependents->pdata[i]; |
291 | return array; |
292 | } |
293 | |
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294 | char * |
295 | lttv_module_name(LttvModule *m) |
296 | { |
297 | return g_module_name(m->module); |
298 | } |
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299 | |
300 | static void |
301 | list_independent(gpointer key, gpointer value, gpointer user_data) |
302 | { |
303 | LttvModule *m = (LttvModule *)value; |
304 | |
305 | if(m->load_count > 0) g_ptr_array_add((GPtrArray *)user_data, m); |
306 | } |
307 | |
308 | |
309 | void |
310 | lttv_module_unload_all() |
311 | { |
312 | guint i; |
313 | |
314 | LttvModule *m; |
315 | |
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316 | GPtrArray *independent_modules; |
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317 | |
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318 | while(g_hash_table_size(modules) != 0) { |
319 | independent_modules = g_ptr_array_new(); |
320 | g_hash_table_foreach(modules, list_independent, independent_modules); |
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321 | |
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322 | for(i = 0 ; i < independent_modules->len ; i++) { |
323 | m = (LttvModule *)independent_modules->pdata[i]; |
324 | lttv_module_unload(m); |
325 | } |
326 | g_ptr_array_free(independent_modules, TRUE); |
eccb5352 |
327 | } |
eccb5352 |
328 | } |