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68270f0f JRJ |
1 | /* |
2 | * Copyright (C) 2014 - Jonathan Rajotte <jonathan.r.julien@gmail.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License, version 2 only, as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
15 | */ | |
16 | ||
17 | /* | |
71f82f2b | 18 | * Usage: extract_xml [-v|-e] xml_path xpath_expression |
68270f0f JRJ |
19 | * Evaluate XPath expression and prints result node set. |
20 | * args[1] path to the xml file | |
21 | * args[2] xpath expression to extract | |
71f82f2b | 22 | * If -e look if node exist return "true" else nothing |
68270f0f JRJ |
23 | * If -v is set the name of the node will appear with his value delimited by |
24 | * a semicolon(;) | |
25 | * Ex: | |
26 | * Command:extract_xml ../file.xml /test/node/text() | |
27 | * Output: | |
28 | * a | |
29 | * b | |
30 | * c | |
31 | * With -v | |
32 | * node;a; | |
33 | * node;b; | |
34 | * node;c; | |
35 | */ | |
83d6d6c4 JR |
36 | #include <assert.h> |
37 | #include <stdbool.h> | |
68270f0f | 38 | #include <stdio.h> |
83d6d6c4 | 39 | #include <stdlib.h> |
68270f0f | 40 | #include <string.h> |
68270f0f JRJ |
41 | #include <unistd.h> |
42 | ||
43 | #include <libxml/tree.h> | |
44 | #include <libxml/parser.h> | |
45 | #include <libxml/xpath.h> | |
46 | #include <libxml/xpathInternals.h> | |
41af1adf | 47 | #include <common/defaults.h> |
68270f0f JRJ |
48 | |
49 | #if defined(LIBXML_XPATH_ENABLED) | |
50 | ||
83d6d6c4 JR |
51 | static int opt_verbose; |
52 | static int node_exist; | |
53 | static bool result = false; | |
71f82f2b | 54 | |
68270f0f JRJ |
55 | /** |
56 | * print_xpath_nodes: | |
57 | * nodes: the nodes set. | |
58 | * output: the output file handle. | |
59 | * | |
60 | * Print the node content to the file | |
61 | */ | |
62 | static int print_xpath_nodes(xmlDocPtr doc, xmlNodeSetPtr nodes, FILE *output) | |
63 | { | |
71f82f2b | 64 | int ret = 0; |
68270f0f JRJ |
65 | int size; |
66 | int i; | |
67 | ||
68 | xmlNodePtr cur; | |
69 | xmlChar *node_child_value_string = NULL; | |
70 | ||
71 | assert(output); | |
72 | size = (nodes) ? nodes->nodeNr : 0; | |
73 | ||
74 | for (i = 0; i < size; ++i) { | |
75 | assert(nodes->nodeTab[i]); | |
76 | ||
77 | if (nodes->nodeTab[i]->type == XML_NAMESPACE_DECL) { | |
78 | fprintf(stderr, "ERR:%s\n", | |
79 | "This executable does not support xml namespacing\n"); | |
80 | ret = -1; | |
81 | goto end; | |
82 | } else if (nodes->nodeTab[i]->type == XML_ELEMENT_NODE) { | |
83 | cur = nodes->nodeTab[i]; | |
84 | ||
85 | if (xmlChildElementCount(cur) == 0) { | |
86 | if (xmlNodeIsText(cur->children)) { | |
87 | node_child_value_string = xmlNodeListGetString(doc, | |
88 | cur->children, 1); | |
71f82f2b | 89 | if (node_exist) { |
83d6d6c4 | 90 | result = true; |
71f82f2b | 91 | } else if (opt_verbose) { |
68270f0f JRJ |
92 | fprintf(output, "%s;%s;\n", cur->name, |
93 | node_child_value_string); | |
94 | } else { | |
95 | fprintf(output, "%s\n", | |
96 | node_child_value_string); | |
97 | } | |
98 | xmlFree(node_child_value_string); | |
71f82f2b JR |
99 | } else { |
100 | /* We don't want to print non-final element */ | |
101 | if (node_exist) { | |
83d6d6c4 | 102 | result = true; |
71f82f2b JR |
103 | } else { |
104 | fprintf(stderr, "ERR:%s\n", | |
105 | "Xpath expression return non-final xml element"); | |
106 | ret = -1; | |
107 | goto end; | |
108 | } | |
109 | } | |
110 | } else { | |
111 | if (node_exist) { | |
83d6d6c4 | 112 | result = true; |
68270f0f JRJ |
113 | } else { |
114 | /* We don't want to print non-final element */ | |
115 | fprintf(stderr, "ERR:%s\n", | |
116 | "Xpath expression return non-final xml element"); | |
117 | ret = -1; | |
118 | goto end; | |
119 | } | |
68270f0f JRJ |
120 | } |
121 | ||
122 | } else { | |
123 | cur = nodes->nodeTab[i]; | |
71f82f2b | 124 | if (node_exist) { |
83d6d6c4 | 125 | result = true; |
71f82f2b | 126 | } else if (opt_verbose) { |
68270f0f JRJ |
127 | fprintf(output, "%s;%s;\n", cur->parent->name, cur->content); |
128 | } else { | |
129 | fprintf(output, "%s\n", cur->content); | |
68270f0f JRJ |
130 | } |
131 | } | |
132 | } | |
133 | /* Command Success */ | |
134 | ret = 0; | |
135 | ||
136 | end: | |
137 | return ret; | |
138 | } | |
139 | ||
41af1adf JG |
140 | static int register_lttng_namespace(xmlXPathContextPtr xpathCtx) |
141 | { | |
142 | int ret; | |
143 | xmlChar *prefix; | |
144 | xmlChar *ns = NULL; | |
145 | ||
146 | prefix = xmlCharStrdup("lttng"); | |
147 | if (!prefix) { | |
148 | ret = -1; | |
149 | goto end; | |
150 | } | |
151 | ||
152 | ns = xmlCharStrdup(DEFAULT_LTTNG_MI_NAMESPACE); | |
153 | if (!ns) { | |
154 | ret = -1; | |
155 | goto end; | |
156 | } | |
157 | ||
158 | ret = xmlXPathRegisterNs(xpathCtx, prefix, ns); | |
41af1adf | 159 | end: |
0916f272 | 160 | xmlFree(prefix); |
41af1adf JG |
161 | xmlFree(ns); |
162 | return ret; | |
163 | } | |
164 | ||
68270f0f JRJ |
165 | /* |
166 | * Extract element corresponding to xpath | |
167 | * xml_path The path to the xml file | |
168 | * xpath: The xpath to evaluate. | |
169 | * | |
170 | * Evaluate an xpath expression onto an xml file. | |
171 | * and print the result one by line. | |
172 | * | |
173 | * Returns 0 on success and a negative value otherwise. | |
174 | */ | |
175 | static int extract_xpath(const char *xml_path, const xmlChar *xpath) | |
176 | { | |
41af1adf | 177 | int ret; |
68270f0f JRJ |
178 | xmlDocPtr doc = NULL; |
179 | xmlXPathContextPtr xpathCtx = NULL; | |
180 | xmlXPathObjectPtr xpathObj = NULL; | |
181 | ||
182 | assert(xml_path); | |
183 | assert(xpath); | |
184 | ||
185 | /* Parse the xml file */ | |
186 | doc = xmlParseFile(xml_path); | |
187 | if (!doc) { | |
188 | fprintf(stderr, "ERR parsing: xml file invalid \"%s\"\n", xml_path); | |
189 | return -1; | |
190 | } | |
191 | ||
192 | /* Initialize a xpath context */ | |
193 | xpathCtx = xmlXPathNewContext(doc); | |
194 | if (!xpathCtx) { | |
195 | fprintf(stderr, "ERR: XPath context invalid\n"); | |
196 | xmlFreeDoc(doc); | |
197 | return -1; | |
198 | } | |
199 | ||
41af1adf JG |
200 | /* Register the LTTng MI namespace */ |
201 | ret = register_lttng_namespace(xpathCtx); | |
202 | if (ret) { | |
203 | fprintf(stderr, "ERR: Could not register lttng namespace\n"); | |
204 | xmlXPathFreeContext(xpathCtx); | |
205 | xmlFreeDoc(doc); | |
206 | return -1; | |
207 | } | |
208 | ||
68270f0f JRJ |
209 | /* Evaluate xpath expression */ |
210 | xpathObj = xmlXPathEvalExpression(xpath, xpathCtx); | |
211 | if (!xpathObj) { | |
212 | fprintf(stderr, "ERR: invalid xpath expression \"%s\"\n", xpath); | |
213 | xmlXPathFreeContext(xpathCtx); | |
214 | xmlFreeDoc(doc); | |
215 | return -1; | |
216 | } | |
217 | ||
218 | /* Print results */ | |
219 | if (print_xpath_nodes(doc, xpathObj->nodesetval, stdout)) { | |
220 | xmlXPathFreeObject(xpathObj); | |
221 | xmlXPathFreeContext(xpathCtx); | |
222 | xmlFreeDoc(doc); | |
223 | return -1; | |
224 | } | |
83d6d6c4 JR |
225 | if (node_exist && result) { |
226 | fprintf(stdout, "true\n"); | |
227 | } | |
68270f0f JRJ |
228 | |
229 | /* Cleanup */ | |
230 | xmlXPathFreeObject(xpathObj); | |
231 | xmlXPathFreeContext(xpathCtx); | |
232 | xmlFreeDoc(doc); | |
233 | ||
234 | return 0; | |
235 | } | |
236 | ||
237 | int main(int argc, char **argv) | |
238 | { | |
239 | int opt; | |
240 | ||
241 | /* Parse command line and process file */ | |
71f82f2b | 242 | while ((opt = getopt(argc, argv, "ve")) != -1) { |
68270f0f JRJ |
243 | switch (opt) { |
244 | case 'v': | |
245 | opt_verbose = 1; | |
246 | break; | |
71f82f2b JR |
247 | case 'e': |
248 | node_exist = 1; | |
249 | break; | |
68270f0f JRJ |
250 | default: |
251 | abort(); | |
252 | } | |
253 | } | |
254 | ||
255 | if (!(optind + 1 < argc)) { | |
256 | fprintf(stderr, "ERR:%s\n", "Arguments missing"); | |
257 | return -1; | |
258 | } | |
259 | ||
260 | /* Init libxml */ | |
261 | xmlInitParser(); | |
262 | xmlKeepBlanksDefault(0); | |
263 | if (access(argv[optind], F_OK)) { | |
264 | fprintf(stderr, "ERR:%s\n", "Xml path not valid"); | |
265 | return -1; | |
266 | } | |
267 | /* Do the main job */ | |
268 | if (extract_xpath(argv[optind], (xmlChar *)argv[optind+1])) { | |
269 | return -1; | |
270 | } | |
271 | ||
272 | /* Shutdown libxml */ | |
273 | xmlCleanupParser(); | |
274 | ||
275 | return 0; | |
276 | } | |
277 | ||
278 | #else | |
279 | int main(void) | |
280 | { | |
281 | fprintf(stderr, "XPath support not compiled in\n"); | |
282 | return -1; | |
283 | } | |
284 | #endif |