Line data Source code
1 : /*
2 : * contrib/xml2/xslt_proc.c
3 : *
4 : * XSLT processing functions (requiring libxslt)
5 : *
6 : * John Gray, for Torchbox 2003-04-01
7 : */
8 : #include "postgres.h"
9 :
10 : #include "fmgr.h"
11 : #include "utils/builtins.h"
12 : #include "utils/xml.h"
13 : #include "varatt.h"
14 :
15 : #ifdef USE_LIBXSLT
16 :
17 : /* libxml includes */
18 :
19 : #include <libxml/xpath.h>
20 : #include <libxml/tree.h>
21 : #include <libxml/xmlmemory.h>
22 :
23 : /* libxslt includes */
24 :
25 : #include <libxslt/xslt.h>
26 : #include <libxslt/xsltInternals.h>
27 : #include <libxslt/security.h>
28 : #include <libxslt/transform.h>
29 : #include <libxslt/xsltutils.h>
30 : #endif /* USE_LIBXSLT */
31 :
32 :
33 : #ifdef USE_LIBXSLT
34 :
35 : /* declarations to come from xpath.c */
36 : extern PgXmlErrorContext *pgxml_parser_init(PgXmlStrictness strictness);
37 :
38 : /* local defs */
39 : static const char **parse_params(text *paramstr);
40 : #endif /* USE_LIBXSLT */
41 :
42 :
43 0 : PG_FUNCTION_INFO_V1(xslt_process);
44 :
45 : Datum
46 0 : xslt_process(PG_FUNCTION_ARGS)
47 : {
48 : #ifdef USE_LIBXSLT
49 :
50 0 : text *doct = PG_GETARG_TEXT_PP(0);
51 0 : text *ssheet = PG_GETARG_TEXT_PP(1);
52 0 : text *volatile result = NULL;
53 0 : text *paramstr;
54 0 : const char **params;
55 0 : PgXmlErrorContext *xmlerrcxt;
56 0 : volatile xsltStylesheetPtr stylesheet = NULL;
57 0 : volatile xmlDocPtr doctree = NULL;
58 0 : volatile xmlDocPtr restree = NULL;
59 0 : volatile xsltSecurityPrefsPtr xslt_sec_prefs = NULL;
60 0 : volatile xsltTransformContextPtr xslt_ctxt = NULL;
61 0 : volatile int resstat = -1;
62 0 : xmlChar *volatile resstr = NULL;
63 :
64 0 : if (fcinfo->nargs == 3)
65 : {
66 0 : paramstr = PG_GETARG_TEXT_PP(2);
67 0 : params = parse_params(paramstr);
68 0 : }
69 : else
70 : {
71 : /* No parameters */
72 0 : params = palloc_object(const char *);
73 0 : params[0] = NULL;
74 : }
75 :
76 : /* Setup parser */
77 0 : xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
78 :
79 0 : PG_TRY();
80 : {
81 0 : xmlDocPtr ssdoc;
82 0 : bool xslt_sec_prefs_error;
83 0 : int reslen = 0;
84 :
85 : /* Parse document */
86 0 : doctree = xmlReadMemory((char *) VARDATA_ANY(doct),
87 0 : VARSIZE_ANY_EXHDR(doct), NULL, NULL,
88 : XML_PARSE_NOENT);
89 :
90 0 : if (doctree == NULL || pg_xml_error_occurred(xmlerrcxt))
91 0 : xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_XML_DOCUMENT,
92 : "error parsing XML document");
93 :
94 : /* Same for stylesheet */
95 0 : ssdoc = xmlReadMemory((char *) VARDATA_ANY(ssheet),
96 0 : VARSIZE_ANY_EXHDR(ssheet), NULL, NULL,
97 : XML_PARSE_NOENT);
98 :
99 0 : if (ssdoc == NULL || pg_xml_error_occurred(xmlerrcxt))
100 0 : xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_XML_DOCUMENT,
101 : "error parsing stylesheet as XML document");
102 :
103 : /* After this call we need not free ssdoc separately */
104 0 : stylesheet = xsltParseStylesheetDoc(ssdoc);
105 :
106 0 : if (stylesheet == NULL || pg_xml_error_occurred(xmlerrcxt))
107 0 : xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
108 : "failed to parse stylesheet");
109 :
110 0 : xslt_ctxt = xsltNewTransformContext(stylesheet, doctree);
111 :
112 0 : xslt_sec_prefs_error = false;
113 0 : if ((xslt_sec_prefs = xsltNewSecurityPrefs()) == NULL)
114 0 : xslt_sec_prefs_error = true;
115 :
116 0 : if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_READ_FILE,
117 0 : xsltSecurityForbid) != 0)
118 0 : xslt_sec_prefs_error = true;
119 0 : if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_WRITE_FILE,
120 0 : xsltSecurityForbid) != 0)
121 0 : xslt_sec_prefs_error = true;
122 0 : if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_CREATE_DIRECTORY,
123 0 : xsltSecurityForbid) != 0)
124 0 : xslt_sec_prefs_error = true;
125 0 : if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_READ_NETWORK,
126 0 : xsltSecurityForbid) != 0)
127 0 : xslt_sec_prefs_error = true;
128 0 : if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_WRITE_NETWORK,
129 0 : xsltSecurityForbid) != 0)
130 0 : xslt_sec_prefs_error = true;
131 0 : if (xsltSetCtxtSecurityPrefs(xslt_sec_prefs, xslt_ctxt) != 0)
132 0 : xslt_sec_prefs_error = true;
133 :
134 0 : if (xslt_sec_prefs_error)
135 0 : ereport(ERROR,
136 : (errmsg("could not set libxslt security preferences")));
137 :
138 0 : restree = xsltApplyStylesheetUser(stylesheet, doctree, params,
139 0 : NULL, NULL, xslt_ctxt);
140 :
141 0 : if (restree == NULL || pg_xml_error_occurred(xmlerrcxt))
142 0 : xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
143 : "failed to apply stylesheet");
144 :
145 0 : resstat = xsltSaveResultToString((xmlChar **) &resstr, &reslen,
146 0 : restree, stylesheet);
147 :
148 0 : if (resstat >= 0)
149 0 : result = cstring_to_text_with_len((char *) resstr, reslen);
150 0 : }
151 0 : PG_CATCH();
152 : {
153 0 : if (restree != NULL)
154 0 : xmlFreeDoc(restree);
155 0 : if (xslt_ctxt != NULL)
156 0 : xsltFreeTransformContext(xslt_ctxt);
157 0 : if (xslt_sec_prefs != NULL)
158 0 : xsltFreeSecurityPrefs(xslt_sec_prefs);
159 0 : if (stylesheet != NULL)
160 0 : xsltFreeStylesheet(stylesheet);
161 0 : if (doctree != NULL)
162 0 : xmlFreeDoc(doctree);
163 0 : if (resstr != NULL)
164 0 : xmlFree(resstr);
165 0 : xsltCleanupGlobals();
166 :
167 0 : pg_xml_done(xmlerrcxt, true);
168 :
169 0 : PG_RE_THROW();
170 : }
171 0 : PG_END_TRY();
172 :
173 0 : xmlFreeDoc(restree);
174 0 : xsltFreeTransformContext(xslt_ctxt);
175 0 : xsltFreeSecurityPrefs(xslt_sec_prefs);
176 0 : xsltFreeStylesheet(stylesheet);
177 0 : xmlFreeDoc(doctree);
178 0 : xsltCleanupGlobals();
179 :
180 0 : if (resstr)
181 0 : xmlFree(resstr);
182 :
183 0 : pg_xml_done(xmlerrcxt, false);
184 :
185 : /* XXX this is pretty dubious, really ought to throw error instead */
186 0 : if (resstat < 0)
187 0 : PG_RETURN_NULL();
188 :
189 0 : PG_RETURN_TEXT_P(result);
190 : #else /* !USE_LIBXSLT */
191 :
192 : ereport(ERROR,
193 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
194 : errmsg("xslt_process() is not available without libxslt")));
195 : PG_RETURN_NULL();
196 : #endif /* USE_LIBXSLT */
197 0 : }
198 :
199 : #ifdef USE_LIBXSLT
200 :
201 : static const char **
202 0 : parse_params(text *paramstr)
203 : {
204 0 : char *pos;
205 0 : char *pstr;
206 0 : char *nvsep = "=";
207 0 : char *itsep = ",";
208 0 : const char **params;
209 0 : int max_params;
210 0 : int nparams;
211 :
212 0 : pstr = text_to_cstring(paramstr);
213 :
214 0 : max_params = 20; /* must be even! */
215 0 : params = (const char **) palloc((max_params + 1) * sizeof(char *));
216 0 : nparams = 0;
217 :
218 0 : pos = pstr;
219 :
220 0 : while (*pos != '\0')
221 : {
222 0 : if (nparams >= max_params)
223 : {
224 0 : max_params *= 2;
225 0 : params = (const char **) repalloc(params,
226 0 : (max_params + 1) * sizeof(char *));
227 0 : }
228 0 : params[nparams++] = pos;
229 0 : pos = strstr(pos, nvsep);
230 0 : if (pos != NULL)
231 : {
232 0 : *pos = '\0';
233 0 : pos++;
234 0 : }
235 : else
236 : {
237 : /* No equal sign, so ignore this "parameter" */
238 0 : nparams--;
239 0 : break;
240 : }
241 :
242 : /* since max_params is even, we still have nparams < max_params */
243 0 : params[nparams++] = pos;
244 0 : pos = strstr(pos, itsep);
245 0 : if (pos != NULL)
246 : {
247 0 : *pos = '\0';
248 0 : pos++;
249 0 : }
250 : else
251 0 : break;
252 : }
253 :
254 : /* Add the terminator marker; we left room for it in the palloc's */
255 0 : params[nparams] = NULL;
256 :
257 0 : return params;
258 0 : }
259 :
260 : #endif /* USE_LIBXSLT */
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