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