root/src/noit_xml.c

Revision 8e9cf57ebf8fd9d4375a893d47cef1aaecce0662, 4.4 kB (checked in by Theo Schlossnagle <jesus@omniti.com>, 2 years ago)

on-disk backing store implementation

  • Property mode set to 100644
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1 /*
2  * Copyright (c) 2007, OmniTI Computer Consulting, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are
7  * met:
8  *
9  *     * Redistributions of source code must retain the above copyright
10  *       notice, this list of conditions and the following disclaimer.
11  *     * Redistributions in binary form must reproduce the above
12  *       copyright notice, this list of conditions and the following
13  *       disclaimer in the documentation and/or other materials provided
14  *       with the distribution.
15  *     * Neither the name OmniTI Computer Consulting, Inc. nor the names
16  *       of its contributors may be used to endorse or promote products
17  *       derived from this software without specific prior written
18  *       permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32
33 #include "noit_defines.h"
34 #include "noit_xml.h"
35 #include "utils/noit_log.h"
36 #include "utils/noit_mkdir.h"
37 #include <fcntl.h>
38 #include <unistd.h>
39 #include <errno.h>
40 #include <assert.h>
41
42 struct noit_xml_buffer_ptr {
43   char *buff;
44   int raw_len;
45   int len;
46   int allocd;
47 };
48 static int
49 noit_xml_save_writer(void *vstr, const char *buffer, int len) {
50   struct noit_xml_buffer_ptr *clv = vstr;
51   if(!clv->buff) {
52     clv->allocd = 8192;
53     clv->buff = malloc(clv->allocd);
54   }
55   while(len + clv->len > clv->allocd) {
56     char *newbuff;
57     int newsize = clv->allocd;
58     newsize <<= 1;
59     newbuff = realloc(clv->buff, newsize);
60     if(!newbuff) {
61       return -1;
62     }
63     clv->allocd = newsize;
64     clv->buff = newbuff;
65   }
66   memcpy(clv->buff + clv->len, buffer, len);
67   clv->len += len;
68   return len;
69 }
70 static int
71 noit_xml_save_closer(void *vstr) {
72   struct noit_xml_buffer_ptr *clv = vstr;
73   if(clv->buff == NULL) return 0;
74   clv->buff[clv->len] = '\0';
75   return 0;
76 }
77
78 char *
79 noit_xmlSaveToBuffer(xmlDocPtr doc) {
80   xmlOutputBufferPtr out;
81   xmlCharEncodingHandlerPtr enc;
82   struct noit_xml_buffer_ptr buf = { NULL,0,0,0 };
83
84   enc = xmlGetCharEncodingHandler(XML_CHAR_ENCODING_UTF8);
85   out = xmlOutputBufferCreateIO(noit_xml_save_writer,
86                                 noit_xml_save_closer,
87                                 &buf, enc);
88   assert(out);
89   xmlSaveFormatFileTo(out, doc, "utf8", 1);
90   return buf.buff;
91 }
92
93 int
94 noit_xmlSaveToFile(xmlDocPtr doc, const char *filename) {
95   int rv = -1, fd, have_backup = 0, once;
96   char tmpfile[PATH_MAX], bakfile[PATH_MAX];
97   xmlOutputBufferPtr out;
98   xmlCharEncodingHandlerPtr enc;
99
100   snprintf(tmpfile, sizeof(tmpfile), "%s.tmp", filename);
101   snprintf(bakfile, sizeof(bakfile), "%s.bak", filename);
102   once = 1;
103  mkbkup:
104   if(link(filename, bakfile) == 0) {
105     unlink(filename);
106     have_backup = 1;
107   }
108   else if (errno != ENOENT) {
109     if(!once) return -1;
110     once = 0;
111     if(errno == EEXIST) {
112       unlink(bakfile);
113       goto mkbkup;
114     }
115     noitL(noit_error, "Cannot create backup for %s: %s\n",
116           filename, strerror(errno));
117     return -1;
118   }
119   else {
120     noitL(noit_debug, "link(%s,%s) -> %s\n", filename, bakfile, strerror(errno));
121   }
122
123  retry:
124   fd = open(tmpfile, O_WRONLY | O_CREAT | O_EXCL, 0640);
125   if(fd < 0) {
126     if(!once) return -1;
127     once = 0;
128     if(errno == ENOENT) {
129       if(mkdir_for_file(tmpfile, 0750) == 0) goto retry;
130     }
131     if(errno == EEXIST) {
132       unlink(tmpfile);
133       goto retry;
134     }
135     return -1;
136   }
137   enc = xmlGetCharEncodingHandler(XML_CHAR_ENCODING_UTF8);
138   out = xmlOutputBufferCreateFd(fd, enc);
139   assert(out);
140   xmlSaveFormatFileTo(out, doc, "utf8", 1);
141   close(fd);
142   rv = 0;
143   if(link(tmpfile, filename)) {
144     rv = -1;
145     if(link(bakfile, filename) != 0) have_backup = 0;
146   }
147   unlink(tmpfile);
148   if(have_backup)
149     unlink(bakfile);
150   return rv;
151 }
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