1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25 #include "curl_setup.h"
26
27 #if !defined(CURL_DISABLE_COOKIES) || !defined(CURL_DISABLE_ALTSVC) || \
28 !defined(CURL_DISABLE_HSTS)
29
30 #ifdef HAVE_FCNTL_H
31 #include <fcntl.h>
32 #endif
33
34 #include "urldata.h"
35 #include "rand.h"
36 #include "fopen.h"
37 /* The last 3 #include files should be in this order */
38 #include "curl_printf.h"
39 #include "curl_memory.h"
40 #include "memdebug.h"
41
42 /*
43 The dirslash() function breaks a null-terminated pathname string into
44 directory and filename components then returns the directory component up
45 to, *AND INCLUDING*, a final '/'. If there is no directory in the path,
46 this instead returns a "" string.
47
48 This function returns a pointer to malloc'ed memory.
49
50 The input path to this function is expected to have a file name part.
51 */
52
53 #ifdef _WIN32
54 #define PATHSEP "\\"
55 #define IS_SEP(x) (((x) == '/') || ((x) == '\\'))
56 #elif defined(MSDOS) || defined(__EMX__) || defined(OS2)
57 #define PATHSEP "\\"
58 #define IS_SEP(x) ((x) == '\\')
59 #else
60 #define PATHSEP "/"
61 #define IS_SEP(x) ((x) == '/')
62 #endif
63
dirslash(const char * path)64 static char *dirslash(const char *path)
65 {
66 size_t n;
67 struct dynbuf out;
68 DEBUGASSERT(path);
69 Curl_dyn_init(&out, CURL_MAX_INPUT_LENGTH);
70 n = strlen(path);
71 if(n) {
72 /* find the rightmost path separator, if any */
73 while(n && !IS_SEP(path[n-1]))
74 --n;
75 /* skip over all the path separators, if any */
76 while(n && IS_SEP(path[n-1]))
77 --n;
78 }
79 if(Curl_dyn_addn(&out, path, n))
80 return NULL;
81 /* if there was a directory, append a single trailing slash */
82 if(n && Curl_dyn_addn(&out, PATHSEP, 1))
83 return NULL;
84 return Curl_dyn_ptr(&out);
85 }
86
87 /*
88 * Curl_fopen() opens a file for writing with a temp name, to be renamed
89 * to the final name when completed. If there is an existing file using this
90 * name at the time of the open, this function will clone the mode from that
91 * file. if 'tempname' is non-NULL, it needs a rename after the file is
92 * written.
93 */
Curl_fopen(struct Curl_easy * data,const char * filename,FILE ** fh,char ** tempname)94 CURLcode Curl_fopen(struct Curl_easy *data, const char *filename,
95 FILE **fh, char **tempname)
96 {
97 CURLcode result = CURLE_WRITE_ERROR;
98 unsigned char randbuf[41];
99 char *tempstore = NULL;
100 struct_stat sb;
101 int fd = -1;
102 char *dir = NULL;
103 *tempname = NULL;
104
105 *fh = fopen(filename, FOPEN_WRITETEXT);
106 if(!*fh)
107 goto fail;
108 if(fstat(fileno(*fh), &sb) == -1 || !S_ISREG(sb.st_mode)) {
109 return CURLE_OK;
110 }
111 fclose(*fh);
112 *fh = NULL;
113
114 result = Curl_rand_alnum(data, randbuf, sizeof(randbuf));
115 if(result)
116 goto fail;
117
118 dir = dirslash(filename);
119 if(dir) {
120 /* The temp file name should not end up too long for the target file
121 system */
122 tempstore = aprintf("%s%s.tmp", dir, randbuf);
123 free(dir);
124 }
125
126 if(!tempstore) {
127 result = CURLE_OUT_OF_MEMORY;
128 goto fail;
129 }
130
131 result = CURLE_WRITE_ERROR;
132 #if (defined(ANDROID) || defined(__ANDROID__)) && \
133 (defined(__i386__) || defined(__arm__))
134 fd = open(tempstore, O_WRONLY | O_CREAT | O_EXCL, (mode_t)(0600|sb.st_mode));
135 #else
136 fd = open(tempstore, O_WRONLY | O_CREAT | O_EXCL, 0600|sb.st_mode);
137 #endif
138 if(fd == -1)
139 goto fail;
140
141 *fh = fdopen(fd, FOPEN_WRITETEXT);
142 if(!*fh)
143 goto fail;
144
145 *tempname = tempstore;
146 return CURLE_OK;
147
148 fail:
149 if(fd != -1) {
150 close(fd);
151 unlink(tempstore);
152 }
153
154 free(tempstore);
155 return result;
156 }
157
158 #endif /* ! disabled */
159
