diff options
Diffstat (limited to 'lib/fopen.c')
-rw-r--r-- | lib/fopen.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/lib/fopen.c b/lib/fopen.c new file mode 100644 index 0000000..ad3691b --- /dev/null +++ b/lib/fopen.c @@ -0,0 +1,113 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al. + * + * This software is licensed as described in the file COPYING, which + * you should have received as part of this distribution. The terms + * are also available at https://curl.se/docs/copyright.html. + * + * You may opt to use, copy, modify, merge, publish, distribute and/or sell + * copies of the Software, and permit persons to whom the Software is + * furnished to do so, under the terms of the COPYING file. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + * SPDX-License-Identifier: curl + * + ***************************************************************************/ + +#include "curl_setup.h" + +#if !defined(CURL_DISABLE_COOKIES) || !defined(CURL_DISABLE_ALTSVC) || \ + !defined(CURL_DISABLE_HSTS) + +#ifdef HAVE_FCNTL_H +#include <fcntl.h> +#endif + +#include "urldata.h" +#include "rand.h" +#include "fopen.h" +/* The last 3 #include files should be in this order */ +#include "curl_printf.h" +#include "curl_memory.h" +#include "memdebug.h" + +/* + * Curl_fopen() opens a file for writing with a temp name, to be renamed + * to the final name when completed. If there is an existing file using this + * name at the time of the open, this function will clone the mode from that + * file. if 'tempname' is non-NULL, it needs a rename after the file is + * written. + */ +CURLcode Curl_fopen(struct Curl_easy *data, const char *filename, + FILE **fh, char **tempname) +{ + CURLcode result = CURLE_WRITE_ERROR; + unsigned char randsuffix[9]; + char *tempstore = NULL; + struct_stat sb; + int fd = -1; + *tempname = NULL; + + if(stat(filename, &sb) == -1 || !S_ISREG(sb.st_mode)) { + /* a non-regular file, fallback to direct fopen() */ + *fh = fopen(filename, FOPEN_WRITETEXT); + if(*fh) + return CURLE_OK; + goto fail; + } + + result = Curl_rand_hex(data, randsuffix, sizeof(randsuffix)); + if(result) + goto fail; + + tempstore = aprintf("%s.%s.tmp", filename, randsuffix); + if(!tempstore) { + result = CURLE_OUT_OF_MEMORY; + goto fail; + } + + result = CURLE_WRITE_ERROR; + fd = open(tempstore, O_WRONLY | O_CREAT | O_EXCL, 0600); + if(fd == -1) + goto fail; + +#ifdef HAVE_FCHMOD + { + struct_stat nsb; + if((fstat(fd, &nsb) != -1) && + (nsb.st_uid == sb.st_uid) && (nsb.st_gid == sb.st_gid)) { + /* if the user and group are the same, clone the original mode */ + if(fchmod(fd, sb.st_mode) == -1) + goto fail; + } + } +#endif + + *fh = fdopen(fd, FOPEN_WRITETEXT); + if(!*fh) + goto fail; + + *tempname = tempstore; + return CURLE_OK; + +fail: + if(fd != -1) { + close(fd); + unlink(tempstore); + } + + free(tempstore); + + *tempname = NULL; + return result; +} + +#endif /* ! disabled */ |