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5cc3285574
When a non-empty list is appended to, and used as the returnvalue, the list pointer can leak in case of an allocation failure in the curl_slist_append() call. This is correctly handled in curl code usage but we weren't explicitly pointing it out in the API call documentation. Fix by extending the RETURNVALUE manpage section and example code. Closes #3424 Reported-by: dnivras on github Reviewed-by: Daniel Stenberg <daniel@haxx.se>
73 lines
2.5 KiB
Groff
73 lines
2.5 KiB
Groff
.\" **************************************************************************
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.\" * _ _ ____ _
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.\" * Project ___| | | | _ \| |
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.\" * / __| | | | |_) | |
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.\" * | (__| |_| | _ <| |___
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.\" * \___|\___/|_| \_\_____|
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.\" *
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.\" * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
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.\" *
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.\" * This software is licensed as described in the file COPYING, which
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.\" * you should have received as part of this distribution. The terms
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.\" * are also available at https://curl.haxx.se/docs/copyright.html.
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.\" *
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.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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.\" * copies of the Software, and permit persons to whom the Software is
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.\" * furnished to do so, under the terms of the COPYING file.
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.\" *
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.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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.\" * KIND, either express or implied.
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.\" *
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.\" **************************************************************************
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.TH curl_slist_append 3 "19 Jun 2003" "libcurl 7.10.4" "libcurl Manual"
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.SH NAME
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curl_slist_append - add a string to an slist
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.SH SYNOPSIS
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.B #include <curl/curl.h>
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.sp
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.BI "struct curl_slist *curl_slist_append(struct curl_slist *" list,
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.BI "const char * "string ");"
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.ad
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.SH DESCRIPTION
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\fIcurl_slist_append(3)\fP appends a string to a linked list of strings. The
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existing \fBlist\fP should be passed as the first argument and the new list is
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returned from this function. Pass in NULL in the \fBlist\fP argument to create
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a new list. The specified \fBstring\fP has been appended when this function
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returns. \fIcurl_slist_append(3)\fP copies the string.
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The list should be freed again (after usage) with
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\fIcurl_slist_free_all(3)\fP.
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.SH RETURN VALUE
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A null pointer is returned if anything went wrong, otherwise the new list
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pointer is returned. To avoid overwriting an existing non-empty list on
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failure, the new list should be returned to a temporary variable which can
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be tested for NULL before updating the original list pointer.
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.SH EXAMPLE
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.nf
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CURL *handle;
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struct curl_slist *slist=NULL;
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struct curl_slist *temp=NULL;
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slist = curl_slist_append(slist, "pragma:");
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if (slist == NULL)
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return -1;
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temp = curl_slist_append(slist, "Accept:")
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if (temp == NULL) {
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curl_slist_free_all(slist);
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return -1;
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}
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slist = temp;
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curl_easy_setopt(handle, CURLOPT_HTTPHEADER, slist);
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curl_easy_perform(handle);
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curl_slist_free_all(slist); /* free the list again */
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.fi
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.SH "SEE ALSO"
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.BR curl_slist_free_all "(3), "
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