[bug#38873] [PATCH] gnu: curl: Make libcurl respect SSL_CERT_{DIR, FILE}

[Jakub Kądziołka]

* gnu/packages/curl.scm (curl-7.66.0): Use patch.
* gnu/packages/patches/libcurl-use-ssl-cert-env.patch: New file.

This fixes the SSL errors occuring when trying to use rust:cargo's
download functionality.

As an additional advantage, this will probably allow removing some
package-specific work-arounds that have already been made. I have
found such work-arounds in cmake and kodi, but am not familiar enough
with either to confidently remove them.
---
 gnu/packages/curl.scm                         |  4 +-
 .../patches/libcurl-use-ssl-cert-env.patch    | 61 +++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 gnu/packages/patches/libcurl-use-ssl-cert-env.patch

diff --git a/gnu/packages/curl.scm b/gnu/packages/curl.scm
index aa5d24c401..c5cd88ec2e 100644
--- a/gnu/packages/curl.scm
+++ b/gnu/packages/curl.scm
@@ -9,6 +9,7 @@
 ;;; Copyright © 2017, 2018 Tobias Geerinckx-Rice <address@hidden>
 ;;; Copyright © 2018 Roel Janssen <address@hidden>
 ;;; Copyright © 2019 Ricardo Wurmus <address@hidden>
+;;; Copyright © 2020 Jakub Kądziołka <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -153,7 +154,8 @@ tunneling, and so on.")
                                   version ".tar.xz"))
               (sha256
                (base32
-                "1hcqxpibhknhjy56wcxz5vd6m9ggx3ykwp3wp5wx05ih36481d6v"))))))
+                "1hcqxpibhknhjy56wcxz5vd6m9ggx3ykwp3wp5wx05ih36481d6v"))
+              (patches (search-patches "libcurl-use-ssl-cert-env.patch"))))))
 
 (define-public kurly
   (package
diff --git a/gnu/packages/patches/libcurl-use-ssl-cert-env.patch 
b/gnu/packages/patches/libcurl-use-ssl-cert-env.patch
new file mode 100644
index 0000000000..a68e64adc1
--- /dev/null
+++ b/gnu/packages/patches/libcurl-use-ssl-cert-env.patch
@@ -0,0 +1,61 @@
+Make libcurl respect the SSL_CERT_{DIR,FILE} variables by default. The 
variables
+are fetched during initialization to preserve thread-safety 
(curl_global_init(3)
+must be called when no other threads exist).
+===================================================================
+--- curl-7.66.0.orig/lib/easy.c        2020-01-02 15:43:11.883921171 +0100
++++ curl-7.66.0/lib/easy.c     2020-01-02 16:18:54.691882797 +0100
+@@ -134,6 +134,9 @@
+ #  pragma warning(default:4232) /* MSVC extension, dllimport identity */
+ #endif
+ 
++char * Curl_ssl_cert_dir = NULL;
++char * Curl_ssl_cert_file = NULL;
++
+ /**
+  * curl_global_init() globally initializes curl given a bitwise set of the
+  * different features of what to initialize.
+@@ -155,6 +158,9 @@
+ #endif
+   }
+ 
++  Curl_ssl_cert_dir = curl_getenv("SSL_CERT_DIR");
++  Curl_ssl_cert_file = curl_getenv("SSL_CERT_FILE");
++
+   if(!Curl_ssl_init()) {
+     DEBUGF(fprintf(stderr, "Error: Curl_ssl_init failed\n"));
+     return CURLE_FAILED_INIT;
+@@ -260,6 +266,9 @@
+   Curl_ssl_cleanup();
+   Curl_resolver_global_cleanup();
+ 
++  free(Curl_ssl_cert_dir);
++  free(Curl_ssl_cert_file);
++
+ #ifdef WIN32
+   Curl_win32_cleanup(init_flags);
+ #endif
+diff -ur curl-7.66.0.orig/lib/url.c curl-7.66.0/lib/url.c
+--- curl-7.66.0.orig/lib/url.c 2020-01-02 15:43:11.883921171 +0100
++++ curl-7.66.0/lib/url.c      2020-01-02 16:21:11.563880346 +0100
+@@ -524,6 +524,21 @@
+     if(result)
+       return result;
+ #endif
++    extern char * Curl_ssl_cert_dir;
++    extern char * Curl_ssl_cert_file;
++    if(Curl_ssl_cert_dir) {
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAPATH_ORIG], 
Curl_ssl_cert_dir))
++            return result;
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAPATH_PROXY], 
Curl_ssl_cert_dir))
++            return result;
++    }
++
++    if(Curl_ssl_cert_file) {
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAFILE_ORIG], 
Curl_ssl_cert_file))
++            return result;
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAFILE_PROXY], 
Curl_ssl_cert_file))
++            return result;
++    }
+   }
+ 
+   set->wildcard_enabled = FALSE;
-- 
2.24.1