Authorities list: implement InstallAll & ReplaceAll

This change implements the design in
https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/49317.

InstallAll: enumerate all certs in the input file and install all of
them;
ReplaceAll: replace all certs with the new authorities list
Atomic: implemented via creating temporary folder and issuing swap.

Added ability to unit test service reload as well.

Tested:
1. Unit tests
2. Tested loading/deleting authorities list in QEMU.

```
root@xxx:~# busctl call xyz.openbmc_project.Certs.Manager.Authority.Ldap \
> /xyz/openbmc_project/certs/authority/ldap \
> xyz.openbmc_project.Certs.InstallAll \
> InstallAll s /tmp/trust_bundle.pem
as 3 "/xyz/openbmc_project/certs/authority/ldap/1"
"/xyz/openbmc_project/certs/authority/ldap/2"
"/xyz/openbmc_project/certs/authority/ldap/3"
root@xxx:~# ls /etc/ssl/certs/authority/
10a5d8b0.0  5b49ceaa.0	f3ddaa86.0  file0qmgPV	fileDbjTzW  fileR4TtjO
trust_bundle
root@xxx:~# busctl call
xyz.openbmc_project.Certs.Manager.Authority.Ldap
/xyz/openbmc_project/certs/authority/ldap
xyz.openbmc_project.Certs.ReplaceAll ReplaceAll s /tmp/trust_bundle.pem
root@xxx:~# ls /etc/ssl/certs/authority/
10a5d8b0.0  5b49ceaa.0	f3ddaa86.0  file1obsEZ	fileOqVoaC  filerUBZCj
trust_bundle

root@xxx:~# wget -qO- http://localhost/redfish/v1/Managers/bmc/Truststore/Certificates/
{
  "@odata.id": "/redfish/v1/Managers/bmc/Truststore/Certificates/",
  "@odata.type": "#CertificateCollection.CertificateCollection",
  "Description": "A Collection of TrustStore certificate instances",
  "Members": [
    {
      "@odata.id": "/redfish/v1/Managers/bmc/Truststore/Certificates/1"
    },
    {
      "@odata.id": "/redfish/v1/Managers/bmc/Truststore/Certificates/2"
    },
    {
      "@odata.id": "/redfish/v1/Managers/bmc/Truststore/Certificates/3"
    }
  ],
  "Members@odata.count": 3,
  "Name": "TrustStore Certificates Collection"
}
root@xxx:~# wget -qO- http://localhost/redfish/v1/Managers/bmc/Truststore/Certificates/1
{
  "@odata.id": "/redfish/v1/Managers/bmc/Truststore/Certificates/1",
  "@odata.type": "#Certificate.v1_0_0.Certificate",
  "CertificateString": "-----BEGIN CERTIFICATE-----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\nam3byOT1AiEAyrr3FAP+7js7z+h8d94hTyy1kTn+4NOvUWrVzHUmJI8=\n-----END CERTIFICATE-----\n",
  "Description": "TrustStore Certificate",
  "Id": "1",
  "Issuer": {
    "CommonName": "{d2ed50bd-7314-481d-89a4-5d2912f20d94}",
    "Organization": "campus-ash",
    "OrganizationalUnit": "root"
  },
  "KeyUsage": [
    "CRLSigning",
    "ServerAuthentication",
    "ClientAuthentication",
    ""
  ],
  "Name": "TrustStore Certificate",
  "Subject": {
    "CommonName": "{d2ed50bd-7314-481d-89a4-5d2912f20d94}",
    "Organization": "campus-ash",
    "OrganizationalUnit": "root"
  },
  "ValidNotAfter": "9999-12-31T23:59:59+00:00",
  "ValidNotBefore": "1970-01-01T00:00:00+00:00"
}
```

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I495f5c1c1c4a2ac880dd3233be31b84a78d79a43
diff --git a/x509_utils.cpp b/x509_utils.cpp
index 9a589dd..ba1a2ef 100644
--- a/x509_utils.cpp
+++ b/x509_utils.cpp
@@ -225,4 +225,31 @@
 
     return {idBuff};
 }
+
+std::unique_ptr<X509, decltype(&::X509_free)> parseCert(const std::string& pem)
+{
+    if (pem.size() > INT_MAX)
+    {
+        log<level::ERR>("Error occurred during parseCert: PEM is too long");
+        elog<InvalidCertificate>(Reason("Invalid PEM: too long"));
+    }
+    X509Ptr cert(X509_new(), ::X509_free);
+    if (!cert)
+    {
+        log<level::ERR>("Error occurred during X509_new call",
+                        entry("ERRCODE=%lu", ERR_get_error()));
+        elog<InternalFailure>();
+    }
+
+    BIOMemPtr bioCert(BIO_new_mem_buf(pem.data(), static_cast<int>(pem.size())),
+                      ::BIO_free);
+    X509* x509 = cert.get();
+    if (!PEM_read_bio_X509(bioCert.get(), &x509, nullptr, nullptr))
+    {
+        log<level::ERR>("Error occurred during PEM_read_bio_X509 call",
+                        entry("PEM=%s", pem.c_str()));
+        elog<InternalFailure>();
+    }
+    return cert;
+}
 } // namespace phosphor::certs