Add host os_release facility

4 files changed, 413 insertions, 0 deletions

diff --git a/bpkg/host-os-release.cxx b/bpkg/host-os-release.cxx
new file mode 100644
index 0000000..1a5a980
--- /dev/null
+++ b/bpkg/host-os-release.cxx
@@ -0,0 +1,121 @@
+// file      : bpkg/host-os-release.cxx -*- C++ -*-
+// license   : MIT; see accompanying LICENSE file
+
+#include <bpkg/host-os-release.hxx>
+
+#include <libbutl/string-parser.hxx> // parse_quoted()
+
+#include <bpkg/diagnostics.hxx>
+
+using namespace butl;
+
+namespace bpkg
+{
+  // Note: not static for access from the unit test.
+  //
+  os_release
+  host_os_release_linux (path f = {})
+  {
+    os_release r;
+
+    // According to os-release(5), we should use /etc/os-release and fallback
+    // to /usr/lib/os-release if the former does not exist. It also lists the
+    // fallback values for individual variables, in case some are not present.
+    //
+    if (!f.empty ()
+        ? exists (f)
+        : (exists (f = path ("/etc/os-release")) ||
+           exists (f = path ("/usr/lib/os-release"))))
+    {
+      try
+      {
+        ifdstream ifs (f, ifdstream::badbit);
+
+        string l;
+        for (uint64_t ln (1); !eof (getline (ifs, l)); ++ln)
+        {
+          trim (l);
+
+          // Skip blanks lines and comments.
+          //
+          if (l.empty () || l[0] == '#')
+            continue;
+
+          // The variable assignments are in the "shell style" and so can be
+          // quoted/escaped. For now we only handle quoting, which is what all
+          // the instances seen in the wild seems to use.
+          //
+          size_t p (l.find ('='));
+          if (p == string::npos)
+            continue;
+
+          string n (l, 0, p);
+          l.erase (0, p + 1);
+
+          using string_parser::parse_quoted;
+          using string_parser::invalid_string;
+
+          try
+          {
+            if (n == "ID_LIKE")
+            {
+              r.like_ids.clear ();
+
+              vector<string> vs (parse_quoted (l, true /* unquote */));
+              for (const string& v: vs)
+              {
+                for (size_t b (0), e (0); next_word (v, b, e); )
+                {
+                  r.like_ids.push_back (string (v, b, e - b));
+                }
+              }
+            }
+            else if (string* p = (n == "ID"               ?  &r.name_id :
+                                  n == "VERSION_ID"       ?  &r.version_id :
+                                  n == "VARIANT_ID"       ?  &r.variant_id :
+                                  n == "NAME"             ?  &r.name :
+                                  n == "VERSION_CODENAME" ?  &r.version_codename :
+                                  n == "VARIANT"          ?  &r.variant :
+                                  nullptr))
+            {
+              vector<string> vs (parse_quoted (l, true /* unquote */));
+              switch (vs.size ())
+              {
+              case 0:  *p =  ""; break;
+              case 1:  *p = move (vs.front ()); break;
+              default: throw invalid_string (0, "multiple values");
+              }
+            }
+          }
+          catch (const invalid_string& e)
+          {
+            location loc (move (f).string (), ln);
+            fail (loc) << "invalid " << n << " value: " << e;
+          }
+        }
+
+        ifs.close ();
+      }
+      catch (const io_error& e)
+      {
+        fail << "unable to read from " << f << ": " << e;
+      }
+    }
+
+    // Assign fallback values.
+    //
+    if (r.name_id.empty ()) r.name_id = "linux";
+    if (r.name.empty ())    r.name    = "Linux";
+
+    return r;
+  }
+
+  optional<os_release>
+  host_os_release (const target_triplet& host)
+  {
+    if (host.class_ == "linux")
+      return host_os_release_linux ();
+    else
+      return nullopt;
+  }
+}
diff --git a/bpkg/host-os-release.hxx b/bpkg/host-os-release.hxx
new file mode 100644
index 0000000..3f85cb2
--- /dev/null
+++ b/bpkg/host-os-release.hxx
@@ -0,0 +1,59 @@
+// file      : bpkg/host-os-release.hxx -*- C++ -*-
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef BPKG_HOST_OS_RELEASE_HXX
+#define BPKG_HOST_OS_RELEASE_HXX
+
+#include <bpkg/types.hxx>
+#include <bpkg/utility.hxx>
+
+namespace bpkg
+{
+  // Information extracted from /etc/os-release on Linux. See os-release(5)
+  // for background. For other platforms we derive the equivalent information
+  // from other sources. Some examples:
+  //
+  // {"debian", {}, "10", "",
+  //  "Debian GNU/Linux", "buster", ""}
+  //
+  // {"fedora", {}, "35", "workstation",
+  //  "Fedora Linux", "", "Workstation Edition"}
+  //
+  // {"ubuntu", {"debian"}, "20.04", "",
+  //  "Ubuntu", "focal", ""}
+  //
+  // {"windows", {}, "10", "",
+  //  "Windows", "", ""}
+  //
+  // Note that version_id may be empty, for example, on Debian testing:
+  //
+  // {"debian", {}, "", "",
+  //  "Debian GNU/Linux", "", ""}
+  //
+  // Note also that we don't extract PRETTY_NAME because its content is
+  // unpredictable. For example, it may include variant, as in "Fedora Linux
+  // 35 (Workstation Edition)". Instead, construct it from the individual
+  // components as appropriate, normally "$name $version ($version_codename)".
+  //
+  struct os_release
+  {
+    string         name_id;    // ID
+    vector<string> like_ids;   // ID_LIKE
+    string         version_id; // VERSION_ID
+    string         variant_id; // VARIANT_ID
+
+    string name;             // NAME
+    string version_codename; // VERSION_CODENAME
+    string variant;          // VARIANT
+  };
+
+  // Return the release information for the specified host or nullopt if the
+  // specific host is unknown/unsupported. Note that "host" here implies that
+  // we may be examining files, environment variables, etc., of the machine we
+  // are running on.
+  //
+  optional<os_release>
+  host_os_release (const target_triplet& host);
+}
+
+#endif // BPKG_HOST_OS_RELEASE_HXX
diff --git a/bpkg/host-os-release.test.cxx b/bpkg/host-os-release.test.cxx
new file mode 100644
index 0000000..e65c3ca
--- /dev/null
+++ b/bpkg/host-os-release.test.cxx
@@ -0,0 +1,55 @@
+// file      : bpkg/host-os-release.test.cxx -*- C++ -*-
+// license   : MIT; see accompanying LICENSE file
+
+#include <bpkg/host-os-release.hxx>
+
+#include <bpkg/types.hxx>
+#include <bpkg/utility.hxx>
+
+#include <iostream>
+
+#undef NDEBUG
+#include <cassert>
+
+using namespace std;
+
+namespace bpkg
+{
+  extern os_release
+  host_os_release_linux (path f = {});
+
+  int
+  main (int argc, char* argv[])
+  {
+    assert (argc >= 2); // <host-target-triplet>
+
+    target_triplet host (argv[1]);
+
+    os_release r;
+    if (host.class_ == "linux")
+    {
+      assert (argc == 3); // <host-target-triplet> <file-path>
+      r = host_os_release_linux (path (argv[2]));
+    }
+    else
+      assert (false);
+
+    cout << r.name_id << '\n';
+    for (auto b (r.like_ids.begin ()), i (b); i != r.like_ids.end (); ++i)
+      cout << (i != b ? "|" : "") << *i;
+    cout << '\n'
+         << r.version_id << '\n'
+         << r.variant_id << '\n'
+         << r.name << '\n'
+         << r.version_codename << '\n'
+         << r.variant << '\n';
+
+    return 0;
+  }
+}
+
+int
+main (int argc, char* argv[])
+{
+  return bpkg::main (argc, argv);
+}
diff --git a/bpkg/host-os-release.test.testscript b/bpkg/host-os-release.test.testscript
new file mode 100644
index 0000000..b32c477
--- /dev/null
+++ b/bpkg/host-os-release.test.testscript
@@ -0,0 +1,178 @@
+# file      : bpkg/host-os-release.test.testscript
+# license   : MIT; see accompanying LICENSE file
+
+: linux
+:
+$* x86_64-linux-gnu os-release >>EOO
+  linux
+
+
+
+  Linux
+
+
+  EOO
+
+: debian-10
+:
+cat <<EOI >=os-release;
+  PRETTY_NAME="Debian GNU/Linux 10 (buster)"
+  NAME="Debian GNU/Linux"
+  VERSION_ID="10"
+  VERSION="10 (buster)"
+  VERSION_CODENAME=buster
+  ID=debian
+  HOME_URL="https://www.debian.org/"
+  SUPPORT_URL="https://www.debian.org/support"
+  BUG_REPORT_URL="https://bugs.debian.org/"
+  EOI
+$* x86_64-linux-gnu os-release >>EOO
+  debian
+
+  10
+
+  Debian GNU/Linux
+  buster
+
+  EOO
+
+: debian-testing
+:
+cat <<EOI >=os-release;
+  PRETTY_NAME="Debian GNU/Linux bookworm/sid"
+  NAME="Debian GNU/Linux"
+  ID=debian
+  HOME_URL="https://www.debian.org/"
+  SUPPORT_URL="https://www.debian.org/support"
+  BUG_REPORT_URL="https://bugs.debian.org/"
+  EOI
+$* x86_64-linux-gnu os-release >>EOO
+  debian
+
+
+
+  Debian GNU/Linux
+
+
+  EOO
+
+: ubuntu-20.04
+:
+cat <<EOI >=os-release;
+  NAME="Ubuntu"
+  VERSION="20.04.1 LTS (Focal Fossa)"
+  ID=ubuntu
+  ID_LIKE=debian
+  PRETTY_NAME="Ubuntu 20.04.1 LTS"
+  VERSION_ID="20.04"
+  HOME_URL="https://www.ubuntu.com/"
+  SUPPORT_URL="https://help.ubuntu.com/"
+  BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
+  PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
+  VERSION_CODENAME=focal
+  UBUNTU_CODENAME=focal
+  EOI
+$* x86_64-linux-gnu os-release >>EOO
+  ubuntu
+  debian
+  20.04
+
+  Ubuntu
+  focal
+
+  EOO
+
+: fedora-35
+:
+cat <<EOI >=os-release;
+  NAME="Fedora Linux"
+  VERSION="35 (Workstation Edition)"
+  ID=fedora
+  VERSION_ID=35
+  VERSION_CODENAME=""
+  PLATFORM_ID="platform:f35"
+  PRETTY_NAME="Fedora Linux 35 (Workstation Edition)"
+  ANSI_COLOR="0;38;2;60;110;180"
+  LOGO=fedora-logo-icon
+  CPE_NAME="cpe:/o:fedoraproject:fedora:35"
+  HOME_URL="https://fedoraproject.org/"
+  DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f35/system-administrators-guide/"
+  SUPPORT_URL="https://ask.fedoraproject.org/"
+  BUG_REPORT_URL="https://bugzilla.redhat.com/"
+  REDHAT_BUGZILLA_PRODUCT="Fedora"
+  REDHAT_BUGZILLA_PRODUCT_VERSION=35
+  REDHAT_SUPPORT_PRODUCT="Fedora"
+  REDHAT_SUPPORT_PRODUCT_VERSION=35
+  PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
+  VARIANT="Workstation Edition"
+  VARIANT_ID=workstation
+  EOI
+$* x86_64-linux-gnu os-release >>EOO
+  fedora
+
+  35
+  workstation
+  Fedora Linux
+
+  Workstation Edition
+  EOO
+
+: rhel-8.2
+:
+cat <<EOI >=os-release;
+  NAME="Red Hat Enterprise Linux"
+  VERSION="8.2 (Ootpa)"
+  ID="rhel"
+  ID_LIKE="fedora"
+  VERSION_ID="8.2"
+  PLATFORM_ID="platform:el8"
+  PRETTY_NAME="Red Hat Enterprise Linux 8.2 (Ootpa)"
+  ANSI_COLOR="0;31"
+  CPE_NAME="cpe:/o:redhat:enterprise_linux:8.2:GA"
+  HOME_URL="https://www.redhat.com/"
+  BUG_REPORT_URL="https://bugzilla.redhat.com/"
+
+  REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 8"
+  REDHAT_BUGZILLA_PRODUCT_VERSION=8.2
+  REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
+  REDHAT_SUPPORT_PRODUCT_VERSION="8.2"
+  EOI
+$* x86_64-linux-gnu os-release >>EOO
+  rhel
+  fedora
+  8.2
+
+  Red Hat Enterprise Linux
+
+
+  EOO
+
+: centos-8
+:
+cat <<EOI >=os-release;
+  NAME="CentOS Linux"
+  VERSION="8 (Core)"
+  ID="centos"
+  ID_LIKE="rhel fedora"
+  VERSION_ID="8"
+  PLATFORM_ID="platform:el8"
+  PRETTY_NAME="CentOS Linux 8 (Core)"
+  ANSI_COLOR="0;31"
+  CPE_NAME="cpe:/o:centos:centos:8"
+  HOME_URL="https://www.centos.org/"
+  BUG_REPORT_URL="https://bugs.centos.org/"
+
+  CENTOS_MANTISBT_PROJECT="CentOS-8"
+  CENTOS_MANTISBT_PROJECT_VERSION="8"
+  REDHAT_SUPPORT_PRODUCT="centos"
+  REDHAT_SUPPORT_PRODUCT_VERSION="8"
+  EOI
+$* x86_64-linux-gnu os-release >>EOO
+  centos
+  rhel|fedora
+  8
+
+  CentOS Linux
+
+
+  EOO