First version of SharedLibInfo

library/system/src/lib/yast2/shared_lib_info.rb

@@ -0,0 +1,115 @@
+# encoding: utf-8
+# ------------------------------------------------------------------------------
+# Copyright (c) 2021 SUSE LLC
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of version 2 of the GNU General Public License as published by the
+# Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# ------------------------------------------------------------------------------
+
+require "yast"
+
+# Class to get information about shared libraries used by a process from its
+# /proc/self/maps file.
+#
+# You can also get information for a different process by specifying its
+# /proc/$pid/maps file.
+#
+# For testing, a fixed file can be used.
+module Yast2
+  class SharedLibInfo
+    include Yast::Logger
+
+    # @return [Array<String>] Complete paths of the shared libs
+    attr_reader :shared_libs
+
+    def initialize(maps_file = "/proc/self/maps")
+      clear
+      read(maps_file)
+    end
+
+    def clear
+      @shared_libs = []
+    end
+
+    def read(maps_file = "/proc/self/maps")
+      return if maps_file.nil? || maps_file.empty?
+
+      open(maps_file).each { |line| parse_maps_line(line) }
+      @shared_libs.uniq!
+    end
+
+    # Return the directory name of a shared lib with a full path.
+    # This is really only an alias for File.dirname().
+    #
+    def self.dirname(lib)
+      File.dirname(lib)
+    end
+
+    # Return the library basename of a shared lib (with or without a full
+    # path). Unlike File.basename(), this also cuts off the SO number.
+    #
+    # Example:
+    #   "/usr/lib64/libscr.so.3.0.0" -> "libscr"
+    #   "/usr/lib64/libc-2.33.so"    -> "libc-2.33"
+    #
+    def self.lib_basename(lib)
+      split_lib_name(lib).first
+    end
+
+    # Return the so number of a shared lib (with or without a full
+    # path).
+    #
+    # Example:
+    #   "/usr/lib64/libscr.so.3.0.0" -> "3.0.0"
+    #   "/usr/lib64/libc-2.33.so"    -> nil
+    #
+    def self.so_number(lib)
+      split_lib_name(lib).last
+    end
+
+    # Split a library name (with or without a full path) up into its base name
+    # and its SO number and return both.
+    #
+    # Example:
+    #   "/usr/lib64/libscr.so.3.0.0" -> ["libscr", "3.0.0"]
+    #   "/usr/lib64/libc-2.33.so"    -> ["libc-2.33", nil]
+    #
+    def self.split_lib_name(lib)
+      full_name = File.basename(lib) # "libscr.so.3.0.0"
+      full_name.split(/\.so\.?/) # ["libscr", "3.0.0"]
+    end
+
+    private
+
+    # Parse one entry of /proc/self/maps and add an entry to @shared_libs if
+    # applicable.
+    #
+    # @param line [String] one line of /proc/self/maps
+    # @return [String, nil] the shared lib with path on this line
+    #
+    def parse_maps_line(line)
+      # Sample lines:
+      #
+      # 7fb22485f000-7fb22486f000 r--p 000f0000 08:02 132839    /usr/lib64/yui/libyui-qt.so.15.0.0
+      # 7fb22486f000-7fb224872000 rw-p 00100000 08:02 132839    /usr/lib64/yui/libyui-qt.so.15.0.0
+      # 7fb2248a2000-7fb2248d8000 r--p 00000000 08:02 1054948   /usr/lib64/libyui.so.15.0.0
+      # 7f8cadbc5000-7f8cadbc9000 rw-p 00000000 00:00 0
+      # 7fffe6181000-7fffe6183000 r-xp 00000000 00:00 0         [vdso]
+      #
+      # See also
+      # https://www.kernel.org/doc/html/latest/filesystems/proc.html
+      line.strip!
+      return nil if line.empty? || line.start_with?("#")
+
+      path = line.split[5]
+      @shared_libs << path unless path.nil? || path.start_with?("[")
+      path
+    end
+  end
+end