win32: interpret absolute paths as relative to %SYSTEMDRIVE%

BusyBox contains hardcoded references to absolute paths which
are unique in the *nix world but on Microsoft Windows are
interpreted as being on the current drive.  To make these unique
again consider them to be relative to %SYSTEMDRIVE%.

Support this by adding functions to:

- determine the system drive (not using the environment variable);
- change a process's current directory to the root of the system drive;
- make relative paths absolute before changing directory (if needed).

The following applications have been modified:

- ash references /etc/profile from the system drive;
- dpkg places its data store on and installs files to the system drive;
- rpm installs files to the system drive;
- man looks for configuration files and man pages on the system drive.

See GitHub issue #158.

1 files changed, 13 insertions, 1 deletions

diff --git a/miscutils/man.c b/miscutils/man.c
index 3c1a79085..0bc11e623 100644
--- a/miscutils/man.c
+++ b/miscutils/man.c
@@ -253,11 +253,22 @@ int man_main(int argc UNUSED_PARAM, char **argv)
         int cur_mp;
         int opt, not_found;
         char *token[2];
+#if ENABLE_PLATFORM_MINGW32
+        char **ptr;
+#endif
 
         INIT_G();
 
         opt = getopt32(argv, "^+" "aw" "\0" "-1"/*at least one arg*/);
         argv += optind;
+#if ENABLE_PLATFORM_MINGW32
+        /* add system drive prefix to filenames, if necessary */
+        for (ptr = argv; *ptr; ++ptr) {
+                if (strchr(*ptr, '/') || strchr(*ptr, '\\'))
+                        *ptr = xabsolute_path(*ptr);
+        }
+        chdir_system_drive();
+#endif
 
         sec_list = xstrdup("0p:1:1p:2:3:3p:4:5:6:7:8:9");
 
@@ -311,7 +322,8 @@ int man_main(int argc UNUSED_PARAM, char **argv)
                 char *relpath = concat_path_file(dirname(exepath), "man");
                 if (count_mp == 0) {
                         /* default must match path set above */
-                        man_path_list = add_MANPATH(man_path_list, &count_mp, "/usr/man");
+                        man_path_list = add_MANPATH(man_path_list, &count_mp,
+                                                                                (char *)"/usr/man");
                 }
                 man_path_list = add_MANPATH(man_path_list, &count_mp, relpath);
                 free(relpath);