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authorBoris Kolpackov <boris@codesynthesis.com>2016-08-02 11:25:16 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2016-08-02 11:25:16 +0200
commita22840fe77ef20f9c5488b9f2b8cf90663c537db (patch)
treebcd7ff018bbf64e606fce00d7a82d23d04328a3e /butl/process.cxx
parent9125ed697fe61abd1a742686e816b44b887a8d69 (diff)
Fix process::path_search() to look in parent program's directory
Diffstat (limited to 'butl/process.cxx')
-rw-r--r--butl/process.cxx110
1 files changed, 71 insertions, 39 deletions
diff --git a/butl/process.cxx b/butl/process.cxx
index 5c9a0f0..b78321c 100644
--- a/butl/process.cxx
+++ b/butl/process.cxx
@@ -12,7 +12,7 @@
# include <io.h> // _open_osfhandle(), _get_osfhandle(), _close()
# include <fcntl.h> // _O_TEXT
-# include <stdlib.h> // getenv()
+# include <stdlib.h> // _MAX_PATH, getenv()
# include <sys/types.h> // stat
# include <sys/stat.h> // stat(), S_IS*
@@ -249,6 +249,11 @@ namespace butl
#else // _WIN32
+ // Why do we search for the program ourselves when CreateProcess() can be
+ // made to do that for us? Well, that's a bit of a historic mystery. We
+ // could use it to disable search in the current working directory. Or we
+ // could handle batch files automatically.
+ //
static path
path_search (const path& f)
{
@@ -257,58 +262,85 @@ namespace butl
// If there is a directory component in the file, then the PATH search
// does not apply.
//
- if (!f.directory ().empty ())
+ if (!f.simple ())
return f;
- string paths;
-
- // If there is no PATH in the environment then the default search path is
- // the current directory.
- //
- if (const char* s = getenv ("PATH"))
+ path r;
+ auto search = [&r, &f] (const char* d, size_t n) -> bool
{
- paths = s;
+ string s (move (r).string ()); // Reuse buffer.
+
+ if (n != 0)
+ {
+ s.assign (d, n);
+
+ if (!traits::is_separator (s.back ()))
+ s += traits::directory_separator;
+ }
+
+ s += f.string ();
+ r = path (move (s)); // Move back into result.
- // Also check the current directory.
+ // Check that the file exist without checking for permissions, etc.
//
- paths += traits::path_separator;
- }
- else
- paths = traits::path_separator;
+ struct stat info;
+ if (stat (r.string ().c_str (), &info) == 0 && S_ISREG (info.st_mode))
+ return true;
+
+ // Also try the path with the .exe extension.
+ //
+ r += ".exe";
- struct stat info;
+ if (stat (r.string ().c_str (), &info) == 0 && S_ISREG (info.st_mode))
+ return true;
- for (size_t b (0), e (paths.find (traits::path_separator));
- b != string::npos;)
+ return false;
+ };
+
+ // The search order is documented in CreateProcess(). First we look in
+ // the directory of the parent executable.
+ //
{
- dir_path p (string (paths, b, e != string::npos ? e - b : e));
+ char d[_MAX_PATH + 1];
+ DWORD n (GetModuleFileName (NULL, d, _MAX_PATH + 1));
- // Empty path (i.e., a double colon or a colon at the beginning or end
- // of PATH) means search in the current dirrectory.
- //
- if (p.empty ())
- p = dir_path (".");
+ if (n == 0 || n == _MAX_PATH + 1) // Failed or truncated.
+ throw process_error (last_error_msg ());
- path dp (p / f);
+ const char* p (traits::rfind_separator (d, n));
+ assert (p != nullptr);
- // Just check that the file exist without checking for permissions, etc.
- //
- if (stat (dp.string ().c_str (), &info) == 0 && S_ISREG (info.st_mode))
- return dp;
+ if (search (d, p - d + 1)) // Include trailing slash.
+ return r;
+ }
- // Also try the path with the .exe extension.
- //
- dp += ".exe";
+ // Next look in the current working directory. Crazy, I know.
+ //
+ if (search ("", 0))
+ return r;
- if (stat (dp.string ().c_str (), &info) == 0 && S_ISREG (info.st_mode))
- return dp;
+ // Finally, search in PATH.
+ //
+ if (const char* s = getenv ("PATH"))
+ {
+ string ps (s);
- if (e == string::npos)
- b = e;
- else
+ for (size_t b (0), e (ps.find (traits::path_separator));
+ b != string::npos;)
{
- b = e + 1;
- e = paths.find (traits::path_separator, b);
+ // Empty path (i.e., a double colon or a colon at the beginning or end
+ // of PATH) means search in the current dirrectory.
+ //
+ if (search (ps.c_str () + b, (e != string::npos ? e : ps.size ()) - b))
+ return r;
+
+ if (e == string::npos)
+ b = e;
+ else
+ {
+ b = e + 1;
+ e = ps.find (traits::path_separator, b);
+ }
}
}
@@ -448,7 +480,7 @@ namespace butl
// Do PATH search.
//
- if (file.directory ().empty ())
+ if (file.simple ())
file = path_search (file);
if (file.empty ())