run-command: trigger PATH lookup properly on Cygwin

On Cygwin, the codepath for POSIX-like systems is taken in
run-command.c::start_command(). The prepare_cmd() helper
function is called to decide if the command needs to be looked
up in the PATH. The logic there is to do the PATH-lookup if
and only if it does not have any slash '/' in it. If this test
passes we end up attempting to run the command by appending the
string after each colon-separated component of PATH.

The Cygwin environment supports both Windows and POSIX style
paths, so both forwardslahes '/' and back slashes '\' can be
used as directory separators for any external program the user
supplies.

Examples for path strings which are being incorrectly searched
for in the PATH instead of being executed as is:

- "C:\Program Files\some-program.exe"
- "a\b\c.exe"

To handle these, the PATH lookup detection logic in prepare_cmd()
is taught to know about this Cygwin quirk, by introducing
has_dir_sep(path) helper function to abstract away the difference
between true POSIX and Cygwin systems.

Signed-off-by: Andras Kucsma <r0maikx02b@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/compat/win32/path-utils.h b/compat/win32/path-utils.h
index f2e70872cd20675dd2f84f72e7608799f16941ad..bba2b644080f064cb5160ce41da16841afadeeed 100644 (file)
--- a/compat/win32/path-utils.h
+++ b/compat/win32/path-utils.h
@@ -20,6 +20,17 @@ static inline char *win32_find_last_dir_sep(const char *path)
        return ret;
 }
 #define find_last_dir_sep win32_find_last_dir_sep
+static inline int win32_has_dir_sep(const char *path)
+{
+       /*
+        * See how long the non-separator part of the given path is, and
+        * if and only if it covers the whole path (i.e. path[len] is NUL),
+        * there is no separator in the path---otherwise there is a separator.
+        */
+       size_t len = strcspn(path, "/\\");
+       return !!path[len];
+}
+#define has_dir_sep(path) win32_has_dir_sep(path)
 int win32_offset_1st_component(const char *path);
 #define offset_1st_component win32_offset_1st_component
 

diff --git a/git-compat-util.h b/git-compat-util.h
index aed0b5d4f9028a5ae38e8676ec2d1c3a63dfdc97..8ba576e81e3e52843cc84350978a26df8e3344e7 100644 (file)
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -389,6 +389,14 @@ static inline char *git_find_last_dir_sep(const char *path)
 #define find_last_dir_sep git_find_last_dir_sep
 #endif
 
+#ifndef has_dir_sep
+static inline int git_has_dir_sep(const char *path)
+{
+       return !!strchr(path, '/');
+}
+#define has_dir_sep(path) git_has_dir_sep(path)
+#endif
+
 #ifndef query_user_email
 #define query_user_email() NULL
 #endif

diff --git a/run-command.c b/run-command.c
index f5e1149f9b395e77c3d55a147332c1117746d7b1..0f41af3b550f1f58d89f496b539e44f28559fbf6 100644 (file)
--- a/run-command.c
+++ b/run-command.c
@@ -421,12 +421,12 @@ static int prepare_cmd(struct argv_array *out, const struct child_process *cmd)
        }
 
        /*
-        * If there are no '/' characters in the command then perform a path
-        * lookup and use the resolved path as the command to exec.  If there
-        * are '/' characters, we have exec attempt to invoke the command
-        * directly.
+        * If there are no dir separator characters in the command then perform
+        * a path lookup and use the resolved path as the command to exec. If
+        * there are dir separator characters, we have exec attempt to invoke
+        * the command directly.
         */
-       if (!strchr(out->argv[1], '/')) {
+       if (!has_dir_sep(out->argv[1])) {
                char *program = locate_in_PATH(out->argv[1]);
                if (program) {
                        free((char *)out->argv[1]);