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[PATCH] git-compat-util: work around for access(X_OK) under root




On some OSes like AIX, access with X_OK is always true if launched under
root.
Add NEED_ACCESS_ROOT_HANDLER in order to use an access helper function.
It checks with stat if any executable flags is set when the current user
is root.

Signed-off-by: Clément Chigot <clement.chigot@xxxxxxxx>
---
 Makefile          |  8 ++++++++
 compat/access.c   | 29 +++++++++++++++++++++++++++++
 config.mak.uname  |  1 +
 git-compat-util.h |  8 ++++++++
 4 files changed, 46 insertions(+)
 create mode 100644 compat/access.c

diff --git a/Makefile b/Makefile
index 9f1b6e8926..513d835d01 100644
--- a/Makefile
+++ b/Makefile
@@ -439,6 +439,9 @@ all::
 #
 # Define FILENO_IS_A_MACRO if fileno() is a macro, not a real function.
 #
+# Define NEED_ACCESS_ROOT_HANDLER if access() with X_OK returns always true
+# when launched as root.
+#
 # Define PAGER_ENV to a SP separated VAR=VAL pairs to define
 # default environment variables to be passed when a pager is spawned, e.g.
 #
@@ -1833,6 +1836,11 @@ ifdef FILENO_IS_A_MACRO
 	COMPAT_OBJS += compat/fileno.o
 endif
 
+ifdef NEED_ACCESS_ROOT_HANDLER
+	COMPAT_CFLAGS += -DNEED_ACCESS_ROOT_HANDLER
+	COMPAT_OBJS += compat/access.o
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
diff --git a/compat/access.c b/compat/access.c
new file mode 100644
index 0000000000..e4202d4585
--- /dev/null
+++ b/compat/access.c
@@ -0,0 +1,29 @@
+#include "../git-compat-util.h"
+
+/* Do the same thing access(2) does, but use the effective uid and gid,
+   and don't make the mistake of telling root that any file is
+   executable.  This version uses stat(2). */
+int git_access (const char *path, int mode)
+{
+	struct stat st;
+	uid_t euid = geteuid();
+	uid_t uid = getuid();
+
+	if (stat(path, &st) < 0)
+		return -1;
+
+	if (!(uid) || !(euid)) {
+		/* Root can read or write any file. */
+		if (!(mode & X_OK))
+			return 0;
+
+		/* Root can execute any file that has any one of the execute
+		   bits set. */
+		if (st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))
+			return 0;
+		errno = EACCES;
+		return -1;
+	}
+
+	return access(path, X_OK);
+}
diff --git a/config.mak.uname b/config.mak.uname
index 86cbe47627..ce13ab8295 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -270,6 +270,7 @@ ifeq ($(uname_S),AIX)
 	NEEDS_LIBICONV = YesPlease
 	BASIC_CFLAGS += -D_LARGE_FILES
 	FILENO_IS_A_MACRO = UnfortunatelyYes
+	NEED_ACCESS_ROOT_HANDLER = UnfortunatelyYes
 	ifeq ($(shell expr "$(uname_V)" : '[1234]'),1)
 		NO_PTHREADS = YesPlease
 	else
diff --git a/git-compat-util.h b/git-compat-util.h
index 31b47932bd..bb8df9d2e5 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -1242,6 +1242,14 @@ int git_fileno(FILE *stream);
 # endif
 #endif
 
+#ifdef NEED_ACCESS_ROOT_HANDLER
+#ifdef access
+#undef access
+#endif
+#define access git_access
+extern int git_access(const char *path, int mode);
+#endif
+
 /*
  * Our code often opens a path to an optional file, to work on its
  * contents when we can successfully open it.  We can ignore a failure
-- 
2.17.1



Clément Chigot
ATOS Bull SAS
1 rue de Provence - 38432 Échirolles - France