libredirect: add support for openat and dlopen

gobject-introspection uses glib’s g_module_open function, which in turn relies
on dlopen. I also implemented openat, since I initially thought this function
was used but turns out dlopen uses the openat signal directly. We might as
well keep it, even thought I do not need it at the moment.

1 files changed, 21 insertions, 0 deletions

diff --git a/pkgs/build-support/libredirect/libredirect.c b/pkgs/build-support/libredirect/libredirect.c
index ba1e6c57e12..dcf3a2016bc 100644
--- a/pkgs/build-support/libredirect/libredirect.c
+++ b/pkgs/build-support/libredirect/libredirect.c
@@ -91,6 +91,20 @@ int open64(const char * path, int flags, ...)
     return open64_real(rewrite(path, buf), flags, mode);
 }
 
+int openat(int dirfd, const char * path, int flags, ...)
+{
+    int (*openat_real) (int, const char *, int, mode_t) = dlsym(RTLD_NEXT, "openat");
+    mode_t mode = 0;
+    if (flags & O_CREAT) {
+        va_list ap;
+        va_start(ap, flags);
+        mode = va_arg(ap, mode_t);
+        va_end(ap);
+    }
+    char buf[PATH_MAX];
+    return openat_real(dirfd, rewrite(path, buf), flags, mode);
+}
+
 FILE * fopen(const char * path, const char * mode)
 {
     FILE * (*fopen_real) (const char *, const char *) = dlsym(RTLD_NEXT, "fopen");
@@ -152,3 +166,10 @@ int execv(const char *path, char *const argv[])
     char buf[PATH_MAX];
     return execv_real(rewrite(path, buf), argv);
 }
+
+void *dlopen(const char *filename, int flag)
+{
+    void * (*__dlopen_real) (const char *, int) = dlsym(RTLD_NEXT, "dlopen");
+    char buf[PATH_MAX];
+    return __dlopen_real(rewrite(filename, buf), flag);
+}