Merge branch 'patch-1' into 'master'

Clean up everything and add lots of new functions

I hope everything here is okay. I fixed some bugs in existing functions (mostly wrong prototypes or off-by-one errors) and formatted everything to a consistent style. If you'd like me to adjust the style, that's no problem. It wasn't very consistent to start with (within the code, and compared to the documentation).

*I added specific notes you may want to comment on to some of the commit messages.*

Major features:
* Pass correct `argv[0]` in loader
* Intercept `readlink("/proc/self/exe")` to allow re-exec
* Add almost all reasonable-to-implement functions in LSB 5.0.0 core generic libc. Remaining functions are:
  - Impossible-to-implement: sigreturn
  - Not useful: reentrant random (`*rand48_r`, etc.), argz, envz, pmap, rpc (clnt_*, svc*, xdr*), bindresvport
  - Got tired of it: checked wchar
* Add additional functions used by android and its NDK tools (clang, cmake, lldb, ninja, etc.).

At this point, I am able to run Android Studio with the bundled prebuilt JDK, and compile, install, and run an android application (including one with native libraries) on a real device, with only a few minor issues:
* must export `LD_LIBRARY_PATH=/opt/android-studio/jre/jre/lib/amd64/server` because musl and glibc interpret the variable differently with regards to `dlopen`. This is something that has to be patched in musl builds of openjdk, so it's not a gcompat issue.
* ld.bfd fails to parse the argument `--sysroot=/path`, but can parse `--sysroot /path`. So there's some difference with `getopt_long_only` (or getopt in general). May be a bug, may be just an API difference. May be it can be patched up.
* LLDB fails to connect to the android phone for native debugging -- I haven't tried it on glibc yet, so it may not be a gcompat issue at all (may be a phone or the app issue).

I'd be happy to send some documentation later.

See merge request !1

1 files changed, 79 insertions, 0 deletions

diff --git a/libgcompat/netdb.c b/libgcompat/netdb.c
new file mode 100644
index 0000000..ae7713a
--- /dev/null
+++ b/libgcompat/netdb.c
@@ -0,0 +1,79 @@
+#include <errno.h>  /* ENOENT */
+#include <netdb.h>  /* getproto* */
+#include <stddef.h> /* NULL, size_t */
+#include <string.h> /* memcpy */
+
+/**
+ * Retrieve information from the network protocol database by protocol name,
+ * reentrantly.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-getprotobyname-r.html
+ */
+int getprotobyname_r(const char *name, struct protoent *result_buf, char *buf,
+                     size_t buflen, struct protoent **result)
+{
+	struct protoent *prototmp = getprotobyname(name);
+
+	/* musl does not reuse static storage, so no race is possible. */
+	if (prototmp == NULL) {
+		*result = NULL;
+		return ENOENT;
+	}
+	*result = memcpy(result_buf, prototmp, sizeof(*result_buf));
+
+	return 0;
+}
+
+/**
+ * Retrieve information from the network protocol database by protocol number,
+ * reentrantly.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-getprotobynumber-r.html
+ */
+int getprotobynumber_r(int proto, struct protoent *result_buf, char *buf,
+                       size_t buflen, struct protoent **result)
+{
+	struct protoent *prototmp = getprotobynumber(proto);
+
+	/* musl does not reuse static storage, so no race is possible. */
+	if (prototmp == NULL) {
+		*result = NULL;
+		return ENOENT;
+	}
+	*result = memcpy(result_buf, prototmp, sizeof(*result_buf));
+
+	return 0;
+}
+
+/**
+ * Read the next entry of the protocol database, reentrantly.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-getprotoent-r.html
+ */
+int getprotoent_r(struct protoent *result_buf, char *buf, size_t buflen,
+                  struct protoent **result)
+{
+	struct protoent *prototmp = getprotoent();
+
+	/* musl does not reuse static storage, so no race is possible. */
+	if (prototmp == NULL) {
+		*result = NULL;
+		return ENOENT;
+	}
+	*result = memcpy(result_buf, prototmp, sizeof(*result_buf));
+
+	return 0;
+}
+
+/**
+ * Read the next entry of the network services database, reentrantly.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-getservent-r.html
+ */
+int getservent_r(struct servent *result_buf, char *buf, size_t buflen,
+                 struct servent **result)
+{
+	/* musl does not implement getservent(). */
+	*result = NULL;
+	return ENOENT;
+}