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, 172 insertions, 0 deletions

diff --git a/libgcompat/unistd.c b/libgcompat/unistd.c
new file mode 100644
index 0000000..e19ec8e
--- /dev/null
+++ b/libgcompat/unistd.c
@@ -0,0 +1,172 @@
+#include <assert.h> /* assert */
+#include <limits.h> /* NGROUPS_MAX */
+#include <stddef.h> /* NULL, size_t */
+#include <unistd.h> /* confstr, getcwd, getgroups, ... */
+
+#include "alias.h" /* alias */
+
+/**
+ * Get configurable variables, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---confstr-chk-1.html
+ */
+size_t __confstr_chk(int name, char *buf, size_t len, size_t buflen)
+{
+	assert(buf != NULL ? buflen >= len : len == 0);
+
+	return confstr(name, buf, len);
+}
+
+/**
+ * Get the pathname of the current working directory, with buffer overflow
+ * checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---getcwd-chk-1.html
+ */
+char *__getcwd_chk(char *buf, size_t len, size_t buflen)
+{
+	assert(buf != NULL);
+	assert(buflen >= len);
+
+	return getcwd(buf, len);
+}
+
+/**
+ * Get supplementary group IDs, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---getgroups-chk-1.html
+ */
+int __getgroups_chk(int gidsetsize, gid_t *grouplist, size_t listlen)
+{
+	assert(grouplist != NULL);
+	assert(listlen / sizeof(*grouplist) >= (size_t) gidsetsize);
+
+	return getgroups(gidsetsize, grouplist);
+}
+
+/**
+ * Get name of current host, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---gethostname-chk-1.html
+ */
+int __gethostname_chk(char *name, size_t namelen, size_t buflen)
+{
+	assert(name != NULL);
+	assert(buflen >= namelen);
+
+	return gethostname(name, namelen);
+}
+
+/**
+ * Get login name, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---getlogin-r-chk-1.html
+ */
+int __getlogin_r_chk(char *name, size_t namelen, size_t buflen)
+{
+	assert(name != NULL);
+	assert(buflen >= namelen);
+
+	return getlogin_r(name, namelen);
+}
+
+/**
+ * Get memory page size.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---getpagesize.html
+ */
+int __getpagesize(void)
+{
+	return getpagesize();
+}
+
+/**
+ * Get the process group ID for a process.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---getpgid-1.html
+ */
+pid_t __getpgid(pid_t pid)
+{
+	return getpgid(pid);
+}
+
+/**
+ * Read from a file, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---pread-chk-1.html
+ */
+ssize_t __pread_chk(int fd, void *buf, size_t nbytes, off_t offset,
+                    size_t buflen)
+{
+	assert(buf != NULL);
+	assert(buflen >= nbytes);
+
+	return pread(fd, buf, nbytes, offset);
+}
+alias(__pread_chk, __pread64_chk);
+
+/**
+ * Read from a file, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---read-chk-1.html
+ */
+ssize_t __read_chk(int fd, void *buf, size_t nbytes, size_t buflen)
+{
+	assert(buf != NULL);
+	assert(buflen >= nbytes);
+
+	return read(fd, buf, nbytes);
+}
+
+/**
+ * Read the contents of a symbolic link, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---readlink-chk-1.html
+ */
+ssize_t __readlink_chk(const char *path, char *buf, size_t len, size_t buflen)
+{
+	assert(buf != NULL);
+	assert(buflen >= len);
+
+	return readlink(path, buf, len);
+}
+
+/**
+ * Get configurable system variables.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---sysconf.html
+ */
+long __sysconf(int name)
+{
+	return sysconf(name);
+}
+
+/**
+ * Find the pathname of a terminal, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---ttyname-r-chk-1.html
+ */
+int __ttyname_r_chk(int fd, char *name, size_t namelen, size_t buflen)
+{
+	assert(name != NULL);
+	assert(buflen >= namelen);
+
+	return ttyname_r(fd, name, namelen);
+}
+
+/**
+ * Test whether a process is in a group.
+ */
+int group_member(gid_t gid)
+{
+	gid_t groups[NGROUPS_MAX];
+	int ngroups = getgroups(NGROUPS_MAX, groups);
+
+	for (int i = 0; i < ngroups; ++i) {
+		if (groups[i] == gid) {
+			return 1;
+		}
+	}
+
+	return 0;
+}