gamemode: Add common helpers to build gamemode

gamemode-zig/build.zig

@@ -10,12 +10,21 @@ pub fn link(exe: *std.build.LibExeObjStep) void {
     exe.linkSystemLibrary("gamemode");
 }
 
-/// TODO:
+// TODO: to build we still need to generate a config file called build_common.h
+// (see https://github.com/FeralInteractive/gamemode/blob/4dc99dff76218718763a6b07fc1900fa6d1dafd9/meson.build) line 151
+
 /// Build and link gamemode
 pub fn buildAndLink(b: *std.build.Builder, exe: *std.build.LibExeObjStep) void {
-    const lib = b.addSharedLibrarySource("gamemode", std.build.FileSource{ .path = thisDir() ++ "/c/client_impl.c" }, .unversioned);
+    const lib_common = b.addStaticLibrary("common", null);
-    lib.linkLibC();
+    lib_common.addCSourceFiles(&.{ (comptime thisDir()) ++ "/c/common/common-helpers.c", (comptime thisDir()) ++ "/c/common/common-pidfds.c" }, &.{});
-    exe.linkLibrary(lib);
+    lib_common.linkLibC();
+
+    const lib_gamemode = b.addSharedLibrarySource("gamemode", null, .unversioned);
+    lib_gamemode.addCSourceFile((comptime thisDir()) ++ "/c/client_impl.c", &.{});
+    lib_gamemode.linkLibC();
+    lib_gamemode.linkLibrary(lib_common);
+
+    exe.linkLibrary(lib_gamemode);
 }
 
 fn thisDir() []const u8 {

gamemode-zig/c/common/common-helpers.c

@@ -0,0 +1,42 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+Copyright (c) 2019, Red Hat
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#define _GNU_SOURCE
+#include "common-helpers.h"
+
+/* Starting with C99 we can use "inline" without "static" and thus avoid
+ * having multiple (local) definitions of the same inline function. One
+ * consequence of that is that if the compiler decides to *not* inline
+ * a specific call to the function the linker will expect an definition.
+ */
+extern inline void cleanup_close(int *fd);
+extern inline void cleanup_free(void *ptr);

gamemode-zig/c/common/common-helpers.h

@@ -0,0 +1,103 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#pragma once
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/param.h>
+#include <unistd.h>
+
+/**
+ * Value clamping helper, works like MIN/MAX but constraints a value within the range.
+ */
+#define CLAMP(l, u, value) MAX(MIN(l, u), MIN(MAX(l, u), value))
+
+/**
+ * Little helper to safely print into a buffer, returns a pointer into the buffer
+ */
+#define buffered_snprintf(b, s, ...)                                                               \
+	(snprintf(b, sizeof(b), s, __VA_ARGS__) < (ssize_t)sizeof(b) ? b : NULL)
+
+/**
+ * Little helper to safely print into a buffer, returns a newly allocated string
+ */
+#define safe_snprintf(b, s, ...)                                                                   \
+	(snprintf(b, sizeof(b), s, __VA_ARGS__) < (ssize_t)sizeof(b) ? strndup(b, sizeof(b)) : NULL)
+
+/**
+ * Helper function: Test, if haystack ends with needle.
+ */
+static inline const char *strtail(const char *haystack, const char *needle)
+{
+	char *pos = strstr(haystack, needle);
+	if (pos && (strlen(pos) == strlen(needle)))
+		return pos;
+	return NULL;
+}
+
+/**
+ * Helper function for autoclosing file-descriptors. Does nothing if the argument
+ * is NULL or the referenced integer < 0.
+ */
+inline void cleanup_close(int *fd_ptr)
+{
+	if (fd_ptr == NULL || *fd_ptr < 0)
+		return;
+
+	(void)close(*fd_ptr);
+}
+
+/**
+ * Helper macro for autoclosing file-descriptors: use by prefixing the variable,
+ * like "autoclose_fd int fd = -1;".
+ */
+#define autoclose_fd __attribute__((cleanup(cleanup_close)))
+
+/**
+ * Helper function for auto-freeing dynamically allocated memory. Does nothing
+ * if *ptr is NULL (ptr must not be NULL).
+ */
+inline void cleanup_free(void *ptr)
+{
+	/* The function is defined to work with 'void *' because
+	 * that will make sure it compiles without warning also
+	 * for all types; what we are getting passed into is a
+	 * pointer to a pointer though, so we need to cast */
+	void *target = *(void **)ptr;
+	free(target); /* free can deal with NULL */
+}
+
+/**
+ * Helper macro for auto-freeing dynamically allocated memory: use by
+ * prefixing the variable, like "autofree char *data = NULL;".
+ */
+#define autofree __attribute__((cleanup(cleanup_free)))

gamemode-zig/c/common/common-pidfds.c

@@ -0,0 +1,200 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+Copyright (c) 2019, Red Hat
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+*/
+#define _GNU_SOURCE
+#include <build-config.h>
+
+#include "common-helpers.h"
+#include "common-pidfds.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#if !HAVE_FN_PIDFD_OPEN
+#include <sys/syscall.h>
+
+#ifndef __NR_pidfd_open
+#define __NR_pidfd_open 434
+#endif
+
+static int pidfd_open(pid_t pid, unsigned int flags)
+{
+	return (int)syscall(__NR_pidfd_open, pid, flags);
+}
+#endif
+
+/* pidfd functions */
+int open_pidfds(pid_t *pids, int *fds, int count)
+{
+	int i = 0;
+
+	for (i = 0; i < count; i++) {
+		int pid = pids[i];
+		int fd = pidfd_open(pid, 0);
+
+		if (fd < 0)
+			break;
+
+		fds[i] = fd;
+	}
+
+	return i;
+}
+
+static int parse_pid(const char *str, pid_t *pid)
+{
+	unsigned long long int v;
+	char *end;
+	pid_t p;
+
+	errno = 0;
+	v = strtoull(str, &end, 0);
+	if (end == str)
+		return -ENOENT;
+	else if (errno != 0)
+		return -errno;
+
+	p = (pid_t)v;
+
+	if (p < 1 || (unsigned long long int)p != v)
+		return -ERANGE;
+
+	if (pid)
+		*pid = p;
+
+	return 0;
+}
+
+static int parse_status_field_pid(const char *val, pid_t *pid)
+{
+	const char *t;
+
+	t = strrchr(val, '\t');
+	if (t == NULL)
+		return -ENOENT;
+
+	return parse_pid(t, pid);
+}
+
+static int pidfd_to_pid(int fdinfo, int pidfd, pid_t *pid)
+{
+	autofree char *key = NULL;
+	autofree char *val = NULL;
+	char name[256] = {
+		0,
+	};
+	bool found = false;
+	FILE *f = NULL;
+	size_t keylen = 0;
+	size_t vallen = 0;
+	ssize_t n;
+	int fd;
+	int r = 0;
+
+	*pid = 0;
+
+	buffered_snprintf(name, "%d", pidfd);
+
+	fd = openat(fdinfo, name, O_RDONLY | O_CLOEXEC | O_NOCTTY);
+
+	if (fd != -1)
+		f = fdopen(fd, "r");
+
+	if (f == NULL)
+		return -errno;
+
+	do {
+		n = getdelim(&key, &keylen, ':', f);
+		if (n == -1) {
+			r = errno;
+			break;
+		}
+
+		n = getdelim(&val, &vallen, '\n', f);
+		if (n == -1) {
+			r = errno;
+			break;
+		}
+
+		// TODO: strstrip (key);
+
+		if (!strncmp(key, "Pid", 3)) {
+			r = parse_status_field_pid(val, pid);
+			found = r > -1;
+		}
+
+	} while (r == 0 && !found);
+
+	fclose(f);
+
+	if (r < 0)
+		return r;
+	else if (!found)
+		return -ENOENT;
+
+	return 0;
+}
+
+int pidfds_to_pids(int *fds, pid_t *pids, int count)
+{
+	int fdinfo = -1;
+	int r = 0;
+	int i;
+
+	fdinfo = open_fdinfo_dir();
+	if (fdinfo == -1)
+		return -1;
+
+	for (i = 0; i < count && r == 0; i++)
+		r = pidfd_to_pid(fdinfo, fds[i], &pids[i]);
+
+	(void)close(fdinfo);
+
+	if (r != 0)
+		errno = -r;
+
+	return i;
+}
+
+/* misc directory helpers */
+int open_fdinfo_dir(void)
+{
+	return open("/proc/self/fdinfo", O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC | O_NOCTTY);
+}

gamemode-zig/c/common/common-pidfds.h

@@ -0,0 +1,53 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+Copyright (c) 2019, Red Hat
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#include <sys/types.h>
+
+/* Open pidfds for up to count process ids specified in pids. The
+ * pointer fds needs to point to an array with at least count
+ * entries. Will stop when it encounters an error (and sets errno).
+ * Returns the number of successfully opened pidfds (or -1 in case
+ * of other errors. */
+int open_pidfds(pid_t *pids, int *fds, int count);
+
+/* Translate up to count process ids to the corresponding process ids.
+ * The pointer pids needs to point to an array with at least count
+ * entries. Will stop when it encounters an error (and sets errno).
+ * Returns the number of successfully translated pidfds (or -1 in
+ * case of other errors. */
+int pidfds_to_pids(int *fds, pid_t *pids, int count);
+
+/* Helper to open the fdinfo directory for the current process, i.e.
+ * does open("/proc/self/fdinfo", ...). Returns the file descriptor
+ * for the directory, ownership is transferred and caller needs to
+ * call close on it. */
+int open_fdinfo_dir(void);

gamemode-zig/fetch_upstream.sh

@@ -5,7 +5,14 @@ cd ./c
 wget "https://github.com/FeralInteractive/gamemode/raw/master/lib/gamemode_client.h"
 wget "https://github.com/FeralInteractive/gamemode/raw/master/lib/client_impl.c"
 wget "https://github.com/FeralInteractive/gamemode/raw/master/lib/client_loader.c"
-cd ..
+
+cd ./common
+wget "https://github.com/FeralInteractive/gamemode/raw/b11d2912e280acb87d9ad114d6c7cd8846c4ef02/common/common-helpers.c"
+wget "https://github.com/FeralInteractive/gamemode/raw/b11d2912e280acb87d9ad114d6c7cd8846c4ef02/common/common-pidfds.c"
+wget "https://github.com/FeralInteractive/gamemode/raw/b11d2912e280acb87d9ad114d6c7cd8846c4ef02/common/common-helpers.h"
+wget "https://github.com/FeralInteractive/gamemode/raw/b11d2912e280acb87d9ad114d6c7cd8846c4ef02/common/common-pidfds.h"
+
+cd ../..
 
 # The output from translate-c isn't perfect, so we need this fix
 zig translate-c ./c/gamemode_client.h -lc | sed "s#functor\(.*\)@alignCast\(.*\),\(.*\))#functor\1\3#" > ./src/gamemode_client.zig