softmmu: split off vl.c:main() into main.c

A program might rely on functions implemented in vl.c, but implement its
own main(). By placing main into a separate source file, there are no
complaints about duplicate main()s when linking against vl.o. For
example, the virtual-device fuzzer uses a main() provided by libfuzzer,
and needs to perform some initialization before running the softmmu
initialization. Now, main simply calls three vl.c functions which
handle the guest initialization, main loop and cleanup.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-id: 20200220041118.23264-3-alxndr@bu.edu
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

6 files changed, 69 insertions, 28 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 6e26d2ec2a..969329f83e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2032,6 +2032,7 @@ F: include/sysemu/runstate.h
 F: util/main-loop.c
 F: util/qemu-timer.c
 F: softmmu/vl.c
+F: softmmu/main.c
 F: qapi/run-state.json
 
 Human Monitor (HMP)
diff --git a/Makefile.target b/Makefile.target
index 06c36d1161..6f4dd72022 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -203,7 +203,7 @@ endif
 COMMON_LDADDS = ../libqemuutil.a
 
 # build either PROG or PROGW
-$(QEMU_PROG_BUILD): $(all-obj-y) $(COMMON_LDADDS)
+$(QEMU_PROG_BUILD): $(all-obj-y) $(COMMON_LDADDS) $(softmmu-main-y)
 	$(call LINK, $(filter-out %.mak, $^))
 ifdef CONFIG_DARWIN
 	$(call quiet-command,Rez -append $(SRC_PATH)/pc-bios/qemu.rsrc -o $@,"REZ","$(TARGET_DIR)$@")
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index c0678c1ca3..dec64fcc17 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -115,6 +115,10 @@ QemuOpts *qemu_get_machine_opts(void);
 
 bool defaults_enabled(void);
 
+void qemu_init(int argc, char **argv, char **envp);
+void qemu_main_loop(void);
+void qemu_cleanup(void);
+
 extern QemuOptsList qemu_legacy_drive_opts;
 extern QemuOptsList qemu_common_drive_opts;
 extern QemuOptsList qemu_drive_opts;
diff --git a/softmmu/Makefile.objs b/softmmu/Makefile.objs
index d80a5ffe5a..dd15c24346 100644
--- a/softmmu/Makefile.objs
+++ b/softmmu/Makefile.objs
@@ -1,2 +1,3 @@
+softmmu-main-y = softmmu/main.o
 obj-y += vl.o
 vl.o-cflags := $(GPROF_CFLAGS) $(SDL_CFLAGS)
diff --git a/softmmu/main.c b/softmmu/main.c
new file mode 100644
index 0000000000..7adc530c73
--- /dev/null
+++ b/softmmu/main.c
@@ -0,0 +1,53 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2020 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "sysemu/sysemu.h"
+
+#ifdef CONFIG_SDL
+#if defined(__APPLE__) || defined(main)
+#include <SDL.h>
+int main(int argc, char **argv)
+{
+    return qemu_main(argc, argv, NULL);
+}
+#undef main
+#define main qemu_main
+#endif
+#endif /* CONFIG_SDL */
+
+#ifdef CONFIG_COCOA
+#undef main
+#define main qemu_main
+#endif /* CONFIG_COCOA */
+
+int main(int argc, char **argv, char **envp)
+{
+    qemu_init(argc, argv, envp);
+    qemu_main_loop();
+    qemu_cleanup();
+
+    return 0;
+}
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 794f2e5733..080d3b5106 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -36,25 +36,6 @@
 #include "sysemu/seccomp.h"
 #include "sysemu/tcg.h"
 
-#ifdef CONFIG_SDL
-#if defined(__APPLE__) || defined(main)
-#include <SDL.h>
-int qemu_main(int argc, char **argv, char **envp);
-int main(int argc, char **argv)
-{
-    return qemu_main(argc, argv, NULL);
-}
-#undef main
-#define main qemu_main
-#endif
-#endif /* CONFIG_SDL */
-
-#ifdef CONFIG_COCOA
-#undef main
-#define main qemu_main
-#endif /* CONFIG_COCOA */
-
-
 #include "qemu/error-report.h"
 #include "qemu/sockets.h"
 #include "sysemu/accel.h"
@@ -1670,7 +1651,7 @@ static bool main_loop_should_exit(void)
     return false;
 }
 
-static void main_loop(void)
+void qemu_main_loop(void)
 {
 #ifdef CONFIG_PROFILER
     int64_t ti;
@@ -2805,7 +2786,7 @@ static void configure_accelerators(const char *progname)
     }
 }
 
-int main(int argc, char **argv, char **envp)
+void qemu_init(int argc, char **argv, char **envp)
 {
     int i;
     int snapshot, linux_boot;
@@ -3357,7 +3338,7 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_watchdog:
                 if (watchdog) {
                     error_report("only one watchdog option may be given");
-                    return 1;
+                    exit(1);
                 }
                 watchdog = optarg;
                 break;
@@ -4269,7 +4250,7 @@ int main(int argc, char **argv, char **envp)
     parse_numa_opts(current_machine);
 
     /* do monitor/qmp handling at preconfig state if requested */
-    main_loop();
+    qemu_main_loop();
 
     audio_init_audiodevs();
 
@@ -4387,7 +4368,7 @@ int main(int argc, char **argv, char **envp)
     if (vmstate_dump_file) {
         /* dump and exit */
         dump_vmstate_json_to_file(vmstate_dump_file);
-        return 0;
+        exit(0);
     }
 
     if (incoming) {
@@ -4404,8 +4385,11 @@ int main(int argc, char **argv, char **envp)
     accel_setup_post(current_machine);
     os_setup_post();
 
-    main_loop();
+    return;
+}
 
+void qemu_cleanup(void)
+{
     gdbserver_cleanup();
 
     /*
@@ -4442,6 +4426,4 @@ int main(int argc, char **argv, char **envp)
     qemu_chr_cleanup();
     user_creatable_cleanup();
     /* TODO: unref root container, check all devices are ok */
-
-    return 0;
 }