Second round of cleanups (#83)

* get rid of as many extern / function definition in QEMU codebase.

* mostly moved cpu / gdb related code.

* move qemu snapshot code in dedicated files.

Author: rmalmain

accel/tcg/tcg-runtime.c

@@ -39,99 +39,6 @@
 
 #include "libafl/exit.h"
 
-#ifndef CONFIG_USER_ONLY
-
-#include "sysemu/runstate.h"
-#include "migration/snapshot.h"
-#include "qapi/error.h"
-#include "qemu/error-report.h"
-#include "qemu/main-loop.h"
-#include "hw/core/cpu.h"
-#include "sysemu/hw_accel.h"
-#include <stdlib.h>
-#include <string.h>
-
-void libafl_save_qemu_snapshot(char *name, bool sync);
-void libafl_load_qemu_snapshot(char *name, bool sync);
-
-static void save_snapshot_cb(void* opaque)
-{
-    char* name = (char*)opaque;
-    Error *err = NULL;
-    if(!save_snapshot(name, true, NULL, false, NULL, &err)) {
-        error_report_err(err);
-        error_report("Could not save snapshot");
-    }
-    free(opaque);
-}
-
-void libafl_save_qemu_snapshot(char *name, bool sync)
-{
-    // use snapshots synchronously, use if main loop is not running
-    if (sync) {
-        //TODO: eliminate this code duplication
-        //by passing a heap-allocated buffer from rust to c,
-        //which c needs to free
-        Error *err = NULL;
-        if(!save_snapshot(name, true, NULL, false, NULL, &err)) {
-            error_report_err(err);
-            error_report("Could not save snapshot");
-        }
-        return;
-    }
-    char* name_buffer = malloc(strlen(name)+1);
-    strcpy(name_buffer, name);
-    aio_bh_schedule_oneshot_full(qemu_get_aio_context(), save_snapshot_cb, (void*)name_buffer, "save_snapshot");
-}
-
-static void load_snapshot_cb(void* opaque)
-{
-    char* name = (char*)opaque;
-    Error *err = NULL;
-
-    int saved_vm_running = runstate_is_running();
-    vm_stop(RUN_STATE_RESTORE_VM);
-
-    bool loaded = load_snapshot(name, NULL, false, NULL, &err);
-
-    if(!loaded) {
-        error_report_err(err);
-        error_report("Could not load snapshot");
-    }
-    if (loaded && saved_vm_running) {
-        vm_start();
-    }
-    free(opaque);
-}
-
-void libafl_load_qemu_snapshot(char *name, bool sync)
-{
-    // use snapshots synchronously, use if main loop is not running
-    if (sync) {
-        //TODO: see libafl_save_qemu_snapshot
-        Error *err = NULL;
-
-        int saved_vm_running = runstate_is_running();
-        vm_stop(RUN_STATE_RESTORE_VM);
-
-        bool loaded = load_snapshot(name, NULL, false, NULL, &err);
-
-        if(!loaded) {
-            error_report_err(err);
-            error_report("Could not load snapshot");
-        }
-        if (loaded && saved_vm_running) {
-            vm_start();
-        }
-        return;
-    }
-    char* name_buffer = malloc(strlen(name)+1);
-    strcpy(name_buffer, name);
-    aio_bh_schedule_oneshot_full(qemu_get_aio_context(), load_snapshot_cb, (void*)name_buffer, "load_snapshot");
-}
-
-#endif
-
 void HELPER(libafl_qemu_handle_breakpoint)(CPUArchState *env, uint64_t pc)
 {
     CPUState* cpu = env_cpu(env);

cpu-target.c

@@ -47,139 +47,10 @@
 
 //// --- Begin LibAFL code ---
 
-#include "exec/gdbstub.h"
-
-#include "libafl/exit.h"
-#include "libafl/hook.h"
-
-int gdb_write_register(CPUState *cpu, uint8_t *mem_buf, int reg);
-
-static __thread GByteArray *libafl_qemu_mem_buf = NULL;
-
-target_ulong libafl_page_from_addr(target_ulong addr);
-
-CPUState* libafl_qemu_get_cpu(int cpu_index);
-int libafl_qemu_num_cpus(void);
-CPUState* libafl_qemu_current_cpu(void);
-int libafl_qemu_cpu_index(CPUState*);
-
-int libafl_qemu_write_reg(CPUState* cpu, int reg, uint8_t* val);
-int libafl_qemu_read_reg(CPUState* cpu, int reg, uint8_t* val);
-int libafl_qemu_num_regs(CPUState* cpu);
-
 #ifndef CONFIG_USER_ONLY
-hwaddr libafl_qemu_current_paging_id(CPUState* cpu);
+#include "libafl/syx-snapshot/device-save.h"
 #endif
 
-void libafl_flush_jit(void);
-
-extern int libafl_restoring_devices;
-
-/*
-void* libafl_qemu_g2h(CPUState *cpu, target_ulong x);
-target_ulong libafl_qemu_h2g(CPUState *cpu, void* x);
-
-void* libafl_qemu_g2h(CPUState *cpu, target_ulong x)
-{
-    return g2h(cpu, x);
-}
-
-target_ulong libafl_qemu_h2g(CPUState *cpu, void* x)
-{
-    return h2g(cpu, x);
-}
-*/
-
-target_ulong libafl_page_from_addr(target_ulong addr) {
-    return addr & TARGET_PAGE_MASK;
-}
-
-CPUState* libafl_qemu_get_cpu(int cpu_index)
-{
-    CPUState *cpu;
-    CPU_FOREACH(cpu) {
-        if (cpu->cpu_index == cpu_index)
-            return cpu;
-    }
-    return NULL;
-}
-
-int libafl_qemu_num_cpus(void)
-{
-    CPUState *cpu;
-    int num = 0;
-    CPU_FOREACH(cpu) {
-        num++;
-    }
-    return num;
-}
-
-CPUState* libafl_qemu_current_cpu(void)
-{
-#ifndef CONFIG_USER_ONLY
-    if (current_cpu == NULL) {
-        return libafl_last_exit_cpu();
-    }
-#endif
-    return current_cpu;
-}
-
-int libafl_qemu_cpu_index(CPUState* cpu)
-{
-    if (cpu) return cpu->cpu_index;
-    return -1;
-}
-
-int libafl_qemu_write_reg(CPUState* cpu, int reg, uint8_t* val)
-{
-    return gdb_write_register(cpu, val, reg);
-}
-
-int libafl_qemu_read_reg(CPUState* cpu, int reg, uint8_t* val)
-{
-    int len;
-
-    if (libafl_qemu_mem_buf == NULL) {
-        libafl_qemu_mem_buf = g_byte_array_sized_new(64);
-    }
-
-    g_byte_array_set_size(libafl_qemu_mem_buf, 0);
-
-    len = gdb_read_register(cpu, libafl_qemu_mem_buf, reg);
-
-    if (len > 0) {
-        memcpy(val, libafl_qemu_mem_buf->data, len);
-    }
-
-    return len;
-}
-
-int libafl_qemu_num_regs(CPUState* cpu)
-{
-    CPUClass *cc = CPU_GET_CLASS(cpu);
-    return cc->gdb_num_core_regs;
-}
-
-#ifndef CONFIG_USER_ONLY
-hwaddr libafl_qemu_current_paging_id(CPUState* cpu)
-{
-    CPUClass* cc = CPU_GET_CLASS(cpu);
-    if (cc->sysemu_ops && cc->sysemu_ops->get_paging_id) {
-        return cc->sysemu_ops->get_paging_id(cpu);
-    } else {
-        return 0;
-    }
-}
-#endif
-
-void libafl_flush_jit(void)
-{
-    CPUState *cpu;
-    CPU_FOREACH(cpu) {
-        tb_flush(cpu);
-    }
-}
-
 //// --- End LibAFL code ---
 
 #ifndef CONFIG_USER_ONLY
@@ -203,7 +74,9 @@ static int cpu_common_post_load(void *opaque, int version_id)
 
     // flushing the TBs every restore makes it really slow
     // TODO handle writes to X code with specific calls to tb_invalidate_phys_addr
-    if (!libafl_restoring_devices) tb_flush(cpu);
+    if (!libafl_devices_is_restoring()) {
+        tb_flush(cpu);
+    }
 
 //// --- End LibAFL code ---
 
@@ -462,23 +335,6 @@ void list_cpus(void)
     cpu_list();
 }
 
-//// --- Begin LibAFL code ---
-#if defined(CONFIG_USER_ONLY)
-void libafl_breakpoint_invalidate(CPUState *cpu, target_ulong pc)
-{
-  mmap_lock();
-  tb_invalidate_phys_range(pc, pc + 1);
-  mmap_unlock();
-}
-#else
-void libafl_breakpoint_invalidate(CPUState *cpu, target_ulong pc)
-{
-  // TODO invalidate only the virtual pages related to the TB
-  tb_flush(cpu);
-}
-#endif
-//// --- End LibAFL code ---
-
 /* enable or disable single step mode. EXCP_DEBUG is returned by the
    CPU loop after each instruction */
 void cpu_single_step(CPUState *cpu, int enabled)

gdbstub/gdbstub.c

@@ -1648,30 +1648,6 @@ static void handle_query_thread_extra(GArray *params, void *user_ctx)
     gdb_put_strbuf();
 }
 
-//// --- Begin LibAFL code ---
-
-struct libafl_custom_gdb_cmd* libafl_qemu_gdb_cmds;
-
-void libafl_qemu_add_gdb_cmd(int (*callback)(void*, uint8_t*, size_t), void* data);
-void libafl_qemu_add_gdb_cmd(int (*callback)(void*, uint8_t*, size_t), void* data)
-{
-    struct libafl_custom_gdb_cmd* c = malloc(sizeof(struct libafl_custom_gdb_cmd));
-    c->callback = callback;
-    c->data = data;
-    c->next = libafl_qemu_gdb_cmds;
-    libafl_qemu_gdb_cmds = c;
-}
-
-void libafl_qemu_gdb_reply(const char* buf, size_t len);
-void libafl_qemu_gdb_reply(const char* buf, size_t len)
-{
-    g_autoptr(GString) hex_buf = g_string_new("O");
-    gdb_memtohex(hex_buf, (const uint8_t *) buf, len);
-    gdb_put_packet(hex_buf->str);
-}
-
-//// --- End LibAFL code ---
-
 static void handle_query_supported(GArray *params, void *user_ctx)
 {
     CPUClass *cc;

gdbstub/internals.h

@@ -240,16 +240,4 @@ void gdb_breakpoint_remove_all(CPUState *cs);
 int gdb_target_memory_rw_debug(CPUState *cs, hwaddr addr,
                                uint8_t *buf, int len, bool is_write);
 
-//// --- Begin LibAFL code ---
-
-struct libafl_custom_gdb_cmd {
-    int (*callback)(void*, uint8_t*, size_t);
-    void* data;
-    struct libafl_custom_gdb_cmd* next;
-};
-
-extern struct libafl_custom_gdb_cmd* libafl_qemu_gdb_cmds;
-
-//// --- End LibAFL code ---
-
 #endif /* GDBSTUB_INTERNALS_H */

gdbstub/system.c

@@ -30,6 +30,10 @@
 #include "trace.h"
 #include "internals.h"
 
+//// --- Begin LibAFL code ---
+#include "libafl/gdb.h"
+//// --- End LibAFL code ---
+
 /* System emulation specific state */
 typedef struct {
     CharBackend chr;
@@ -531,14 +535,7 @@ void gdb_handle_query_rcmd(GArray *params, void *ctx)
 
     //// --- Begin LibAFL code ---
 
-    struct libafl_custom_gdb_cmd** c = &libafl_qemu_gdb_cmds;
-    int recognized = 0;
-    while (*c) {
-        recognized |= (*c)->callback((*c)->data, gdbserver_state.mem_buf->data, gdbserver_state.mem_buf->len);
-        c = &(*c)->next;
-    }
-
-    if (recognized) {
+    if (libafl_qemu_gdb_exec()) {
         gdb_put_packet("OK");
         return;
     }

gdbstub/user-target.c

@@ -14,6 +14,11 @@
 #ifdef CONFIG_LINUX
 #include "linux-user/loader.h"
 #include "linux-user/qemu.h"
+
+//// --- Begin LibAFL code ---
+#include "libafl/gdb.h"
+//// --- End LibAFL code ---
+
 #endif
 
 /*
@@ -305,27 +310,17 @@ void gdb_handle_query_rcmd(GArray *params, void *user_ctx)
     g_assert(gdbserver_state.mem_buf->len == 0);
     len = len / 2;
     gdb_hextomem(gdbserver_state.mem_buf, get_param(params, 0)->data, len);
-    
-    //// --- Begin LibAFL code ---
-
-    struct libafl_custom_gdb_cmd** c = &libafl_qemu_gdb_cmds;
-    int recognized = 0;
-    while (*c) {
-        recognized |= (*c)->callback((*c)->data, gdbserver_state.mem_buf->data, gdbserver_state.mem_buf->len);
-        c = &(*c)->next;
-    }
 
-    if (recognized) {
+    if (libafl_qemu_gdb_exec()) {
         gdb_put_packet("OK");
     } else {
         gdb_put_packet("");
     }
 }
+#endif
 
 //// --- End LibAFL code ---
 
-#endif
-
 static const char *get_filename_param(GArray *params, int i)
 {
     const char *hex_filename = get_param(params, i)->data;