1 files changed, 86 insertions, 58 deletions

diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index 5f28d5c..349d348 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -75,8 +75,6 @@ void gdb_init_gdbserver_state(void)
     gdbserver_state.sstep_flags &= gdbserver_state.supported_sstep_flags;
 }
 
-bool gdb_has_xml;
-
 /* writes 2*len+1 bytes in buf */
 void gdb_memtohex(GString *buf, const uint8_t *mem, int len)
 {
@@ -351,67 +349,75 @@ static CPUState *gdb_get_cpu(uint32_t pid, uint32_t tid)
     }
 }
 
+bool gdb_has_xml(void)
+{
+    return !!gdb_get_cpu_process(gdbserver_state.g_cpu)->target_xml;
+}
+
 static const char *get_feature_xml(const char *p, const char **newp,
                                    GDBProcess *process)
 {
-    size_t len;
-    int i;
-    const char *name;
     CPUState *cpu = gdb_get_first_cpu_in_process(process);
     CPUClass *cc = CPU_GET_CLASS(cpu);
+    size_t len;
 
-    len = 0;
-    while (p[len] && p[len] != ':')
-        len++;
-    *newp = p + len;
+    /*
+     * qXfer:features:read:ANNEX:OFFSET,LENGTH'
+     *                     ^p    ^newp
+     */
+    char *term = strchr(p, ':');
+    *newp = term + 1;
+    len = term - p;
 
-    name = NULL;
+    /* Is it the main target xml? */
     if (strncmp(p, "target.xml", len) == 0) {
-        char *buf = process->target_xml;
-        const size_t buf_sz = sizeof(process->target_xml);
-
-        /* Generate the XML description for this CPU.  */
-        if (!buf[0]) {
+        if (!process->target_xml) {
             GDBRegisterState *r;
+            GString *xml = g_string_new("<?xml version=\"1.0\"?>");
+
+            g_string_append(xml,
+                            "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">"
+                            "<target>");
 
-            pstrcat(buf, buf_sz,
-                    "<?xml version=\"1.0\"?>"
-                    "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">"
-                    "<target>");
             if (cc->gdb_arch_name) {
-                gchar *arch = cc->gdb_arch_name(cpu);
-                pstrcat(buf, buf_sz, "<architecture>");
-                pstrcat(buf, buf_sz, arch);
-                pstrcat(buf, buf_sz, "</architecture>");
-                g_free(arch);
+                g_autofree gchar *arch = cc->gdb_arch_name(cpu);
+                g_string_append_printf(xml,
+                                       "<architecture>%s</architecture>",
+                                       arch);
             }
-            pstrcat(buf, buf_sz, "<xi:include href=\"");
-            pstrcat(buf, buf_sz, cc->gdb_core_xml_file);
-            pstrcat(buf, buf_sz, "\"/>");
+            g_string_append(xml, "<xi:include href=\"");
+            g_string_append(xml, cc->gdb_core_xml_file);
+            g_string_append(xml, "\"/>");
             for (r = cpu->gdb_regs; r; r = r->next) {
-                pstrcat(buf, buf_sz, "<xi:include href=\"");
-                pstrcat(buf, buf_sz, r->xml);
-                pstrcat(buf, buf_sz, "\"/>");
+                g_string_append(xml, "<xi:include href=\"");
+                g_string_append(xml, r->xml);
+                g_string_append(xml, "\"/>");
             }
-            pstrcat(buf, buf_sz, "</target>");
+            g_string_append(xml, "</target>");
+
+            process->target_xml = g_string_free(xml, false);
+            return process->target_xml;
         }
-        return buf;
     }
+    /* Is it dynamically generated by the target? */
     if (cc->gdb_get_dynamic_xml) {
-        char *xmlname = g_strndup(p, len);
+        g_autofree char *xmlname = g_strndup(p, len);
         const char *xml = cc->gdb_get_dynamic_xml(cpu, xmlname);
-
-        g_free(xmlname);
         if (xml) {
             return xml;
         }
     }
-    for (i = 0; ; i++) {
-        name = xml_builtin[i][0];
-        if (!name || (strncmp(name, p, len) == 0 && strlen(name) == len))
-            break;
+    /* Is it one of the encoded gdb-xml/ files? */
+    for (int i = 0; xml_builtin[i][0]; i++) {
+        const char *name = xml_builtin[i][0];
+        if ((strncmp(name, p, len) == 0) &&
+            strlen(name) == len) {
+            return xml_builtin[i][1];
+        }
     }
-    return name ? xml_builtin[i][1] : NULL;
+
+    /* failed */
+    return NULL;
 }
 
 static int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg)
@@ -450,12 +456,6 @@ static int gdb_write_register(CPUState *cpu, uint8_t *mem_buf, int reg)
     return 0;
 }
 
-/* Register a supplemental set of CPU registers.  If g_pos is nonzero it
-   specifies the first register number and these registers are included in
-   a standard "g" packet.  Direction is relative to gdb, i.e. get_reg is
-   gdb reading a CPU register, and set_reg is gdb modifying a CPU register.
- */
-
 void gdb_register_coprocessor(CPUState *cpu,
                               gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg,
                               int num_regs, const char *xml, int g_pos)
@@ -597,6 +597,15 @@ static int gdb_handle_vcont(const char *p)
      *  or incorrect parameters passed.
      */
     res = 0;
+
+    /*
+     * target_count and last_target keep track of how many CPUs we are going to
+     * step or resume, and a pointer to the state structure of one of them,
+     * respectivelly
+     */
+    int target_count = 0;
+    CPUState *last_target = NULL;
+
     while (*p) {
         if (*p++ != ';') {
             return -ENOTSUP;
@@ -637,6 +646,9 @@ static int gdb_handle_vcont(const char *p)
             while (cpu) {
                 if (newstates[cpu->cpu_index] == 1) {
                     newstates[cpu->cpu_index] = cur_action;
+
+                    target_count++;
+                    last_target = cpu;
                 }
 
                 cpu = gdb_next_attached_cpu(cpu);
@@ -654,6 +666,9 @@ static int gdb_handle_vcont(const char *p)
             while (cpu) {
                 if (newstates[cpu->cpu_index] == 1) {
                     newstates[cpu->cpu_index] = cur_action;
+
+                    target_count++;
+                    last_target = cpu;
                 }
 
                 cpu = gdb_next_cpu_in_process(cpu);
@@ -671,11 +686,25 @@ static int gdb_handle_vcont(const char *p)
             /* only use if no previous match occourred */
             if (newstates[cpu->cpu_index] == 1) {
                 newstates[cpu->cpu_index] = cur_action;
+
+                target_count++;
+                last_target = cpu;
             }
             break;
         }
     }
 
+    /*
+     * if we're about to resume a specific set of CPUs/threads, make it so that
+     * in case execution gets interrupted, we can send GDB a stop reply with a
+     * correct value. it doesn't really matter which CPU we tell GDB the signal
+     * happened in (VM pauses stop all of them anyway), so long as it is one of
+     * the ones we resumed/single stepped here.
+     */
+    if (target_count > 0) {
+        gdbserver_state.c_cpu = last_target;
+    }
+
     gdbserver_state.signal = signal;
     gdb_continue_partial(newstates);
     return res;
@@ -807,7 +836,7 @@ static inline int startswith(const char *string, const char *pattern)
   return !strncmp(string, pattern, strlen(pattern));
 }
 
-static int process_string_cmd(void *user_ctx, const char *data,
+static int process_string_cmd(const char *data,
                               const GdbCmdParseEntry *cmds, int num_cmds)
 {
     int i;
@@ -834,7 +863,7 @@ static int process_string_cmd(void *user_ctx, const char *data,
         }
 
         gdbserver_state.allow_stop_reply = cmd->allow_stop_reply;
-        cmd->handler(params, user_ctx);
+        cmd->handler(params, NULL);
         return 0;
     }
 
@@ -852,7 +881,7 @@ static void run_cmd_parser(const char *data, const GdbCmdParseEntry *cmd)
 
     /* In case there was an error during the command parsing we must
     * send a NULL packet to indicate the command is not supported */
-    if (process_string_cmd(NULL, data, cmd, 1)) {
+    if (process_string_cmd(data, cmd, 1)) {
         gdb_put_packet("");
     }
 }
@@ -1052,7 +1081,7 @@ static void handle_set_reg(GArray *params, void *user_ctx)
 {
     int reg_size;
 
-    if (!gdb_has_xml) {
+    if (!gdb_get_cpu_process(gdbserver_state.g_cpu)->target_xml) {
         gdb_put_packet("");
         return;
     }
@@ -1073,7 +1102,7 @@ static void handle_get_reg(GArray *params, void *user_ctx)
 {
     int reg_size;
 
-    if (!gdb_has_xml) {
+    if (!gdb_get_cpu_process(gdbserver_state.g_cpu)->target_xml) {
         gdb_put_packet("");
         return;
     }
@@ -1365,7 +1394,7 @@ static void handle_v_commands(GArray *params, void *user_ctx)
         return;
     }
 
-    if (process_string_cmd(NULL, get_param(params, 0)->data,
+    if (process_string_cmd(get_param(params, 0)->data,
                            gdb_v_commands_table,
                            ARRAY_SIZE(gdb_v_commands_table))) {
         gdb_put_packet("");
@@ -1540,7 +1569,6 @@ static void handle_query_xfer_features(GArray *params, void *user_ctx)
         return;
     }
 
-    gdb_has_xml = true;
     p = get_param(params, 0)->data;
     xml = get_feature_xml(p, &p, process);
     if (!xml) {
@@ -1709,13 +1737,13 @@ static void handle_gen_query(GArray *params, void *user_ctx)
         return;
     }
 
-    if (!process_string_cmd(NULL, get_param(params, 0)->data,
+    if (!process_string_cmd(get_param(params, 0)->data,
                             gdb_gen_query_set_common_table,
                             ARRAY_SIZE(gdb_gen_query_set_common_table))) {
         return;
     }
 
-    if (process_string_cmd(NULL, get_param(params, 0)->data,
+    if (process_string_cmd(get_param(params, 0)->data,
                            gdb_gen_query_table,
                            ARRAY_SIZE(gdb_gen_query_table))) {
         gdb_put_packet("");
@@ -1728,13 +1756,13 @@ static void handle_gen_set(GArray *params, void *user_ctx)
         return;
     }
 
-    if (!process_string_cmd(NULL, get_param(params, 0)->data,
+    if (!process_string_cmd(get_param(params, 0)->data,
                             gdb_gen_query_set_common_table,
                             ARRAY_SIZE(gdb_gen_query_set_common_table))) {
         return;
     }
 
-    if (process_string_cmd(NULL, get_param(params, 0)->data,
+    if (process_string_cmd(get_param(params, 0)->data,
                            gdb_gen_set_table,
                            ARRAY_SIZE(gdb_gen_set_table))) {
         gdb_put_packet("");
@@ -2216,6 +2244,6 @@ void gdb_create_default_process(GDBState *s)
     process = &s->processes[s->process_num - 1];
     process->pid = pid;
     process->attached = false;
-    process->target_xml[0] = '\0';
+    process->target_xml = NULL;
 }