[PATCH 4/4] plugins/execlog: add address range matching

[Sven Schnelle <svens@stackframe.org>]

Allow to match memory ranges with the address matches. This
allows to give a range of adresses like '-dfilter=0-0x400'
which would only log memory accesses between 0 and 400.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 contrib/plugins/execlog.c | 65 +++++++++++++++++++++++++++++++--------
 1 file changed, 52 insertions(+), 13 deletions(-)

diff --git a/contrib/plugins/execlog.c b/contrib/plugins/execlog.c
index 33fef9bfc6..a505f98be8 100644
--- a/contrib/plugins/execlog.c
+++ b/contrib/plugins/execlog.c
@@ -30,6 +30,11 @@ struct execlog_ctx {
     bool log;
 };
 
+struct address_match {
+    uint64_t low;
+    uint64_t high;
+};
+
 /*
  * Expand last_exec array.
  *
@@ -47,17 +52,18 @@ static void expand_last_exec(int cpu_index)
     g_rw_lock_writer_unlock(&expand_array_lock);
 }
 
-static bool match_vaddr(struct execlog_ctx *ctx, uint64_t vaddr)
+static bool match_address_range(GArray *match, uint64_t vaddr)
 {
-    for (int i = 0; i < dmatches->len; i++) {
-        uint64_t v = g_array_index(dmatches, uint64_t, i);
-        if (v == vaddr) {
-            ctx->log = true;
+    for (int i = 0; i < match->len; i++) {
+        struct address_match *m =
+            g_array_index(match, struct address_match *, i);
+        if (vaddr >= m->low && vaddr <= m->high) {
             return true;
         }
     }
     return false;
 }
+
 /**
  * Add memory read or write information to current instruction log
  */
@@ -70,9 +76,10 @@ static void vcpu_mem(unsigned int cpu_index, qemu_plugin_meminfo_t info,
     struct execlog_ctx *ctx = g_ptr_array_index(last_exec, cpu_index);
     g_rw_lock_reader_unlock(&expand_array_lock);
 
-    if (dmatches && !match_vaddr(ctx, vaddr)) {
+    if (dmatches && !match_address_range(dmatches, vaddr)) {
         return;
     }
+    ctx->log = true;
     GString *s = ctx->s;
     /* Indicate type of memory access */
     if (qemu_plugin_mem_is_store(info)) {
@@ -166,8 +173,7 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
         if (skip && amatches) {
             int j;
             for (j = 0; j < amatches->len && skip; j++) {
-                uint64_t v = g_array_index(amatches, uint64_t, j);
-                if (v == insn_vaddr) {
+                if (match_address_range(amatches, insn_vaddr)) {
                     skip = false;
                 }
             }
@@ -197,6 +203,16 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
     }
 }
 
+static void free_matches(GArray *matches)
+{
+    if (!matches) {
+        return;
+    }
+
+    for (int i = 0; i < matches->len; i++) {
+        g_free(g_array_index(matches, struct address_match *, i));
+    }
+}
 /**
  * On plugin exit, print last instruction in cache
  */
@@ -212,6 +228,9 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
             qemu_plugin_outs("\n");
         }
     }
+
+    free_matches(amatches);
+    free_matches(dmatches);
 }
 
 /* Add a match to the array of matches */
@@ -223,14 +242,34 @@ static void parse_insn_match(char *match)
     g_ptr_array_add(imatches, match);
 }
 
-static void parse_vaddr_match(GArray **matches, char *match)
+static void parse_vaddr_match(GArray **matches, char *token)
 {
-    uint64_t v = g_ascii_strtoull(match, NULL, 16);
+    uint64_t low, high;
+    gchar *endp;
 
-    if (!matches) {
-        *matches = g_array_new(false, true, sizeof(uint64_t));
+    low = g_ascii_strtoull(token, &endp, 16);
+    if (endp == token) {
+        fprintf(stderr, "Invalid address(range) specified: %s\n", token);
+        return;
+    }
+
+    if (*endp != '-') {
+        high = low;
+    } else {
+        high = g_ascii_strtoull(endp + 1, &endp, 16);
+        if (endp == token) {
+            fprintf(stderr, "Invalid address(range) specified: %s\n", token);
+            return;
+        }
+    }
+
+    if (!*matches) {
+        *matches = g_array_new(false, true, sizeof(struct address_match));
     }
-    g_array_append_val(*matches, v);
+    struct address_match *match = g_new(struct address_match, 1);
+    match->low = low;
+    match->high = high;
+    g_array_append_val(*matches, match);
 }
 
 /**
-- 
2.43.2