linux-user: Add strace support for printing arguments of ioctl()

This patch implements functionality for strace argument printing for ioctls.
When running ioctls through qemu with "-strace", they get printed in format:

    "ioctl(fd_num,0x*,0x*) = ret_value"

where the request code an the ioctl's third argument get printed in a hexadicemal
format. This patch changes that by enabling strace to print both the request code
name and the contents of the third argument. For example, when running ioctl
RTC_SET_TIME with "-strace", with changes from this patch, it gets printed in
this way:

    "ioctl(3,RTC_SET_TIME,{12,13,15,20,10,119,0,0,0}) = 0"

In case of IOC_R type ioctls, the contents of the third argument get printed
after the return value, and the argument inside the ioctl call gets printed
as pointer in hexadecimal format. For example, when running RTC_RD_TIME with
"-strace", with changes from this patch, it gets printed in this way:

    "ioctl(3,RTC_RD_TIME,0x40800374) = 0 ({22,9,13,11,5,120,0,0,0})"

In case of IOC_RW type ioctls, the contents of the third argument get printed
both inside the ioctl call and after the return value.

Implementation notes:

    Functions "print_ioctl()" and "print_syscall_ret_ioctl()", that are defined
    in "strace.c", are listed in file "strace.list" as "call" and "result"
    value for ioctl. Structure definition "IOCTLEntry" as well as predefined
    values for IOC_R, IOC_W and IOC_RW were cut and pasted from file "syscall.c"
    to file "qemu.h" so that they can be used by these functions to print the
    contents of the third ioctl argument. Also, the "static" identifier for array
    "ioctl_entries[]" was removed and this array was declared as "extern" in "qemu.h"
    so that it can also be used by these functions. To decode the structure type
    of the ioctl third argument, function "thunk_print()" was defined in file
    "thunk.c" and its definition is somewhat simillar to that of function
    "thunk_convert()".

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200619124727.18080-3-filip.bozuta@syrmia.com>
[lv: fix close-bracket]
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

1 files changed, 154 insertions, 0 deletions

diff --git a/thunk.c b/thunk.c
index 7f31cffe09..c5d9719747 100644
--- a/thunk.c
+++ b/thunk.c
@@ -271,6 +271,160 @@ const argtype *thunk_convert(void *dst, const void *src,
     return type_ptr;
 }
 
+const argtype *thunk_print(void *arg, const argtype *type_ptr)
+{
+    int type;
+
+    type = *type_ptr++;
+
+    switch (type) {
+    case TYPE_CHAR:
+        qemu_log("%c", *(uint8_t *)arg);
+        break;
+    case TYPE_SHORT:
+        qemu_log("%" PRId16, tswap16(*(uint16_t *)arg));
+        break;
+    case TYPE_INT:
+        qemu_log("%" PRId32, tswap32(*(uint32_t *)arg));
+        break;
+    case TYPE_LONGLONG:
+        qemu_log("%" PRId64, tswap64(*(uint64_t *)arg));
+        break;
+    case TYPE_ULONGLONG:
+        qemu_log("%" PRIu64, tswap64(*(uint64_t *)arg));
+        break;
+#if HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 32
+    case TYPE_PTRVOID:
+        qemu_log("0x%" PRIx32, tswap32(*(uint32_t *)arg));
+        break;
+    case TYPE_LONG:
+        qemu_log("%" PRId32, tswap32(*(uint32_t *)arg));
+        break;
+    case TYPE_ULONG:
+        qemu_log("%" PRIu32, tswap32(*(uint32_t *)arg));
+        break;
+#elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 32
+    case TYPE_PTRVOID:
+        qemu_log("0x%" PRIx32, tswap32(*(uint64_t *)arg & 0xffffffff));
+        break;
+    case TYPE_LONG:
+        qemu_log("%" PRId32, tswap32(*(uint64_t *)arg & 0xffffffff));
+        break;
+    case TYPE_ULONG:
+        qemu_log("%" PRIu32, tswap32(*(uint64_t *)arg & 0xffffffff));
+        break;
+#elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
+    case TYPE_PTRVOID:
+        qemu_log("0x%" PRIx64, tswap64(*(uint64_t *)arg));
+        break;
+    case TYPE_LONG:
+        qemu_log("%" PRId64, tswap64(*(uint64_t *)arg));
+        break;
+    case TYPE_ULONG:
+        qemu_log("%" PRIu64, tswap64(*(uint64_t *)arg));
+        break;
+#else
+    case TYPE_PTRVOID:
+        qemu_log("0x%" PRIx64, tswap64(*(uint64_t *)arg));
+        break;
+    case TYPE_LONG:
+        qemu_log("%" PRId64, tswap64(*(uint64_t *)arg));
+        break;
+    case TYPE_ULONG:
+        qemu_log("%" PRIu64, tswap64(*(uint64_t *)arg));
+        break;
+#endif
+    case TYPE_OLDDEVT:
+    {
+        uint64_t val = 0;
+        switch (thunk_type_size(type_ptr - 1, 1)) {
+        case 2:
+            val = *(uint16_t *)arg;
+            break;
+        case 4:
+            val = *(uint32_t *)arg;
+            break;
+        case 8:
+            val = *(uint64_t *)arg;
+            break;
+        }
+        switch (thunk_type_size(type_ptr - 1, 0)) {
+        case 2:
+            qemu_log("%" PRIu16, tswap16(val));
+            break;
+        case 4:
+            qemu_log("%" PRIu32, tswap32(val));
+            break;
+        case 8:
+            qemu_log("%" PRIu64, tswap64(val));
+            break;
+        }
+    }
+    break;
+    case TYPE_ARRAY:
+        {
+            int i, array_length, arg_size;
+            uint8_t *a;
+            int is_string = 0;
+
+            array_length = *type_ptr++;
+            arg_size = thunk_type_size(type_ptr, 0);
+            a = arg;
+
+            if (*type_ptr == TYPE_CHAR) {
+                qemu_log("\"");
+                is_string = 1;
+            } else {
+                qemu_log("[");
+            }
+
+            for (i = 0; i < array_length; i++) {
+                if (i > 0 && !is_string) {
+                    qemu_log(",");
+                }
+                thunk_print(a, type_ptr);
+                a += arg_size;
+            }
+
+            if (is_string) {
+                qemu_log("\"");
+            } else {
+                qemu_log("]");
+            }
+
+            type_ptr = thunk_type_next(type_ptr);
+        }
+        break;
+    case TYPE_STRUCT:
+        {
+            int i;
+            const StructEntry *se;
+            uint8_t  *a;
+            const argtype *field_types;
+            const int *arg_offsets;
+
+            se = struct_entries + *type_ptr++;
+            a = arg;
+
+            field_types = se->field_types;
+            arg_offsets = se->field_offsets[0];
+
+            qemu_log("{");
+            for (i = 0; i < se->nb_fields; i++) {
+                if (i > 0) {
+                    qemu_log(",");
+                }
+                field_types = thunk_print(a + arg_offsets[i], field_types);
+            }
+            qemu_log("}");
+        }
+        break;
+    default:
+        g_assert_not_reached();
+    }
+    return type_ptr;
+}
+
 /* from em86 */
 
 /* Utility function: Table-driven functions to translate bitmasks