implement syscall mask getter

[lttng-modules.git] / lttng-syscalls.c

diff --git a/lttng-syscalls.c b/lttng-syscalls.c
index 0a8074f805ea2efd8e826be92c5d9fee3eac3534..96d90c58c586a2affa6d46ed17c993c69bcb98cb 100644 (file)
--- a/lttng-syscalls.c
+++ b/lttng-syscalls.c
@@ -31,6 +31,7 @@
 #include <asm/ptrace.h>
 #include <asm/syscall.h>
 
+#include "lib/bitfield.h"
 #include "wrapper/tracepoint.h"
 #include "lttng-events.h"
 
@@ -950,6 +951,12 @@ int get_compat_syscall_nr(const char *syscall_name)
        return syscall_nr;
 }
 
+static
+uint32_t get_sc_tables_len(void)
+{
+       return ARRAY_SIZE(sc_table) + ARRAY_SIZE(compat_sc_table);
+}
+
 int lttng_syscall_filter_enable(struct lttng_channel *chan,
                const char *name)
 {
@@ -1112,22 +1119,40 @@ void syscall_list_stop(struct seq_file *m, void *p)
 {
 }
 
+static
+int get_sc_table(const struct trace_syscall_entry *entry,
+               const struct trace_syscall_entry **table,
+               unsigned int *bitness)
+{
+       if (entry >= sc_table && entry < sc_table + ARRAY_SIZE(sc_table)) {
+               if (bitness)
+                       *bitness = BITS_PER_LONG;
+               if (table)
+                       *table = sc_table;
+               return 0;
+       }
+       if (!(entry >= compat_sc_table
+                       && entry < compat_sc_table + ARRAY_SIZE(compat_sc_table))) {
+               return -EINVAL;
+       }
+       if (bitness)
+               *bitness = 32;
+       if (table)
+               *table = compat_sc_table;
+       return 0;
+}
+
 static
 int syscall_list_show(struct seq_file *m, void *p)
 {
        const struct trace_syscall_entry *table, *entry = p;
        unsigned int bitness;
+       int ret;
 
-       if (entry >= sc_table && entry < sc_table + ARRAY_SIZE(sc_table)) {
-               bitness = BITS_PER_LONG;
-               table = sc_table;
-       } else {
-               bitness = 32;
-               table = compat_sc_table;
-               WARN_ON_ONCE(!(entry >= compat_sc_table
-                       && entry < compat_sc_table + ARRAY_SIZE(compat_sc_table)));
-       }
-       seq_printf(m,   "syscall { id = %u; name = %s; bitness = %u; };\n",
+       ret = get_sc_table(entry, &table, &bitness);
+       if (ret)
+               return ret;
+       seq_printf(m,   "syscall { index = %lu; name = %s; bitness = %u; };\n",
                entry - table,
                entry->desc->name,
                bitness);
@@ -1155,3 +1180,40 @@ const struct file_operations lttng_syscall_list_fops = {
        .llseek = seq_lseek,
        .release = seq_release,
 };
+
+long lttng_channel_syscall_mask(struct lttng_channel *channel,
+               struct lttng_kernel_syscall_mask __user *usyscall_mask)
+{
+       uint32_t len, sc_tables_len, bitmask_len;
+       int ret = 0, bit;
+       char *tmp_mask;
+       struct lttng_syscall_filter *filter;
+
+       ret = get_user(len, &usyscall_mask->len);
+       if (ret)
+               return ret;
+       sc_tables_len = get_sc_tables_len();
+       bitmask_len = ALIGN(sc_tables_len, 8) >> 3;
+       if (len < sc_tables_len) {
+               return put_user(sc_tables_len, &usyscall_mask->len);
+       }
+       /* Array is large enough, we can copy array to user-space. */
+       tmp_mask = kzalloc(bitmask_len, GFP_KERNEL);
+       if (!tmp_mask)
+               return -ENOMEM;
+       filter = channel->sc_filter;
+
+       for (bit = 0; bit < ARRAY_SIZE(sc_table); bit++) {
+               bt_bitfield_write_be(tmp_mask, char, bit, 1,
+                       test_bit(bit, filter->sc));
+       }
+       for (; bit < sc_tables_len; bit++) {
+               bt_bitfield_write_be(tmp_mask, char, bit, 1,
+                       test_bit(bit - ARRAY_SIZE(sc_table),
+                               filter->sc_compat));
+       }
+       if (copy_to_user(usyscall_mask->mask, tmp_mask, bitmask_len))
+               ret = -EFAULT;
+       kfree(tmp_mask);
+       return ret;
+}