From 2d2464bd8910c4c8a090675338159f6642c83f41 Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Fri, 12 Sep 2014 14:12:43 -0400
Subject: [PATCH] Implement syscall listing

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 lttng-abi.c      | 39 ++++++++++++++++++++++
 lttng-abi.h      |  1 +
 lttng-events.h   |  1 +
 lttng-syscalls.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 125 insertions(+)

diff --git a/lttng-abi.c b/lttng-abi.c
index 6dc59aed..ab0a1128 100644
--- a/lttng-abi.c
+++ b/lttng-abi.c
@@ -143,6 +143,43 @@ fd_error:
 	return ret;
 }
 
+static
+int lttng_abi_syscall_list(void)
+{
+	struct file *syscall_list_file;
+	int file_fd, ret;
+
+	file_fd = get_unused_fd();
+	if (file_fd < 0) {
+		ret = file_fd;
+		goto fd_error;
+	}
+
+	syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
+					  &lttng_syscall_list_fops,
+					  NULL, O_RDWR);
+	if (IS_ERR(syscall_list_file)) {
+		ret = PTR_ERR(syscall_list_file);
+		goto file_error;
+	}
+	ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
+	if (ret < 0)
+		goto open_error;
+	fd_install(file_fd, syscall_list_file);
+	if (file_fd < 0) {
+		ret = file_fd;
+		goto fd_error;
+	}
+	return file_fd;
+
+open_error:
+	fput(syscall_list_file);
+file_error:
+	put_unused_fd(file_fd);
+fd_error:
+	return ret;
+}
+
 static
 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 {
@@ -249,6 +286,8 @@ long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 	case LTTNG_KERNEL_TRACEPOINT_LIST:
 		return lttng_abi_tracepoint_list();
+	case LTTNG_KERNEL_SYSCALL_LIST:
+		return lttng_abi_syscall_list();
 	case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 	case LTTNG_KERNEL_WAIT_QUIESCENT:
 		synchronize_trace();
diff --git a/lttng-abi.h b/lttng-abi.h
index b626b88e..27943579 100644
--- a/lttng-abi.h
+++ b/lttng-abi.h
@@ -157,6 +157,7 @@ struct lttng_kernel_context {
 #define LTTNG_KERNEL_WAIT_QUIESCENT		_IO(0xF6, 0x48)
 #define LTTNG_KERNEL_CALIBRATE			\
 	_IOWR(0xF6, 0x49, struct lttng_kernel_calibrate)
+#define LTTNG_KERNEL_SYSCALL_LIST		_IO(0xF6, 0x49)
 
 /* Session FD ioctl */
 #define LTTNG_KERNEL_METADATA			\
diff --git a/lttng-events.h b/lttng-events.h
index cf5acafa..92a61789 100644
--- a/lttng-events.h
+++ b/lttng-events.h
@@ -556,6 +556,7 @@ void lttng_ftrace_destroy_private(struct lttng_event *event)
 int lttng_calibrate(struct lttng_kernel_calibrate *calibrate);
 
 extern const struct file_operations lttng_tracepoint_list_fops;
+extern const struct file_operations lttng_syscall_list_fops;
 
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,35))
 #define TRACEPOINT_HAS_DATA_ARG
diff --git a/lttng-syscalls.c b/lttng-syscalls.c
index c23f1d9e..25b8431a 100644
--- a/lttng-syscalls.c
+++ b/lttng-syscalls.c
@@ -27,6 +27,7 @@
 #include <linux/bitmap.h>
 #include <linux/in.h>
 #include <linux/in6.h>
+#include <linux/seq_file.h>
 #include <asm/ptrace.h>
 #include <asm/syscall.h>
 
@@ -1070,3 +1071,86 @@ error:
 		kfree(filter);
 	return ret;
 }
+
+static
+const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
+{
+	const struct trace_syscall_entry *entry;
+	int iter = 0;
+
+	for (entry = sc_table;
+			entry < sc_table + ARRAY_SIZE(sc_table);
+			 entry++) {
+		if (iter++ >= *pos)
+			return entry;
+	}
+	for (entry = compat_sc_table;
+			entry < compat_sc_table + ARRAY_SIZE(compat_sc_table);
+			 entry++) {
+		if (iter++ >= *pos)
+			return entry;
+	}
+	/* End of list */
+	return NULL;
+}
+
+static
+void *syscall_list_start(struct seq_file *m, loff_t *pos)
+{
+	return (void *) syscall_list_get_entry(pos);
+}
+
+static
+void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
+{
+	(*ppos)++;
+	return (void *) syscall_list_get_entry(ppos);
+}
+
+static
+void syscall_list_stop(struct seq_file *m, void *p)
+{
+}
+
+static
+int syscall_list_show(struct seq_file *m, void *p)
+{
+	const struct trace_syscall_entry *table, *entry = p;
+	unsigned int bitness;
+
+	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 { name = %s; bitness = %u; };\n",
+		entry->desc->name,
+		bitness);
+	return 0;
+}
+
+static
+const struct seq_operations lttng_syscall_list_seq_ops = {
+	.start = syscall_list_start,
+	.next = syscall_list_next,
+	.stop = syscall_list_stop,
+	.show = syscall_list_show,
+};
+
+static
+int lttng_syscall_list_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &lttng_syscall_list_seq_ops);
+}
+
+const struct file_operations lttng_syscall_list_fops = {
+	.owner = THIS_MODULE,
+	.open = lttng_syscall_list_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
-- 
2.34.1