kernel

linux-6.8.1/include/linux/trace_seq.h

@@ -0,0 +1,160 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TRACE_SEQ_H
+#define _LINUX_TRACE_SEQ_H
+
+#include <linux/seq_buf.h>
+
+#include <asm/page.h>
+
+/*
+ * Trace sequences are used to allow a function to call several other functions
+ * to create a string of data to use.
+ *
+ * Have the trace seq to be 8K which is typically PAGE_SIZE * 2 on
+ * most architectures. The TRACE_SEQ_BUFFER_SIZE (which is
+ * TRACE_SEQ_SIZE minus the other fields of trace_seq), is the
+ * max size the output of a trace event may be.
+ */
+
+#define TRACE_SEQ_SIZE		8192
+#define TRACE_SEQ_BUFFER_SIZE	(TRACE_SEQ_SIZE - \
+	(sizeof(struct seq_buf) + sizeof(size_t) + sizeof(int)))
+
+struct trace_seq {
+	char			buffer[TRACE_SEQ_BUFFER_SIZE];
+	struct seq_buf		seq;
+	size_t			readpos;
+	int			full;
+};
+
+static inline void
+trace_seq_init(struct trace_seq *s)
+{
+	seq_buf_init(&s->seq, s->buffer, TRACE_SEQ_BUFFER_SIZE);
+	s->full = 0;
+	s->readpos = 0;
+}
+
+/**
+ * trace_seq_used - amount of actual data written to buffer
+ * @s: trace sequence descriptor
+ *
+ * Returns the amount of data written to the buffer.
+ *
+ * IMPORTANT!
+ *
+ * Use this instead of @s->seq.len if you need to pass the amount
+ * of data from the buffer to another buffer (userspace, or what not).
+ * The @s->seq.len on overflow is bigger than the buffer size and
+ * using it can cause access to undefined memory.
+ */
+static inline int trace_seq_used(struct trace_seq *s)
+{
+	return seq_buf_used(&s->seq);
+}
+
+/**
+ * trace_seq_buffer_ptr - return pointer to next location in buffer
+ * @s: trace sequence descriptor
+ *
+ * Returns the pointer to the buffer where the next write to
+ * the buffer will happen. This is useful to save the location
+ * that is about to be written to and then return the result
+ * of that write.
+ */
+static inline char *
+trace_seq_buffer_ptr(struct trace_seq *s)
+{
+	return s->buffer + seq_buf_used(&s->seq);
+}
+
+/**
+ * trace_seq_has_overflowed - return true if the trace_seq took too much
+ * @s: trace sequence descriptor
+ *
+ * Returns true if too much data was added to the trace_seq and it is
+ * now full and will not take anymore.
+ */
+static inline bool trace_seq_has_overflowed(struct trace_seq *s)
+{
+	return s->full || seq_buf_has_overflowed(&s->seq);
+}
+
+/*
+ * Currently only defined when tracing is enabled.
+ */
+#ifdef CONFIG_TRACING
+extern __printf(2, 3)
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
+extern __printf(2, 0)
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
+extern void
+trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
+extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
+extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
+			     int cnt);
+extern void trace_seq_puts(struct trace_seq *s, const char *str);
+extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
+extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
+extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+				unsigned int len);
+extern int trace_seq_path(struct trace_seq *s, const struct path *path);
+
+extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+			     int nmaskbits);
+
+extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
+			      int prefix_type, int rowsize, int groupsize,
+			      const void *buf, size_t len, bool ascii);
+char *trace_seq_acquire(struct trace_seq *s, unsigned int len);
+
+#else /* CONFIG_TRACING */
+static inline __printf(2, 3)
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+{
+}
+static inline void
+trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+{
+}
+
+static inline void
+trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+		  int nmaskbits)
+{
+}
+
+static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
+{
+	return 0;
+}
+static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
+				    int cnt)
+{
+	return 0;
+}
+static inline void trace_seq_puts(struct trace_seq *s, const char *str)
+{
+}
+static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
+{
+}
+static inline void
+trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
+{
+}
+static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+				       unsigned int len)
+{
+}
+static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
+{
+	return 0;
+}
+static inline char *trace_seq_acquire(struct trace_seq *s, unsigned int len)
+{
+	return NULL;
+}
+#endif /* CONFIG_TRACING */
+
+#endif /* _LINUX_TRACE_SEQ_H */