From 312af3705d02b198f09d6efa69c68ba1598fb721 Mon Sep 17 00:00:00 2001
From: Hristo Venev <hristo@venev.name>
Date: Sat, 6 Jun 2020 22:13:15 +0300
Subject: Fix wraparound.
---
vc-log.c | 52 +++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 41 insertions(+), 11 deletions(-)
diff --git a/vc-log.c b/vc-log.c
index 56ce5ef..27aedd3 100644
--- a/vc-log.c
+++ b/vc-log.c
@@ -183,6 +183,40 @@ static size_t vc_sym_find(const char *want) {
}
}
+struct vc_log_header {
+ uint32_t time;
+ uint16_t seq;
+ uint16_t size;
+ uint32_t category;
+};
+
+_Static_assert(sizeof(struct vc_log_header) == 12, "");
+
+static void vc_log_memcpy(size_t start, size_t end, size_t *p_at, void *buf, size_t size) {
+ size_t at = *p_at;
+ if(size > end - start) abort();
+ if(at < start || at > end) abort();
+ if(at == end) at = start;
+ size_t left = end - at;
+ if(size > left) {
+ vc_read(buf, at, left);
+ at = start;
+ size -= left;
+ buf = (char*)buf + left;
+ }
+ *p_at = at + size;
+ vc_read(buf, at, size);
+}
+
+static const char *decode_category(uint32_t bits) {
+ switch(bits) {
+ case 65536:
+ return "vcos";
+ default:
+ return "unknown";
+ }
+}
+
static void vc_log_read(size_t descriptor_ptr) {
uint8_t fmt = vc_read_u8(descriptor_ptr);
size_t ptr = vc_read_ptr(descriptor_ptr + 4);
@@ -207,23 +241,19 @@ static void vc_log_read(size_t descriptor_ptr) {
size_t at = l_next_msg;
do {
- uint32_t time = vc_read_u32(at + 0);
- uint32_t seq = vc_read_u16(at + 4);
- size_t size = vc_read_u16(at + 6);
- if(size < 12) {
- printf("short message: %zu\n", size);
+ struct vc_log_header hdr;
+ vc_log_memcpy(l_start, l_end, &at, &hdr, sizeof(hdr));
+ if(hdr.size < 8) {
+ printf("short message: %u\n", hdr.size);
return;
}
- size_t len = size - 12;
+ size_t len = hdr.size - sizeof(hdr);
char *s = malloc(len + 1);
if(!s) abort();
- vc_read(s, at + 12, len);
+ vc_log_memcpy(l_start, l_end, &at, s, len);
s[len] = 0;
- printf("[%5u.%06u] %s\n", time / 1000000, time % 1000000, s);
+ printf("[%5u.%06u] %s: %s\n", hdr.time / 1000000, hdr.time % 1000000, decode_category(hdr.category), s);
free(s);
-
- at += size;
- if(at == l_end) at = l_start;
} while(at != l_ptr);
}
--
cgit