From 312af3705d02b198f09d6efa69c68ba1598fb721 Mon Sep 17 00:00:00 2001 From: Hristo Venev 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