1 files changed, 72 insertions, 6 deletions

diff --git a/trace-read.c b/trace-read.c
index d37636a..f65043b 100644
--- a/trace-read.c
+++ b/trace-read.c
@@ -18,6 +18,7 @@
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */
+#define _LARGEFILE64_SOURCE
 #define _GNU_SOURCE
 #include <dirent.h>
 #include <stdio.h>
@@ -39,6 +40,8 @@
 
 static int input_fd;
 
+static int read_page;
+
 static int file_bigendian;
 static int host_bigendian;
 static int long_size;
@@ -286,6 +289,27 @@ struct cpu_data {
 static int cpus;
 static struct cpu_data *cpu_data;
 
+static void init_read(int cpu)
+{
+        off64_t ret;
+        off64_t save_seek;
+
+        cpu_data[cpu].page = malloc_or_die(PAGE_SIZE);
+
+        /* other parts of the code may expect the pointer to not move */
+        save_seek = lseek64(input_fd, 0, SEEK_CUR);
+
+        ret = lseek64(input_fd, (off64_t)cpu_data[cpu].offset, SEEK_SET);
+        if (ret < 0)
+                die("failed to lseek");
+        ret = read(input_fd, cpu_data[cpu].page, PAGE_SIZE);
+        if (ret < 0)
+                die("failed to read page");
+
+        /* reset the file pointer back */
+        lseek64(input_fd, save_seek, SEEK_SET);
+}
+
 static void init_cpu(int cpu)
 {
         if (!cpu_data[cpu].size) {
@@ -293,27 +317,69 @@ static void init_cpu(int cpu)
                 return;
         }
 
+        if (read_page) {
+                init_read(cpu);
+                return;
+        }
+
         cpu_data[cpu].page = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE,
                                   input_fd, cpu_data[cpu].offset);
-        if (cpu_data[cpu].page == MAP_FAILED)
-                die("failed to mmap cpu %d at offset 0x%llx",
-                    cpu, cpu_data[cpu].offset);
+        if (cpu_data[cpu].page == MAP_FAILED) {
+                /* fall back to just reading pages */
+                fprintf(stderr, "Can not mmap file, will read instead\n");
+                read_page = 1;
+
+                init_read(cpu);
+        }
+}
+
+static void update_cpu_data_index(int cpu)
+{
+        cpu_data[cpu].offset += PAGE_SIZE;
+        cpu_data[cpu].size -= PAGE_SIZE;
+        cpu_data[cpu].index = 0;
 }
 
 static void get_next_page(int cpu)
 {
+        off64_t save_seek;
+        off64_t ret;
+
         if (!cpu_data[cpu].page)
                 return;
 
+        if (read_page) {
+                if (cpu_data[cpu].size <= PAGE_SIZE) {
+                        free(cpu_data[cpu].page);
+                        cpu_data[cpu].page = NULL;
+                        return;
+                }
+
+                update_cpu_data_index(cpu);
+
+                /* other parts of the code may expect the pointer to not move */
+                save_seek = lseek64(input_fd, 0, SEEK_CUR);
+
+                ret = lseek64(input_fd, cpu_data[cpu].offset, SEEK_SET);
+                if (ret < 0)
+                        die("failed to lseek");
+                ret = read(input_fd, cpu_data[cpu].page, PAGE_SIZE);
+                if (ret < 0)
+                        die("failed to read page");
+
+                /* reset the file pointer back */
+                lseek64(input_fd, save_seek, SEEK_SET);
+
+                return;
+        }
+
         munmap(cpu_data[cpu].page, PAGE_SIZE);
         cpu_data[cpu].page = NULL;
 
         if (cpu_data[cpu].size <= PAGE_SIZE)
                 return;
 
-        cpu_data[cpu].offset += PAGE_SIZE;
-        cpu_data[cpu].size -= PAGE_SIZE;
-        cpu_data[cpu].index = 0;
+        update_cpu_data_index(cpu);
         
         cpu_data[cpu].page = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE,
                                   input_fd, cpu_data[cpu].offset);