csim: Allow redirecting trace output to a file using command line flag

This is useful when booting an operating system with tracing enabled
as it allows showing the printed messages on the terminal and storing
the trace log to a separate file. All categorized trace messages are
now redirected to the --trace-output file when passed. If this option is
not gived, the current behaviour of using stdout is retained.

Example usage:
`./c_emulator/riscv_sim_RV64 -b os-boot/rv64-64mb.dtb --trace-output /dev/stderr os-boot/linux-rv64-64mb.bbl --trace-output /tmp/linux.log`

1 files changed, 45 insertions, 25 deletions

diff --git a/c_emulator/riscv_sim.c b/c_emulator/riscv_sim.c
index fdb9ce0..5a73896 100644
--- a/c_emulator/riscv_sim.c
+++ b/c_emulator/riscv_sim.c
@@ -48,10 +48,14 @@ const char *RV32ISA = "RV32IMAC";
 #define CSR_MTVAL 0x343
 #define CSR_MIP 0x344
 
+#define OPT_TRACE_OUTPUT 1000
+
 static bool do_dump_dts = false;
 static bool do_show_times = false;
 struct tv_spike_t *s = NULL;
 char *term_log = NULL;
+static const char *trace_log_path = NULL;
+FILE *trace_log = NULL;
 char *dtb_file = NULL;
 unsigned char *dtb = NULL;
 size_t dtb_len = 0;
@@ -111,33 +115,34 @@ char *sailcov_file = NULL;
 #endif
 
 static struct option options[] = {
-    {"enable-dirty-update",         no_argument,       0, 'd'},
-    {"enable-misaligned",           no_argument,       0, 'm'},
-    {"enable-pmp",                  no_argument,       0, 'P'},
-    {"enable-next",                 no_argument,       0, 'N'},
-    {"ram-size",                    required_argument, 0, 'z'},
-    {"disable-compressed",          no_argument,       0, 'C'},
-    {"disable-writable-misa",       no_argument,       0, 'I'},
-    {"disable-fdext",               no_argument,       0, 'F'},
-    {"mtval-has-illegal-inst-bits", no_argument,       0, 'i'},
-    {"device-tree-blob",            required_argument, 0, 'b'},
-    {"terminal-log",                required_argument, 0, 't'},
-    {"show-times",                  required_argument, 0, 'p'},
-    {"report-arch",                 no_argument,       0, 'a'},
-    {"test-signature",              required_argument, 0, 'T'},
-    {"signature-granularity",       required_argument, 0, 'g'},
+    {"enable-dirty-update",         no_argument,       0, 'd'             },
+    {"enable-misaligned",           no_argument,       0, 'm'             },
+    {"enable-pmp",                  no_argument,       0, 'P'             },
+    {"enable-next",                 no_argument,       0, 'N'             },
+    {"ram-size",                    required_argument, 0, 'z'             },
+    {"disable-compressed",          no_argument,       0, 'C'             },
+    {"disable-writable-misa",       no_argument,       0, 'I'             },
+    {"disable-fdext",               no_argument,       0, 'F'             },
+    {"mtval-has-illegal-inst-bits", no_argument,       0, 'i'             },
+    {"device-tree-blob",            required_argument, 0, 'b'             },
+    {"terminal-log",                required_argument, 0, 't'             },
+    {"show-times",                  required_argument, 0, 'p'             },
+    {"report-arch",                 no_argument,       0, 'a'             },
+    {"test-signature",              required_argument, 0, 'T'             },
+    {"signature-granularity",       required_argument, 0, 'g'             },
 #ifdef RVFI_DII
-    {"rvfi-dii",                    required_argument, 0, 'r'},
+    {"rvfi-dii",                    required_argument, 0, 'r'             },
 #endif
-    {"help",                        no_argument,       0, 'h'},
-    {"trace",                       optional_argument, 0, 'v'},
-    {"no-trace",                    optional_argument, 0, 'V'},
-    {"inst-limit",                  required_argument, 0, 'l'},
-    {"enable-zfinx",                no_argument,       0, 'x'},
+    {"help",                        no_argument,       0, 'h'             },
+    {"trace",                       optional_argument, 0, 'v'             },
+    {"no-trace",                    optional_argument, 0, 'V'             },
+    {"trace-output",                required_argument, 0, OPT_TRACE_OUTPUT},
+    {"inst-limit",                  required_argument, 0, 'l'             },
+    {"enable-zfinx",                no_argument,       0, 'x'             },
 #ifdef SAILCOV
-    {"sailcov-file",                required_argument, 0, 'c'},
+    {"sailcov-file",                required_argument, 0, 'c'             },
 #endif
-    {0,                             0,                 0, 0  }
+    {0,                             0,                 0, 0               }
 };
 
 static void print_usage(const char *argv0, int ec)
@@ -352,6 +357,10 @@ char *process_args(int argc, char **argv)
       sailcov_file = strdup(optarg);
       break;
 #endif
+    case OPT_TRACE_OUTPUT:
+      trace_log_path = optarg;
+      fprintf(stderr, "using %s for trace output.\n", trace_log_path);
+      break;
     case '?':
       print_usage(argv[0], 1);
       break;
@@ -626,6 +635,9 @@ void close_logs(void)
     exit(EXIT_FAILURE);
   }
 #endif
+  if (trace_log != stdout) {
+    fclose(trace_log);
+  }
 }
 
 void finish(int ec)
@@ -726,8 +738,8 @@ void flush_logs(void)
   if (config_print_instr) {
     fprintf(stderr, "\n");
     fflush(stderr);
-    fprintf(stdout, "\n");
-    fflush(stdout);
+    fprintf(trace_log, "\n");
+    fflush(trace_log);
   }
 }
 
@@ -1010,6 +1022,14 @@ void init_logs()
     exit(1);
   }
 
+  if (trace_log_path == NULL) {
+    trace_log = stdout;
+  } else if ((trace_log = fopen(trace_log_path, "w+")) < 0) {
+    fprintf(stderr, "Cannot create trace log '%s': %s\n", trace_log,
+            strerror(errno));
+    exit(1);
+  }
+
 #ifdef SAILCOV
   if (sailcov_file != NULL) {
     sail_set_coverage_file(sailcov_file);