[llvm-commits] [compiler-rt] r172828 - in /compiler-rt/trunk/lib: asan/lit_tests/log_path_fork_test.cc sanitizer_common/sanitizer_common.cc

[Alexander Potapenko]

Author: glider
Date: Fri Jan 18 10:44:27 2013
New Revision: 172828

URL: http://llvm.org/viewvc/llvm-project?rev=172828&view=rev
Log:
[ASan] Fix the log_path option to use different log files for parent and child processes after fork().

Added:
    compiler-rt/trunk/lib/asan/lit_tests/log_path_fork_test.cc
Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc

Added: compiler-rt/trunk/lib/asan/lit_tests/log_path_fork_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/lit_tests/log_path_fork_test.cc?rev=172828&view=auto
==============================================================================
--- compiler-rt/trunk/lib/asan/lit_tests/log_path_fork_test.cc (added)
+++ compiler-rt/trunk/lib/asan/lit_tests/log_path_fork_test.cc Fri Jan 18 10:44:27 2013
@@ -0,0 +1,22 @@
+// RUN: %clangxx_asan  %s -o %t
+// RUN: rm -f %t.log.*
+// Set verbosity to 1 so that the log files are opened prior to fork().
+// RUN: ASAN_OPTIONS="log_path=%t.log verbosity=1" not %t 2> %t.out
+// RUN: for f in %t.log.* ; do FileCheck %s < $f; done
+// RUN: [ `ls %t.log.* | wc -l` == 2 ]
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char **argv) {
+  void *x = malloc(10);
+  free(x);
+  if (fork() == -1) return 1;
+  // There are two processes at this point, thus there should be two distinct
+  // error logs.
+  free(x);
+  return 0;
+}
+
+// CHECK: ERROR: AddressSanitizer

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc?rev=172828&r1=172827&r2=172828&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc Fri Jan 18 10:44:27 2013
@@ -23,10 +23,16 @@
   return PageSize;
 }
 
-// By default, dump to stderr. If report_fd is kInvalidFd, try to obtain file
-// descriptor by opening file in report_path.
+static bool log_to_file = false;  // Set to true by __sanitizer_set_report_path
+
+// By default, dump to stderr. If |log_to_file| is true and |report_fd_pid|
+// isn't equal to the current PID, try to obtain file descriptor by opening
+// file "report_path_prefix.<PID>".
 static fd_t report_fd = kStderrFd;
-static char report_path[4096];  // Set via __sanitizer_set_report_path.
+static char report_path_prefix[4096];  // Set via __sanitizer_set_report_path.
+// PID of process that opened |report_fd|. If a fork() occurs, the PID of the
+// child thread will be different from |report_fd_pid|.
+static int report_fd_pid = 0;
 
 static void (*DieCallback)(void);
 void SetDieCallback(void (*callback)(void)) {
@@ -56,15 +62,23 @@
 }
 
 static void MaybeOpenReportFile() {
-  if (report_fd != kInvalidFd)
-    return;
-  fd_t fd = internal_open(report_path, true);
+  if (!log_to_file || (report_fd_pid == GetPid())) return;
+  char report_path_full[4096];
+  internal_snprintf(report_path_full, sizeof(report_path_full),
+                    "%s.%d", report_path_prefix, GetPid());
+  fd_t fd = internal_open(report_path_full, true);
   if (fd == kInvalidFd) {
     report_fd = kStderrFd;
-    Report("ERROR: Can't open file: %s\n", report_path);
+    log_to_file = false;
+    Report("ERROR: Can't open file: %s\n", report_path_full);
     Die();
   }
+  if (report_fd != kInvalidFd) {
+    // We're in the child. Close the parent's log.
+    internal_close(report_fd);
+  }
   report_fd = fd;
+  report_fd_pid = GetPid();
 }
 
 bool PrintsToTty() {
@@ -184,14 +198,16 @@
 void __sanitizer_set_report_path(const char *path) {
   if (!path) return;
   uptr len = internal_strlen(path);
-  if (len > sizeof(report_path) - 100) {
+  if (len > sizeof(report_path_prefix) - 100) {
     Report("ERROR: Path is too long: %c%c%c%c%c%c%c%c...\n",
            path[0], path[1], path[2], path[3],
            path[4], path[5], path[6], path[7]);
     Die();
   }
-  internal_snprintf(report_path, sizeof(report_path), "%s.%d", path, GetPid());
+  internal_strncpy(report_path_prefix, path, sizeof(report_path_prefix));
+  report_path_prefix[len] = '\0';
   report_fd = kInvalidFd;
+  log_to_file = true;
 }
 
 void __sanitizer_set_report_fd(int fd) {