Fix profiling when IO_Fork from the IO package is used

configure.ac

@@ -546,7 +546,7 @@ dnl Define kernel version
 dnl
 
 
-gap_kernel_major_version=5
+gap_kernel_major_version=6
 gap_kernel_minor_version=0
 AC_SUBST([gap_kernel_major_version])
 AC_SUBST([gap_kernel_minor_version])

doc/ref/debug.xml

@@ -791,6 +791,12 @@ limitations which users should be aware of:
     is most obvious when looking at code coverage examples, which will appear
     to miss lines of code in files not in a function.
   </Item>
+  <Item>
+    If the current GAP is forked, using the <C>IO_fork</C> function in the
+    <Package>IO</Package> package,
+    a new profile output file will be created for the new child process, with
+    the process ID of the child attached to the end of the filename.
+  </Item>
 </List>
 
 Profiles are transformed into a human-readable form with

src/profile.c

@@ -22,11 +22,14 @@
 #include "modules.h"
 #include "plist.h"
 #include "stringobj.h"
+#include "sysfiles.h"
 #include "vars.h"
 
 #include "hpc/thread.h"
 
 #include <sys/time.h>                   // for gettimeofday
+#include <sys/types.h>
+#include <unistd.h>
 #ifdef HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>               // definition of 'struct rusage'
 #endif
@@ -114,6 +117,8 @@ struct ProfileState
 {
   // C steam we are writing to
   FILE* Stream;
+  // Filename we are writing to
+  char filename[GAP_PATH_MAX];
   // Did we use 'popen' to open the stream (matters when closing)
   int StreamWasPopened;
   // Are we currently outputting repeats (false=code coverage)
@@ -337,6 +342,32 @@ static void fcloseMaybeCompressed(struct ProfileState* ps)
   ps->Stream = 0;
 }
 
+// When a child is forked off, we force profile information to be stored
+// in a new file for the child, to avoid corruption
+void InformProfilingThatThisIsAForkedGAP(void)
+{
+    HashLock(&profileState);
+    if (profileState_Active) {
+        char filenamecpy[GAP_PATH_MAX];
+        // Allow 20 chracters to allow space for .%d.gz
+        const int SUPPORTED_PATH_LEN = GAP_PATH_MAX - 20;
+        if(strlen(profileState.filename) > SUPPORTED_PATH_LEN) {
+           Pr("Filename can be at most %d character when forking", SUPPORTED_PATH_LEN, 0L);
+           SyExit(1);
+        }
+        if (endsWithgz(profileState.filename)) {
+            snprintf(filenamecpy, sizeof(filenamecpy), "%.*s.%d.gz",
+                     SUPPORTED_PATH_LEN, profileState.filename, getpid());
+        }
+        else {
+            snprintf(filenamecpy, sizeof(filenamecpy), "%.*s.%d",
+                     SUPPORTED_PATH_LEN, (char*)profileState.filename, getpid());
+        }
+        fcloseMaybeCompressed(&profileState);
+        fopenMaybeCompressed(filenamecpy, &profileState);
+    }
+}
+
 static inline Int8 CPUmicroseconds(void)
 {
 #ifdef HAVE_GETRUSAGE
@@ -576,6 +607,8 @@ void enableAtStartup(char * filename, Int repeats, TickMethod tickMethod)
         exit(1);
     }
 
+    strlcpy(profileState.filename, filename, GAP_PATH_MAX);
+
     ActivateHooks(&profileHooks);
 
     profileState_Active = 1;
@@ -706,6 +739,8 @@ Obj FuncACTIVATE_PROFILING(Obj self,
 
     fopenMaybeCompressed(CONST_CSTR_STRING(filename), &profileState);
 
+    strlcpy(profileState.filename, CONST_CSTR_STRING(filename), GAP_PATH_MAX);
+
     if(profileState.Stream == 0) {
       HashUnlock(&profileState);
       return Fail;

src/profile.h

@@ -19,6 +19,11 @@
 *F * * * * * * * * * * * * * initialize module * * * * * * * * * * * * * * *
 */
 
+// When a child is forked off, we force profile information to be stored
+// in a new file for the child, to avoid corruption.
+// This function is for use by the IO package
+void InformProfilingThatThisIsAForkedGAP(void);
+
 
 /****************************************************************************
 **