execve(): clear host user-space PTEs before context switching

executer/user/mcexec.c

@@ -1217,18 +1217,57 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
 				int ret = -1;
 				struct program_load_desc *desc;
 				struct remote_transfer trans;
+				FILE *fp;
+				int status;
+				char path[2048];
+				char *filename;
 
 				/* Load descriptor phase */
 				case 1:
-					if (load_elf_desc((char *)w.sr.args[1], &desc) != 0) {
+
+					filename = (char *)w.sr.args[1];
+
+					/* Is filename without path? */
+					if (0 && strncmp(filename, "/", 1) 
+						//&& strncmp(filename, ".", 1)
+						) {
+
+						char *PATH = getenv("PATH");
+						fprintf(stderr, "PATH: %s\n", PATH);
+
+						/* Open command for reading. */
+						sprintf(path, "/usr/bin/which %s", filename);
+						fp = popen(path, "r");
+						if (fp == NULL) {
+							fprintf(stderr, "execve(): failed to run which\n" );
+							goto return_execve1;
+						}
+
+						/* Read the output a line at a time - output it. */
+						if (fgets(path, sizeof(path)-1, fp) == NULL) {
+							fprintf(stderr, "execve(): failed to read which\n" );
+							pclose(fp);
+							goto return_execve1;
+						}
+
+						/* close */
+						pclose(fp);
+					}
+					else {
+						sprintf(path, "%s", filename);
+					}
+
+					__dprintf("execve: filename: %s\n", filename);
+					__dprintf("execve: LD_LIBRARY_PATH: %s\n", getenv("LD_LIBRARY_PATH") ? getenv("LD_LIBRARY_PATH") : "(empty)");
+
+					if (load_elf_desc(path, &desc) != 0) {
 						fprintf(stderr, 
-							"execve(): error loading ELF for file %s\n", 
+							"execve(): error loading ELF for file %s\n", path);
-							(char *)w.sr.args[1]);
 						goto return_execve1;
 					}
 
 					__dprintf("execve(): load_elf_desc() for %s OK, num sections: %d\n",
-						w.sr.args[1], desc->num_sections);
+						path, desc->num_sections);
 
 					/* Copy descriptor to co-kernel side */
 					trans.userp = (void*)desc;
@@ -1246,7 +1285,7 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
 					}
 					
 					__dprintf("execve(): load_elf_desc() for %s OK\n",
-						w.sr.args[1]);
+						path);
 
 					/* We can't be sure next phase will succeed */
 					/* TODO: what shall we do with fp in desc?? */
@@ -1279,7 +1318,7 @@ return_execve1:
 						goto return_execve1;
 					}
 					
-					printf("execve(): transfer ELF desc OK\n");
+					__dprintf("execve(): transfer ELF desc OK\n");
 
 					transfer_image(fd, desc);	
 					__dprintf("execve(): image transferred\n");

kernel/include/process.h

@@ -84,6 +84,9 @@
 //#define USE_LARGE_PAGES
 #endif
 
+#define USER_STACK_NR_PAGES 8192
+#define KERNEL_STACK_NR_PAGES 25
+
 #include <waitq.h>
 #include <futex.h>
 #include <rlimit.h>

kernel/process.c

@@ -43,9 +43,6 @@
 #endif
 
 
-#define USER_STACK_NR_PAGES 8192
-#define KERNEL_STACK_NR_PAGES 25
-
 extern long do_arch_prctl(unsigned long code, unsigned long address);
 static void insert_vm_range_list(struct process_vm *vm, 
 		struct vm_range *newrange);

kernel/syscall.c

@@ -1228,6 +1228,11 @@ SYSCALL_DECLARE(execve)
 	/* Unmap all memory areas of the process, userspace will be gone */
 	free_process_memory_ranges(cpu_local_var(current));
 
+	ihk_mc_init_user_process(&cpu_local_var(current)->ctx, 
+			&cpu_local_var(current)->uctx,
+			((char *)cpu_local_var(current)) + 
+			KERNEL_STACK_NR_PAGES * PAGE_SIZE, desc->entry, 0);
+
 	/* Create virtual memory ranges and update args/envs */
 	if (prepare_process_ranges_args_envs(cpu_local_var(current), desc, desc, 
 				PTATTR_NO_EXECUTE | PTATTR_WRITABLE | PTATTR_FOR_USER,
@@ -1236,6 +1241,18 @@ SYSCALL_DECLARE(execve)
 		panic("");
 	}
 	
+	/* Clear host user space PTEs */
+	request.number = __NR_munmap;
+	request.args[0] = cpu_local_var(current)->vm->region.user_start;
+	request.args[1] = cpu_local_var(current)->vm->region.user_end - 
+		cpu_local_var(current)->vm->region.user_start;
+	dkprintf("execve(): requesting host PTE clear\n");
+
+	if (do_syscall(&request, ctx, ihk_mc_get_processor_id(), 0)) {
+		kprintf("execve(): ERROR: clearing PTEs in host process\n");
+		panic("");
+	}		
+
 	/* Request host to transfer ELF image */
 	request.number = __NR_execve;  
 	request.args[0] = 2;  /* 2nd phase - transfer ELF image */
@@ -1250,8 +1267,13 @@ SYSCALL_DECLARE(execve)
 		panic("");
 	}
 
-	dkprintf("execve(): returning to new process\n");
+	/* Switch to new execution context */
+	dkprintf("execve(): switching to new process\n");
 	
+	ihk_mc_switch_context(NULL, &cpu_local_var(current)->ctx, 
+		cpu_local_var(current));
+
+	/* Never reach here */
 	return 0;
 }