[syslinux:elflink] elflink: Move more code from core/ into ldlinux

syslinux-bot for Matt Fleming matt.fleming at linux.intel.com
Wed Apr 27 14:30:53 PDT 2011


Commit-ID:  43d7cbaa55806ecb33b0cc5aa56e97b0f8027c45
Gitweb:     http://syslinux.zytor.com/commit/43d7cbaa55806ecb33b0cc5aa56e97b0f8027c45
Author:     Matt Fleming <matt.fleming at linux.intel.com>
AuthorDate: Fri, 8 Apr 2011 13:21:51 +0100
Committer:  Matt Fleming <matt.fleming at linux.intel.com>
CommitDate: Tue, 26 Apr 2011 09:53:31 +0100

elflink: Move more code from core/ into ldlinux

ldlinux now contains all the code necessary to load and execute
modules, none is contained in the core.

This change also allows us to change the spawn_load() prototype and to
push the job of processing arguments to executable functions (e.g. the
contents of char *argv[] as passed to a module's main function) into
ldlinux/execute.c instead of doing it in spawn_load(). Moving it into
ldlinux/ makes sense because the only core user of spawn_load() is
load_env32() and we don't require any sort of argument processing in
that path.

Signed-off-by: Matt Fleming <matt.fleming at linux.intel.com>


---
 com32/elflink/ldlinux/Makefile                    |    2 +-
 {core/elflink => com32/elflink/ldlinux}/execute.c |   67 ++++++++++++++++++---
 {core/elflink => com32/elflink/ldlinux}/kernel.c  |    0
 com32/include/sys/exec.h                          |    3 +-
 com32/lib/sys/module/exec.c                       |   47 ++++++++-------
 core/elflink/load_env32.c                         |    7 ++-
 6 files changed, 92 insertions(+), 34 deletions(-)

diff --git a/com32/elflink/ldlinux/Makefile b/com32/elflink/ldlinux/Makefile
index 6fbe1b1..09aa4af 100644
--- a/com32/elflink/ldlinux/Makefile
+++ b/com32/elflink/ldlinux/Makefile
@@ -19,7 +19,7 @@ CFLAGS += -I../modules -I$(topdir)/core/elflink -I$(topdir)/core/include
 all: ldlinux.c32
 
 ldlinux.c32 : ldlinux.o cli.o readconfig.o refstr.o colors.o getadv.o \
-		adv.o ipappend.o
+		adv.o ipappend.o execute.o kernel.o
 	$(LD) $(LDFLAGS) -o $@ $^
 
 tidy dist:
diff --git a/core/elflink/execute.c b/com32/elflink/ldlinux/execute.c
similarity index 73%
rename from core/elflink/execute.c
rename to com32/elflink/ldlinux/execute.c
index 7e70323..f67d707 100644
--- a/core/elflink/execute.c
+++ b/com32/elflink/ldlinux/execute.c
@@ -43,13 +43,10 @@ static inline int my_isspace(char c)
 
 void execute(const char *cmdline, enum kernel_type type)
 {
-	com32sys_t ireg;
 	const char *p, *const *pp;
-	char *q;
 	const char *kernel, *args;
-
-	/* work around for spawn_load parameter */
-	char *spawn_load_param[2] = { NULL, NULL};
+	com32sys_t ireg;
+	char *q;
 
 	memset(&ireg, 0, sizeof ireg);
 
@@ -87,18 +84,70 @@ void execute(const char *cmdline, enum kernel_type type)
 
 	if (type == KT_COM32) {
 		/* new entry for elf format c32 */
-		spawn_load_param[0] = args;
+		char **argv;
+		int i, argc;
+
+		q = args;
+		for (argc = 0; *q; q++) {
+			argc++;
+
+			/* Find the end of this arg */
+			while(*q && !my_isspace(*q))
+				q++;
+
+			/*
+			 * Now skip all whitespace between arguments.
+			 */
+			while (*q && my_isspace(*q))
+				q++;
+		}
+
+		/*
+		 * Generate a copy of argv on the stack as this is
+		 * traditionally where process arguments go.
+		 *
+		 * argv[0] must be the command name, so bump argc to
+		 * include argv[0].
+		 */
+		argc += 1;
+		argv = alloca(argc * sizeof(char *));
+		argv[0] = kernel;
+
+		for (q = args, i = 1; i < argc - 1; i++) {
+			char *start;
+			int len = 0;
+
+			start = q;
+
+			/* Find the end of this arg */
+			while(*q && !my_isspace(*q)) {
+				q++;
+				len++;
+			}
+
+			argv[i] = malloc(len + 1);
+			strncpy(argv[i], start, len);
+			argv[i][len] = '\0';
+
+			/*
+			 * Now skip all whitespace between arguments.
+			 */
+			while (*q && my_isspace(*q))
+				q++;
+		}
+
+		argv[argc] = NULL;
 		module_load_dependencies(kernel, "modules.dep");
-		spawn_load(kernel, spawn_load_param);
+		spawn_load(kernel, argc, argv);
 	} else if (type <= KT_KERNEL) {
 		/* Need add one item for kernel load, as we don't use
 		* the assembly runkernel.inc any more */
 		new_linux_kernel(kernel, cmdline);
 	} else if (type == KT_CONFIG) {
 		/* kernel contains the config file name */
-		spawn_load_param[0] = args;
+		char *spawn_load_param[2] = { args, NULL };
 		module_load_dependencies("ui.c32", "modules.dep");
-		spawn_load(kernel, spawn_load_param);
+		spawn_load(kernel, 1, spawn_load_param);
 	} else {
 		/* process the image need int 22 support */
 		if (type == KT_LOCALBOOT) {
diff --git a/core/elflink/kernel.c b/com32/elflink/ldlinux/kernel.c
similarity index 100%
rename from core/elflink/kernel.c
rename to com32/elflink/ldlinux/kernel.c
diff --git a/com32/include/sys/exec.h b/com32/include/sys/exec.h
index 31b62be..656f8e2 100644
--- a/com32/include/sys/exec.h
+++ b/com32/include/sys/exec.h
@@ -33,6 +33,7 @@
  * spawn_load - Load a library module or executes an executable one
  * @name	the name of the library/executable to use, including the extension
  * 			(e.g. 'sort.c32')
+ * @argc:	the number of string arguments in @argv
  * @argv:	a NULL-terminated vector of string arguments, starting with
  * 			the program name.
  *
@@ -40,7 +41,7 @@
  * kind of module it is ( executable or library ), after which is performs the
  * appropriate action, either spawning or simply loading the module into memory.
  */
-extern int spawn_load(const char *name,const char **argv);
+extern int spawn_load(const char *name, int argc, char **argv);
 
 extern int module_load_dependencies(const char*name,const char*dep_file);
 
diff --git a/com32/lib/sys/module/exec.c b/com32/lib/sys/module/exec.c
index 78df72e..1ed3263 100644
--- a/com32/lib/sys/module/exec.c
+++ b/com32/lib/sys/module/exec.c
@@ -220,12 +220,25 @@ int spawnl(const char *name, const char *arg, ...)
 
 struct elf_module *cur_module;
 
-int spawn_load(const char *name,const char **argv)
+/*
+ * Load a module and runs its start function.
+ *
+ * For library modules the start function is module->init_func and for
+ * executable modules its module->main_func.
+ *
+ * "name" is the name of the module to load.
+ *
+ * "argv" and "argc" are only passed to module->main_func, for library
+ * modules these arguments can be NULL and 0, respectively.
+ *
+ * "argv" is an array of arguments to pass to module->main_func.
+ * argv[0] must be a pointer to "name" and argv[argc] must be NULL.
+ *
+ * "argc" is the number of arguments in "argv".
+ */
+int spawn_load(const char *name, int argc, char **argv)
 {
 	int res, ret_val = 0;
-	const char **arg;
-	int argc;
-	char **argp, **args;
 	struct elf_module *previous;
 	//malloc_tag_t prev_mem_tag;
 	struct elf_module *module = module_alloc(name);
@@ -238,6 +251,11 @@ int spawn_load(const char *name,const char **argv)
 	if (module == NULL)
 		return -1;
 
+	if (get_module_type(module) == EXEC_MODULE) {
+		if (!argc || !argv || strcmp(argv[0], name))
+			return -1;
+	}
+
 	if (!strcmp(cur_module->name, module->name)) {
 		dprintf("We is running this module %s already!", module->name);
 
@@ -295,21 +313,6 @@ int spawn_load(const char *name,const char **argv)
 		__syslinux_current = module;
 		//__mem_set_tag_global((malloc_tag_t)module);
 
-		// Generate a new process copy of argv (on the stack)
-		argc = 0;
-		for (arg = argv; *arg; arg++)
-			argc++;
-
-		args = alloca((argc+1) * sizeof(char *));
-
-		for (arg = argv, argp = args; *arg; arg++, argp++) {
-			size_t l = strlen(*arg)+1;
-			*argp = alloca(l);
-			memcpy(*argp, *arg, l);
-		}
-
-		*args = NULL;
-
 		// Execute the program
 		ret_val = setjmp(module->u.x.process_exit);
 
@@ -318,7 +321,7 @@ int spawn_load(const char *name,const char **argv)
 		else if (!module->main_func)
 			ret_val = -1;
 		else
-			exit((module->main_func)(argc, args)); /* Actually run! */
+			exit((module->main_func)(argc, argv)); /* Actually run! */
 
 
 		// Clean up the allocation context
@@ -468,13 +471,13 @@ int module_load_dependencies(const char *name,const char *dep_file)
 		i++;	/* skip a space */
 
 		if (strlen(temp_name)) {
-			char *argv[2] = { NULL, NULL };
+			char *argv[2] = { temp_name, NULL };
 			int ret;
 
 			ret = module_load_dependencies(temp_name,
 						       MODULES_DEP);
 			if (!ret) {
-				if (spawn_load(temp_name, argv) < 0)
+				if (spawn_load(temp_name, 1, argv) < 0)
 					continue;
 			}
 		}
diff --git a/core/elflink/load_env32.c b/core/elflink/load_env32.c
index 501f267..8a71634 100644
--- a/core/elflink/load_env32.c
+++ b/core/elflink/load_env32.c
@@ -18,6 +18,8 @@
 #include "menu.h"
 #include "core-elf.h"
 
+#define LDLINUX	"ldlinux.c32"
+
 typedef void (*constructor_t) (void);
 constructor_t __ctors_start[], __ctors_end[];
 
@@ -68,10 +70,13 @@ static void call_constr(void)
 /* note to self: do _*NOT*_ use static key word on this function */
 void load_env32(com32sys_t * regs)
 {
+	char *argv[] = { LDLINUX, NULL };
+
 	dprintf("Starting 32 bit elf module subsystem...\n");
 	call_constr();
 
 	init_module_subsystem(&core_module);
 
-	execute("ldlinux.c32", KT_COM32);
+	module_load_dependencies(LDLINUX, "modules.dep");
+	spawn_load(LDLINUX, 1, argv);
 }



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