execute mode: reimplemented with well-formed semantics.

1 files changed, 146 insertions, 44 deletions

diff --git a/src/logic/slbt_exec_execute.c b/src/logic/slbt_exec_execute.c
index 1bba779..68b3022 100644
--- a/src/logic/slbt_exec_execute.c
+++ b/src/logic/slbt_exec_execute.c
@@ -16,16 +16,113 @@
 #include "slibtool_snprintf_impl.h"
 #include "slibtool_errinfo_impl.h"
 
+
+/*******************************************************************/
+/* --mode=execute: wrapper script and execution argument vector    */
+/*                                                                 */
+/* The purpose of executable wrapper scripts is to properly handle */
+/* one common scenario where:                                      */
+/*                                                                 */
+/* (1) a build project would entail both executable programs and   */
+/*     dynamically linked libraries; and                           */
+/*                                                                 */
+/* (2) one or more of the project's executable programs would have */
+/*     one or more of the project's libraries as a dynamic runtime */
+/*     dependency.                                                 */
+/*                                                                 */
+/* Since the project's dependency libraries are not yet installed, */
+/* correct resolution of a program's dynamic library dependencies  */
+/* must depend on an appropriate setting of the LD_LIBRARY_PATH    */
+/* encironment variable (on Linxu or Midipix) or an equivalent     */
+/* environment variable on any of the other supported platforms.   */
+/*                                                                 */
+/* Here, too, there are two distinct cases:                        */
+/*                                                                 */
+/* (a) the executable wrapper script is directly invoked from the  */
+/*     shell command line or otherwise; or                         */
+/*                                                                 */
+/* (b) the build target associated with the executable program is  */
+/*     an argument passed to `slibtool --mode=execute` either as   */
+/*     the name of the program to be executed (and thus as the     */
+/*     first non-slibtool argument) or for processing by another   */
+/*     program.                                                    */
+/*                                                                 */
+/* The first case is handled entirely from within the executable   */
+/* wrapper script. The load environment variable is set based on   */
+/* the path that was stored in it by slibtool at link time, and    */
+/* the real executable is then exec'ed.                            */
+/*                                                                 */
+/* In the second case, slibtool would start by testing whether the */
+/* first non-slibtool argument is the wrapper script of a newly    */
+/* built executable program. If it is, then slibtool would invoke  */
+/* the wrapper script rather than the executable program, and add  */
+/* the path to the executable to the argument vector before all    */
+/* other arguments, makign it ${1} from the wrapper script's point */
+/* of view. Then again, and irrespective of the previous step,     */
+/* slibtool will replace any remaining command-line argument which */
+/* points to a build target associated with a newly built program  */
+/* with the path to the program itself (that is, the one located   */
+/* under the internal .libs/ directory).                           */
+/*                                                                 */
+/* For the sake of consistency and robustness, wrapper scripts are */
+/* created at link time for _all_ executable programs, including   */
+/* those programs which appear to have system libraries as their   */
+/* sole dynamic library dependencies.                              */
+/*******************************************************************/
+
+
+static int slbt_argument_is_an_executable_wrapper_script(
+	const struct slbt_driver_ctx *  dctx,
+	const char *                    arg,
+	char                            (*altarg)[PATH_MAX])
+{
+	int           fdcwd;
+	const char *  base;
+	char *        mark;
+	struct stat   st;
+
+	/* the extra characters: .libs/.exe.wrapper */
+	if (strlen(arg) > (PATH_MAX - 20))
+		return SLBT_BUFFER_ERROR(dctx);
+
+	/* path/to/progname --> path/to/.libs/progname.exe.wapper */
+	if ((base = strrchr(arg,'/')))
+		base++;
+
+	if (!base)
+		base = arg;
+
+	mark  = *altarg;
+	mark += base - arg;
+
+	strcpy(*altarg,arg);
+	mark += sprintf(mark,".libs/%s",base);
+	strcpy(mark,".exe.wrapper");
+
+	/* not an executable wrapper script? */
+	fdcwd = slbt_driver_fdcwd(dctx);
+
+	if (fstatat(fdcwd,*altarg,&st,0) < 0)
+		return (errno == ENOENT)
+			? 0 : SLBT_SYSTEM_ERROR(dctx,*altarg);
+
+	/* path/to/.libs/progname.exe.wapper --> path/to/.libs/progname */
+	*mark = '\0';
+
+	return 1;
+}
+
+
 int slbt_exec_execute(const struct slbt_driver_ctx * dctx)
 {
-	int			fdcwd;
+	int			ret;
+	char **                 parg;
+	char **                 aarg;
 	char *			program;
-	char *			script;
-	char *			base;
-	char *			mark;
-	char			exeref [PATH_MAX];
+	char *                  exeref;
 	char			wrapper[PATH_MAX];
-	struct stat		st;
+	char			exeprog[PATH_MAX];
+	char			argbuf [PATH_MAX];
 	struct slbt_exec_ctx *	ectx;
 
 	/* dry run */
@@ -38,57 +135,62 @@ int slbt_exec_execute(const struct slbt_driver_ctx * dctx)
 
 	slbt_disable_placeholders(ectx);
 
-	/* script, program */
-	program = ectx->cargv[0];
-	script  = ectx->cargv[1];
-
-	if (script) {
-		/* exeref */
-		if ((base = strrchr(script,'/')))
-			base++;
-		else
-			base = script;
-
-		strcpy(exeref,script);
-		mark = exeref + (base - script);
-		sprintf(mark,".libs/%s",base);
-
-		/* wrapper */
-		if (slbt_snprintf(wrapper,sizeof(wrapper),
-					"%s.exe.wrapper",
-					exeref) < 0) {
-			slbt_ectx_free_exec_ctx(ectx);
-			return SLBT_BUFFER_ERROR(dctx);
-		}
+	/* original and alternate argument vectors */
+	parg = ectx->cargv;
+	aarg = ectx->altv;
 
-		/* fdcwd */
-		fdcwd = slbt_driver_fdcwd(dctx);
+	/* program (first non-slibtool argument) */
+	if (!(program = ectx->cargv[0]))
+		return SLBT_CUSTOM_ERROR(
+			dctx,
+			SLBT_ERR_FLOW_ERROR);
 
-		/* swap vector */
-		if (!fstatat(fdcwd,script,&st,0) && !fstatat(fdcwd,wrapper,&st,0)) {
-			ectx->cargv[0] = wrapper;
-			ectx->cargv[1] = program;
-			ectx->cargv[2] = exeref;
+	/* init the wrapper argument based on the first qualifying argument */
+	for (exeref=0; !exeref && *parg; parg++) {
+		strcpy(argbuf,*parg);
+
+		if ((ret = slbt_argument_is_an_executable_wrapper_script(
+				dctx,argbuf,&exeprog)) < 0) {
+			return SLBT_NESTED_ERROR(dctx);
+
+		} else if (ret == 1) {
+			sprintf(wrapper,"%s.exe.wrapper",exeprog);
+			exeref  = *parg;
+			*aarg++ = wrapper;
 		} else {
-			script = program;
+			strcpy(*parg,argbuf);
 		}
+	}
 
-		/* execute mode */
-		ectx->program = script;
-		ectx->argv    = ectx->cargv;
-	} else {
-		ectx->program = program;
-		ectx->argv    = ectx->cargv;
+	/* transform in place as needed all arguments */
+	for (parg=ectx->cargv; *parg; parg++) {
+		if ((ret = slbt_argument_is_an_executable_wrapper_script(
+				dctx,*parg,&argbuf)) < 0) {
+			return SLBT_NESTED_ERROR(dctx);
+
+		} else if (ret == 1) {
+			strcpy(*parg,argbuf);
+			*aarg++ = *parg;
+		} else {
+			*aarg++ = *parg;
+		}
 	}
 
+	*aarg = 0;
+
+	/* execute mode */
+	ectx->program = ectx->altv[0];
+	ectx->argv    = ectx->altv;
+
 	/* step output */
-	if (!(dctx->cctx->drvflags & SLBT_DRIVER_SILENT))
+	if (!(dctx->cctx->drvflags & SLBT_DRIVER_SILENT)) {
 		if (slbt_output_execute(ectx)) {
 			slbt_ectx_free_exec_ctx(ectx);
 			return SLBT_NESTED_ERROR(dctx);
 		}
+	}
 
-	execvp(ectx->cargv[0],ectx->argv);
+	execvp(ectx->altv[0],ectx->altv);
 
 	slbt_ectx_free_exec_ctx(ectx);
 	return SLBT_SYSTEM_ERROR(dctx,0);