driver: move the host params logic to its own translation unit.

4 files changed, 703 insertions, 642 deletions

diff --git a/project/common.mk b/project/common.mk
index e8c60f4..1fa7ca9 100644
--- a/project/common.mk
+++ b/project/common.mk
@@ -11,6 +11,7 @@ API_SRCS = \
 	src/arbits/output/slbt_ar_output_members.c \
 	src/driver/slbt_amain.c \
 	src/driver/slbt_driver_ctx.c \
+	src/driver/slbt_host_params.c \
 	src/fallback/slbt_archive_import_mri.c \
 	src/helper/slbt_archive_import.c \
 	src/helper/slbt_copy_file.c \
diff --git a/src/driver/slbt_driver_ctx.c b/src/driver/slbt_driver_ctx.c
index 126dc85..ec468a2 100644
--- a/src/driver/slbt_driver_ctx.c
+++ b/src/driver/slbt_driver_ctx.c
@@ -26,6 +26,10 @@
 
 extern char ** environ;
 
+/* annotation strings */
+static const char cfgexplicit[] = "command-line argument";
+static const char cfglconf[]    = "derived from <libtool>";
+
 /* package info */
 static const struct slbt_source_version slbt_src_version = {
 	SLBT_TAG_VER_MAJOR,
@@ -44,72 +48,9 @@ static const struct slbt_fd_ctx slbt_default_fdctx = {
 	.fdlog = (-1),
 };
 
-/* flavor settings */
-#define SLBT_FLAVOR_SETTINGS(flavor,          \
-		bfmt,pic,                     \
-		arp,ars,dsop,dsos,osds,osdf,  \
-		exep,exes,impp,imps,          \
-		ldenv)                        \
-	static const struct slbt_flavor_settings flavor = {  \
-		bfmt,arp,ars,dsop,dsos,osds,osdf,           \
-		exep,exes,impp,imps,                       \
-		ldenv,pic}
-
-SLBT_FLAVOR_SETTINGS(host_flavor_default,       \
-	"elf","-fPIC",                          \
-	"lib",".a","lib",".so",".so","",        \
-	"","","","",                            \
-	"LD_LIBRARY_PATH");
-
-SLBT_FLAVOR_SETTINGS(host_flavor_midipix,       \
-	"pe","-fPIC",                           \
-	"lib",".a","lib",".so",".so","",        \
-	"","","lib",".lib.a",                   \
-	"LD_LIBRARY_PATH");
-
-SLBT_FLAVOR_SETTINGS(host_flavor_mingw,         \
-	"pe",0,                                 \
-	"lib",".a","lib",".dll","",".dll",      \
-	"",".exe","lib",".dll.a",               \
-	"PATH");
-
-SLBT_FLAVOR_SETTINGS(host_flavor_cygwin,        \
-	"pe",0,                                 \
-	"lib",".a","lib",".dll","",".dll",      \
-	"",".exe","lib",".dll.a",               \
-	"PATH");
-
-SLBT_FLAVOR_SETTINGS(host_flavor_darwin,        \
-	"macho","-fPIC",                        \
-	"lib",".a","lib",".dylib","",".dylib",  \
-	"","","","",                            \
-	"DYLD_LIBRARY_PATH");
-
-
-/* annotation strings */
-static const char cfgexplicit[] = "command-line argument";
-static const char cfghost[]     = "derived from <host>";
-static const char cfglconf[]    = "derived from <libtool>";
-static const char cfgtarget[]   = "derived from <target>";
-static const char cfgcompiler[] = "derived from <compiler>";
-static const char cfgnmachine[] = "native (cached in ccenv/host.mk)";
-static const char cfgxmachine[] = "foreign (derived from -dumpmachine)";
-static const char cfgnative[]   = "native";
-
-
 /* default compiler argv */
 static char * slbt_default_cargv[] = {"cc",0};
 
-/* elf rpath */
-static const char*ldrpath_elf[] = {
-	"/lib",
-	"/lib/64",
-	"/usr/lib",
-	"/usr/lib64",
-	"/usr/local/lib",
-	"/usr/local/lib64",
-	0};
-
 static const char aclr_reset [] = "\x1b[0m";
 static const char aclr_bold  [] = "\x1b[1m";
 static const char aclr_red   [] = "\x1b[31m";
@@ -119,11 +60,6 @@ static const char aclr_blue  [] = "\x1b[34m";
 static const char aclr_cyan  [] = "\x1b[36m";
 static const char aclr_white [] = "\x1b[37m";
 
-struct slbt_driver_ctx_alloc {
-	struct argv_meta *		meta;
-	struct slbt_driver_ctx_impl	ctx;
-	uint64_t			guard;
-};
 
 static void slbt_output_raw_vector(int fderr, char ** argv, char ** envp, bool fcolor)
 {
@@ -774,499 +710,6 @@ static int slbt_split_argv(
 	return 0;
 }
 
-static void slbt_get_host_quad(
-	char *	hostbuf,
-	char ** hostquad)
-{
-	char *	mark;
-	char *	ch;
-	int	i;
-
-	for (i=0, ch=hostbuf, mark=hostbuf; *ch && i<4; ch++) {
-		if (*ch == '-') {
-			*ch = 0;
-			hostquad[i++] = mark;
-			mark = &ch[1];
-		}
-	}
-
-	if (i<4)
-		hostquad[i] = mark;
-
-	if (i==3) {
-		hostquad[1] = hostquad[2];
-		hostquad[2] = hostquad[3];
-		hostquad[3] = 0;
-	}
-}
-
-static void slbt_spawn_ar(char ** argv, int * ecode)
-{
-	int	estatus;
-	pid_t	pid;
-
-	*ecode = 127;
-
-	if ((pid = fork()) < 0) {
-		return;
-
-	} else if (pid == 0) {
-		execvp(argv[0],argv);
-		_exit(errno);
-
-	} else {
-		waitpid(pid,&estatus,0);
-
-		if (WIFEXITED(estatus))
-			*ecode = WEXITSTATUS(estatus);
-	}
-}
-
-static int slbt_init_host_params(
-	const struct slbt_driver_ctx *	dctx,
-	const struct slbt_common_ctx *	cctx,
-	struct slbt_host_strs *		drvhost,
-	struct slbt_host_params *	host,
-	struct slbt_host_params *	cfgmeta,
-	const char *                    cfgmeta_ar,
-	const char *                    cfgmeta_ranlib)
-{
-	int		fdcwd;
-	int		arprobe;
-	int		arfd;
-	int		ecode;
-	size_t		toollen;
-	char *		dash;
-	char *		base;
-	char *		mark;
-	const char *	machine;
-	bool		ftarget       = false;
-	bool		fhost         = false;
-	bool		fcompiler     = false;
-	bool		fnative       = false;
-	bool		fdumpmachine  = false;
-	char		buf        [256];
-	char		hostbuf    [256];
-	char		machinebuf [256];
-	char *		hostquad   [4];
-	char *		machinequad[4];
-	char *		arprobeargv[4];
-	char		archivename[] = "/tmp/slibtool.ar.probe.XXXXXXXXXXXXXXXX";
-
-	/* base */
-	if ((base = strrchr(cctx->cargv[0],'/')))
-		base++;
-	else
-		base = cctx->cargv[0];
-
-	fdumpmachine  = (cctx->mode == SLBT_MODE_COMPILE)
-			|| (cctx->mode == SLBT_MODE_LINK)
-			|| (cctx->mode == SLBT_MODE_INFO);
-
-	fdumpmachine &= (!strcmp(base,"xgcc")
-			|| !strcmp(base,"xg++"));
-
-	/* support the portbld <--> unknown synonym */
-	if (!(drvhost->machine = strdup(SLBT_MACHINE)))
-		return -1;
-
-	if ((mark = strstr(drvhost->machine,"-portbld-")))
-		memcpy(mark,"-unknown",8);
-
-	/* host */
-	if (host->host) {
-		cfgmeta->host = cfgexplicit;
-		fhost         = true;
-
-	} else if (cctx->target) {
-		host->host    = cctx->target;
-		cfgmeta->host = cfgtarget;
-		ftarget       = true;
-
-	} else if (strrchr(base,'-')) {
-		if (!(drvhost->host = strdup(cctx->cargv[0])))
-			return -1;
-
-		dash          = strrchr(drvhost->host,'-');
-		*dash         = 0;
-		host->host    = drvhost->host;
-		cfgmeta->host = cfgcompiler;
-		fcompiler     = true;
-
-	} else if (!fdumpmachine) {
-		host->host    = drvhost->machine;
-		cfgmeta->host = cfgnmachine;
-
-	} else if (slbt_dump_machine(cctx->cargv[0],buf,sizeof(buf)) < 0) {
-		if (dctx)
-			slbt_dprintf(
-				slbt_driver_fderr(dctx),
-				"%s: could not determine host "
-				"via -dumpmachine\n",
-				dctx->program);
-		return -1;
-
-	} else {
-		if (!(drvhost->host = strdup(buf)))
-			return -1;
-
-		host->host    = drvhost->host;
-		fcompiler     = true;
-		fnative       = !strcmp(host->host,drvhost->machine);
-		cfgmeta->host = fnative ? cfgnmachine : cfgxmachine;
-
-		if (!fnative) {
-			strcpy(hostbuf,host->host);
-			strcpy(machinebuf,drvhost->machine);
-
-			slbt_get_host_quad(hostbuf,hostquad);
-			slbt_get_host_quad(machinebuf,machinequad);
-
-			if (hostquad[2] && machinequad[2])
-				fnative = !strcmp(hostquad[0],machinequad[0])
-					&& !strcmp(hostquad[1],machinequad[1])
-					&& !strcmp(hostquad[2],machinequad[2]);
-		}
-	}
-
-	/* flavor */
-	if (host->flavor) {
-		cfgmeta->flavor = cfgexplicit;
-	} else {
-		if (fhost) {
-			machine         = host->host;
-			cfgmeta->flavor = cfghost;
-		} else if (ftarget) {
-			machine         = cctx->target;
-			cfgmeta->flavor = cfgtarget;
-		} else if (fcompiler) {
-			machine         = drvhost->host;
-			cfgmeta->flavor = cfgcompiler;
-		} else {
-			machine         = drvhost->machine;
-			cfgmeta->flavor = cfgnmachine;
-		}
-
-		dash = strrchr(machine,'-');
-		cfgmeta->flavor = cfghost;
-
-		if ((dash && !strcmp(dash,"-bsd")) || strstr(machine,"-bsd-"))
-			host->flavor = "bsd";
-		else if ((dash && !strcmp(dash,"-cygwin")) || strstr(machine,"-cygwin-"))
-			host->flavor = "cygwin";
-		else if ((dash && !strcmp(dash,"-darwin")) || strstr(machine,"-darwin"))
-			host->flavor = "darwin";
-		else if ((dash && !strcmp(dash,"-linux")) || strstr(machine,"-linux-"))
-			host->flavor = "linux";
-		else if ((dash && !strcmp(dash,"-midipix")) || strstr(machine,"-midipix-"))
-			host->flavor = "midipix";
-		else if ((dash && !strcmp(dash,"-mingw")) || strstr(machine,"-mingw-"))
-			host->flavor = "mingw";
-		else if ((dash && !strcmp(dash,"-mingw32")) || strstr(machine,"-mingw32-"))
-			host->flavor = "mingw";
-		else if ((dash && !strcmp(dash,"-mingw64")) || strstr(machine,"-mingw64-"))
-			host->flavor = "mingw";
-		else if ((dash && !strcmp(dash,"-windows")) || strstr(machine,"-windows-"))
-			host->flavor = "mingw";
-		else {
-			host->flavor   = "default";
-			cfgmeta->flavor = "fallback, unverified";
-		}
-
-		if (fcompiler && !fnative)
-			if ((mark = strstr(drvhost->machine,host->flavor)))
-				if (mark > drvhost->machine)
-					fnative = (*--mark == '-');
-	}
-
-	/* toollen */
-	toollen =  fnative ? 0 : strlen(host->host);
-	toollen += strlen("-utility-name");
-
-	/* ar */
-	if (host->ar)
-		cfgmeta->ar = cfgmeta_ar ? cfgmeta_ar : cfgexplicit;
-	else {
-		if (!(drvhost->ar = calloc(1,toollen)))
-			return -1;
-
-		if (fnative) {
-			strcpy(drvhost->ar,"ar");
-			cfgmeta->ar = cfgnative;
-			arprobe = 0;
-		} else if (cctx->mode == SLBT_MODE_LINK) {
-			arprobe = true;
-		} else if (cctx->mode == SLBT_MODE_INFO) {
-			arprobe = true;
-		} else {
-			arprobe = false;
-		}
-
-		/* arprobe */
-		if (arprobe) {
-			sprintf(drvhost->ar,"%s-ar",host->host);
-			cfgmeta->ar = cfghost;
-			ecode       = 127;
-
-			/* empty archive */
-			if ((arfd = mkstemp(archivename)) >= 0) {
-				slbt_dprintf(arfd,"!<arch>\n");
-
-				arprobeargv[0] = drvhost->ar;
-				arprobeargv[1] = "-t";
-				arprobeargv[2] = archivename;
-				arprobeargv[3] = 0;
-
-				/* <target>-ar */
-				slbt_spawn_ar(
-					arprobeargv,
-					&ecode);
-			}
-
-			/* <target>-<compiler>-ar */
-			if (ecode && !strchr(base,'-')) {
-				sprintf(drvhost->ar,"%s-%s-ar",host->host,base);
-
-				slbt_spawn_ar(
-					arprobeargv,
-					&ecode);
-			}
-
-			/* <compiler>-ar */
-			if (ecode && !strchr(base,'-')) {
-				sprintf(drvhost->ar,"%s-ar",base);
-
-				slbt_spawn_ar(
-					arprobeargv,
-					&ecode);
-			}
-
-			/* if target is the native target, fallback to native ar */
-			if (ecode && !strcmp(host->host,SLBT_MACHINE)) {
-				strcpy(drvhost->ar,"ar");
-				cfgmeta->ar = cfgnative;
-			}
-
-			/* fdcwd */
-			fdcwd = slbt_driver_fdcwd(dctx);
-
-			/* clean up */
-			if (arfd >= 0) {
-				unlinkat(fdcwd,archivename,0);
-				close(arfd);
-			}
-		}
-
-		host->ar = drvhost->ar;
-	}
-
-	/* ranlib */
-	if (host->ranlib)
-		cfgmeta->ranlib = cfgmeta_ranlib ? cfgmeta_ranlib : cfgexplicit;
-	else {
-		if (!(drvhost->ranlib = calloc(1,toollen)))
-			return -1;
-
-		if (fnative) {
-			strcpy(drvhost->ranlib,"ranlib");
-			cfgmeta->ranlib = cfgnative;
-		} else {
-			sprintf(drvhost->ranlib,"%s-ranlib",host->host);
-			cfgmeta->ranlib = cfghost;
-		}
-
-		host->ranlib = drvhost->ranlib;
-	}
-
-	/* windres */
-	if (host->windres)
-		cfgmeta->windres = cfgexplicit;
-
-	else if (strcmp(host->flavor,"cygwin")
-			&& strcmp(host->flavor,"midipix")
-			&& strcmp(host->flavor,"mingw")) {
-		host->windres    = "";
-		cfgmeta->windres = "not applicable";
-
-	} else {
-		if (!(drvhost->windres = calloc(1,toollen)))
-			return -1;
-
-		if (fnative) {
-			strcpy(drvhost->windres,"windres");
-			cfgmeta->windres = cfgnative;
-		} else {
-			sprintf(drvhost->windres,"%s-windres",host->host);
-			cfgmeta->windres = cfghost;
-		}
-
-		host->windres = drvhost->windres;
-	}
-
-	/* dlltool */
-	if (host->dlltool)
-		cfgmeta->dlltool = cfgexplicit;
-
-	else if (strcmp(host->flavor,"cygwin")
-			&& strcmp(host->flavor,"midipix")
-			&& strcmp(host->flavor,"mingw")) {
-		host->dlltool = "";
-		cfgmeta->dlltool = "not applicable";
-
-	} else {
-		if (!(drvhost->dlltool = calloc(1,toollen)))
-			return -1;
-
-		if (fnative) {
-			strcpy(drvhost->dlltool,"dlltool");
-			cfgmeta->dlltool = cfgnative;
-		} else {
-			sprintf(drvhost->dlltool,"%s-dlltool",host->host);
-			cfgmeta->dlltool = cfghost;
-		}
-
-		host->dlltool = drvhost->dlltool;
-	}
-
-	/* mdso */
-	if (host->mdso)
-		cfgmeta->mdso = cfgexplicit;
-
-	else if (strcmp(host->flavor,"cygwin")
-			&& strcmp(host->flavor,"midipix")
-			&& strcmp(host->flavor,"mingw")) {
-		host->mdso = "";
-		cfgmeta->mdso = "not applicable";
-
-	} else {
-		if (!(drvhost->mdso = calloc(1,toollen)))
-			return -1;
-
-		if (fnative) {
-			strcpy(drvhost->mdso,"mdso");
-			cfgmeta->mdso = cfgnative;
-		} else {
-			sprintf(drvhost->mdso,"%s-mdso",host->host);
-			cfgmeta->mdso = cfghost;
-		}
-
-		host->mdso = drvhost->mdso;
-	}
-
-	return 0;
-}
-
-static void slbt_free_host_params(struct slbt_host_strs * host)
-{
-	if (host->machine)
-		free(host->machine);
-
-	if (host->host)
-		free(host->host);
-
-	if (host->flavor)
-		free(host->flavor);
-
-	if (host->ar)
-		free(host->ar);
-
-	if (host->ranlib)
-		free(host->ranlib);
-
-	if (host->windres)
-		free(host->windres);
-
-	if (host->dlltool)
-		free(host->dlltool);
-
-	if (host->mdso)
-		free(host->mdso);
-
-	memset(host,0,sizeof(*host));
-}
-
-static void slbt_init_flavor_settings(
-	struct slbt_common_ctx *	cctx,
-	const struct slbt_host_params * ahost,
-	struct slbt_flavor_settings *	psettings)
-{
-	const struct slbt_host_params *     host;
-	const struct slbt_flavor_settings * settings;
-
-	host = ahost ? ahost : &cctx->host;
-
-	if (!strcmp(host->flavor,"midipix"))
-		settings = &host_flavor_midipix;
-	else if (!strcmp(host->flavor,"mingw"))
-		settings = &host_flavor_mingw;
-	else if (!strcmp(host->flavor,"cygwin"))
-		settings = &host_flavor_cygwin;
-	else if (!strcmp(host->flavor,"darwin"))
-		settings = &host_flavor_darwin;
-	else
-		settings = &host_flavor_default;
-
-	if (!ahost) {
-		if (!strcmp(settings->imagefmt,"elf"))
-			cctx->drvflags |= SLBT_DRIVER_IMAGE_ELF;
-		else if (!strcmp(settings->imagefmt,"pe"))
-			cctx->drvflags |= SLBT_DRIVER_IMAGE_PE;
-		else if (!strcmp(settings->imagefmt,"macho"))
-			cctx->drvflags |= SLBT_DRIVER_IMAGE_MACHO;
-	}
-
-	memcpy(psettings,settings,sizeof(*settings));
-
-	if (cctx->shrext)
-		psettings->dsosuffix = cctx->shrext;
-}
-
-static int slbt_init_ldrpath(
-	struct slbt_common_ctx *  cctx,
-	struct slbt_host_params * host)
-{
-	char *         buf;
-	const char **  ldrpath;
-
-	if (!cctx->rpath || !(cctx->drvflags & SLBT_DRIVER_IMAGE_ELF)) {
-		host->ldrpath = 0;
-		return 0;
-	}
-
-	/* common? */
-	for (ldrpath=ldrpath_elf; *ldrpath; ldrpath ++)
-		if (!(strcmp(cctx->rpath,*ldrpath))) {
-			host->ldrpath = 0;
-			return 0;
-		}
-
-	/* buf */
-	if (!(buf = malloc(12 + strlen(cctx->host.host))))
-		return -1;
-
-	/* /usr/{host}/lib */
-	sprintf(buf,"/usr/%s/lib",cctx->host.host);
-
-	if (!(strcmp(cctx->rpath,buf))) {
-		host->ldrpath = 0;
-		free(buf);
-		return 0;
-	}
-
-	/* /usr/{host}/lib64 */
-	sprintf(buf,"/usr/%s/lib64",cctx->host.host);
-
-	if (!(strcmp(cctx->rpath,buf))) {
-		host->ldrpath = 0;
-		free(buf);
-		return 0;
-	}
-
-	host->ldrpath = cctx->rpath;
-
-	free(buf);
-	return 0;
-}
 
 static int slbt_init_version_info(
 	struct slbt_driver_ctx_impl *	ictx,
@@ -2023,6 +1466,7 @@ int slbt_get_driver_ctx(
 	return 0;
 }
 
+
 static void slbt_free_driver_ctx_impl(struct slbt_driver_ctx_alloc * ictx)
 {
 	struct slbt_error_info ** perr;
@@ -2057,6 +1501,7 @@ static void slbt_free_driver_ctx_impl(struct slbt_driver_ctx_alloc * ictx)
 	free(ictx);
 }
 
+
 void slbt_free_driver_ctx(struct slbt_driver_ctx * ctx)
 {
 	struct slbt_driver_ctx_alloc *	ictx;
@@ -2070,93 +1515,13 @@ void slbt_free_driver_ctx(struct slbt_driver_ctx * ctx)
 	}
 }
 
-void slbt_reset_alternate_host(const struct slbt_driver_ctx * ctx)
-{
-	struct slbt_driver_ctx_alloc *	ictx;
-	uintptr_t			addr;
-
-	addr = (uintptr_t)ctx - offsetof(struct slbt_driver_ctx_alloc,ctx);
-	addr = addr - offsetof(struct slbt_driver_ctx_impl,ctx);
-	ictx = (struct slbt_driver_ctx_alloc *)addr;
-
-	slbt_free_host_params(&ictx->ctx.ahost);
-}
-
-int  slbt_set_alternate_host(
-	const struct slbt_driver_ctx *	ctx,
-	const char *			host,
-	const char *			flavor)
-{
-	struct slbt_driver_ctx_alloc *	ictx;
-	uintptr_t			addr;
-
-	addr = (uintptr_t)ctx - offsetof(struct slbt_driver_ctx_alloc,ctx);
-	addr = addr - offsetof(struct slbt_driver_ctx_impl,ctx);
-	ictx = (struct slbt_driver_ctx_alloc *)addr;
-	slbt_free_host_params(&ictx->ctx.ahost);
-
-	if (!(ictx->ctx.ahost.host = strdup(host)))
-		return SLBT_SYSTEM_ERROR(ctx,0);
-
-	if (!(ictx->ctx.ahost.flavor = strdup(flavor))) {
-		slbt_free_host_params(&ictx->ctx.ahost);
-		return SLBT_SYSTEM_ERROR(ctx,0);
-	}
-
-	ictx->ctx.cctx.ahost.host   = ictx->ctx.ahost.host;
-	ictx->ctx.cctx.ahost.flavor = ictx->ctx.ahost.flavor;
-
-	if (slbt_init_host_params(
-			0,
-			ctx->cctx,
-			&ictx->ctx.ahost,
-			&ictx->ctx.cctx.ahost,
-			&ictx->ctx.cctx.acfgmeta,
-			0,0)) {
-		slbt_free_host_params(&ictx->ctx.ahost);
-		return SLBT_CUSTOM_ERROR(ctx,SLBT_ERR_HOST_INIT);
-	}
-
-	slbt_init_flavor_settings(
-		&ictx->ctx.cctx,
-		&ictx->ctx.cctx.ahost,
-		&ictx->ctx.cctx.asettings);
-
-	if (slbt_init_ldrpath(
-			&ictx->ctx.cctx,
-			&ictx->ctx.cctx.ahost)) {
-		slbt_free_host_params(&ictx->ctx.ahost);
-		return SLBT_CUSTOM_ERROR(ctx,SLBT_ERR_LDRPATH_INIT);
-	}
-
-	return 0;
-}
-
-int slbt_get_flavor_settings(
-	const char *                            flavor,
-	const struct slbt_flavor_settings **    settings)
-{
-	if (!strcmp(flavor,"midipix"))
-		*settings = &host_flavor_midipix;
-	else if (!strcmp(flavor,"mingw"))
-		*settings = &host_flavor_mingw;
-	else if (!strcmp(flavor,"cygwin"))
-		*settings = &host_flavor_cygwin;
-	else if (!strcmp(flavor,"darwin"))
-		*settings = &host_flavor_darwin;
-	else if (!strcmp(flavor,"default"))
-		*settings = &host_flavor_default;
-	else
-		*settings = 0;
-
-	return *settings ? 0 : -1;
-}
 
 const struct slbt_source_version * slbt_source_version(void)
 {
 	return &slbt_src_version;
 }
 
+
 int slbt_get_driver_fdctx(
 	const struct slbt_driver_ctx *	dctx,
 	struct slbt_fd_ctx *		fdctx)
@@ -2175,6 +1540,7 @@ int slbt_get_driver_fdctx(
 	return 0;
 }
 
+
 int slbt_set_driver_fdctx(
 	struct slbt_driver_ctx *	dctx,
 	const struct slbt_fd_ctx *	fdctx)
diff --git a/src/driver/slbt_host_params.c b/src/driver/slbt_host_params.c
new file mode 100644
index 0000000..b83fa8a
--- /dev/null
+++ b/src/driver/slbt_host_params.c
@@ -0,0 +1,663 @@
+/*******************************************************************/
+/*  slibtool: a skinny libtool implementation, written in C        */
+/*  Copyright (C) 2016--2021  SysDeer Technologies, LLC            */
+/*  Released under the Standard MIT License; see COPYING.SLIBTOOL. */
+/*******************************************************************/
+
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <spawn.h>
+#include <sys/wait.h>
+
+#include <slibtool/slibtool.h>
+#include "slibtool_driver_impl.h"
+#include "slibtool_errinfo_impl.h"
+#include "slibtool_ar_impl.h"
+
+
+/* annotation strings */
+static const char cfgexplicit[] = "command-line argument";
+static const char cfghost[]     = "derived from <host>";
+static const char cfgtarget[]   = "derived from <target>";
+static const char cfgcompiler[] = "derived from <compiler>";
+static const char cfgnmachine[] = "native (cached in ccenv/host.mk)";
+static const char cfgxmachine[] = "foreign (derived from -dumpmachine)";
+static const char cfgnative[]   = "native";
+
+/* elf rpath */
+static const char*ldrpath_elf[] = {
+	"/lib",
+	"/lib/64",
+	"/usr/lib",
+	"/usr/lib64",
+	"/usr/local/lib",
+	"/usr/local/lib64",
+	0};
+
+/* flavor settings */
+#define SLBT_FLAVOR_SETTINGS(flavor,          \
+		bfmt,pic,                     \
+		arp,ars,dsop,dsos,osds,osdf,  \
+		exep,exes,impp,imps,          \
+		ldenv)                        \
+	static const struct slbt_flavor_settings flavor = {  \
+		bfmt,arp,ars,dsop,dsos,osds,osdf,           \
+		exep,exes,impp,imps,                       \
+		ldenv,pic}
+
+SLBT_FLAVOR_SETTINGS(host_flavor_default,       \
+	"elf","-fPIC",                          \
+	"lib",".a","lib",".so",".so","",        \
+	"","","","",                            \
+	"LD_LIBRARY_PATH");
+
+SLBT_FLAVOR_SETTINGS(host_flavor_midipix,       \
+	"pe","-fPIC",                           \
+	"lib",".a","lib",".so",".so","",        \
+	"","","lib",".lib.a",                   \
+	"LD_LIBRARY_PATH");
+
+SLBT_FLAVOR_SETTINGS(host_flavor_mingw,         \
+	"pe",0,                                 \
+	"lib",".a","lib",".dll","",".dll",      \
+	"",".exe","lib",".dll.a",               \
+	"PATH");
+
+SLBT_FLAVOR_SETTINGS(host_flavor_cygwin,        \
+	"pe",0,                                 \
+	"lib",".a","lib",".dll","",".dll",      \
+	"",".exe","lib",".dll.a",               \
+	"PATH");
+
+SLBT_FLAVOR_SETTINGS(host_flavor_darwin,        \
+	"macho","-fPIC",                        \
+	"lib",".a","lib",".dylib","",".dylib",  \
+	"","","","",                            \
+	"DYLD_LIBRARY_PATH");
+
+
+static void slbt_get_host_quad(
+	char *	hostbuf,
+	char ** hostquad)
+{
+	char *	mark;
+	char *	ch;
+	int	i;
+
+	for (i=0, ch=hostbuf, mark=hostbuf; *ch && i<4; ch++) {
+		if (*ch == '-') {
+			*ch = 0;
+			hostquad[i++] = mark;
+			mark = &ch[1];
+		}
+	}
+
+	if (i<4)
+		hostquad[i] = mark;
+
+	if (i==3) {
+		hostquad[1] = hostquad[2];
+		hostquad[2] = hostquad[3];
+		hostquad[3] = 0;
+	}
+}
+
+
+static void slbt_spawn_ar(char ** argv, int * ecode)
+{
+	int	estatus;
+	pid_t	pid;
+
+	*ecode = 127;
+
+	if ((pid = fork()) < 0) {
+		return;
+
+	} else if (pid == 0) {
+		execvp(argv[0],argv);
+		_exit(errno);
+
+	} else {
+		waitpid(pid,&estatus,0);
+
+		if (WIFEXITED(estatus))
+			*ecode = WEXITSTATUS(estatus);
+	}
+}
+
+
+int slbt_init_host_params(
+	const struct slbt_driver_ctx *	dctx,
+	const struct slbt_common_ctx *	cctx,
+	struct slbt_host_strs *		drvhost,
+	struct slbt_host_params *	host,
+	struct slbt_host_params *	cfgmeta,
+	const char *                    cfgmeta_ar,
+	const char *                    cfgmeta_ranlib)
+{
+	int		fdcwd;
+	int		arprobe;
+	int		arfd;
+	int		ecode;
+	size_t		toollen;
+	char *		dash;
+	char *		base;
+	char *		mark;
+	const char *	machine;
+	bool		ftarget       = false;
+	bool		fhost         = false;
+	bool		fcompiler     = false;
+	bool		fnative       = false;
+	bool		fdumpmachine  = false;
+	char		buf        [256];
+	char		hostbuf    [256];
+	char		machinebuf [256];
+	char *		hostquad   [4];
+	char *		machinequad[4];
+	char *		arprobeargv[4];
+	char		archivename[] = "/tmp/slibtool.ar.probe.XXXXXXXXXXXXXXXX";
+
+	/* base */
+	if ((base = strrchr(cctx->cargv[0],'/')))
+		base++;
+	else
+		base = cctx->cargv[0];
+
+	fdumpmachine  = (cctx->mode == SLBT_MODE_COMPILE)
+			|| (cctx->mode == SLBT_MODE_LINK)
+			|| (cctx->mode == SLBT_MODE_INFO);
+
+	fdumpmachine &= (!strcmp(base,"xgcc")
+			|| !strcmp(base,"xg++"));
+
+	/* support the portbld <--> unknown synonym */
+	if (!(drvhost->machine = strdup(SLBT_MACHINE)))
+		return -1;
+
+	if ((mark = strstr(drvhost->machine,"-portbld-")))
+		memcpy(mark,"-unknown",8);
+
+	/* host */
+	if (host->host) {
+		cfgmeta->host = cfgexplicit;
+		fhost         = true;
+
+	} else if (cctx->target) {
+		host->host    = cctx->target;
+		cfgmeta->host = cfgtarget;
+		ftarget       = true;
+
+	} else if (strrchr(base,'-')) {
+		if (!(drvhost->host = strdup(cctx->cargv[0])))
+			return -1;
+
+		dash          = strrchr(drvhost->host,'-');
+		*dash         = 0;
+		host->host    = drvhost->host;
+		cfgmeta->host = cfgcompiler;
+		fcompiler     = true;
+
+	} else if (!fdumpmachine) {
+		host->host    = drvhost->machine;
+		cfgmeta->host = cfgnmachine;
+
+	} else if (slbt_dump_machine(cctx->cargv[0],buf,sizeof(buf)) < 0) {
+		if (dctx)
+			slbt_dprintf(
+				slbt_driver_fderr(dctx),
+				"%s: could not determine host "
+				"via -dumpmachine\n",
+				dctx->program);
+		return -1;
+
+	} else {
+		if (!(drvhost->host = strdup(buf)))
+			return -1;
+
+		host->host    = drvhost->host;
+		fcompiler     = true;
+		fnative       = !strcmp(host->host,drvhost->machine);
+		cfgmeta->host = fnative ? cfgnmachine : cfgxmachine;
+
+		if (!fnative) {
+			strcpy(hostbuf,host->host);
+			strcpy(machinebuf,drvhost->machine);
+
+			slbt_get_host_quad(hostbuf,hostquad);
+			slbt_get_host_quad(machinebuf,machinequad);
+
+			if (hostquad[2] && machinequad[2])
+				fnative = !strcmp(hostquad[0],machinequad[0])
+					&& !strcmp(hostquad[1],machinequad[1])
+					&& !strcmp(hostquad[2],machinequad[2]);
+		}
+	}
+
+	/* flavor */
+	if (host->flavor) {
+		cfgmeta->flavor = cfgexplicit;
+	} else {
+		if (fhost) {
+			machine         = host->host;
+			cfgmeta->flavor = cfghost;
+		} else if (ftarget) {
+			machine         = cctx->target;
+			cfgmeta->flavor = cfgtarget;
+		} else if (fcompiler) {
+			machine         = drvhost->host;
+			cfgmeta->flavor = cfgcompiler;
+		} else {
+			machine         = drvhost->machine;
+			cfgmeta->flavor = cfgnmachine;
+		}
+
+		dash = strrchr(machine,'-');
+		cfgmeta->flavor = cfghost;
+
+		if ((dash && !strcmp(dash,"-bsd")) || strstr(machine,"-bsd-"))
+			host->flavor = "bsd";
+		else if ((dash && !strcmp(dash,"-cygwin")) || strstr(machine,"-cygwin-"))
+			host->flavor = "cygwin";
+		else if ((dash && !strcmp(dash,"-darwin")) || strstr(machine,"-darwin"))
+			host->flavor = "darwin";
+		else if ((dash && !strcmp(dash,"-linux")) || strstr(machine,"-linux-"))
+			host->flavor = "linux";
+		else if ((dash && !strcmp(dash,"-midipix")) || strstr(machine,"-midipix-"))
+			host->flavor = "midipix";
+		else if ((dash && !strcmp(dash,"-mingw")) || strstr(machine,"-mingw-"))
+			host->flavor = "mingw";
+		else if ((dash && !strcmp(dash,"-mingw32")) || strstr(machine,"-mingw32-"))
+			host->flavor = "mingw";
+		else if ((dash && !strcmp(dash,"-mingw64")) || strstr(machine,"-mingw64-"))
+			host->flavor = "mingw";
+		else if ((dash && !strcmp(dash,"-windows")) || strstr(machine,"-windows-"))
+			host->flavor = "mingw";
+		else {
+			host->flavor   = "default";
+			cfgmeta->flavor = "fallback, unverified";
+		}
+
+		if (fcompiler && !fnative)
+			if ((mark = strstr(drvhost->machine,host->flavor)))
+				if (mark > drvhost->machine)
+					fnative = (*--mark == '-');
+	}
+
+	/* toollen */
+	toollen =  fnative ? 0 : strlen(host->host);
+	toollen += strlen("-utility-name");
+
+	/* ar */
+	if (host->ar)
+		cfgmeta->ar = cfgmeta_ar ? cfgmeta_ar : cfgexplicit;
+	else {
+		if (!(drvhost->ar = calloc(1,toollen)))
+			return -1;
+
+		if (fnative) {
+			strcpy(drvhost->ar,"ar");
+			cfgmeta->ar = cfgnative;
+			arprobe = 0;
+		} else if (cctx->mode == SLBT_MODE_LINK) {
+			arprobe = true;
+		} else if (cctx->mode == SLBT_MODE_INFO) {
+			arprobe = true;
+		} else {
+			arprobe = false;
+		}
+
+		/* arprobe */
+		if (arprobe) {
+			sprintf(drvhost->ar,"%s-ar",host->host);
+			cfgmeta->ar = cfghost;
+			ecode       = 127;
+
+			/* empty archive */
+			if ((arfd = mkstemp(archivename)) >= 0) {
+				slbt_dprintf(arfd,"!<arch>\n");
+
+				arprobeargv[0] = drvhost->ar;
+				arprobeargv[1] = "-t";
+				arprobeargv[2] = archivename;
+				arprobeargv[3] = 0;
+
+				/* <target>-ar */
+				slbt_spawn_ar(
+					arprobeargv,
+					&ecode);
+			}
+
+			/* <target>-<compiler>-ar */
+			if (ecode && !strchr(base,'-')) {
+				sprintf(drvhost->ar,"%s-%s-ar",host->host,base);
+
+				slbt_spawn_ar(
+					arprobeargv,
+					&ecode);
+			}
+
+			/* <compiler>-ar */
+			if (ecode && !strchr(base,'-')) {
+				sprintf(drvhost->ar,"%s-ar",base);
+
+				slbt_spawn_ar(
+					arprobeargv,
+					&ecode);
+			}
+
+			/* if target is the native target, fallback to native ar */
+			if (ecode && !strcmp(host->host,SLBT_MACHINE)) {
+				strcpy(drvhost->ar,"ar");
+				cfgmeta->ar = cfgnative;
+			}
+
+			/* fdcwd */
+			fdcwd = slbt_driver_fdcwd(dctx);
+
+			/* clean up */
+			if (arfd >= 0) {
+				unlinkat(fdcwd,archivename,0);
+				close(arfd);
+			}
+		}
+
+		host->ar = drvhost->ar;
+	}
+
+	/* ranlib */
+	if (host->ranlib)
+		cfgmeta->ranlib = cfgmeta_ranlib ? cfgmeta_ranlib : cfgexplicit;
+	else {
+		if (!(drvhost->ranlib = calloc(1,toollen)))
+			return -1;
+
+		if (fnative) {
+			strcpy(drvhost->ranlib,"ranlib");
+			cfgmeta->ranlib = cfgnative;
+		} else {
+			sprintf(drvhost->ranlib,"%s-ranlib",host->host);
+			cfgmeta->ranlib = cfghost;
+		}
+
+		host->ranlib = drvhost->ranlib;
+	}
+
+	/* windres */
+	if (host->windres)
+		cfgmeta->windres = cfgexplicit;
+
+	else if (strcmp(host->flavor,"cygwin")
+			&& strcmp(host->flavor,"midipix")
+			&& strcmp(host->flavor,"mingw")) {
+		host->windres    = "";
+		cfgmeta->windres = "not applicable";
+
+	} else {
+		if (!(drvhost->windres = calloc(1,toollen)))
+			return -1;
+
+		if (fnative) {
+			strcpy(drvhost->windres,"windres");
+			cfgmeta->windres = cfgnative;
+		} else {
+			sprintf(drvhost->windres,"%s-windres",host->host);
+			cfgmeta->windres = cfghost;
+		}
+
+		host->windres = drvhost->windres;
+	}
+
+	/* dlltool */
+	if (host->dlltool)
+		cfgmeta->dlltool = cfgexplicit;
+
+	else if (strcmp(host->flavor,"cygwin")
+			&& strcmp(host->flavor,"midipix")
+			&& strcmp(host->flavor,"mingw")) {
+		host->dlltool = "";
+		cfgmeta->dlltool = "not applicable";
+
+	} else {
+		if (!(drvhost->dlltool = calloc(1,toollen)))
+			return -1;
+
+		if (fnative) {
+			strcpy(drvhost->dlltool,"dlltool");
+			cfgmeta->dlltool = cfgnative;
+		} else {
+			sprintf(drvhost->dlltool,"%s-dlltool",host->host);
+			cfgmeta->dlltool = cfghost;
+		}
+
+		host->dlltool = drvhost->dlltool;
+	}
+
+	/* mdso */
+	if (host->mdso)
+		cfgmeta->mdso = cfgexplicit;
+
+	else if (strcmp(host->flavor,"cygwin")
+			&& strcmp(host->flavor,"midipix")
+			&& strcmp(host->flavor,"mingw")) {
+		host->mdso = "";
+		cfgmeta->mdso = "not applicable";
+
+	} else {
+		if (!(drvhost->mdso = calloc(1,toollen)))
+			return -1;
+
+		if (fnative) {
+			strcpy(drvhost->mdso,"mdso");
+			cfgmeta->mdso = cfgnative;
+		} else {
+			sprintf(drvhost->mdso,"%s-mdso",host->host);
+			cfgmeta->mdso = cfghost;
+		}
+
+		host->mdso = drvhost->mdso;
+	}
+
+	return 0;
+}
+
+
+void slbt_free_host_params(struct slbt_host_strs * host)
+{
+	if (host->machine)
+		free(host->machine);
+
+	if (host->host)
+		free(host->host);
+
+	if (host->flavor)
+		free(host->flavor);
+
+	if (host->ar)
+		free(host->ar);
+
+	if (host->ranlib)
+		free(host->ranlib);
+
+	if (host->windres)
+		free(host->windres);
+
+	if (host->dlltool)
+		free(host->dlltool);
+
+	if (host->mdso)
+		free(host->mdso);
+
+	memset(host,0,sizeof(*host));
+}
+
+
+void slbt_init_flavor_settings(
+	struct slbt_common_ctx *	cctx,
+	const struct slbt_host_params * ahost,
+	struct slbt_flavor_settings *	psettings)
+{
+	const struct slbt_host_params *     host;
+	const struct slbt_flavor_settings * settings;
+
+	host = ahost ? ahost : &cctx->host;
+
+	if (!strcmp(host->flavor,"midipix"))
+		settings = &host_flavor_midipix;
+	else if (!strcmp(host->flavor,"mingw"))
+		settings = &host_flavor_mingw;
+	else if (!strcmp(host->flavor,"cygwin"))
+		settings = &host_flavor_cygwin;
+	else if (!strcmp(host->flavor,"darwin"))
+		settings = &host_flavor_darwin;
+	else
+		settings = &host_flavor_default;
+
+	if (!ahost) {
+		if (!strcmp(settings->imagefmt,"elf"))
+			cctx->drvflags |= SLBT_DRIVER_IMAGE_ELF;
+		else if (!strcmp(settings->imagefmt,"pe"))
+			cctx->drvflags |= SLBT_DRIVER_IMAGE_PE;
+		else if (!strcmp(settings->imagefmt,"macho"))
+			cctx->drvflags |= SLBT_DRIVER_IMAGE_MACHO;
+	}
+
+	memcpy(psettings,settings,sizeof(*settings));
+
+	if (cctx->shrext)
+		psettings->dsosuffix = cctx->shrext;
+}
+
+
+int slbt_init_ldrpath(
+	struct slbt_common_ctx *  cctx,
+	struct slbt_host_params * host)
+{
+	char *         buf;
+	const char **  ldrpath;
+
+	if (!cctx->rpath || !(cctx->drvflags & SLBT_DRIVER_IMAGE_ELF)) {
+		host->ldrpath = 0;
+		return 0;
+	}
+
+	/* common? */
+	for (ldrpath=ldrpath_elf; *ldrpath; ldrpath ++)
+		if (!(strcmp(cctx->rpath,*ldrpath))) {
+			host->ldrpath = 0;
+			return 0;
+		}
+
+	/* buf */
+	if (!(buf = malloc(12 + strlen(cctx->host.host))))
+		return -1;
+
+	/* /usr/{host}/lib */
+	sprintf(buf,"/usr/%s/lib",cctx->host.host);
+
+	if (!(strcmp(cctx->rpath,buf))) {
+		host->ldrpath = 0;
+		free(buf);
+		return 0;
+	}
+
+	/* /usr/{host}/lib64 */
+	sprintf(buf,"/usr/%s/lib64",cctx->host.host);
+
+	if (!(strcmp(cctx->rpath,buf))) {
+		host->ldrpath = 0;
+		free(buf);
+		return 0;
+	}
+
+	host->ldrpath = cctx->rpath;
+
+	free(buf);
+	return 0;
+}
+
+
+void slbt_reset_alternate_host(const struct slbt_driver_ctx * ctx)
+{
+	struct slbt_driver_ctx_alloc *	ictx;
+	uintptr_t			addr;
+
+	addr = (uintptr_t)ctx - offsetof(struct slbt_driver_ctx_alloc,ctx);
+	addr = addr - offsetof(struct slbt_driver_ctx_impl,ctx);
+	ictx = (struct slbt_driver_ctx_alloc *)addr;
+
+	slbt_free_host_params(&ictx->ctx.ahost);
+}
+
+int  slbt_set_alternate_host(
+	const struct slbt_driver_ctx *	ctx,
+	const char *			host,
+	const char *			flavor)
+{
+	struct slbt_driver_ctx_alloc *	ictx;
+	uintptr_t			addr;
+
+	addr = (uintptr_t)ctx - offsetof(struct slbt_driver_ctx_alloc,ctx);
+	addr = addr - offsetof(struct slbt_driver_ctx_impl,ctx);
+	ictx = (struct slbt_driver_ctx_alloc *)addr;
+	slbt_free_host_params(&ictx->ctx.ahost);
+
+	if (!(ictx->ctx.ahost.host = strdup(host)))
+		return SLBT_SYSTEM_ERROR(ctx,0);
+
+	if (!(ictx->ctx.ahost.flavor = strdup(flavor))) {
+		slbt_free_host_params(&ictx->ctx.ahost);
+		return SLBT_SYSTEM_ERROR(ctx,0);
+	}
+
+	ictx->ctx.cctx.ahost.host   = ictx->ctx.ahost.host;
+	ictx->ctx.cctx.ahost.flavor = ictx->ctx.ahost.flavor;
+
+	if (slbt_init_host_params(
+			0,
+			ctx->cctx,
+			&ictx->ctx.ahost,
+			&ictx->ctx.cctx.ahost,
+			&ictx->ctx.cctx.acfgmeta,
+			0,0)) {
+		slbt_free_host_params(&ictx->ctx.ahost);
+		return SLBT_CUSTOM_ERROR(ctx,SLBT_ERR_HOST_INIT);
+	}
+
+	slbt_init_flavor_settings(
+		&ictx->ctx.cctx,
+		&ictx->ctx.cctx.ahost,
+		&ictx->ctx.cctx.asettings);
+
+	if (slbt_init_ldrpath(
+			&ictx->ctx.cctx,
+			&ictx->ctx.cctx.ahost)) {
+		slbt_free_host_params(&ictx->ctx.ahost);
+		return SLBT_CUSTOM_ERROR(ctx,SLBT_ERR_LDRPATH_INIT);
+	}
+
+	return 0;
+}
+
+int slbt_get_flavor_settings(
+	const char *                            flavor,
+	const struct slbt_flavor_settings **    settings)
+{
+	if (!strcmp(flavor,"midipix"))
+		*settings = &host_flavor_midipix;
+	else if (!strcmp(flavor,"mingw"))
+		*settings = &host_flavor_mingw;
+	else if (!strcmp(flavor,"cygwin"))
+		*settings = &host_flavor_cygwin;
+	else if (!strcmp(flavor,"darwin"))
+		*settings = &host_flavor_darwin;
+	else if (!strcmp(flavor,"default"))
+		*settings = &host_flavor_default;
+	else
+		*settings = 0;
+
+	return *settings ? 0 : -1;
+}
diff --git a/src/internal/slibtool_driver_impl.h b/src/internal/slibtool_driver_impl.h
index c72f19e..32ae6c8 100644
--- a/src/internal/slibtool_driver_impl.h
+++ b/src/internal/slibtool_driver_impl.h
@@ -141,6 +141,12 @@ struct slbt_driver_ctx_impl {
 	struct slbt_error_info	erribuf[64];
 };
 
+struct slbt_driver_ctx_alloc {
+	struct argv_meta *		meta;
+	struct slbt_driver_ctx_impl	ctx;
+	uint64_t			guard;
+};
+
 struct slbt_exec_ctx_impl {
 	int			argc;
 	char *			args;
@@ -162,6 +168,31 @@ struct slbt_archive_ctx_impl {
 	struct slbt_archive_ctx		actx;
 };
 
+
+int slbt_init_host_params(
+	const struct slbt_driver_ctx *	dctx,
+	const struct slbt_common_ctx *	cctx,
+	struct slbt_host_strs *		drvhost,
+	struct slbt_host_params *	host,
+	struct slbt_host_params *	cfgmeta,
+	const char *                    cfgmeta_ar,
+	const char *                    cfgmeta_ranlib);
+
+
+void slbt_free_host_params(struct slbt_host_strs * host);
+
+
+void slbt_init_flavor_settings(
+	struct slbt_common_ctx *	cctx,
+	const struct slbt_host_params * ahost,
+	struct slbt_flavor_settings *	psettings);
+
+
+int slbt_init_ldrpath(
+	struct slbt_common_ctx *  cctx,
+	struct slbt_host_params * host);
+
+
 static inline struct slbt_archive_ctx_impl * slbt_get_archive_ictx(const struct slbt_archive_ctx * actx)
 {
 	uintptr_t addr;