link mode: move the executable creation logic to its own translation unit.

1 files changed, 273 insertions, 0 deletions

diff --git a/src/logic/linkcmd/slbt_linkcmd_executable.c b/src/logic/linkcmd/slbt_linkcmd_executable.c
new file mode 100644
index 0000000..a602c8e
--- /dev/null
+++ b/src/logic/linkcmd/slbt_linkcmd_executable.c
@@ -0,0 +1,273 @@
+/*******************************************************************/
+/*  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 <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include <slibtool/slibtool.h>
+#include "slibtool_driver_impl.h"
+#include "slibtool_errinfo_impl.h"
+#include "slibtool_linkcmd_impl.h"
+#include "slibtool_mapfile_impl.h"
+#include "slibtool_metafile_impl.h"
+#include "slibtool_snprintf_impl.h"
+#include "slibtool_symlink_impl.h"
+#include "slibtool_spawn_impl.h"
+
+static int slbt_linkcmd_exit(
+	struct slbt_deps_meta *	depsmeta,
+	int			ret)
+{
+	if (depsmeta->altv)
+		free(depsmeta->altv);
+
+	if (depsmeta->args)
+		free(depsmeta->args);
+
+	return ret;
+}
+
+static void slbt_emit_fdwrap_dl_path_fixup(
+	char *	cwd,
+	char *	dpfixup,
+	size_t	dpfixup_size,
+	char *	wrapper)
+{
+	char *	p;
+	char *	q;
+	char *	wrapper_dname;
+
+	/* obtain cwd-relative directory name of wrapper */
+	for (p=cwd,q=wrapper; *p && *q && (*p==*q); p++,q++)
+		(void)0;
+
+	wrapper_dname = (*q == '/') ? (q + 1) : q;
+
+	dpfixup[0] = 0; strncat(dpfixup,"${0%/*}",dpfixup_size - 1);
+
+	/* append parent directory fixup for each level of depth in wrapper_dname */
+	for (p=wrapper_dname,q=0; *p; ) {
+		if ((p[0] == '.') && (p[1] == '/')) {
+			p++; p++;
+		} else if ((q = strchr(p, '/'))) {
+			strncat(dpfixup,"/..",dpfixup_size-1); p = (q + 1);
+		} else {
+			break;
+		}
+	}
+
+	strncat(dpfixup,"/",dpfixup_size-1);
+}
+
+int slbt_exec_link_create_executable(
+	const struct slbt_driver_ctx *	dctx,
+	struct slbt_exec_ctx *		ectx,
+	const char *			exefilename)
+{
+	int	fdcwd;
+	int	fdwrap;
+	char ** parg;
+	char ** xarg;
+	char *	base;
+	char *	ccwrap;
+	char	cwd    [PATH_MAX];
+	char	dpfixup[PATH_MAX];
+	char	output [PATH_MAX];
+	char	wrapper[PATH_MAX];
+	char	wraplnk[PATH_MAX];
+	bool	fabspath;
+	bool	fpic;
+	const struct slbt_source_version * verinfo;
+	struct slbt_deps_meta depsmeta = {0,0,0,0};
+	struct stat st;
+
+	/* initial state */
+	slbt_reset_arguments(ectx);
+
+	/* placeholders */
+	slbt_reset_placeholders(ectx);
+
+	/* fdcwd */
+	fdcwd = slbt_driver_fdcwd(dctx);
+
+	/* fpic */
+	fpic = !(dctx->cctx->drvflags & SLBT_DRIVER_ALL_STATIC);
+
+	/* input argument adjustment */
+	for (parg=ectx->cargv; *parg; parg++)
+		slbt_adjust_object_argument(*parg,fpic,true,fdcwd);
+
+	/* linker argument adjustment */
+	for (parg=ectx->cargv, xarg=ectx->xargv; *parg; parg++, xarg++)
+		if (slbt_adjust_linker_argument(
+				dctx,
+				*parg,xarg,true,
+				dctx->cctx->settings.dsosuffix,
+				dctx->cctx->settings.arsuffix,
+				&depsmeta) < 0)
+			return SLBT_NESTED_ERROR(dctx);
+
+	/* --no-undefined */
+	if (dctx->cctx->drvflags & SLBT_DRIVER_NO_UNDEFINED)
+		*ectx->noundef = "-Wl,--no-undefined";
+
+	/* executable wrapper: create */
+	if (slbt_snprintf(wrapper,sizeof(wrapper),
+				"%s.wrapper.tmp",
+				dctx->cctx->output) < 0)
+		return SLBT_BUFFER_ERROR(dctx);
+
+	if ((fdwrap = openat(fdcwd,wrapper,O_RDWR|O_CREAT|O_TRUNC,0644)) < 0)
+		return SLBT_SYSTEM_ERROR(dctx,wrapper);
+
+	slbt_exec_set_fdwrapper(ectx,fdwrap);
+
+	/* executable wrapper: header */
+	verinfo = slbt_source_version();
+
+	/* cwd, DL_PATH fixup */
+	if (slbt_realpath(fdcwd,".",O_DIRECTORY,cwd,sizeof(cwd)))
+		return SLBT_SYSTEM_ERROR(dctx,0);
+
+	slbt_emit_fdwrap_dl_path_fixup(
+		cwd,dpfixup,sizeof(dpfixup),
+		wrapper);
+
+	if (slbt_dprintf(fdwrap,
+			"#!/bin/sh\n"
+			"# libtool compatible executable wrapper\n"
+			"# Generated by %s (slibtool %d.%d.%d)\n"
+			"# [commit reference: %s]\n\n"
+
+			"if [ -z \"$%s\" ]; then\n"
+			"\tDL_PATH=\n"
+			"\tCOLON=\n"
+			"\tLCOLON=\n"
+			"else\n"
+			"\tDL_PATH=\n"
+			"\tCOLON=\n"
+			"\tLCOLON=':'\n"
+			"fi\n\n"
+			"DL_PATH_FIXUP=\"%s\";\n\n",
+
+			dctx->program,
+			verinfo->major,verinfo->minor,verinfo->revision,
+			verinfo->commit,
+			dctx->cctx->settings.ldpathenv,
+			dpfixup) < 0)
+		return SLBT_SYSTEM_ERROR(dctx,0);
+
+	/* output */
+	if (slbt_snprintf(output,sizeof(output),
+			"%s",exefilename) < 0)
+		return SLBT_BUFFER_ERROR(dctx);
+
+	*ectx->lout[0] = "-o";
+	*ectx->lout[1] = output;
+
+	/* static? */
+	if (dctx->cctx->drvflags & SLBT_DRIVER_ALL_STATIC)
+		*ectx->dpic = "-static";
+
+	/* .libs/libfoo.so --> -L.libs -lfoo */
+	if (slbt_exec_link_adjust_argument_vector(
+			dctx,ectx,&depsmeta,cwd,false))
+		return SLBT_NESTED_ERROR(dctx);
+
+	/* using alternate argument vector */
+	ccwrap        = (char *)dctx->cctx->ccwrap;
+	ectx->argv    = depsmeta.altv;
+	ectx->program = ccwrap ? ccwrap : depsmeta.altv[0];
+
+	/* executable wrapper symlink */
+	if (slbt_snprintf(wraplnk,sizeof(wraplnk),
+			"%s.exe.wrapper",
+			exefilename) < 0)
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_BUFFER_ERROR(dctx));
+
+	/* executable wrapper: base name */
+	base = strrchr(wraplnk,'/');
+	base++;
+
+	/* executable wrapper: footer */
+	fabspath = (exefilename[0] == '/');
+
+	if (slbt_dprintf(fdwrap,
+			"DL_PATH=\"${DL_PATH}${LCOLON}${%s}\"\n\n"
+			"export %s=\"$DL_PATH\"\n\n"
+			"if [ $(basename \"$0\") = \"%s\" ]; then\n"
+			"\tprogram=\"$1\"; shift\n"
+			"\texec \"$program\" \"$@\"\n"
+			"fi\n\n"
+			"exec %s/%s \"$@\"\n",
+			dctx->cctx->settings.ldpathenv,
+			dctx->cctx->settings.ldpathenv,
+			base,
+			fabspath ? "" : cwd,
+			fabspath ? &exefilename[1] : exefilename) < 0)
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_SYSTEM_ERROR(dctx,0));
+
+	/* sigh */
+	if (slbt_exec_link_finalize_argument_vector(dctx,ectx))
+		return SLBT_NESTED_ERROR(dctx);
+
+	/* step output */
+	if (!(dctx->cctx->drvflags & SLBT_DRIVER_SILENT))
+		if (slbt_output_link(dctx,ectx))
+			return slbt_linkcmd_exit(
+				&depsmeta,
+				SLBT_NESTED_ERROR(dctx));
+
+	/* spawn */
+	if ((slbt_spawn(ectx,true) < 0) && (ectx->pid < 0)) {
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_SPAWN_ERROR(dctx));
+
+	} else if (ectx->exitcode) {
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_CUSTOM_ERROR(
+				dctx,
+				SLBT_ERR_LINK_ERROR));
+	}
+
+	/* executable wrapper: finalize */
+	slbt_exec_close_fdwrapper(ectx);
+
+	if (slbt_create_symlink(
+			dctx,ectx,
+			dctx->cctx->output,wraplnk,
+			SLBT_SYMLINK_WRAPPER))
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_NESTED_ERROR(dctx));
+
+	if (fstatat(fdcwd,wrapper,&st,0))
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_SYSTEM_ERROR(dctx,wrapper));
+
+	if (renameat(fdcwd,wrapper,fdcwd,dctx->cctx->output))
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_SYSTEM_ERROR(dctx,dctx->cctx->output));
+
+	if (fchmodat(fdcwd,dctx->cctx->output,0755,0))
+		return slbt_linkcmd_exit(
+			&depsmeta,
+			SLBT_SYSTEM_ERROR(dctx,dctx->cctx->output));
+
+	return slbt_linkcmd_exit(&depsmeta,0);
+}