/*
 * Copyright (c) 2008 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup rtld
 * @brief
 * @{
 */
/**
 * @file
 */

#include <errno.h>
#include <rtld/module.h>
#include <rtld/rtld.h>
#include <rtld/rtld_debug.h>
#include <stdlib.h>
#include <str.h>

rtld_t *runtime_env;
static rtld_t rt_env_static;

/** Initialize the runtime linker for use in a statically-linked executable. */
errno_t rtld_init_static(void)
{
	errno_t rc;

	runtime_env = &rt_env_static;
	list_initialize(&runtime_env->modules);
	list_initialize(&runtime_env->imodules);
	runtime_env->program = NULL;
	runtime_env->next_id = 1;

	rc = module_create_static_exec(runtime_env, NULL);
	if (rc != EOK)
		return rc;

	modules_process_tls(runtime_env);

	return EOK;
}

/** Initialize and process a dynamically linked executable.
 *
 * @param p_info Program info
 * @return EOK on success or non-zero error code
 */
errno_t rtld_prog_process(elf_finfo_t *p_info, rtld_t **rre)
{
	rtld_t *env;
	module_t *prog;

	DPRINTF("Load dynamically linked program.\n");

	/* Allocate new RTLD environment to pass to the loaded program */
	env = calloc(1, sizeof(rtld_t));
	if (env == NULL)
		return ENOMEM;

	env->next_id = 1;

	prog = calloc(1, sizeof(module_t));
	if (prog == NULL) {
		free(env);
		return ENOMEM;
	}

	/*
	 * First we need to process dynamic sections of the executable
	 * program and insert it into the module graph.
	 */

	DPRINTF("Parse program .dynamic section at %p\n", p_info->dynamic);
	dynamic_parse(p_info->dynamic, 0, &prog->dyn);
	prog->bias = 0;
	prog->dyn.soname = "[program]";
	prog->rtld = env;
	prog->id = rtld_get_next_id(env);
	prog->exec = true;
	prog->local = false;

	prog->tdata = p_info->tls.tdata;
	prog->tdata_size = p_info->tls.tdata_size;
	prog->tbss_size = p_info->tls.tbss_size;
	prog->tls_align = p_info->tls.tls_align;

	DPRINTF("prog tdata at %p size %zu, tbss size %zu\n",
	    prog->tdata, prog->tdata_size, prog->tbss_size);

	/* Initialize list of loaded modules */
	list_initialize(&env->modules);
	list_initialize(&env->imodules);
	list_append(&prog->modules_link, &env->modules);

	/* Pointer to program module. Used as root of the module graph. */
	env->program = prog;

	/*
	 * Now we can continue with loading all other modules.
	 */

	DPRINTF("Load all program dependencies\n");
	errno_t rc = module_load_deps(prog, 0);
	if (rc != EOK) {
		return rc;
	}

	/* Compute static TLS size */
	modules_process_tls(env);

	/*
	 * Now relocate/link all modules together.
	 */

	/* Process relocations in all modules */
	DPRINTF("Relocate all modules\n");
	modules_process_relocs(env, prog);

	*rre = env;
	return EOK;
}

/** Create TLS (Thread Local Storage) data structures.
 *
 * @return Pointer to TCB.
 */
tcb_t *rtld_tls_make(rtld_t *rtld)
{
	tcb_t *tcb;
	void **dtv;
	size_t nmods;
	size_t i;

	tcb = tls_alloc_arch(rtld->tls_size, rtld->tls_align);
	if (tcb == NULL)
		return NULL;

	/** Allocate dynamic thread vector */
	nmods = list_count(&rtld->imodules);
	dtv = malloc((nmods + 1) * sizeof(void *));
	if (dtv == NULL) {
		tls_free(tcb);
		return NULL;
	}

	/*
	 * We define generation number to be equal to vector length.
	 * We start with a vector covering the initially loaded modules.
	 */
	DTV_GN(dtv) = nmods;

	/*
	 * Copy thread local data from the initialization images of initial
	 * modules. Zero out thread-local uninitialized data.
	 */

	i = 1;
	list_foreach(rtld->imodules, imodules_link, module_t, m) {
		assert(i++ == m->id);

		dtv[m->id] = (void *) tcb + m->tpoff;

		assert(((uintptr_t) dtv[m->id]) % m->tls_align == 0);

		memcpy(dtv[m->id], m->tdata, m->tdata_size);
		memset(dtv[m->id] + m->tdata_size, 0, m->tbss_size);
	}

	tcb->dtv = dtv;
	return tcb;
}

unsigned long rtld_get_next_id(rtld_t *rtld)
{
	return rtld->next_id++;
}

/** Get address of thread-local variable.
 *
 * @param rtld RTLD instance
 * @param tcb TCB of the thread whose instance to return
 * @param mod_id Module ID
 * @param offset Offset within TLS block of the module
 *
 * @return Address of thread-local variable
 */
void *rtld_tls_get_addr(rtld_t *rtld, tcb_t *tcb, unsigned long mod_id,
    unsigned long offset)
{
	module_t *m;
	size_t dtv_len;
	void *tls_block;

	dtv_len = DTV_GN(tcb->dtv);
	if (dtv_len < mod_id) {
		/* Vector is short */

		tcb->dtv = realloc(tcb->dtv, (1 + mod_id) * sizeof(void *));
		/* XXX This can fail if OOM */
		assert(tcb->dtv != NULL);
		/* Zero out new part of vector */
		memset(tcb->dtv + (1 + dtv_len), 0, (mod_id - dtv_len) *
		    sizeof(void *));
	}

	if (tcb->dtv[mod_id] == NULL) {
		/* TLS block is not allocated */

		m = module_by_id(rtld, mod_id);
		assert(m != NULL);
		/* Should not be initial module, those have TLS pre-allocated */
		assert(!link_used(&m->imodules_link));

		tls_block = memalign(m->tls_align, m->tdata_size + m->tbss_size);
		/* XXX This can fail if OOM */
		assert(tls_block != NULL);

		/* Copy tdata */
		memcpy(tls_block, m->tdata, m->tdata_size);
		/* Zero out tbss */
		memset(tls_block + m->tdata_size, 0, m->tbss_size);

		tcb->dtv[mod_id] = tls_block;
	}

	return (uint8_t *)(tcb->dtv[mod_id]) + offset;
}

/** @}
 */