Blame src/driver/mdso_unit_ctx.c

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/****************************************************************/
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/*  mdso: midipix dso scavenger                                 */
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/*  Copyright (C) 2015--2016  Z. Gilboa                         */
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/*  Released under GPLv2 and GPLv3; see COPYING.MDSO.           */
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/****************************************************************/
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#include <stdint.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sys/mman.h>
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#include <mdso/mdso.h>
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#include "mdso_driver_impl.h"
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static int mdso_free_unit_ctx_impl(struct mdso_unit_ctx_impl * ctx, int status)
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{
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	if (ctx) {
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		if (ctx->expsyms && ctx->expsyms->buffer)
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			free(ctx->expsyms->buffer);
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		if (ctx->expsyms)
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			free(ctx->expsyms);
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		mdso_unmap_input(&ctx->map);
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		free(ctx);
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	}
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	return status;
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}
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static FILE * mdso_stdin_to_tmp(const struct mdso_driver_ctx * dctx)
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{
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	struct mdso_driver_ctx_impl *	ictx;
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	uintptr_t			addr;
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	int				fdtmp;
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	FILE *	ftmp;
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	char	buf[4096];
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	ssize_t	nread;
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	int	ret;
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	addr = (uintptr_t)dctx - offsetof(struct mdso_driver_ctx_impl,ctx);
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	ictx = (struct mdso_driver_ctx_impl *)addr;
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	if (ictx->fdtmpin >= 0) {
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		if ((fdtmp = dup(ictx->fdtmpin)) < 0)
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			return 0;
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		if (!(ftmp = fdopen(fdtmp,"r")))
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			close(fdtmp);
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		return ftmp;
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	}
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	if (!(ftmp = tmpfile()))
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		return 0;
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	if ((ictx->fdtmpin = dup(fileno(ftmp))) < 0) {
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		fclose(ftmp);
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		return 0;
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	}
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	nread = read(0,buf,sizeof(buf)-1);
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	while (nread) {
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		if (nread > 0) {
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			buf[nread] = '\0';
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			ret = fputs(buf,ftmp);
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		} else
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			ret = (errno == EINTR) ? 0 : -1;
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		if (ret < 0) {
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			fclose(ftmp);
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			return 0;
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		}
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		nread = read(0,buf,sizeof(buf)-1);
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	}
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	return ftmp;
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}
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static int mdso_create_symbol_vector(struct mdso_unit_ctx_impl * ctx)
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{
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	int		nsyms;
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	size_t		nbytes;
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	size_t		size;
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	char *		dst;
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	const char *	ch;
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	const char **	sym;
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	const char	exphdr[] = "EXPORTS\n";
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	const char	imphdr[] = "IMPORTS\n";
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	ch	= ctx->map.addr;
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	nbytes	= ctx->map.size;
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	for (nsyms=0; nbytes; ch++,nbytes--)
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		nsyms += (*ch == '\n');
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	size = offsetof(struct mdso_unit_ctx_impl,expsyms);
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	size += (nsyms+1)*sizeof(const char *);
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	if (!(ctx->expsyms = calloc(1,size)))
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		return -1;
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	if (!(ctx->expsyms->buffer = calloc(1,ctx->map.size)))
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		return -1;
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	ch	= ctx->map.addr;
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	nbytes	= ctx->map.size;
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	sym	= ctx->expsyms->syms;
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	dst	= ctx->expsyms->buffer;
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	size	= strlen(exphdr);
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	/* support .def input files */
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	if ((nbytes >= size) && !(strncmp(ch,exphdr,size))) {
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		ch	+= size;
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		nbytes	-= size;
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	}
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	/* advance to first symbol */
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	for (; nbytes && ((*ch==' ')
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			|| (*ch=='\t')
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			|| (*ch=='\r')
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			|| (*ch=='\n')); nbytes--)
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		ch++;
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	/* support .def input files */
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	size = strlen(imphdr);
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	while (nbytes && ((nbytes < size) || (strncmp(ch,imphdr,size)))) {
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		/* vector */
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		*sym++ = dst;
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		/* symbol */
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		for (; nbytes && ((*ch!=' ')
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				&& (*ch!='\t')
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				&& (*ch!='\r')
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				&& (*ch!='\n')); nbytes--)
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			*dst++ = *ch++;
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		dst++;
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		/* discard rest of input line */
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		for (; nbytes && (*ch!='\n'); nbytes--)
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			ch++;
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		/* advance to next symbol */
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		for (; nbytes && ((*ch==' ')
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				|| (*ch=='\t')
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				|| (*ch=='\r')
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				|| (*ch=='\n')); nbytes--)
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			ch++;
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	}
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	return 0;
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}
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int mdso_get_unit_ctx(
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	const struct mdso_driver_ctx *	dctx,
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	const char *			path,
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	struct mdso_unit_ctx **		pctx)
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{
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	struct mdso_unit_ctx_impl *	ctx;
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	FILE *				ftmp;
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	int				fd;
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	if (!dctx || !(ctx = calloc(1,sizeof(*ctx))))
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		return -1;
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	if (strcmp(path,"-"))
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		fd = -1;
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	else if (!(ftmp = mdso_stdin_to_tmp(dctx)))
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		return mdso_free_unit_ctx_impl(ctx,-1);
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	else if ((fd = dup(fileno(ftmp))) < 0)
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		return mdso_free_unit_ctx_impl(ctx,-1);
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	else
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		fclose(ftmp);
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	if (mdso_map_input(fd,path,PROT_READ,&ctx->map))
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		return mdso_free_unit_ctx_impl(ctx,-1);
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	if (fd > 0)
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		close(fd);
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	if (mdso_create_symbol_vector(ctx))
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		return mdso_free_unit_ctx_impl(ctx,-1);
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	memcpy(&ctx->cctx,dctx->cctx,
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		sizeof(ctx->cctx));
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	ctx->path	= path;
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	ctx->uctx.path	= &ctx->path;
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	ctx->uctx.map	= &ctx->map;
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	ctx->uctx.cctx	= &ctx->cctx;
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	ctx->uctx.syms	= ctx->expsyms->syms;
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	*pctx = &ctx->uctx;
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	return 0;
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}
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void mdso_free_unit_ctx(struct mdso_unit_ctx * ctx)
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{
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	struct mdso_unit_ctx_impl *	ictx;
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	uintptr_t			addr;
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	if (ctx) {
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		addr = (uintptr_t)ctx - offsetof(struct mdso_unit_ctx_impl,uctx);
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		ictx = (struct mdso_unit_ctx_impl *)addr;
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		mdso_free_unit_ctx_impl(ictx,0);
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	}
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}