API redesign 4/10: pe_common_ctx: protect the common context structure against direct modification.

5 files changed, 34 insertions, 13 deletions

diff --git a/include/perk/perk.h b/include/perk/perk.h
index e2001e1..f19e596 100644
--- a/include/perk/perk.h
+++ b/include/perk/perk.h
@@ -131,7 +131,7 @@ struct pe_driver_ctx {
 	const char **			units;
 	const char *			program;
 	const char *			module;
-	struct pe_common_ctx		cctx;
+	const struct pe_common_ctx *	cctx;
 };
 
 struct pe_unit_ctx {
diff --git a/src/driver/pe_driver_ctx.c b/src/driver/pe_driver_ctx.c
index 9daad39..9f9dd88 100644
--- a/src/driver/pe_driver_ctx.c
+++ b/src/driver/pe_driver_ctx.c
@@ -1,8 +1,10 @@
 #include <stdint.h>
 #include <unistd.h>
 #include <fcntl.h>
+
 #include <perk/perk.h>
 #include <perk/perk_output.h>
+#include "perk_impl.h"
 #include "argv/argv.h"
 
 enum app_tags {
@@ -47,7 +49,7 @@ struct pe_driver_ctx_alloc {
 	struct pe_output_ctx	outctx;
 	struct pe_linker_ctx	lnkctx;
 	struct pe_server_ctx	srvctx;
-	struct pe_driver_ctx	ctx;
+	struct pe_driver_ctx_impl	ctx;
 	uint64_t		guard;
 	const char *		units[];
 };
@@ -85,7 +87,7 @@ static int pe_driver_usage(
 	return PERK_USAGE;
 }
 
-static struct pe_driver_ctx * pe_driver_ctx_alloc(struct argv_meta * meta, size_t nunits)
+static struct pe_driver_ctx_impl * pe_driver_ctx_alloc(struct argv_meta * meta, size_t nunits)
 {
 	struct pe_driver_ctx_alloc *	ictx;
 	size_t				size;
@@ -108,7 +110,7 @@ static struct pe_driver_ctx * pe_driver_ctx_alloc(struct argv_meta * meta, size_
 		if (!entry->fopt)
 			*units++ = entry->arg;
 
-	ictx->ctx.units = ictx->units;
+	ictx->ctx.ctx.units = ictx->units;
 	return &ictx->ctx;
 }
 
@@ -124,7 +126,7 @@ int pe_get_driver_ctx(
 	uint32_t		flags,
 	struct pe_driver_ctx ** pctx)
 {
-	struct pe_driver_ctx *	ctx;
+	struct pe_driver_ctx_impl *	ctx;
 	struct argv_meta *	meta;
 	struct argv_entry *	entry;
 	size_t			nunits;
@@ -199,7 +201,7 @@ int pe_get_driver_ctx(
 	if (pretty && !strcmp(pretty,"yaml"))
 		fflags |= PERK_PRETTY_YAML;
 
-	ctx->program		= program;
+	ctx->ctx.program	= program;
 	ctx->cctx.drvflags	= dflags;
 	ctx->cctx.fmtflags	= fflags;
 	ctx->cctx.output	= output;
@@ -212,7 +214,9 @@ int pe_get_driver_ctx(
 	ctx->cctx.fddst		= AT_FDCWD;
 	ctx->cctx.fdtmp		= AT_FDCWD;
 
-	*pctx = ctx;
+	ctx->ctx.cctx		= &ctx->cctx;
+
+	*pctx = &ctx->ctx;
 	return PERK_OK;
 }
 
@@ -245,6 +249,7 @@ void pe_free_driver_ctx(struct pe_driver_ctx * ctx)
 
 	if (ctx) {
 		addr = (uintptr_t)ctx - offsetof(struct pe_driver_ctx_alloc,ctx);
+		addr = addr - offsetof(struct pe_driver_ctx_impl,ctx);
 		ictx = (struct pe_driver_ctx_alloc *)addr;
 		pe_free_driver_ctx_impl(ictx);
 	}
diff --git a/src/driver/pe_unit_ctx.c b/src/driver/pe_unit_ctx.c
index bed99c6..b86719c 100644
--- a/src/driver/pe_unit_ctx.c
+++ b/src/driver/pe_unit_ctx.c
@@ -26,17 +26,17 @@ int pe_get_unit_ctx(
 	if (!dctx || !(ctx = calloc(sizeof(*ctx),1)))
 		return -1;
 
-	prot = (dctx->cctx.actflags & PERK_ACTION_MAP_READWRITE)
+	prot = (dctx->cctx->actflags & PERK_ACTION_MAP_READWRITE)
 		? PROT_READ | PROT_WRITE
 		: PROT_READ;
 
-	if (pe_map_raw_image(dctx->cctx.fdin,path,prot,&ctx->map))
+	if (pe_map_raw_image(dctx->cctx->fdin,path,prot,&ctx->map))
 		return pe_free_unit_ctx_impl(ctx,-1);
 
 	if (pe_get_image_meta(&ctx->map,&ctx->meta))
 		return pe_free_unit_ctx_impl(ctx,-1);
 
-	memcpy(&ctx->cctx,&dctx->cctx,
+	memcpy(&ctx->cctx,dctx->cctx,
 		sizeof(ctx->cctx));
 
 	ctx->path	= path;
diff --git a/src/internal/perk_impl.h b/src/internal/perk_impl.h
new file mode 100644
index 0000000..dd8ff4d
--- /dev/null
+++ b/src/internal/perk_impl.h
@@ -0,0 +1,16 @@
+#ifndef PERK_IMPL_H
+#define PERK_IMPL_H
+
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/types.h>
+
+#include <perk/perk.h>
+#include <perk/perk_meta.h>
+
+struct pe_driver_ctx_impl {
+	struct pe_common_ctx	cctx;
+	struct pe_driver_ctx	ctx;
+};
+
+#endif
diff --git a/src/perk.c b/src/perk.c
index 652141b..c057fc2 100644
--- a/src/perk.c
+++ b/src/perk.c
@@ -15,9 +15,9 @@ static ssize_t perk_version(struct pe_driver_ctx * dctx)
 	char	buf[512];
 	size_t	len;
 
-	if (dctx->cctx.fdout >= 0) {
+	if (dctx->cctx->fdout >= 0) {
 		len = sprintf(buf,vermsg,dctx->program,PERK_GIT_VERSION);
-		return write(dctx->cctx.fdout,buf,len);
+		return write(dctx->cctx->fdout,buf,len);
 	} else
 		return fprintf(stdout,vermsg,dctx->program,PERK_GIT_VERSION);
 }
@@ -68,7 +68,7 @@ static int perk_main(int argc, const char ** argv, const char ** envp)
 	if ((ret = pe_get_driver_ctx(argv,envp,PERK_DRIVER_FLAGS,&dctx)))
 		return (ret == PERK_USAGE) ? !--argc : 2;
 
-	if (dctx->cctx.drvflags & PERK_DRIVER_VERSION)
+	if (dctx->cctx->drvflags & PERK_DRIVER_VERSION)
 		if ((perk_version(dctx)) < 0)
 			return perk_exit(dctx,2);