From 03d68fb5cf6e47af479aa8a99a4b6aaba7da455a Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Sun, 14 Jan 2024 11:07:37 +0000
Subject: ash: add more checks to forkshell debug
Rearrange the handling of pointer relocation during forkshell and
add a couple of additional sanity checks. There's no functional
change to non-debug builds.
---
shell/ash.c | 51 ++++++++++++++++++++++++++++++++++++---------------
1 file changed, 36 insertions(+), 15 deletions(-)
diff --git a/shell/ash.c b/shell/ash.c
index e45c8d61d..90f4c9773 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9844,6 +9844,7 @@ static char *funcstring_end; /* end of block to allocate strings from */
static int fs_size;
# if FORKSHELL_DEBUG
static void *fs_start;
+static void *fs_funcstring;
static const char **annot;
# endif
#endif
@@ -9995,36 +9996,55 @@ static union node *copynode(union node *);
# if FORKSHELL_DEBUG
# define FREE 1
# define NO_FREE 2
-# define ANNOT(dst,note) { \
- if (annot) \
- annot[(char *)&dst - (char *)fs_start] = note; \
- }
+# define MARK_PTR(dst,note,flag) forkshell_mark_ptr((void *)&dst, note, flag)
# else
# define FREE 1
# define NO_FREE 1
-# define ANNOT(dst,note)
+# define MARK_PTR(dst,note,flag) forkshell_mark_ptr((void *)&dst, flag)
# endif
-/* The relocation map is offset from the start of the forkshell data
- * block by 'fs_size' bytes. The flag relating to a particular destination
- * pointer is thus at (dst+fs_size). */
-# define MARK_PTR(dst,flag) {*((char *)&dst + fs_size) = flag;}
+#if FORKSHELL_DEBUG
+static void forkshell_mark_ptr(void *dst, const char *note, int flag)
+#else
+static void forkshell_mark_ptr(void *dst, int flag)
+#endif
+{
+ /* The relocation map is offset from the start of the forkshell data
+ * block by 'fs_size' bytes. The flag relating to a particular
+ * destination pointer is thus at (dst+fs_size). */
+ *((char *)dst + fs_size) = flag;
+
+#if FORKSHELL_DEBUG
+ if (dst < fs_start || dst >= fs_funcstring) {
+ fprintf(stderr, "dst (%p) out of range (%p %p)\n",
+ dst, fs_start, fs_funcstring);
+ }
+ if (annot) {
+ if (annot[(char *)dst - (char *)fs_start]) {
+ fprintf(stderr, "duplicate annotation: %s %s\n",
+ annot[(char *)dst - (char *)fs_start], note);
+ }
+ annot[(char *)dst - (char *)fs_start] = note;
+ }
+#endif
+}
# define SAVE_PTR(dst,note,flag) { \
if (fs_size) { \
- MARK_PTR(dst,flag); ANNOT(dst,note); \
+ MARK_PTR(dst,note,flag); \
} \
}
# define SAVE_PTR2(dst1,note1,flag1,dst2,note2,flag2) { \
if (fs_size) { \
- MARK_PTR(dst1,flag1); MARK_PTR(dst2,flag2); \
- ANNOT(dst1,note1); ANNOT(dst2,note2); \
+ MARK_PTR(dst1,note1,flag1); \
+ MARK_PTR(dst2,note2,flag2); \
} \
}
# define SAVE_PTR3(dst1,note1,flag1,dst2,note2,flag2,dst3,note3,flag3) { \
if (fs_size) { \
- MARK_PTR(dst1,flag1); MARK_PTR(dst2,flag2); MARK_PTR(dst3,flag3); \
- ANNOT(dst1,note1); ANNOT(dst2,note2); ANNOT(dst3,note3); \
+ MARK_PTR(dst1,note1,flag1); \
+ MARK_PTR(dst2,note2,flag2); \
+ MARK_PTR(dst3,note3,flag3); \
} \
}
#else
@@ -16522,7 +16542,7 @@ spawn_forkshell(struct forkshell *fs, struct job *jp, union node *n, int mode)
#undef SAVE_PTR
#undef SAVE_PTR2
#undef SAVE_PTR3
-#define SAVE_PTR(dst,note,flag) {MARK_PTR(dst,flag); ANNOT(dst,note);}
+#define SAVE_PTR(dst,note,flag) {MARK_PTR(dst,note,flag);}
static int align_len(const char *s)
{
@@ -17224,6 +17244,7 @@ forkshell_prepare(struct forkshell *fs)
funcstring_end = (char *)new + size;
#if FORKSHELL_DEBUG
fs_start = new;
+ fs_funcstring = (char *)new + sizeof(struct forkshell) + ds.funcblocksize;
relocate = (char *)new + size;
annot = (const char **)xzalloc(sizeof(char *)*relocatesize);
#endif
--
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