To make mmap_cache reusable, this change records protection bits of
mmap entry.
* defs.h (MMAP_CACHE_PROT_*): New enums.
* mmap_cache.c (build_mmpa_cache): Don't ignore entries that are not
executable. Just record the protection bits here.
* unwind.c (print_stack_frame): Ignore entries that are not executable
here.
Signed-off-by: Masatake YAMATO <yam...@redhat.com>
---
defs.h | 9 +++++++++
mmap_cache.c | 27 ++++++++++++++++++++++-----
unwind.c | 4 +++-
3 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/defs.h b/defs.h
index 1081a962..f49d6f56 100644
--- a/defs.h
+++ b/defs.h
@@ -732,14 +732,23 @@ struct mmap_cache_t {
* start_addr is 0x7fabbb09b000
* end_addr is 0x7fabbb09f000
* mmap_offset is 0x179000
+ * protections is MMAP_CACHE_PROT_READABLE|MMAP_CACHE_PROT_EXECUTABLE
* binary_filename is "/lib/libc-2.11.1.so"
*/
unsigned long start_addr;
unsigned long end_addr;
unsigned long mmap_offset;
+ unsigned char protections;
char *binary_filename;
};
+enum mmap_cache_protection {
+ MMAP_CACHE_PROT_READABLE = 1 << 0,
+ MMAP_CACHE_PROT_WRITABLE = 1 << 1,
+ MMAP_CACHE_PROT_EXECUTABLE = 1 << 2,
+ MMAP_CACHE_PROT_SHARED = 1 << 3,
+};
+
enum mmap_cache_rebuild_result {
MMAP_CACHE_REBUILD_NOCACHE,
MMAP_CACHE_REBUILD_READY,
diff --git a/mmap_cache.c b/mmap_cache.c
index 0c6e2b7e..a3367027 100644
--- a/mmap_cache.c
+++ b/mmap_cache.c
@@ -68,16 +68,26 @@ build_mmap_cache(struct tcb *tcp)
while (fgets(buffer, sizeof(buffer), fp) != NULL) {
struct mmap_cache_t *entry;
unsigned long start_addr, end_addr, mmap_offset;
+ char read_bit;
+ char write_bit;
char exec_bit;
+ char shared_bit;
char binary_path[sizeof(buffer)];
- if (sscanf(buffer, "%lx-%lx %*c%*c%c%*c %lx %*x:%*x %*d %[^\n]",
- &start_addr, &end_addr, &exec_bit,
- &mmap_offset, binary_path) != 5)
+ if (sscanf(buffer, "%lx-%lx %c%c%c%c %lx %*x:%*x %*d %[^\n]",
+ &start_addr, &end_addr,
+ &read_bit, &write_bit, &exec_bit, &shared_bit,
+ &mmap_offset, binary_path) != 8)
continue;
- /* ignore mappings that have no PROT_EXEC bit set */
- if (exec_bit != 'x')
+ /* skip mappings having unknown protection */
+ if (!(read_bit == '-' || read_bit == 'r'))
+ continue;
+ if (!(write_bit == '-' || write_bit == 'w'))
+ continue;
+ if (!(exec_bit == '-' || exec_bit == 'x'))
+ continue;
+ if (!(shared_bit == 'p' || shared_bit == 's'))
continue;
if (end_addr < start_addr) {
@@ -116,6 +126,13 @@ build_mmap_cache(struct tcb *tcp)
entry->start_addr = start_addr;
entry->end_addr = end_addr;
entry->mmap_offset = mmap_offset;
+ entry->protections = (
+ 0
+ | ((read_bit == 'r')? MMAP_CACHE_PROT_READABLE : 0)
+ | ((write_bit == 'w')? MMAP_CACHE_PROT_WRITABLE : 0)
+ | ((exec_bit == 'x')? MMAP_CACHE_PROT_EXECUTABLE: 0)
+ | ((shared_bit == 's')? MMAP_CACHE_PROT_SHARED : 0)
+ );
entry->binary_filename = xstrdup(binary_path);
tcp->mmap_cache_size++;
}
diff --git a/unwind.c b/unwind.c
index 56a7b9ce..ef98fc99 100644
--- a/unwind.c
+++ b/unwind.c
@@ -139,7 +139,9 @@ print_stack_frame(struct tcb *tcp,
}
cur_mmap_cache = mmap_cache_search(tcp, ip);
- if (cur_mmap_cache) {
+ if (cur_mmap_cache
+ /* ignore mappings that have no PROT_EXEC bit set */
+ && (cur_mmap_cache->protections & MMAP_CACHE_PROT_EXECUTABLE)) {
unsigned long true_offset;
unw_word_t function_offset;
--
2.14.3
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