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authorMike Frysinger <vapier@gentoo.org>2016-07-25 13:49:44 +0530
committerMike Frysinger <vapier@gentoo.org>2016-11-12 02:10:08 -0500
commitc2604c2b909f903efd1b2c924b380e81d8459ec9 (patch)
tree35ba36125e035999c87ff40877f4a22d004cdf6c
parentpaxldso: delete netbsd cache logic (diff)
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paxldso: switch from a static sized path buffer to dynamic
We keep the buffer around to avoid the malloc overhead between calls, and we should really only need to grow it once or twice. This way we work with an sized lib path and not just the static limit.
-rw-r--r--paxldso.c24
1 files changed, 21 insertions, 3 deletions
diff --git a/paxldso.c b/paxldso.c
index 67f317c..61d7962 100644
--- a/paxldso.c
+++ b/paxldso.c
@@ -17,6 +17,9 @@
static void *ldcache = NULL;
static size_t ldcache_size = 0;
+static char *ldso_cache_buf = NULL;
+static size_t ldso_cache_buf_size = 0;
+
/* Defines can be seen in glibc's sysdeps/generic/ldconfig.h */
#define LDSO_CACHE_MAGIC "ld.so-"
#define LDSO_CACHE_MAGIC_LEN (sizeof LDSO_CACHE_MAGIC -1)
@@ -45,8 +48,8 @@ static size_t ldcache_size = 0;
char *ldso_cache_lookup_lib(elfobj *elf, const char *fname)
{
int fd;
+ char *ret = NULL;
char *strs;
- static char buf[__PAX_UTILS_PATH_MAX] = "";
const char *cachefile = root_rel_path("/etc/ld.so.cache");
struct stat st;
@@ -92,6 +95,9 @@ char *ldso_cache_lookup_lib(elfobj *elf, const char *fname)
ldcache = NULL;
return NULL;
}
+
+ ldso_cache_buf_size = 4096;
+ ldso_cache_buf = xrealloc(ldso_cache_buf, ldso_cache_buf_size);
} else
header = ldcache;
@@ -99,6 +105,9 @@ char *ldso_cache_lookup_lib(elfobj *elf, const char *fname)
strs = (char *) &libent[header->nlibs];
for (fd = 0; fd < header->nlibs; ++fd) {
+ const char *lib;
+ size_t lib_len;
+
/* This should be more fine grained, but for now we assume that
* diff arches will not be cached together, and we ignore the
* the different multilib mips cases.
@@ -112,17 +121,26 @@ char *ldso_cache_lookup_lib(elfobj *elf, const char *fname)
continue;
/* Return first hit because that is how the ldso rolls */
- strncpy(buf, strs + libent[fd].liboffset, sizeof(buf));
+ lib = strs + libent[fd].liboffset;
+ lib_len = strlen(lib) + 1;
+ if (lib_len > ldso_cache_buf_size) {
+ ldso_cache_buf = xrealloc(ldso_cache_buf, ldso_cache_buf_size + 4096);
+ ldso_cache_buf_size += 4096;
+ }
+ memcpy(ldso_cache_buf, lib, lib_len);
+ ret = ldso_cache_buf;
break;
}
- return buf;
+ return ret;
}
#endif
static void ldso_cache_cleanup(void)
{
+ free(ldso_cache_buf);
+
if (ldcache != NULL)
munmap(ldcache, ldcache_size);
}