[PATCH] pathtrace.c: introduce user-provided sets of paths
Nikolay Marchuk
marchuk.nikolay.a at gmail.com
Sat Jul 8 08:28:56 UTC 2017
* defs.h (struct path_set): Add a definition for a path set.
(global_path_set): Add a declaration.
(tracing_paths): Change macro body to use global path set variable.
(pathtrace_select_set, pathtrace_match_set): Change declarations.
(pathtrace_select, pathtrace_match): New macroses.
* pathtrace.c (global_path_set): Define global path set.
(pathmatch, upathmatch, fdmatch, pathtrace_match_set): Accept user-provided
set of paths, change return type to bool.
(storepath, pathtrace_select_set): Accept user-provided set of paths.
---
defs.h | 15 ++++++--
pathtrace.c | 120 ++++++++++++++++++++++++++++++------------------------------
2 files changed, 71 insertions(+), 64 deletions(-)
diff --git a/defs.h b/defs.h
index b3a315f..e94e896 100644
--- a/defs.h
+++ b/defs.h
@@ -370,8 +370,11 @@ extern unsigned int qflag;
extern bool not_failing_only;
extern unsigned int show_fd_path;
/* are we filtering traces based on paths? */
-extern const char **paths_selected;
-#define tracing_paths (paths_selected != NULL)
+extern struct path_set {
+ const char **paths_selected;
+ unsigned int num_selected;
+} global_path_set;
+#define tracing_paths (global_path_set.num_selected != 0)
extern unsigned xflag;
extern unsigned followfork;
#ifdef USE_LIBUNWIND
@@ -497,8 +500,12 @@ extern long getrval2(struct tcb *);
#endif
extern const char *signame(const int);
-extern void pathtrace_select(const char *);
-extern int pathtrace_match(struct tcb *);
+extern void pathtrace_select_set(const char *, struct path_set *);
+extern bool pathtrace_match_set(struct tcb *, struct path_set *);
+#define pathtrace_select(tcp) \
+ pathtrace_select_set(tcp, &global_path_set)
+#define pathtrace_match(tcp) \
+ pathtrace_match_set(tcp, &global_path_set)
extern int getfdpath(struct tcb *, int, char *, unsigned);
extern unsigned long getfdinode(struct tcb *, int);
extern enum sock_proto getfdproto(struct tcb *, int);
diff --git a/pathtrace.c b/pathtrace.c
index 9cb0ba7..d46ecd6 100644
--- a/pathtrace.c
+++ b/pathtrace.c
@@ -33,46 +33,46 @@
#include "syscall.h"
-const char **paths_selected;
-static unsigned int num_selected;
+struct path_set global_path_set;
/*
* Return true if specified path matches one that we're tracing.
*/
-static int
-pathmatch(const char *path)
+static bool
+pathmatch(const char *path, struct path_set *set)
{
unsigned i;
- for (i = 0; i < num_selected; ++i) {
- if (strcmp(path, paths_selected[i]) == 0)
- return 1;
+ for (i = 0; i < set->num_selected; ++i) {
+ if (strcmp(path, set->paths_selected[i]) == 0)
+ return true;
}
- return 0;
+ return false;
}
/*
* Return true if specified path (in user-space) matches.
*/
-static int
-upathmatch(struct tcb *const tcp, const kernel_ulong_t upath)
+static bool
+upathmatch(struct tcb *const tcp, const kernel_ulong_t upath,
+ struct path_set *set)
{
char path[PATH_MAX + 1];
return umovestr(tcp, upath, sizeof(path), path) > 0 &&
- pathmatch(path);
+ pathmatch(path, set);
}
/*
* Return true if specified fd maps to a path we're tracing.
*/
-static int
-fdmatch(struct tcb *tcp, int fd)
+static bool
+fdmatch(struct tcb *tcp, int fd, struct path_set *set)
{
char path[PATH_MAX + 1];
int n = getfdpath(tcp, fd, path, sizeof(path));
- return n >= 0 && pathmatch(path);
+ return n >= 0 && pathmatch(path, set);
}
/*
@@ -80,17 +80,17 @@ fdmatch(struct tcb *tcp, int fd)
* Specifying NULL will delete all paths.
*/
static void
-storepath(const char *path)
+storepath(const char *path, struct path_set *set)
{
unsigned i;
- if (pathmatch(path))
+ if (pathmatch(path, set))
return; /* already in table */
- i = num_selected++;
- paths_selected = xreallocarray(paths_selected, num_selected,
- sizeof(paths_selected[0]));
- paths_selected[i] = path;
+ i = set->num_selected++;
+ set->paths_selected = xreallocarray(set->paths_selected,
+ set->num_selected, sizeof(set->paths_selected[0]));
+ set->paths_selected[i] = path;
}
/*
@@ -121,11 +121,11 @@ getfdpath(struct tcb *tcp, int fd, char *buf, unsigned bufsize)
* version of the path. Secifying NULL will delete all paths.
*/
void
-pathtrace_select(const char *path)
+pathtrace_select_set(const char *path, struct path_set *set)
{
char *rpath;
- storepath(path);
+ storepath(path, set);
rpath = realpath(path, NULL);
@@ -139,22 +139,22 @@ pathtrace_select(const char *path)
}
error_msg("Requested path '%s' resolved into '%s'", path, rpath);
- storepath(rpath);
+ storepath(rpath, set);
}
/*
* Return true if syscall accesses a selected path
* (or if no paths have been specified for tracing).
*/
-int
-pathtrace_match(struct tcb *tcp)
+bool
+pathtrace_match_set(struct tcb *tcp, struct path_set *set)
{
const struct_sysent *s;
s = tcp->s_ent;
if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
- return 0;
+ return false;
/*
* Check for special cases where we need to do something
@@ -169,8 +169,8 @@ pathtrace_match(struct tcb *tcp)
case SEN_sendfile64:
case SEN_tee:
/* fd, fd */
- return fdmatch(tcp, tcp->u_arg[0]) ||
- fdmatch(tcp, tcp->u_arg[1]);
+ return fdmatch(tcp, tcp->u_arg[0], set) ||
+ fdmatch(tcp, tcp->u_arg[1], set);
case SEN_faccessat:
case SEN_fchmodat:
@@ -188,28 +188,28 @@ pathtrace_match(struct tcb *tcp)
case SEN_unlinkat:
case SEN_utimensat:
/* fd, path */
- return fdmatch(tcp, tcp->u_arg[0]) ||
- upathmatch(tcp, tcp->u_arg[1]);
+ return fdmatch(tcp, tcp->u_arg[0], set) ||
+ upathmatch(tcp, tcp->u_arg[1], set);
case SEN_link:
case SEN_mount:
case SEN_pivotroot:
/* path, path */
- return upathmatch(tcp, tcp->u_arg[0]) ||
- upathmatch(tcp, tcp->u_arg[1]);
+ return upathmatch(tcp, tcp->u_arg[0], set) ||
+ upathmatch(tcp, tcp->u_arg[1], set);
case SEN_quotactl:
/* x, path */
- return upathmatch(tcp, tcp->u_arg[1]);
+ return upathmatch(tcp, tcp->u_arg[1], set);
case SEN_linkat:
case SEN_renameat2:
case SEN_renameat:
/* fd, path, fd, path */
- return fdmatch(tcp, tcp->u_arg[0]) ||
- fdmatch(tcp, tcp->u_arg[2]) ||
- upathmatch(tcp, tcp->u_arg[1]) ||
- upathmatch(tcp, tcp->u_arg[3]);
+ return fdmatch(tcp, tcp->u_arg[0], set) ||
+ fdmatch(tcp, tcp->u_arg[2], set) ||
+ upathmatch(tcp, tcp->u_arg[1], set) ||
+ upathmatch(tcp, tcp->u_arg[3], set);
case SEN_old_mmap:
#if defined(S390)
@@ -220,29 +220,29 @@ pathtrace_match(struct tcb *tcp)
case SEN_mmap_pgoff:
case SEN_ARCH_mmap:
/* x, x, x, x, fd */
- return fdmatch(tcp, tcp->u_arg[4]);
+ return fdmatch(tcp, tcp->u_arg[4], set);
case SEN_symlinkat:
/* path, fd, path */
- return fdmatch(tcp, tcp->u_arg[1]) ||
- upathmatch(tcp, tcp->u_arg[0]) ||
- upathmatch(tcp, tcp->u_arg[2]);
+ return fdmatch(tcp, tcp->u_arg[1], set) ||
+ upathmatch(tcp, tcp->u_arg[0], set) ||
+ upathmatch(tcp, tcp->u_arg[2], set);
case SEN_copy_file_range:
case SEN_splice:
/* fd, x, fd, x, x, x */
- return fdmatch(tcp, tcp->u_arg[0]) ||
- fdmatch(tcp, tcp->u_arg[2]);
+ return fdmatch(tcp, tcp->u_arg[0], set) ||
+ fdmatch(tcp, tcp->u_arg[2], set);
case SEN_epoll_ctl:
/* x, x, fd, x */
- return fdmatch(tcp, tcp->u_arg[2]);
+ return fdmatch(tcp, tcp->u_arg[2], set);
case SEN_fanotify_mark:
/* x, x, x, fd, path */
- return fdmatch(tcp, tcp->u_arg[3]) ||
- upathmatch(tcp, tcp->u_arg[4]);
+ return fdmatch(tcp, tcp->u_arg[3], set) ||
+ upathmatch(tcp, tcp->u_arg[4], set);
case SEN_oldselect:
case SEN_pselect6:
@@ -259,13 +259,13 @@ pathtrace_match(struct tcb *tcp)
if (SEN_oldselect == s->sen) {
if (sizeof(*select_args) == sizeof(*oldselect_args)) {
if (umove(tcp, tcp->u_arg[0], &select_args)) {
- return 0;
+ return false;
}
} else {
unsigned int n;
if (umove(tcp, tcp->u_arg[0], &oldselect_args)) {
- return 0;
+ return false;
}
for (n = 0; n < 5; ++n) {
@@ -281,7 +281,7 @@ pathtrace_match(struct tcb *tcp)
nfds = (int) args[0];
/* Kernel rejects negative nfds, so we don't parse it either. */
if (nfds <= 0)
- return 0;
+ return false;
/* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */
if (nfds > 1024*1024)
nfds = 1024*1024;
@@ -298,14 +298,14 @@ pathtrace_match(struct tcb *tcp)
j = next_set_bit(fds, j, nfds);
if (j < 0)
break;
- if (fdmatch(tcp, j)) {
+ if (fdmatch(tcp, j, set)) {
free(fds);
- return 1;
+ return true;
}
}
}
free(fds);
- return 0;
+ return false;
}
case SEN_poll:
@@ -321,14 +321,14 @@ pathtrace_match(struct tcb *tcp)
end = start + sizeof(fds) * nfds;
if (nfds == 0 || end < start)
- return 0;
+ return false;
for (cur = start; cur < end; cur += sizeof(fds))
if ((umove(tcp, cur, &fds) == 0)
- && fdmatch(tcp, fds.fd))
- return 1;
+ && fdmatch(tcp, fds.fd, set))
+ return true;
- return 0;
+ return false;
}
case SEN_bpf:
@@ -353,7 +353,7 @@ pathtrace_match(struct tcb *tcp)
* These have TRACE_FILE or TRACE_DESCRIPTOR or TRACE_NETWORK set,
* but they don't have any file descriptor or path args to test.
*/
- return 0;
+ return false;
}
/*
@@ -362,10 +362,10 @@ pathtrace_match(struct tcb *tcp)
*/
if (s->sys_flags & TRACE_FILE)
- return upathmatch(tcp, tcp->u_arg[0]);
+ return upathmatch(tcp, tcp->u_arg[0], set);
if (s->sys_flags & (TRACE_DESC | TRACE_NETWORK))
- return fdmatch(tcp, tcp->u_arg[0]);
+ return fdmatch(tcp, tcp->u_arg[0], set);
- return 0;
+ return false;
}
--
2.1.4
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