pathtrace_match_set will be exposed to LuaJIT scripts.

* defs.h (npaths_selected): Add a declaration.
(tracing_paths): Change macro body to an equivalent but more obvious one
(pathtrace_match): New macro.
* pathtrace.c (num_selected): Rename to npaths_selected, make
non-static.
(pathmatch, upathmatch, fdmatch, pathtrace_match): Accept a
user-provided set of paths, change return type to bool, rename to...
(pathmatch_set, upathmatch_set, fdmatch_set, pathtrace_match_set):
...respectively.
---
 defs.h      |   9 ++-
 pathtrace.c | 223 ++++++++++++++++++++++++++++++------------------------------
 2 files changed, 117 insertions(+), 115 deletions(-)

diff --git a/defs.h b/defs.h
index 52d2f137..42382d8e 100644
--- a/defs.h
+++ b/defs.h
@@ -336,9 +336,10 @@ extern bool count_wallclock;
 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 unsigned npaths_selected;
+/* are we filtering traces based on paths? */
+#define tracing_paths (npaths_selected != 0)
 extern unsigned xflag;
 extern unsigned followfork;
 #ifdef USE_LIBUNWIND
@@ -465,7 +466,9 @@ extern long getrval2(struct tcb *);
 
 extern const char *signame(const int);
 extern void pathtrace_select(const char *);
-extern int pathtrace_match(struct tcb *);
+extern bool pathtrace_match_set(struct tcb *, const char **, unsigned int);
+#define pathtrace_match(tcp) \
+       pathtrace_match_set(tcp, paths_selected, npaths_selected)
 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 9cb0ba77..b8b35926 100644
--- a/pathtrace.c
+++ b/pathtrace.c
@@ -34,64 +34,7 @@
 #include "syscall.h"
 
 const char **paths_selected;
-static unsigned int num_selected;
-
-/*
- * Return true if specified path matches one that we're tracing.
- */
-static int
-pathmatch(const char *path)
-{
-       unsigned i;
-
-       for (i = 0; i < num_selected; ++i) {
-               if (strcmp(path, paths_selected[i]) == 0)
-                       return 1;
-       }
-       return 0;
-}
-
-/*
- * Return true if specified path (in user-space) matches.
- */
-static int
-upathmatch(struct tcb *const tcp, const kernel_ulong_t upath)
-{
-       char path[PATH_MAX + 1];
-
-       return umovestr(tcp, upath, sizeof(path), path) > 0 &&
-               pathmatch(path);
-}
-
-/*
- * Return true if specified fd maps to a path we're tracing.
- */
-static int
-fdmatch(struct tcb *tcp, int fd)
-{
-       char path[PATH_MAX + 1];
-       int n = getfdpath(tcp, fd, path, sizeof(path));
-
-       return n >= 0 && pathmatch(path);
-}
-
-/*
- * Add a path to the set we're tracing.
- * Specifying NULL will delete all paths.
- */
-static void
-storepath(const char *path)
-{
-       unsigned i;
-
-       if (pathmatch(path))
-               return; /* already in table */
-
-       i = num_selected++;
-       paths_selected = xreallocarray(paths_selected, num_selected,
-                                      sizeof(paths_selected[0]));
-       paths_selected[i] = path;
-}
+unsigned int npaths_selected;
 
 /*
  * Get path associated with fd.
@@ -117,44 +60,57 @@ getfdpath(struct tcb *tcp, int fd, char *buf, unsigned 
bufsize)
 }
 
 /*
- * Add a path to the set we're tracing.  Also add the canonicalized
- * version of the path.  Secifying NULL will delete all paths.
+ * Return true if specified path is in a set.
  */
-void
-pathtrace_select(const char *path)
+static bool
+pathmatch_set(const char *path, const char **set, unsigned int nset)
 {
-       char *rpath;
+       unsigned i;
 
-       storepath(path);
+       for (i = 0; i < nset; ++i) {
+               if (strcmp(path, set[i]) == 0)
+                       return true;
+       }
+       return false;
+}
 
-       rpath = realpath(path, NULL);
+/*
+ * Return true if specified path (in user-space) is in a set.
+ */
+static bool
+upathmatch_set(struct tcb *const tcp, const kernel_ulong_t upath,
+              const char **set, unsigned int nset)
+{
+       char path[PATH_MAX + 1];
 
-       if (rpath == NULL)
-               return;
+       return umovestr(tcp, upath, sizeof(path), path) > 0 &&
+               pathmatch_set(path, set, nset);
+}
 
-       /* if realpath and specified path are same, we're done */
-       if (strcmp(path, rpath) == 0) {
-               free(rpath);
-               return;
-       }
+/*
+ * Return true if specified fd maps to a path in a set.
+ */
+static bool
+fdmatch_set(struct tcb *tcp, int fd, const char **set, unsigned int nset)
+{
+       char path[PATH_MAX + 1];
+       int n = getfdpath(tcp, fd, path, sizeof(path));
 
-       error_msg("Requested path '%s' resolved into '%s'", path, rpath);
-       storepath(rpath);
+       return n >= 0 && pathmatch_set(path, set, nset);
 }
 
 /*
- * Return true if syscall accesses a selected path
- * (or if no paths have been specified for tracing).
+ * Return true if syscall accesses a path in a set.
  */
-int
-pathtrace_match(struct tcb *tcp)
+bool
+pathtrace_match_set(struct tcb *tcp, const char **set, unsigned int nset)
 {
        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 +125,8 @@ 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_set(tcp, tcp->u_arg[0], set, nset) ||
+                       fdmatch_set(tcp, tcp->u_arg[1], set, nset);
 
        case SEN_faccessat:
        case SEN_fchmodat:
@@ -188,28 +144,28 @@ 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_set(tcp, tcp->u_arg[0], set, nset) ||
+                       upathmatch_set(tcp, tcp->u_arg[1], set, nset);
 
        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_set(tcp, tcp->u_arg[0], set, nset) ||
+                       upathmatch_set(tcp, tcp->u_arg[1], set, nset);
 
        case SEN_quotactl:
                /* x, path */
-               return upathmatch(tcp, tcp->u_arg[1]);
+               return upathmatch_set(tcp, tcp->u_arg[1], set, nset);
 
        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_set(tcp, tcp->u_arg[0], set, nset) ||
+                       fdmatch_set(tcp, tcp->u_arg[2], set, nset) ||
+                       upathmatch_set(tcp, tcp->u_arg[1], set, nset) ||
+                       upathmatch_set(tcp, tcp->u_arg[3], set, nset);
 
        case SEN_old_mmap:
 #if defined(S390)
@@ -220,29 +176,28 @@ 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_set(tcp, tcp->u_arg[4], set, nset);
 
        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_set(tcp, tcp->u_arg[1], set, nset) ||
+                       upathmatch_set(tcp, tcp->u_arg[0], set, nset) ||
+                       upathmatch_set(tcp, tcp->u_arg[2], set, nset);
 
        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_set(tcp, tcp->u_arg[0], set, nset) ||
+                       fdmatch_set(tcp, tcp->u_arg[2], set, nset);
 
        case SEN_epoll_ctl:
                /* x, x, fd, x */
-               return fdmatch(tcp, tcp->u_arg[2]);
-
+               return fdmatch_set(tcp, tcp->u_arg[2], set, nset);
 
        case SEN_fanotify_mark:
                /* x, x, x, fd, path */
-               return fdmatch(tcp, tcp->u_arg[3]) ||
-                       upathmatch(tcp, tcp->u_arg[4]);
+               return fdmatch_set(tcp, tcp->u_arg[3], set, nset) ||
+                       upathmatch_set(tcp, tcp->u_arg[4], set, nset);
 
        case SEN_oldselect:
        case SEN_pselect6:
@@ -281,7 +236,7 @@ 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 +253,14 @@ pathtrace_match(struct tcb *tcp)
                                j = next_set_bit(fds, j, nfds);
                                if (j < 0)
                                        break;
-                               if (fdmatch(tcp, j)) {
+                               if (fdmatch_set(tcp, j, set, nset)) {
                                        free(fds);
-                                       return 1;
+                                       return true;
                                }
                        }
                }
                free(fds);
-               return 0;
+               return false;
        }
 
        case SEN_poll:
@@ -321,14 +276,14 @@ 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_set(tcp, fds.fd, set, nset))
+                               return true;
 
-               return 0;
+               return false;
        }
 
        case SEN_bpf:
@@ -353,7 +308,7 @@ 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 +317,54 @@ pathtrace_match(struct tcb *tcp)
         */
 
        if (s->sys_flags & TRACE_FILE)
-               return upathmatch(tcp, tcp->u_arg[0]);
+               return upathmatch_set(tcp, tcp->u_arg[0], set, nset);
 
        if (s->sys_flags & (TRACE_DESC | TRACE_NETWORK))
-               return fdmatch(tcp, tcp->u_arg[0]);
+               return fdmatch_set(tcp, tcp->u_arg[0], set, nset);
+
+       return false;
+}
+
+/*
+ * Add a path to the set we're tracing.
+ * Specifying NULL will delete all paths.
+ */
+static void
+storepath(const char *path)
+{
+       unsigned i;
+
+       if (pathmatch_set(path, paths_selected, npaths_selected))
+               return; /* already in table */
 
-       return 0;
+       i = npaths_selected++;
+       paths_selected = xreallocarray(paths_selected, npaths_selected,
+                                      sizeof(paths_selected[0]));
+       paths_selected[i] = path;
+}
+
+/*
+ * Add a path to the set we're tracing.  Also add the canonicalized
+ * version of the path.  Secifying NULL will delete all paths.
+ */
+void
+pathtrace_select(const char *path)
+{
+       char *rpath;
+
+       storepath(path);
+
+       rpath = realpath(path, NULL);
+
+       if (rpath == NULL)
+               return;
+
+       /* if realpath and specified path are same, we're done */
+       if (strcmp(path, rpath) == 0) {
+               free(rpath);
+               return;
+       }
+
+       error_msg("Requested path '%s' resolved into '%s'", path, rpath);
+       storepath(rpath);
 }
-- 
2.11.0


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