Merge pull request #97 from Sutter099/feature/uptr

wkz · web-flow · commit e882e056bdc2 · 2025-08-19T12:54:18.000+02:00
add 'uptr' function to mark userland pointer
diff --git a/include/ply/buffer.h b/include/ply/buffer.h
@@ -8,6 +8,7 @@
 #define _PLY_BUFFER_H
 
 #include <stdint.h>
+#include <poll.h>
 
 #include <linux/perf_event.h>
 
@@ -34,8 +35,10 @@ void buffer_evh_register(struct buffer_evh *evh);
 
 struct buffer;
 
-struct buffer *buffer_new(int mapfd);
+struct ply_return buffer_service(struct buffer *buf, int ready, struct pollfd *fds);
+void buffer_fill_pollset(struct buffer *buf, struct pollfd *fds);
+nfds_t buffer_get_nfds(struct buffer *buf);
 
-struct ply_return buffer_loop(struct buffer *buf, int timeout);
+struct buffer *buffer_new(int mapfd);
 
 #endif	/* _PLY_BUFFER_H */
diff --git a/include/ply/ir.h b/include/ply/ir.h
@@ -148,6 +148,7 @@ struct irstate {
 		int dot:1;
 		int lval:1;
 		int stack:1;
+		int user:1;
 	} hint;
 };
 
@@ -177,7 +178,7 @@ void ir_emit_sym_to_reg  (struct ir *ir, uint16_t dst, struct sym *src);
 void ir_emit_reg_to_sym  (struct ir *ir, struct sym *dst, uint16_t src);
 void ir_emit_sym_to_stack(struct ir *ir, ssize_t offset, struct sym *src);
 void ir_emit_sym_to_sym  (struct ir *ir, struct sym *dst, struct sym *src);
-void ir_emit_read_to_sym (struct ir *ir, struct sym *dst, uint16_t src);
+void ir_emit_read_to_sym (struct ir *ir, struct sym *dst, uint16_t src, int user);
 
 void ir_emit_data  (struct ir *ir, ssize_t dst, const char *src, size_t size);
 void ir_emit_memcpy(struct ir *ir, ssize_t dst, ssize_t src, size_t size);
diff --git a/include/ply/ply.h b/include/ply/ply.h
@@ -8,6 +8,7 @@
 #define _PLY_H
 
 #include <stdio.h>
+#include <poll.h>
 
 #include "sym.h"
 #include "utils.h"
@@ -23,6 +24,22 @@ struct ply_return {
 	unsigned exit:1;
 };
 
+static inline void ply_return_fold(struct ply_return *ret, struct ply_return new)
+{
+	if (ret->err)
+		return;
+
+	if (new.err) {
+		*ret = new;
+		return;
+	}
+
+	if (ret->exit)
+		return;
+
+	*ret = new;
+}
+
 /* api */
 struct ply_probe {
 	struct ply_probe *next, *prev;
@@ -83,7 +100,9 @@ void ply_maps_print(struct ply *ply);
 void ply_map_print(struct ply *ply, struct sym *sym, FILE *fp);
 void ply_map_clear(struct ply *ply, struct sym *sym);
 
-struct ply_return ply_loop(struct ply *ply);
+struct ply_return ply_service(struct ply *ply, int ready, struct pollfd *fds);
+nfds_t ply_get_nfds(struct ply *ply);
+void ply_fill_pollset(struct ply *ply, struct pollfd *fds);
 
 int ply_start(struct ply *ply);
 int ply_stop(struct ply *ply);
diff --git a/include/ply/provider.h b/include/ply/provider.h
@@ -26,6 +26,8 @@ struct provider {
 	int (*ir_pre)   (struct ply_probe *);
 	int (*ir_post)  (struct ply_probe *);
 	int (*attach)   (struct ply_probe *);
+	int (*start)    (struct ply_probe *);
+	int (*stop)     (struct ply_probe *);
 	int (*detach)   (struct ply_probe *);
 };
 
diff --git a/src/libply/built-in/buffer.c b/src/libply/built-in/buffer.c
@@ -153,43 +153,7 @@ struct ply_return buffer_q_drain(struct buffer_q *q)
 	return ret;
 }
 
-struct ply_return buffer_loop(struct buffer *buf, int timeout)
-{
-	struct ply_return ret;
-	uint32_t cpu;
-	int ready;
-
-	for (;;) {
-		ready = poll(buf->poll, buf->ncpus, timeout);
-		if (ready < 0) {
-			ret.err = 1;
-			ret.val = errno;
-			return ret;
-		}
-
-		if (timeout == -1) {
-			assert(ready);
-		} else if (ready == 0) {
-			ret.err = 0;
-			return ret;
-		}
-
-		for (cpu = 0; ready && (cpu < buf->ncpus); cpu++) {
-			if (!(buf->poll[cpu].revents & POLLIN))
-				continue;
-
-			ret = buffer_q_drain(&buf->q[cpu]);
-			if (ret.err | ret.exit)
-				return ret;
-
-			ready--;
-		}
-	}
-
-	return ret;
-}
-
-int buffer_q_init(struct buffer *buf, uint32_t cpu)
+static int buffer_q_init(struct buffer *buf, uint32_t cpu)
 {
 	struct perf_event_attr attr = { 0 };
 	struct buffer_q *q = &buf->q[cpu];
@@ -225,6 +189,34 @@ int buffer_q_init(struct buffer *buf, uint32_t cpu)
 	return 0;
 }
 
+struct ply_return buffer_service(struct buffer *buf, int ready, struct pollfd *fds)
+{
+	struct ply_return ret = {};
+	uint32_t cpu;
+
+	for (cpu = 0; ready && (cpu < buf->ncpus); cpu++) {
+		if (!(fds[cpu].revents & POLLIN))
+			continue;
+
+		ret = buffer_q_drain(&buf->q[cpu]);
+		ready--;
+		if (ret.err || ret.exit)
+			break;
+	}
+
+	return ret;
+}
+
+void buffer_fill_pollset(struct buffer *buf, struct pollfd *fds)
+{
+	memcpy(fds, buf->poll, buf->ncpus * sizeof(*fds));
+}
+
+nfds_t buffer_get_nfds(struct buffer *buf)
+{
+	return buf->ncpus;
+}
+
 struct buffer *buffer_new(int mapfd)
 {
 	struct buffer *buf;
diff --git a/src/libply/built-in/memory.c b/src/libply/built-in/memory.c
@@ -140,7 +140,10 @@ static int str_ir_post(const struct func *func, struct node *n,
 	ir_emit_ldbp(pb->ir, BPF_REG_1, n->sym->irs.stack);
 	ir_emit_insn(ir, MOV_IMM((int32_t)type_sizeof(n->sym->type)), BPF_REG_2, 0);
 	ir_emit_sym_to_reg(ir, BPF_REG_3, ptr->sym);
-	ir_emit_insn(ir, CALL(BPF_FUNC_probe_read_kernel_str), 0, 0);
+	if (ptr->sym->irs.hint.user)
+		ir_emit_insn(ir, CALL(BPF_FUNC_probe_read_user_str), 0, 0);
+	else
+		ir_emit_insn(ir, CALL(BPF_FUNC_probe_read_kernel_str), 0, 0);
 	return 0;
 }
 
@@ -153,7 +156,7 @@ static int mem_ir_post(const struct func *func, struct node *n,
 	ir_init_sym(pb->ir, n->sym);
 
 	ir_emit_sym_to_reg(pb->ir, BPF_REG_3, ptr->sym);
-	ir_emit_read_to_sym(pb->ir, n->sym, BPF_REG_3);
+	ir_emit_read_to_sym(pb->ir, n->sym, BPF_REG_3, ptr->sym->irs.hint.user);
 	return 0;
 }
 
@@ -222,6 +225,36 @@ static struct func str_func = {
 	.ir_post = str_ir_post,
 };
 
+struct type t_uptr_func = {
+	.ttype = T_FUNC,
+	.func = { .type = &t_void, .args = f_1arg },
+};
+
+static int uptr_ir_post(const struct func *func, struct node *n,
+			struct ply_probe *pb)
+{
+	struct node *child = n->expr.args;
+
+	ir_init_sym(pb->ir, n->sym);
+	ir_emit_sym_to_sym(pb->ir, n->sym, child->sym);
+	n->sym->irs.hint.user = 1;
+	return 0;
+}
+
+static int uptr_type_infer(const struct func *func, struct node *n)
+{
+	struct node *arg = n->expr.args;
+
+	n->sym->type = arg->sym->type;
+	return 0;
+}
+
+static struct func uptr_func = {
+	.name = "uptr",
+	.type = &t_uptr_func,
+	.type_infer = uptr_type_infer,
+	.ir_post = uptr_ir_post,
+};
 
 static int struct_deref_rewrite(const struct func *func, struct node *n,
 				 struct ply_probe *pb)
@@ -424,7 +457,7 @@ static int deref_ir_post(const struct func *func, struct node *n,
 		return 0;
 
 	ir_emit_sym_to_reg(pb->ir, BPF_REG_0, ptr->sym);
-	ir_emit_read_to_sym(pb->ir, n->sym, BPF_REG_0);
+	ir_emit_read_to_sym(pb->ir, n->sym, BPF_REG_0, ptr->sym->irs.hint.user);
 	return 0;
 }
 
@@ -603,7 +636,7 @@ static int map_ir_post(const struct func *func, struct node *n,
 	lhit  = ir_alloc_label(pb->ir);
 
 	ir_emit_insn(pb->ir, JMP_IMM(BPF_JEQ, 0, lmiss), BPF_REG_0, 0);
-	ir_emit_read_to_sym(pb->ir, n->sym, BPF_REG_0);
+	ir_emit_read_to_sym(pb->ir, n->sym, BPF_REG_0, 0);
 	ir_emit_insn(pb->ir, JMP_IMM(BPF_JA, 0, lhit), 0, 0);
 
 	ir_emit_label(pb->ir, lmiss);
@@ -948,6 +981,7 @@ void memory_init(void)
 	built_in_register(&strcmp_func);
 	built_in_register(&str_func);
 	built_in_register(&mem_func);
+	built_in_register(&uptr_func);
 	built_in_register(&struct_deref_func);
 	built_in_register(&struct_dot_func);
 	built_in_register(&deref_func);
diff --git a/src/libply/grammar.y b/src/libply/grammar.y
@@ -61,8 +61,8 @@ probes
 ;
 
 probe
-: PSPEC stmt      { __ply_probe_alloc(ply, $1, $2); }
-| PSPEC predicate { __ply_probe_alloc(ply, $1, $2); }
+: PSPEC stmt      { if (__ply_probe_alloc(ply, $1, $2)) YYABORT; }
+| PSPEC predicate { if (__ply_probe_alloc(ply, $1, $2)) YYABORT; }
 ;
 
 /* Support dtrace-style predicates as well as normal if guards. I.e.
diff --git a/src/libply/ir.c b/src/libply/ir.c
@@ -42,6 +42,10 @@ static const char *bpf_func_name(enum bpf_func_id id)
 		return "probe_read_kernel";
 	case BPF_FUNC_probe_read_kernel_str:
 		return "probe_read_kernel_str";
+	case BPF_FUNC_probe_read_user:
+		return "probe_read_user";
+	case BPF_FUNC_probe_read_user_str:
+		return "probe_read_user_str";
 	case BPF_FUNC_trace_printk:
 		return "trace_printk";
 	default:
@@ -405,7 +409,7 @@ void ir_emit_sym_to_sym(struct ir *ir, struct sym *dst, struct sym *src)
 	}
 }
 
-void ir_emit_read_to_sym(struct ir *ir, struct sym *dst, uint16_t src)
+void ir_emit_read_to_sym(struct ir *ir, struct sym *dst, uint16_t src, int user)
 {
 	struct irstate *irs = &dst->irs;
 
@@ -416,7 +420,10 @@ void ir_emit_read_to_sym(struct ir *ir, struct sym *dst, uint16_t src)
 	if (src != BPF_REG_3)
 		ir_emit_insn(ir, MOV, BPF_REG_3, src);
 
-	ir_emit_insn(ir, CALL(BPF_FUNC_probe_read_kernel), 0, 0);
+	if (user)
+		ir_emit_insn(ir, CALL(BPF_FUNC_probe_read_user), 0, 0);
+	else
+		ir_emit_insn(ir, CALL(BPF_FUNC_probe_read_kernel), 0, 0);
 	/* TODO if (r0) exit(r0); */
 }
 
diff --git a/src/libply/libply.c b/src/libply/libply.c
diff --git a/src/libply/provider/special.c b/src/libply/provider/special.c
diff --git a/src/ply/ply.c b/src/ply/ply.c
diff --git a/test/rootfs/lib/ply/test.sh b/test/rootfs/lib/ply/test.sh

Original file line number	Diff line number	Diff line change
`@@ -61,8 +61,8 @@ probes`
`61`	`61`	`;`
`62`	`62`
`63`	`63`	`probe`
`64`		`-: PSPEC stmt { __ply_probe_alloc(ply, $1, $2); }`
`65`		`-\| PSPEC predicate { __ply_probe_alloc(ply, $1, $2); }`
	`64`	`+: PSPEC stmt { if (__ply_probe_alloc(ply, $1, $2)) YYABORT; }`
	`65`	`+\| PSPEC predicate { if (__ply_probe_alloc(ply, $1, $2)) YYABORT; }`
`66`	`66`	`;`
`67`	`67`
`68`	`68`	`/* Support dtrace-style predicates as well as normal if guards. I.e.`