[PATCH bpf-next 3/8] selftests/bpf: Add get_procmap_info helper

[Jiri Olsa <jolsa@kernel.org>]

Adding get_procmap_info that queries the current process VMA range
and permissions through PROCMAP_QUERY. Extend procmap_query to return
the VMA end address and update its callers.

I don't think we need the search fallback, the PROCMAP api is merged
for some time now.

Assisted-by: Codex:GPT-6
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/testing/selftests/bpf/trace_helpers.c | 38 ++++++++++++++++++---
 tools/testing/selftests/bpf/trace_helpers.h |  1 +
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 6d7a4b8c4ab8..d2b2ff0ec2a4 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -286,7 +286,8 @@ unsigned long long module_get_base_addr_sec(const char *module, const char *sec)
 #ifdef PROCMAP_QUERY
 int env_verbosity __weak = 0;
 
-static int procmap_query(int fd, const void *addr, __u32 query_flags, size_t *start, size_t *offset, int *flags)
+static int procmap_query(int fd, const void *addr, __u32 query_flags,
+		 size_t *start, size_t *end, size_t *offset, int *flags)
 {
 	char path_buf[PATH_MAX], build_id_buf[20];
 	struct procmap_query q;
@@ -325,6 +326,7 @@ static int procmap_query(int fd, const void *addr, __u32 query_flags, size_t *st
 	}
 
 	*start = q.vma_start;
+	*end = q.vma_end;
 	*offset = q.vma_offset;
 	*flags = q.vma_flags;
 	return 0;
@@ -333,13 +335,37 @@ static int procmap_query(int fd, const void *addr, __u32 query_flags, size_t *st
 # ifndef PROCMAP_QUERY_VMA_EXECUTABLE
 #  define PROCMAP_QUERY_VMA_EXECUTABLE 0x04
 # endif
-
-static int procmap_query(int fd, const void *addr, __u32 query_flags, size_t *start, size_t *offset, int *flags)
+static int procmap_query(int fd, const void *addr, __u32 query_flags,
+		 size_t *start, size_t *end, size_t *offset, int *flags)
 {
 	return -EOPNOTSUPP;
 }
 #endif
 
+int get_procmap_info(const void *addr, size_t *start, size_t *end, char perms[5])
+{
+	FILE *f;
+	size_t offset;
+	int flags, err;
+
+	f = fopen("/proc/self/maps", "r");
+	if (!f)
+		return -errno;
+
+	err = procmap_query(fileno(f), addr, 0, start, end, &offset, &flags);
+#ifdef PROCMAP_QUERY
+	if (!err && perms) {
+		snprintf(perms, 5, "%c%c%c%c",
+			 (flags & PROCMAP_QUERY_VMA_READABLE) ? 'r' : '-',
+			 (flags & PROCMAP_QUERY_VMA_WRITABLE) ? 'w' : '-',
+			 (flags & PROCMAP_QUERY_VMA_EXECUTABLE) ? 'x' : '-',
+			 (flags & PROCMAP_QUERY_VMA_SHARED) ? 's' : 'p');
+	}
+#endif
+	fclose(f);
+	return err;
+}
+
 ssize_t get_uprobe_offset(const void *addr)
 {
 	size_t start, base, end;
@@ -352,7 +378,8 @@ ssize_t get_uprobe_offset(const void *addr)
 		return -errno;
 
 	/* requested executable VMA only */
-	err = procmap_query(fileno(f), addr, PROCMAP_QUERY_VMA_EXECUTABLE, &start, &base, &flags);
+	err = procmap_query(fileno(f), addr, PROCMAP_QUERY_VMA_EXECUTABLE,
+			    &start, &end, &base, &flags);
 	if (err == -EOPNOTSUPP) {
 		bool found = false;
 
@@ -418,7 +445,8 @@ ssize_t get_rel_offset(uintptr_t addr)
 	if (!f)
 		return -errno;
 
-	err = procmap_query(fileno(f), (const void *)addr, 0, &start, &offset, &flags);
+	err = procmap_query(fileno(f), (const void *)addr, 0,
+			    &start, &end, &offset, &flags);
 	if (err == 0) {
 		fclose(f);
 		return (size_t)addr - start + offset;
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index 0f8d99746084..85b8f8e30232 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -59,6 +59,7 @@ int read_trace_pipe_iter(void (*cb)(const char *str, void *data),
 
 ssize_t get_uprobe_offset(const void *addr);
 ssize_t get_rel_offset(uintptr_t addr);
+int get_procmap_info(const void *addr, size_t *start, size_t *end, char perms[5]);
 
 int read_build_id(const char *path, char *build_id, size_t size);
 
-- 
2.54.0