lib: Helper library for parsing i915 fdinfo output

Tests and intel_gpu_top will share common code for parsing this file.

v2:
 * Fix key-value parsing if valid key line ends with ':'.
 * Return number of drm keys found.
 * Add DRM_CLIENT_FDINFO_MAX_ENGINES. (Umesh)
 * Always zero terminate read buffer. (Umesh)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>

3 files changed, 264 insertions, 0 deletions

diff --git a/lib/igt_drm_fdinfo.c b/lib/igt_drm_fdinfo.c
new file mode 100644
index 00000000..b422f67a
--- /dev/null
+++ b/lib/igt_drm_fdinfo.c
@@ -0,0 +1,188 @@
+/*
+ * Copyright © 2022 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "drmtest.h"
+
+#include "igt_drm_fdinfo.h"
+
+static size_t read_fdinfo(char *buf, const size_t sz, int at, const char *name)
+{
+	size_t count;
+	int fd;
+
+	fd = openat(at, name, O_RDONLY);
+	if (fd < 0)
+		return 0;
+
+	buf[sz - 1] = 0;
+	count = read(fd, buf, sz);
+	buf[sz - 1] = 0;
+	close(fd);
+
+	return count;
+}
+
+static int parse_engine(char *line, struct drm_client_fdinfo *info,
+			size_t prefix_len, uint64_t *val)
+{
+	static const char *e2class[] = {
+		"render",
+		"copy",
+		"video",
+		"video-enhance",
+	};
+	ssize_t name_len;
+	char *name, *p;
+	int found = -1;
+	unsigned int i;
+
+	p = index(line, ':');
+	if (!p || p == line)
+		return -1;
+
+	name_len = p - line - prefix_len;
+	if (name_len < 1)
+		return -1;
+
+	name = line + prefix_len;
+
+	for (i = 0; i < ARRAY_SIZE(e2class); i++) {
+		if (!strncmp(name, e2class[i], name_len)) {
+			found = i;
+			break;
+		}
+	}
+
+	if (found >= 0) {
+		while (*++p && isspace(*p));
+		*val = strtoull(p, NULL, 10);
+	}
+
+	return found;
+}
+
+static const char *find_kv(const char *buf, const char *key, size_t keylen)
+{
+	const char *p = buf;
+
+	if (strncmp(buf, key, keylen))
+		return NULL;
+
+	p = index(buf, ':');
+	if (!p || p == buf)
+		return NULL;
+	if ((p - buf) != keylen)
+		return NULL;
+
+	p++;
+	while (*p && isspace(*p))
+		p++;
+
+	return *p ? p : NULL;
+}
+
+unsigned int
+__igt_parse_drm_fdinfo(int dir, const char *fd, struct drm_client_fdinfo *info)
+{
+	char buf[4096], *_buf = buf;
+	char *l, *ctx = NULL;
+	unsigned int good = 0, num_capacity = 0;
+	size_t count;
+
+	count = read_fdinfo(buf, sizeof(buf), dir, fd);
+	if (!count)
+		return 0;
+
+	while ((l = strtok_r(_buf, "\n", &ctx))) {
+		uint64_t val = 0;
+		const char *v;
+		int idx;
+
+		_buf = NULL;
+
+		if ((v = find_kv(l, "drm-driver", strlen("drm-driver")))) {
+			strncpy(info->driver, v, sizeof(info->driver) - 1);
+			good++;
+		} else if ((v = find_kv(l, "drm-pdev", strlen("drm-pdev")))) {
+			strncpy(info->pdev, v, sizeof(info->pdev) - 1);
+		}  else if ((v = find_kv(l, "drm-client-id",
+					 strlen("drm-client-id")))) {
+			info->id = atol(v);
+			good++;
+		} else if (!strncmp(l, "drm-engine-", 11) &&
+			   strncmp(l, "drm-engine-capacity-", 20)) {
+			idx = parse_engine(l, info, strlen("drm-engine-"),
+					   &val);
+			if (idx >= 0) {
+				if (!info->capacity[idx])
+					info->capacity[idx] = 1;
+				info->busy[idx] = val;
+				info->num_engines++;
+			}
+		} else if (!strncmp(l, "drm-engine-capacity-", 20)) {
+			idx = parse_engine(l, info,
+					   strlen("drm-engine-capacity-"),
+					   &val);
+			if (idx >= 0) {
+				info->capacity[idx] = val;
+				num_capacity++;
+			}
+		}
+	}
+
+	if (good < 2 || !info->num_engines)
+		return 0; /* fdinfo format not as expected */
+
+	return good + info->num_engines + num_capacity;
+}
+
+unsigned int igt_parse_drm_fdinfo(int drm_fd, struct drm_client_fdinfo *info)
+{
+	unsigned int res;
+	char fd[64];
+	int dir, ret;
+
+	ret = snprintf(fd, sizeof(fd), "%u", drm_fd);
+	if (ret < 0 || ret == sizeof(fd))
+		return false;
+
+	dir = open("/proc/self/fdinfo", O_DIRECTORY | O_RDONLY);
+	if (dir < 0)
+		return false;
+
+	res = __igt_parse_drm_fdinfo(dir, fd, info);
+
+	close(dir);
+
+	return res;
+}
diff --git a/lib/igt_drm_fdinfo.h b/lib/igt_drm_fdinfo.h
new file mode 100644
index 00000000..5db63e28
--- /dev/null
+++ b/lib/igt_drm_fdinfo.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright © 2022 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef IGT_DRM_FDINFO_H
+#define IGT_DRM_FDINFO_H
+
+#include <sys/types.h>
+#include <dirent.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#define DRM_CLIENT_FDINFO_MAX_ENGINES 16
+
+struct drm_client_fdinfo {
+	char driver[128];
+	char pdev[128];
+	unsigned long id;
+
+	unsigned int num_engines;
+	unsigned int capacity[DRM_CLIENT_FDINFO_MAX_ENGINES];
+	uint64_t busy[DRM_CLIENT_FDINFO_MAX_ENGINES];
+};
+
+/**
+ * igt_parse_drm_fdinfo: Parses the drm fdinfo file
+ *
+ * @drm_fd: DRM file descriptor
+ * @info: Structure to populate with read data
+ *
+ * Returns the number of valid drm fdinfo keys found or zero if not all
+ * mandatory keys were present or no engines found.
+ */
+unsigned int igt_parse_drm_fdinfo(int drm_fd, struct drm_client_fdinfo *info);
+
+/**
+ * __igt_parse_drm_fdinfo: Parses the drm fdinfo file
+ *
+ * @dir: File descriptor pointing to /proc/pid/fdinfo directory
+ * @fd: String representation of the file descriptor number to parse.
+ * @info: Structure to populate with read data
+ *
+ * Returns the number of valid drm fdinfo keys found or zero if not all
+ * mandatory keys were present or no engines found.
+ */
+unsigned int __igt_parse_drm_fdinfo(int dir, const char *fd,
+				    struct drm_client_fdinfo *info);
+
+#endif /* IGT_DRM_FDINFO_H */
diff --git a/lib/meson.build b/lib/meson.build
index 6fc19586..ccee7a59 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -18,6 +18,7 @@ lib_sources = [
 	'igt_debugfs.c',
 	'igt_device.c',
 	'igt_device_scan.c',
+	'igt_drm_fdinfo.c',
 	'igt_aux.c',
 	'igt_gt.c',
 	'igt_halffloat.c',
@@ -218,6 +219,12 @@ lib_igt_device_scan_build = static_library('igt_device_scan',
 lib_igt_device_scan = declare_dependency(link_with : lib_igt_device_scan_build,
 				  include_directories : inc)
 
+lib_igt_drm_fdinfo_build = static_library('igt_drm_fdinfo',
+	['igt_drm_fdinfo.c'],
+	include_directories : inc)
+
+lib_igt_drm_fdinfo = declare_dependency(link_with : lib_igt_drm_fdinfo_build,
+				  include_directories : inc)
 i915_perf_files = [
   'igt_list.c',
   'i915/perf.c',