[PATCH 05/24] perf daemon: Add client socket support

[Jiri Olsa <jolsa@kernel.org>]

Adding support for client socket side that will be used
to send commands to daemon server socket.

This patch adds only the core support, all commands using
this functionality are coming in following patches.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/builtin-daemon.c | 135 ++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)

diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c
index 495e4ff120ed..e0880c5ee39c 100644
--- a/tools/perf/builtin-daemon.c
+++ b/tools/perf/builtin-daemon.c
@@ -13,6 +13,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <sys/stat.h>
 #include <poll.h>
 #include "builtin.h"
 #include "perf.h"
@@ -44,6 +45,67 @@ static void sig_handler(int sig __maybe_unused)
 	done = true;
 }
 
+static int client_config(const char *var, const char *value, void *cb)
+{
+	struct daemon *daemon = cb;
+
+	if (!strcmp(var, "daemon.base") && !daemon->base_user) {
+		daemon->base = strdup(value);
+		if (!daemon->base)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int check_base(struct daemon *daemon)
+{
+	struct stat st;
+
+	if (!daemon->base) {
+		pr_err("failed: base not defined\n");
+		return -EINVAL;
+	}
+
+	if (stat(daemon->base, &st)) {
+		switch (errno) {
+		case EACCES:
+			pr_err("failed: permission denied for '%s' base\n",
+			       daemon->base);
+			return -EACCES;
+		case ENOENT:
+			pr_err("failed: base '%s' does not exists\n",
+			       daemon->base);
+			return -EACCES;
+		default:
+			pr_err("failed: can't access base '%s': %s\n",
+			       daemon->base, strerror(errno));
+			return -errno;
+		}
+	}
+
+	if ((st.st_mode & S_IFMT) != S_IFDIR) {
+		pr_err("failed: base '%s' is not directory\n",
+		       daemon->base);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int setup_client_config(struct daemon *daemon)
+{
+	struct perf_config_set *set = perf_config_set__load_file(daemon->config_real);
+	int err = -ENOMEM;
+
+	if (set) {
+		err = perf_config_set(set, client_config, daemon);
+		perf_config_set__delete(set);
+	}
+
+	return err ?: check_base(daemon);
+}
+
 static int setup_server_socket(struct daemon *daemon)
 {
 	struct sockaddr_un addr;
@@ -130,6 +192,38 @@ static int handle_server_socket(struct daemon *daemon __maybe_unused, int sock_f
 	return ret;
 }
 
+static int setup_client_socket(struct daemon *daemon)
+{
+	struct sockaddr_un addr;
+	char path[PATH_MAX];
+	int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+
+	if (fd == -1) {
+		perror("failed: socket");
+		return -1;
+	}
+
+	scnprintf(path, sizeof(path), "%s/control", daemon->base);
+
+	if (strlen(path) + 1 >= sizeof(addr.sun_path)) {
+		pr_err("failed: control path too long '%s'\n", path);
+		close(fd);
+		return -1;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sun_family = AF_UNIX;
+	strlcpy(addr.sun_path, path, sizeof(addr.sun_path) - 1);
+
+	if (connect(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
+		perror("failed: connect");
+		close(fd);
+		return -1;
+	}
+
+	return fd;
+}
+
 static void daemon__exit(struct daemon *daemon)
 {
 	free(daemon->config_real);
@@ -222,6 +316,47 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[],
 	return err;
 }
 
+__maybe_unused
+static int send_cmd(struct daemon *daemon, union cmd *cmd)
+{
+	int ret = -1, fd;
+	char *line = NULL;
+	size_t len = 0;
+	ssize_t nread;
+	FILE *in = NULL;
+
+	if (setup_client_config(daemon))
+		return -1;
+
+	fd = setup_client_socket(daemon);
+	if (fd < 0)
+		return -1;
+
+	if (sizeof(*cmd) != writen(fd, cmd, sizeof(*cmd))) {
+		perror("failed: write");
+		goto out;
+	}
+
+	in = fdopen(fd, "r");
+	if (!in) {
+		perror("failed: fdopen");
+		goto out;
+	}
+
+	while ((nread = getline(&line, &len, in)) != -1) {
+		fwrite(line, nread, 1, stdout);
+		fflush(stdout);
+	}
+
+	ret = 0;
+	fclose(in);
+out:
+	/* If in is defined, then fd is closed via fclose. */
+	if (!in)
+		close(fd);
+	return ret;
+}
+
 int cmd_daemon(int argc, const char **argv)
 {
 	struct option daemon_options[] = {
-- 
2.29.2