lib: move get_task_name() from rdma

The function get_task_name() is used to get the name of a process from
its pid, and its implementation is similar to ip/iptuntap.c:pid_name().

Move it to lib/fs.c to use a single implementation and make it easily
reusable.

Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
Acked-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David Ahern <dsahern@kernel.org>

include/utils.h

@@ -308,6 +308,7 @@ char *find_cgroup2_mount(bool do_mount);
 __u64 get_cgroup2_id(const char *path);
 char *get_cgroup2_path(__u64 id, bool full);
 int get_command_name(const char *pid, char *comm, size_t len);
+char *get_task_name(pid_t pid);
 
 int get_rtnl_link_stats_rta(struct rtnl_link_stats64 *stats64,
 			    struct rtattr *tb[]);

ip/iptuntap.c

@@ -260,35 +260,6 @@ static void print_flags(long flags)
 	close_json_array(PRINT_JSON, NULL);
 }
 
-static char *pid_name(pid_t pid)
-{
-	char *comm;
-	FILE *f;
-	int err;
-
-	err = asprintf(&comm, "/proc/%d/comm", pid);
-	if (err < 0)
-		return NULL;
-
-	f = fopen(comm, "r");
-	free(comm);
-	if (!f) {
-		perror("fopen");
-		return NULL;
-	}
-
-	if (fscanf(f, "%ms\n", &comm) != 1) {
-		perror("fscanf");
-		comm = NULL;
-	}
-
-
-	if (fclose(f))
-		perror("fclose");
-
-	return comm;
-}
-
 static void show_processes(const char *name)
 {
 	glob_t globbuf = { };
@@ -346,7 +317,7 @@ static void show_processes(const char *name)
 			} else if (err == 2 &&
 				   !strcmp("iff", key) &&
 				   !strcmp(name, value)) {
-				char *pname = pid_name(pid);
+				char *pname = get_task_name(pid);
 
 				print_string(PRINT_ANY, "name",
 					     "%s", pname ? : "<NULL>");

lib/fs.c

@@ -316,3 +316,27 @@ int get_command_name(const char *pid, char *comm, size_t len)
 
 	return 0;
 }
+
+char *get_task_name(pid_t pid)
+{
+	char *comm;
+	FILE *f;
+
+	if (!pid)
+		return NULL;
+
+	if (asprintf(&comm, "/proc/%d/comm", pid) < 0)
+		return NULL;
+
+	f = fopen(comm, "r");
+	if (!f)
+		return NULL;
+
+	if (fscanf(f, "%ms\n", &comm) != 1)
+		comm = NULL;
+
+	fclose(f);
+
+	return comm;
+}
+

rdma/res.c

@@ -195,30 +195,6 @@ void print_qp_type(struct rd *rd, uint32_t val)
 			   qp_types_to_str(val));
 }
 
-char *get_task_name(uint32_t pid)
-{
-	char *comm;
-	FILE *f;
-
-	if (!pid)
-		return NULL;
-
-	if (asprintf(&comm, "/proc/%d/comm", pid) < 0)
-		return NULL;
-
-	f = fopen(comm, "r");
-	free(comm);
-	if (!f)
-		return NULL;
-
-	if (fscanf(f, "%ms\n", &comm) != 1)
-		comm = NULL;
-
-	fclose(f);
-
-	return comm;
-}
-
 void print_key(struct rd *rd, const char *name, uint64_t val,
 	       struct nlattr *nlattr)
 {

rdma/res.h

@@ -155,7 +155,6 @@ filters qp_valid_filters[MAX_NUMBER_OF_FILTERS] = {
 RES_FUNC(res_qp, RDMA_NLDEV_CMD_RES_QP_GET, qp_valid_filters, false,
 	 RDMA_NLDEV_ATTR_RES_LQPN);
 
-char *get_task_name(uint32_t pid);
 void print_dev(struct rd *rd, uint32_t idx, const char *name);
 void print_link(struct rd *rd, uint32_t idx, const char *name, uint32_t port,
 		struct nlattr **nla_line);