shmctl: decode struct shm_info argument of SHM_INFO command

* ipc_shmctl.c (struct_shm_info_t): New typedef.  Mpersify it.
(print_shm_info): New function.
(SYS_FUNC(shmctl)): Use it to decode struct shm_info argument
of SHM_INFO command.
* tests/ipc_shm.c (print_shm_info): New function.
(main): Use it to check decoding of SHM_INFO command.
* NEWS: Mention this change.

3 files changed, 110 insertions, 50 deletions

diff --git a/NEWS b/NEWS
index dfc7db9d0..5ea586cac 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,8 @@ Noteworthy changes in release ?.? (????-??-??)
     and MSG_INFO msgctl syscall commands.
   * Implemented decoding of struct msqid_ds argument of MSG_STAT
     and MSG_STAT_ANY msgctl syscall commands.
+  * Implemented decoding of struct shm_info argument of SHM_INFO
+    shmctl syscall command.
   * Implemented decoding of struct shmid_ds argument of SHM_STAT
     and SHM_STAT_ANY shmctl syscall commands.
   * Updated lists of BPF_*, CAP_*, FAN_*, IFLA_*, INET_DIAG_REQ_*,
diff --git a/ipc_shmctl.c b/ipc_shmctl.c
index c4c161ecb..22994e330 100644
--- a/ipc_shmctl.c
+++ b/ipc_shmctl.c
@@ -14,11 +14,13 @@
 #include "defs.h"
 
 #include DEF_MPERS_TYPE(shmid_ds_t)
+#include DEF_MPERS_TYPE(struct_shm_info_t)
 
 #include "ipc_defs.h"
 
 #include SHM_H_PROVIDER
 typedef struct NAME_OF_STRUCT_SHMID_DS shmid_ds_t;
+typedef struct shm_info struct_shm_info_t;
 
 #include MPERS_DEFS
 
@@ -28,46 +30,52 @@ typedef struct NAME_OF_STRUCT_SHMID_DS shmid_ds_t;
 #define key NAME_OF_STRUCT_IPC_PERM_KEY
 
 static void
-print_shmid_ds(struct tcb *const tcp, const kernel_ulong_t addr, int cmd)
+print_shmid_ds(struct tcb *const tcp, const kernel_ulong_t addr,
+	       const unsigned int cmd)
 {
-	/* TODO: We don't properly decode old compat ipc calls. */
-	if (cmd & IPC_64)
-		cmd &= ~IPC_64;
 	shmid_ds_t shmid_ds;
-	switch (cmd) {
-	case IPC_SET:
-	case IPC_STAT:
-	case SHM_STAT:
-	case SHM_STAT_ANY:
-		if (umove_or_printaddr(tcp, addr, &shmid_ds))
-			return;
-
-		PRINT_FIELD_UID("{shm_perm={", shmid_ds.shm_perm, uid);
-		PRINT_FIELD_UID(", ", shmid_ds.shm_perm, gid);
-		PRINT_FIELD_NUMERIC_UMODE_T(", ", shmid_ds.shm_perm, mode);
-
-		if (cmd != IPC_SET) {
-			PRINT_FIELD_U(", ", shmid_ds.shm_perm, key);
-			PRINT_FIELD_UID(", ", shmid_ds.shm_perm, cuid);
-			PRINT_FIELD_UID(", ", shmid_ds.shm_perm, cgid);
-		}
-		tprints("}");
-		if (cmd != IPC_SET) {
-			PRINT_FIELD_U(", ", shmid_ds, shm_segsz);
-			PRINT_FIELD_TGID(", ", shmid_ds, shm_cpid, tcp);
-			PRINT_FIELD_TGID(", ", shmid_ds, shm_lpid, tcp);
-			PRINT_FIELD_U(", ", shmid_ds, shm_nattch);
-			PRINT_FIELD_U(", ", shmid_ds, shm_atime);
-			PRINT_FIELD_U(", ", shmid_ds, shm_dtime);
-			PRINT_FIELD_U(", ", shmid_ds, shm_ctime);
-		}
-		tprints("}");
-		break;
 
-	default:
-		printaddr(addr);
-		break;
+	if (umove_or_printaddr(tcp, addr, &shmid_ds))
+		return;
+
+	PRINT_FIELD_UID("{shm_perm={", shmid_ds.shm_perm, uid);
+	PRINT_FIELD_UID(", ", shmid_ds.shm_perm, gid);
+	PRINT_FIELD_NUMERIC_UMODE_T(", ", shmid_ds.shm_perm, mode);
+
+	if (cmd != IPC_SET) {
+		PRINT_FIELD_U(", ", shmid_ds.shm_perm, key);
+		PRINT_FIELD_UID(", ", shmid_ds.shm_perm, cuid);
+		PRINT_FIELD_UID(", ", shmid_ds.shm_perm, cgid);
 	}
+	tprints("}");
+	if (cmd != IPC_SET) {
+		PRINT_FIELD_U(", ", shmid_ds, shm_segsz);
+		PRINT_FIELD_TGID(", ", shmid_ds, shm_cpid, tcp);
+		PRINT_FIELD_TGID(", ", shmid_ds, shm_lpid, tcp);
+		PRINT_FIELD_U(", ", shmid_ds, shm_nattch);
+		PRINT_FIELD_U(", ", shmid_ds, shm_atime);
+		PRINT_FIELD_U(", ", shmid_ds, shm_dtime);
+		PRINT_FIELD_U(", ", shmid_ds, shm_ctime);
+	}
+	tprints("}");
+}
+
+static void
+print_shm_info(struct tcb *const tcp, const kernel_ulong_t addr,
+	       const unsigned int cmd)
+{
+	struct_shm_info_t info;
+
+	if (umove_or_printaddr(tcp, addr, &info))
+		return;
+
+	PRINT_FIELD_D("{", info, used_ids);
+	PRINT_FIELD_U(", ", info, shm_tot);
+	PRINT_FIELD_U(", ", info, shm_rss);
+	PRINT_FIELD_U(", ", info, shm_swp);
+	PRINT_FIELD_U(", ", info, swap_attempts);
+	PRINT_FIELD_U(", ", info, swap_successes);
+	tprints("}");
 }
 
 SYS_FUNC(shmctl)
@@ -78,7 +86,28 @@ SYS_FUNC(shmctl)
 		tprints(", ");
 	} else {
 		const kernel_ulong_t addr = tcp->u_arg[indirect_ipccall(tcp) ? 3 : 2];
-		print_shmid_ds(tcp, addr, tcp->u_arg[1]);
+		unsigned int cmd = tcp->u_arg[1];
+
+		/* TODO: We don't properly decode old compat ipc calls. */
+		if (cmd & IPC_64)
+			cmd &= ~IPC_64;
+
+		switch (cmd) {
+		case IPC_SET:
+		case IPC_STAT:
+		case SHM_STAT:
+		case SHM_STAT_ANY:
+			print_shmid_ds(tcp, addr, cmd);
+			break;
+
+		case SHM_INFO:
+			print_shm_info(tcp, addr, cmd);
+			break;
+
+		default:
+			printaddr(addr);
+			break;
+		}
 	}
 	return 0;
 }
diff --git a/tests/ipc_shm.c b/tests/ipc_shm.c
index 7f74f70c1..03568b1f5 100644
--- a/tests/ipc_shm.c
+++ b/tests/ipc_shm.c
@@ -117,6 +117,32 @@ print_shmid_ds(const char *const str_ipc_cmd,
 		rc);
 }
 
+static void
+print_shm_info(const char *const str_ipc_cmd,
+              const struct shm_info *const info,
+              const int rc)
+{
+	if (rc < 0) {
+		printf("shmctl\\(%d, (%s\\|)?%s, %p\\) = %s\n",
+		       id, str_ipc_64, str_ipc_cmd, info, sprintrc_grep(rc));
+		return;
+	}
+
+	printf("shmctl\\(%d, (%s\\|)?%s, \\{used_ids=%d, shm_tot=%llu"
+	       ", shm_rss=%llu, shm_swp=%llu, swap_attempts=%llu"
+	       ", swap_successes=%llu\\}\\) = %d\n",
+	       id,
+	       str_ipc_64,
+	       str_ipc_cmd,
+	       info->used_ids,
+	       (unsigned long long) info->shm_tot,
+	       (unsigned long long) info->shm_rss,
+	       (unsigned long long) info->shm_swp,
+	       (unsigned long long) info->swap_attempts,
+	       (unsigned long long) info->swap_successes,
+	       rc);
+}
+
 int
 main(void)
 {
@@ -142,7 +168,10 @@ main(void)
 	static const unsigned int huge_flags = 21 << SHM_HUGE_SHIFT;
 	int bogus_flags;
 	int rc;
-	struct shmid_ds ds;
+	union {
+		struct shmid_ds ds;
+		struct shm_info info;
+	} buf;
 
 	rc = shmget(bogus_key, bogus_size, 0);
 	printf("shmget\\(%#llx, %zu, 000\\) = %s\n",
@@ -198,28 +227,28 @@ main(void)
 	       bogus_id, str_ipc_64, str_ipc_stat, bogus_addr,
 	       sprintrc_grep(rc));
 
-	rc = shmctl(id, IPC_STAT, &ds);
+	rc = shmctl(id, IPC_STAT, &buf.ds);
 	if (rc < 0)
 		perror_msg_and_skip("shmctl IPC_STAT");
-	print_shmid_ds(str_ipc_stat, &ds, rc);
+	print_shmid_ds(str_ipc_stat, &buf.ds, rc);
 
-	if (shmctl(id, IPC_SET, &ds))
+	if (shmctl(id, IPC_SET, &buf.ds))
 		perror_msg_and_skip("shmctl IPC_SET");
 	printf("shmctl\\(%d, (%s\\|)?%s, \\{shm_perm=\\{uid=%u, gid=%u"
 	       ", mode=%#o\\}\\}\\) = 0\n",
 	       id, str_ipc_64, str_ipc_set,
-	       (unsigned) ds.shm_perm.uid, (unsigned) ds.shm_perm.gid,
-	       (unsigned) ds.shm_perm.mode);
+	       (unsigned) buf.ds.shm_perm.uid,
+	       (unsigned) buf.ds.shm_perm.gid,
+	       (unsigned) buf.ds.shm_perm.mode);
 
-	rc = shmctl(0, SHM_INFO, &ds);
-	printf("shmctl\\(0, (%s\\|)?%s, %p\\) = %s\n",
-	       str_ipc_64, str_shm_info, &ds, sprintrc_grep(rc));
+	rc = shmctl(id, SHM_INFO, &buf.ds);
+	print_shm_info(str_shm_info, &buf.info, rc);
 
-	rc = shmctl(id, SHM_STAT, &ds);
-	print_shmid_ds(str_shm_stat, &ds, rc);
+	rc = shmctl(id, SHM_STAT, &buf.ds);
+	print_shmid_ds(str_shm_stat, &buf.ds, rc);
 
-	rc = shmctl(id, SHM_STAT_ANY, &ds);
-	print_shmid_ds(str_shm_stat_any, &ds, rc);
+	rc = shmctl(id, SHM_STAT_ANY, &buf.ds);
+	print_shmid_ds(str_shm_stat_any, &buf.ds, rc);
 
 	return 0;
 }