zdtm: check reservation mmaps are restored correctly

mmaps done just for reserving address space something like

void *addr = mmap(NULL, SIZE, PROT_NONE,
	      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

Ensure that these do not have ac flag set in /proc/pid/smaps.

Signed-off-by: Bhavik Sachdev <b.sachdev1904@gmail.com>

test/zdtm/static/Makefile

@@ -215,6 +215,7 @@ TST_NOFILE	:=				\
 		dumpable02			\
 		remap_dead_pid			\
 		remap_dead_pid_root			\
+		reservation_mmaps		\
 		scm00				\
 		scm01				\
 		scm02				\
@@ -663,6 +664,7 @@ mntns_root_bind02:	CFLAGS += -DROOT_BIND02
 maps02: get_smaps_bits.o
 mlock_setuid: get_smaps_bits.o
 thp_disable: get_smaps_bits.o
+reservation_mmaps: get_smaps_bits.o
 inotify01:		CFLAGS += -DINOTIFY01
 unlink_fstat01+:	CFLAGS += -DUNLINK_OVER
 unlink_fstat04:		CFLAGS += -DUNLINK_FSTAT04

test/zdtm/static/get_smaps_bits.c

@@ -80,7 +80,7 @@ static void parse_vmflags(char *buf, unsigned long *flags, unsigned long *madv)
 
 #define is_hex_digit(c) (((c) >= '0' && (c) <= '9') || ((c) >= 'a' && (c) <= 'f') || ((c) >= 'A' && (c) <= 'F'))
 
-static int is_vma_range_fmt(char *line, unsigned long *start, unsigned long *end)
+int is_vma_range_fmt(char *line, unsigned long *start, unsigned long *end)
 {
 	char *p = line;
 	while (*line && is_hex_digit(*line))

test/zdtm/static/get_smaps_bits.h

@@ -2,5 +2,6 @@
 #define ZDTM_GET_SMAPS_BITS_H_
 
 extern int get_smaps_bits(unsigned long where, unsigned long *flags, unsigned long *madv);
+extern int is_vma_range_fmt(char *line, unsigned long *start, unsigned long *end);
 
 #endif /* ZDTM_GET_SMAPS_BITS_H_ */

test/zdtm/static/reservation_mmaps.c

@@ -0,0 +1,132 @@
+#include <sys/mman.h>
+
+#include "zdtmtst.h"
+#include "get_smaps_bits.h"
+
+#define SIZE (4UL * (1UL << 20)) /* 4MB */
+
+const char *test_doc = "Check mmaps done for reserving virtual address space, do not have ac flag set in /proc/pid/smaps\n";
+const char *test_author = "Bhavik Sachdev <b.sachdev1904@gmail.com>";
+
+static void check_ac_flag(char *buf, bool *no_ac)
+{
+	char *tok;
+
+	if (!buf[0])
+		return;
+
+	*no_ac = true;
+	tok = strtok(buf, " \n");
+	if (!tok)
+		return;
+
+#define _vmflag_match(_t, _s) (_t[0] == _s[0] && _t[1] == _s[1])
+
+	do {
+		if (_vmflag_match(tok, "ac")) {
+			*no_ac = false;
+			return;
+		}
+		/*
+		 * Anything else is just ignored.
+		 */
+	} while ((tok = strtok(NULL, " \n")));
+
+#undef _vmflag_match
+	return;
+}
+
+static int is_accountable(unsigned long where, bool *no_ac)
+{
+	unsigned long start = 0, end = 0;
+	FILE *smaps = NULL;
+	char buf[1024];
+	int found = 0;
+
+	if (!where)
+		return 0;
+
+	smaps = fopen("/proc/self/smaps", "r");
+	if (!smaps) {
+		pr_perror("Can't open smaps");
+		return -1;
+	}
+
+	while (fgets(buf, sizeof(buf), smaps)) {
+		is_vma_range_fmt(buf, &start, &end);
+
+		if (!strncmp(buf, "VmFlags: ", 9) && start <= where && where < end) {
+			found = 1;
+			check_ac_flag(buf, no_ac);
+			break;
+		}
+	}
+
+	fclose(smaps);
+
+	if (!found) {
+		pr_perror("VmFlags not found for %lx", where);
+		return -1;
+	}
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	uint32_t crc = ~0;
+	uint8_t *data_mmap, *reservation_mmap;
+	bool no_ac;
+
+	test_init(argc, argv);
+	data_mmap = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+	if (data_mmap == MAP_FAILED) {
+		pr_perror("Failed to mmap %lu Mb memory", SIZE >> 20);
+		return 1;
+	}
+
+	reservation_mmap = mmap(NULL, SIZE, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+	if (reservation_mmap == MAP_FAILED) {
+		pr_perror("Failed to mmap %lu Mb memory", SIZE >> 20);
+		return 1;
+	}
+
+	datagen(data_mmap, SIZE, &crc);
+
+	if (mprotect(data_mmap, SIZE, PROT_NONE)) {
+		pr_perror("Failed to set protections on %p", data_mmap);
+		return 1;
+	}
+
+	test_daemon();
+	test_waitsig();
+
+	/*
+	 * check that a mmap whose memory protection got changed
+	 * to PROT_NONE still has the data stored in it.
+	 */
+	if (mprotect(data_mmap, SIZE, PROT_READ)) {
+		pr_perror("Failed to set protections on %p", data_mmap);
+		return 1;
+	}
+
+	crc = ~0;
+	if (datachk(data_mmap, SIZE, &crc)) {
+		fail("Data mismatch");
+		return 1;
+	}
+
+	/* reservation_mmap should not have ac flag set in /proc/pid/smaps */
+	if (is_accountable((unsigned long)reservation_mmap, &no_ac)) {
+		fail("could not check for no ac flag on reservation mmap");
+		return 1;
+	}
+
+	if (!no_ac) {
+		fail("reservation mmap has ac flag set");
+		return 1;
+	}
+
+	pass();
+	return 0;
+}