From 285025ee086b7631cb102c20300c8da7f2d9a52e Mon Sep 17 00:00:00 2001
From: the lemons <citrons@mondecitronne.com>
Date: Tue, 7 Feb 2023 15:15:00 -0600
Subject: change behavior of jumping between maps

---
 core.c   | 36 +++++++++++++++---------------------
 procfs.c | 31 +++++++++++++++++++++++++++----
 procfs.h |  2 ++
 3 files changed, 44 insertions(+), 25 deletions(-)

diff --git a/core.c b/core.c
index 97953b0..b72f104 100644
--- a/core.c
+++ b/core.c
@@ -50,25 +50,18 @@ static void goto_addr(uintptr_t addr) {
 	pos_y -= (double) screen_height / 2 * scale;
 }
 
-static size_t closest_map(struct procfs_map *maps, size_t n, uintptr_t addr) {
-	uintptr_t min = -1;
-	size_t closest;
-	for (size_t i = 0; i < n; i++) {
-		uintptr_t base = maps[i].base;
-		uintptr_t diff = base > addr ? base - addr : addr - base;
-		if (diff < min) {
-			min = diff; closest = i;
-		}
-	}
-	return closest;
-}
+static size_t current_map = 0;
 
 static void next_map() {
 	struct procfs_map *maps;
 	int n = procfs_maps(pid, &maps);
 	if (n < 1) return;
-	size_t m = closest_map(maps, n, current_addr());
-	goto_addr(maps[(m + 1) % n].base);
+	for (int i = 0; i < n; i++) {
+		current_map = (current_map + 1) % n;
+		if (maps[current_map].prot & PROT_READ)
+			break;
+	}
+	goto_addr(maps[current_map].base);
 	free(maps);
 }
 
@@ -76,11 +69,12 @@ static void prev_map() {
 	struct procfs_map *maps;
 	int n = procfs_maps(pid, &maps);
 	if (n < 1) return;
-	size_t m = closest_map(maps, n, current_addr());
-	if (m != 0)
-		goto_addr(maps[m - 1].base);
-	else
-		goto_addr(maps[n - 1].base);
+	for (int i = 0; i < n; i++) {
+		current_map = current_map > 1 ? current_map - 1 : n - 1;
+		if (maps[current_map].prot & PROT_READ)
+			break;
+	}
+	goto_addr(maps[current_map].base);
 	free(maps);
 }
 
@@ -184,12 +178,12 @@ int main(int argc, char *argv[]) {
 
 	char title[1024];
 	snprintf(title, 1024, "%s [%d]", argv[0], pid);
-	init_sdl(argv[0]);
+	init_sdl(title);
 	viewer = create_viewer(mem_fd, renderer);
 	if (!viewer) abort();
 	atexit(cleanup);
 
-	next_map();
+	prev_map();
 
 	int last_time = 0;
 	int current_time = 0;
diff --git a/procfs.c b/procfs.c
index e3bfb2c..2558f03 100644
--- a/procfs.c
+++ b/procfs.c
@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/mman.h>
 #include <fcntl.h>
 #include <unistd.h>
 
@@ -27,12 +28,33 @@ ssize_t procfs_maps(pid_t pid, struct procfs_map **maps) {
 	if (!*maps) return -1;
 	while (1) {
 		void *base, *max;
-		int matches = fscanf(f, "%p-%p", &base, &max);
+		char prot_str[4];
+		int matches = fscanf(f, "%p-%p %4c", &base, &max, prot_str);
 		if (matches == EOF) goto eof;
-		if (matches < 2) goto err;
+		if (matches < 3) goto err;
+
+		int prot = 0;
+		for (int i = 0; i < 4; i++) {
+			switch (prot_str[i]) {
+				case 'r':
+					prot |= PROT_READ;
+					break;
+				case 'w':
+					prot |= PROT_WRITE;
+					break;
+				case 'x':
+					prot |= PROT_EXEC;
+					break;
+				default:
+					break;
+			}
+		}
+		if (prot == 0) prot = PROT_NONE;
+
 		int c;
 		while ((c = getc(f)) != '\n')
 			if (c == EOF) goto eof;
+
 		n++;
 		if (n > capacity) {
 			capacity <<= 1;
@@ -40,8 +62,9 @@ ssize_t procfs_maps(pid_t pid, struct procfs_map **maps) {
 			if (!r) goto err;
 			*maps = r;
 		}
-		(*maps)[n - 1].base = (uintptr_t) base;
-		(*maps)[n - 1].max = (uintptr_t) max;
+		(*maps)[n - 1] = (struct procfs_map) {
+			(uintptr_t) base, (uintptr_t) max, prot
+		};
 	}
 eof:
 	if (ferror(f)) goto err;
diff --git a/procfs.h b/procfs.h
index b36c242..28ef784 100644
--- a/procfs.h
+++ b/procfs.h
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <stddef.h>
 #include <sys/types.h>
+#include <sys/mman.h>
 
 #ifndef PAGE_SIZE
 #define PAGE_SIZE (4096)
@@ -15,6 +16,7 @@ int read_page(int fd, uintptr_t index, uint8_t *data);
 struct procfs_map {
 	uintptr_t base;
 	uintptr_t max;
+	int prot;
 };
 
 ssize_t procfs_maps(pid_t pid, struct procfs_map **maps);
-- 
cgit v1.2.3