From 5b53f34340bff793106af3c475e5bb3315589e53 Mon Sep 17 00:00:00 2001
From: the lemons <citrons@mondecitronne.com>
Date: Mon, 6 Feb 2023 13:58:46 -0600
Subject: parse /proc/<pid>/maps

---
 procfs.c | 37 +++++++++++++++++++++++++++++++++++++
 procfs.h |  7 +++++++
 2 files changed, 44 insertions(+)

diff --git a/procfs.c b/procfs.c
index 63aef3a..e3bfb2c 100644
--- a/procfs.c
+++ b/procfs.c
@@ -15,6 +15,43 @@ int procfs_open(pid_t pid) {
 	return open(path, O_RDWR);
 }
 
+ssize_t procfs_maps(pid_t pid, struct procfs_map **maps) {
+	char path[2048];
+	sprintf(path, "/proc/%d/maps", pid);
+	FILE *f = fopen(path, "r");
+	if (!f) return -1;
+
+	int n = 0;
+	int capacity = 2;
+	*maps = calloc(capacity, sizeof(**maps));
+	if (!*maps) return -1;
+	while (1) {
+		void *base, *max;
+		int matches = fscanf(f, "%p-%p", &base, &max);
+		if (matches == EOF) goto eof;
+		if (matches < 2) goto err;
+		int c;
+		while ((c = getc(f)) != '\n')
+			if (c == EOF) goto eof;
+		n++;
+		if (n > capacity) {
+			capacity <<= 1;
+			struct procfs_map *r = reallocarray(*maps, capacity, sizeof(*r));
+			if (!r) goto err;
+			*maps = r;
+		}
+		(*maps)[n - 1].base = (uintptr_t) base;
+		(*maps)[n - 1].max = (uintptr_t) max;
+	}
+eof:
+	if (ferror(f)) goto err;
+	if (n == 0) free(*maps);
+	return n;
+err:
+	free(*maps);
+	return -1;
+}
+
 int read_page(int fd, uintptr_t index, uint8_t *data) {
 	if (lseek(fd, index * PAGE_SIZE, SEEK_SET) == -1) 
 		return -1;
diff --git a/procfs.h b/procfs.h
index 7b81a13..b36c242 100644
--- a/procfs.h
+++ b/procfs.h
@@ -12,4 +12,11 @@
 int procfs_open(pid_t pid);
 int read_page(int fd, uintptr_t index, uint8_t *data);
 
+struct procfs_map {
+	uintptr_t base;
+	uintptr_t max;
+};
+
+ssize_t procfs_maps(pid_t pid, struct procfs_map **maps);
+
 #endif
-- 
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