rewrite and port to SDL3

1 files changed, 130 insertions, 0 deletions

diff --git a/src/procfs.c b/src/procfs.c
new file mode 100644
index 0000000..d377e02
--- /dev/null
+++ b/src/procfs.c
@@ -0,0 +1,130 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "procfs.h"
+
+int procfs_open(pid_t pid) {
+	char path[2048];
+	sprintf(path, "/proc/%d/mem", 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;
+	if (*maps) {
+		free(*maps);
+	}
+	*maps = calloc(capacity, sizeof(**maps));
+	if (!*maps) return -1;
+	while (1) {
+		void *base, *max;
+		char prot_str[4];
+		char name[4096] = {0};
+		void *unused;
+		int matches = fscanf(
+			f, "%p-%p %4c %p %p:%p %d",
+			&base, &max, &prot_str, &unused, &unused, &unused, &unused
+		);
+		if (matches == EOF) goto eof;
+		if (matches < 7) goto err;
+
+		int c = ' ';
+		while (c == ' ') {
+			c = fgetc(f);
+		}
+		if (c == EOF) goto err;
+		ungetc(c, f);
+		if (fgets(name, 4096, f) == NULL) goto err;
+		name[strlen(name) - 1] = '\0'; // remove newline
+
+		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;
+
+		if (n > 0) {
+			procfs_map *prev = *maps + (n - 1);
+			if ((strlen(name) == 0 || strncmp(prev->name, name, 1024) == 0) &&
+					prev->max == (uintptr_t)base) {
+				prev->max = (uintptr_t)max;
+				continue;
+			}
+		}
+
+		n++;
+		if (n > capacity) {
+			capacity <<= 1;
+			struct procfs_map *r = reallocarray(*maps, capacity, sizeof(*r));
+			if (!r) goto err;
+			*maps = r;
+		}
+		procfs_map *new = *maps + (n - 1);
+		new->base = (uintptr_t)base;
+		new->max = (uintptr_t)max;
+		new->prot = prot;
+		strncpy(new->name, name, sizeof(new->name) - 1);
+	}
+eof:
+	if (ferror(f)) goto err;
+	fclose(f);
+	if (n == 0) {
+		free(*maps);
+		*maps = NULL;
+	}
+	return n;
+err:
+	fclose(f);
+	free(*maps);
+	*maps = NULL;
+	return -1;
+}
+
+// mmap does not work on /proc/pid/mem, so we issue reads/writes instead
+int read_mem(int fd, uintptr_t addr, uint8_t *data, size_t size) {
+	if (lseek(fd, addr, SEEK_SET) == -1) return -1;
+	size_t n = 0;
+	while (n < size) {
+		ssize_t result = read(fd, data + n, size - n);
+		if (result <= 0) return -1;
+		n += result;
+	}
+	return 0;
+}
+
+int write_mem(int fd, uintptr_t addr, uint8_t *data, size_t size) {
+	if (lseek(fd, addr, SEEK_SET) == -1) return -1;
+	size_t n = 0;
+	while (n < size) {
+		ssize_t result = write(fd, data + n, size - n);
+		if (result <= 0) return -1;
+		n += result;
+	}
+	return 0;
+}