start the big userland migration

userland/linux/pagemap_dump.c

@@ -0,0 +1,116 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#pagemap_dump-out */
+
+#define _XOPEN_SOURCE 700
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <userland/common.h> /* virt_to_phys_user */
+
+int main(int argc, char **argv) {
+    char buffer[BUFSIZ];
+    char maps_file[BUFSIZ];
+    char pagemap_file[BUFSIZ];
+    int maps_fd;
+    int offset = 0;
+    int pagemap_fd;
+    pid_t pid;
+
+    if (argc < 2) {
+        printf("Usage: %s pid\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+    pid = strtoull(argv[1], NULL, 0);
+    snprintf(maps_file, sizeof(maps_file), "/proc/%ju/maps", (uintmax_t)pid);
+    snprintf(pagemap_file, sizeof(pagemap_file), "/proc/%ju/pagemap", (uintmax_t)pid);
+    maps_fd = open(maps_file, O_RDONLY);
+    if (maps_fd < 0) {
+        perror("open maps");
+        return EXIT_FAILURE;
+    }
+    pagemap_fd = open(pagemap_file, O_RDONLY);
+    if (pagemap_fd < 0) {
+        perror("open pagemap");
+        return EXIT_FAILURE;
+    }
+    printf("vaddr pfn soft-dirty file/shared swapped present library\n");
+    for (;;) {
+        ssize_t length = read(maps_fd, buffer + offset, sizeof buffer - offset);
+        if (length <= 0) break;
+        length += offset;
+        for (size_t i = offset; i < (size_t)length; i++) {
+            uintptr_t low = 0, high = 0;
+            if (buffer[i] == '\n' && i) {
+                const char *lib_name;
+                size_t y;
+                /* Parse a line from maps. Each line contains a range that contains many pages. */
+                {
+                    size_t x = i - 1;
+                    while (x && buffer[x] != '\n') x--;
+                    if (buffer[x] == '\n') x++;
+                    while (buffer[x] != '-' && x < sizeof buffer) {
+                        char c = buffer[x++];
+                        low *= 16;
+                        if (c >= '0' && c <= '9') {
+                            low += c - '0';
+                        } else if (c >= 'a' && c <= 'f') {
+                            low += c - 'a' + 10;
+                        } else {
+                            break;
+                        }
+                    }
+                    while (buffer[x] != '-' && x < sizeof buffer) x++;
+                    if (buffer[x] == '-') x++;
+                    while (buffer[x] != ' ' && x < sizeof buffer) {
+                        char c = buffer[x++];
+                        high *= 16;
+                        if (c >= '0' && c <= '9') {
+                            high += c - '0';
+                        } else if (c >= 'a' && c <= 'f') {
+                            high += c - 'a' + 10;
+                        } else {
+                            break;
+                        }
+                    }
+                    lib_name = 0;
+                    for (int field = 0; field < 4; field++) {
+                        x++;
+                        while(buffer[x] != ' ' && x < sizeof buffer) x++;
+                    }
+                    while (buffer[x] == ' ' && x < sizeof buffer) x++;
+                    y = x;
+                    while (buffer[y] != '\n' && y < sizeof buffer) y++;
+                    buffer[y] = 0;
+                    lib_name = buffer + x;
+                }
+                /* Get info about all pages in this page range with pagemap. */
+                {
+                    PagemapEntry entry;
+                    for (uintptr_t vaddr = low; vaddr < high; vaddr += sysconf(_SC_PAGE_SIZE)) {
+                        /* TODO always fails for the last page (vsyscall), why? pread returns 0. */
+                        if (!pagemap_get_entry(&entry, pagemap_fd, vaddr)) {
+                            printf(
+                                "%jx %jx %u %u %u %u %s\n",
+                                (uintmax_t)vaddr,
+                                (uintmax_t)entry.pfn,
+                                entry.soft_dirty,
+                                entry.file_page,
+                                entry.swapped,
+                                entry.present,
+                                lib_name
+                            );
+                        }
+                    }
+                }
+                buffer[y] = '\n';
+            }
+        }
+    }
+    close(maps_fd);
+    close(pagemap_fd);
+    return EXIT_SUCCESS;
+}

userland/linux/virt_to_phys_user.c

@@ -0,0 +1,25 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#userland-physical-address-experiments */
+
+#define _XOPEN_SOURCE 700
+#include <stdio.h> /* printf */
+#include <stdlib.h> /* EXIT_SUCCESS, EXIT_FAILURE, strtoull */
+
+#include <userland/common.h> /* virt_to_phys_user */
+
+int main(int argc, char **argv) {
+    pid_t pid;
+    uintptr_t vaddr, paddr = 0;
+
+    if (argc < 3) {
+        printf("Usage: %s pid vaddr\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+    pid = strtoull(argv[1], NULL, 0);
+    vaddr = strtoull(argv[2], NULL, 0);
+    if (virt_to_phys_user(&paddr, pid, vaddr)) {
+        fprintf(stderr, "error: virt_to_phys_user\n");
+        return EXIT_FAILURE;
+    };
+    printf("0x%jx\n", (uintmax_t)paddr);
+    return EXIT_SUCCESS;
+}