Revert "Revert "Track permissions as bytes""

This reverts commit 9bc29a0.

Author: workingjubilee

src/symbolize/gimli/parse_running_mmaps_unix.rs

@@ -20,7 +20,7 @@ pub(super) struct MapsEntry {
     /// x = execute
     /// s = shared
     /// p = private (copy on write)
-    perms: [char; 4],
+    // perms: [u8; 4],
     /// Offset into the file (or "whatever").
     // offset: u64,
     /// device (major, minor)
@@ -115,14 +115,12 @@ impl FromStr for MapsEntry {
         } else {
             return Err(parse_err);
         };
-        let perms: [char; 4] = {
-            let mut chars = perms_str.chars();
-            let mut c = || chars.next().ok_or("insufficient perms");
-            let perms = [c()?, c()?, c()?, c()?];
-            if chars.next().is_some() {
-                return Err("too many perms");
-            }
-            perms
+        let _perms = if let &[r, w, x, p, ..] = perms_str.as_bytes() {
+            // If a system in the future adds a 5th field to the permission list,
+            // there's no reason to assume previous fields were invalidated.
+            [r, w, x, p]
+        } else {
+            return Err(parse_err);
         };
         let _offset = hex(offset_str)?;
         let _dev = if let Some((major, minor)) = dev_str.split_once(':') {
@@ -135,7 +133,7 @@ impl FromStr for MapsEntry {
 
         Ok(MapsEntry {
             address,
-            perms,
+            // perms,
             // offset,
             // dev,
             // inode,
@@ -155,7 +153,7 @@ fn check_maps_entry_parsing_64bit() {
             .unwrap(),
         MapsEntry {
             address: (0xffffffffff600000, 0xffffffffff601000),
-            perms: ['-', '-', 'x', 'p'],
+            // perms: *b"--xp",
             // offset: 0x00000000,
             // dev: (0x00, 0x00),
             // inode: 0x0,
@@ -170,7 +168,7 @@ fn check_maps_entry_parsing_64bit() {
             .unwrap(),
         MapsEntry {
             address: (0x7f5985f46000, 0x7f5985f48000),
-            perms: ['r', 'w', '-', 'p'],
+            // perms: *b"rw-p",
             // offset: 0x00039000,
             // dev: (0x103, 0x06),
             // inode: 0x76021795,
@@ -183,7 +181,7 @@ fn check_maps_entry_parsing_64bit() {
             .unwrap(),
         MapsEntry {
             address: (0x35b1a21000, 0x35b1a22000),
-            perms: ['r', 'w', '-', 'p'],
+            // perms: *b"rw-p",
             // offset: 0x00000000,
             // dev: (0x00, 0x00),
             // inode: 0x0,
@@ -207,7 +205,7 @@ fn check_maps_entry_parsing_32bit() {
             .unwrap(),
         MapsEntry {
             address: (0x08056000, 0x08077000),
-            perms: ['r', 'w', '-', 'p'],
+            // perms: *b"rw-p",
             // offset: 0x00000000,
             // dev: (0x00, 0x00),
             // inode: 0x0,
@@ -222,7 +220,7 @@ fn check_maps_entry_parsing_32bit() {
             .unwrap(),
         MapsEntry {
             address: (0xb7c79000, 0xb7e02000),
-            perms: ['r', '-', '-', 'p'],
+            // perms: *b"r--p",
             // offset: 0x00000000,
             // dev: (0x08, 0x01),
             // inode: 0x60662705,
@@ -235,7 +233,7 @@ fn check_maps_entry_parsing_32bit() {
             .unwrap(),
         MapsEntry {
             address: (0xb7e02000, 0xb7e03000),
-            perms: ['r', 'w', '-', 'p'],
+            // perms: *b"rw-p",
             // offset: 0x00000000,
             // dev: (0x00, 0x00),
             // inode: 0x0,