Make `NamesIterator` safer

2 files changed, 24 insertions, 9 deletions

diff --git a/src/install/bin.zig b/src/install/bin.zig
index c7c3b3799..c7dd50367 100644
--- a/src/install/bin.zig
+++ b/src/install/bin.zig
@@ -191,16 +191,19 @@ pub const Bin = extern struct {
                     this.i += 1;
                     this.done = true;
                     const base = std.fs.path.basename(this.package_name.slice(this.string_buffer));
-                    if (strings.hasPrefix(base, "./")) return base[2..];
-                    return base;
+                    if (strings.hasPrefix(base, "./"))
+                        return strings.copy(&this.buf, base[2..]);
+
+                    return strings.copy(&this.buf, base);
                 },
                 .named_file => {
                     if (this.i > 0) return null;
                     this.i += 1;
                     this.done = true;
                     const base = std.fs.path.basename(this.bin.value.named_file[0].slice(this.string_buffer));
-                    if (strings.hasPrefix(base, "./")) return base[2..];
-                    return base;
+                    if (strings.hasPrefix(base, "./"))
+                        return strings.copy(&this.buf, base[2..]);
+                    return strings.copy(&this.buf, base);
                 },
 
                 .dir => return try this.nextInDir(),
@@ -209,15 +212,18 @@ pub const Bin = extern struct {
                     const index = this.i;
                     this.i += 2;
                     this.done = this.i >= this.bin.value.map.len;
+                    const current_string = this.bin.value.map.get(
+                        this.extern_string_buf,
+                    )[index];
+
                     const base = std.fs.path.basename(
-                        this.bin.value.map.get(
-                            this.extern_string_buf,
-                        )[index].slice(
+                        current_string.slice(
                             this.string_buffer,
                         ),
                     );
-                    if (strings.hasPrefix(base, "./")) return base[2..];
-                    return base;
+                    if (strings.hasPrefix(base, "./"))
+                        return strings.copy(&this.buf, base[2..]);
+                    return strings.copy(&this.buf, base);
                 },
                 else => return null,
             }
diff --git a/src/string_immutable.zig b/src/string_immutable.zig
index e3e72726f..db1d459af 100644
--- a/src/string_immutable.zig
+++ b/src/string_immutable.zig
@@ -498,6 +498,15 @@ test "StringOrTinyString Lowercase" {
     try std.testing.expectEqualStrings("hello!!!!!", str.slice());
 }
 
+/// Copy a string into a buffer
+/// Return the copied version
+pub fn copy(buf: []u8, src: []const u8) []const u8 {
+    const len = @min(buf.len, src.len);
+    if (len > 0)
+        @memcpy(buf.ptr, src.ptr, len);
+    return buf[0..len];
+}
+
 /// startsWith except it checks for non-empty strings
 pub fn hasPrefix(self: string, str: string) bool {
     return str.len > 0 and startsWith(self, str);