Implement DragonFlyBSD support

blink/cpuid.c

@@ -20,17 +20,18 @@
 #include "blink/endian.h"
 #include "blink/machine.h"
 
-#define INTEL    "GenuineIntel"
-#define BLINK    "GenuineBlink"
-#define LINUX_   "Linux\0\0\0\0\0\0\0"
-#define FREEBSD_ "FreeBSD\0\0\0\0\0\0"
-#define NETBSD_  "NetBSD\0\0\0\0\0\0"
-#define OPENBSD_ "OpenBSD\0\0\0\0\0"
-#define XNU_     "XNU\0\0\0\0\0\0\0\0\0"
-#define WINDOWS_ "Windows\0\0\0\0\0"
-#define CYGWIN_  "Cygwin\0\0\0\0\0\0"
-#define HAIKU_   "Haiku\0\0\0\0\0\0\0"
-#define UNKNOWN_ "Unknown\0\0\0\0\0\0"
+#define INTEL         "GenuineIntel"
+#define BLINK         "GenuineBlink"
+#define LINUX_        "Linux\0\0\0\0\0\0\0"
+#define FREEBSD_      "FreeBSD\0\0\0\0\0\0"
+#define NETBSD_       "NetBSD\0\0\0\0\0\0"
+#define OPENBSD_      "OpenBSD\0\0\0\0\0"
+#define DRAGONFLYBSD_ "DragonFlyBSD"
+#define XNU_          "XNU\0\0\0\0\0\0\0\0\0"
+#define WINDOWS_      "Windows\0\0\0\0\0"
+#define CYGWIN_       "Cygwin\0\0\0\0\0\0"
+#define HAIKU_        "Haiku\0\0\0\0\0\0\0"
+#define UNKNOWN_      "Unknown\0\0\0\0\0\0"
 
 #ifdef __COSMOPOLITAN__
 #define OS                  \
@@ -49,6 +50,8 @@
 #define OS NETBSD_
 #elif defined(__OpenBSD__)
 #define OS OPENBSD_
+#elif defined(__DragonFly__)
+#define OS DRAGONFLYBSD_
 #elif defined(__APPLE__)
 #define OS XNU_
 #elif defined(__CYGWIN__)

blink/elf.c

@@ -178,3 +178,47 @@ Elf64_Sym_ *GetElfSymbolTable(const Elf64_Ehdr_ *elf,  //
   }
   return res;
 }
+
+const char *GetElfOsNameInNoteTag(const Elf64_Ehdr_ *elf, size_t mapsize) {
+  int i;
+  Elf64_Shdr_ *shdr;
+  const char *sect_name;
+  const char *note, *note_end;
+  uint32_t namesz, descsz, type;
+  const char *os_name;
+
+  for (i = 0; i < Read16(elf->shnum); ++i) {
+    shdr = GetElfSectionHeaderAddress(elf, mapsize, i);
+    if (!shdr) continue;
+    if (Read32(shdr->type) != SHT_NOTE_) continue;
+
+    sect_name = GetElfSectionName(elf, mapsize, shdr);
+    if (!sect_name) continue;
+    if (strcmp(sect_name, ".note.ABI-tag") != 0 &&
+        strcmp(sect_name, ".note.tag") != 0 &&
+        strcmp(sect_name, ".note.gnu") != 0)
+      continue;
+
+    note = (const char *)GetElfSectionAddress(elf, mapsize, shdr);
+    if (!note) continue;
+    note_end = note + Read64(shdr->size);
+
+    while (note + 12 <= note_end) {
+      namesz = *(const uint32_t *)(note + 0);
+      descsz = *(const uint32_t *)(note + 4);
+      type   = *(const uint32_t *)(note + 8);
+
+      const char *name_field = note + 12;
+      const char *desc_field = name_field + ((namesz + 3) & ~3);
+      if (desc_field + ((descsz + 3) & ~3) > note_end) break;
+
+      if (namesz && name_field[namesz-1] == '\0') {
+        return name_field;
+      }
+
+      // Advance to next note
+      note = desc_field + ((descsz + 3) & ~3);
+    }
+  }
+  return NULL;
+}

blink/elf.h

@@ -629,5 +629,6 @@ char *GetElfSectionNameStringTable(const Elf64_Ehdr_ *, size_t);
 void *GetElfSectionAddress(const Elf64_Ehdr_ *, size_t, const Elf64_Shdr_ *);
 Elf64_Sym_ *GetElfSymbolTable(const Elf64_Ehdr_ *, size_t, int *);
 i64 GetElfMemorySize(const Elf64_Ehdr_ *, size_t, i64 *);
+const char *GetElfOsNameInNoteTag(const Elf64_Ehdr_ *, size_t);
 
 #endif /* BLINK_ELF_H_ */

blink/loader.c

@@ -293,6 +293,16 @@ static bool IsHaikuExecutable(Elf64_Ehdr_ *ehdr, size_t size) {
 #endif
 }
 
+static bool IsDragonflybsdExecutable(Elf64_Ehdr_ *ehdr, size_t size) {
+#ifdef __DragonFly__
+  const char *name = GetElfOsNameInNoteTag(ehdr, size);
+  if (name && !strcmp(name, "DragonFly")) {
+    return true;
+  }
+#endif
+  return false;
+}
+
 static bool IsShebangExecutable(void *image, size_t size) {
   return size >= 2 && ((char *)image)[0] == '#' && ((char *)image)[1] == '!';
 }
@@ -342,6 +352,10 @@ bool IsSupportedExecutable(const char *path, void *image, size_t size) {
       ExplainWhyItCantBeEmulated(path, "ELF is Haiku executable");
       return false;
     }
+    if (IsDragonflybsdExecutable(ehdr, size)) {
+      ExplainWhyItCantBeEmulated(path, "ELF is DragonFlyBSD executable");
+      return false;
+    }
 #if defined(__ELF__) && !defined(__linux)
     LOGF("blink believes %s is an x86_64-linux executable", path);
 #endif