Symlink Support

aarch64/aarch64_defs.M1

@@ -161,6 +161,7 @@ DEFINE SET_X8_TO_SYS_UNAME 081480d2
 DEFINE SET_X8_TO_SYS_WAIT4 882080d2
 DEFINE SET_X8_TO_SYS_WRITE 080880d2
 DEFINE SET_X8_TO_SYS_UNLINK 488080d2
+DEFINE SET_X8_TO_SYS_SYMLINKAT 880480d2
 DEFINE SET_X8_TO_SYS_UMASK c81480d2
 DEFINE SET_X8_TO_SYS_UNSHARE 280c80d2
 DEFINE SET_X8_TO_SYS_GETEUID e81580d2

aarch64/linux/unistd.c

@@ -145,6 +145,15 @@ int unlink (char* filename)
 	    "SYSCALL");
 }
 
+int symlink(const char *path1, const char *path2)
+{
+	asm("SET_X0_FROM_BP" "SUB_X0_16" "DEREF_X0"
+	    "SET_X2_FROM_X0"
+	    "SET_X1_TO_FCNTL_H_AT_FDCWD"
+	    "SET_X0_FROM_BP" "SUB_X0_8" "DEREF_X0"
+	    "SET_X8_TO_SYS_SYMLINKAT"
+	    "SYSCALL");
+}
 
 int _getcwd(char* buf, int size)
 {

amd64/linux/unistd.c

@@ -141,6 +141,15 @@ int unlink (char* filename)
 	    "syscall");
 }
 
+int symlink(const char *path1, const char *path2)
+{
+	asm("lea_rdi,[rsp+DWORD] %16"
+	    "mov_rdi,[rdi]"
+	    "lea_rsi,[rsp+DWORD] %8"
+	    "mov_rsi,[rsi]"
+	    "mov_rax, %88"
+	    "syscall");
+}
 
 int _getcwd(char* buf, int size)
 {

armv7l/linux/unistd.c

@@ -135,6 +135,15 @@ int unlink (char* filename)
 	    "SYSCALL_ALWAYS");
 }
 
+int symlink(const char *path1, const char *path2)
+{
+	asm("!4 R0 SUB R12 ARITH_ALWAYS"
+	    "!0 R0 LOAD32 R0 MEMORY"
+	    "!8 R1 SUB R12 ARITH_ALWAYS"
+	    "!0 R1 LOAD32 R1 MEMORY"
+	    "!21 R7 LOADI8_ALWAYS"
+	    "SYSCALL_ALWAYS");
+}
 
 int _getcwd(char* buf, int size)
 {

knight/linux/unistd.c

@@ -106,6 +106,11 @@ int unlink (char* filename)
 	    "SYS_UNLINK");
 }
 
+int symlink(const char *path1, const char *path2)
+{
+	/* not implemented */
+	return(-1);
+}
 
 int _getcwd(char* buf, int size)
 {

knight/native/unistd.c

@@ -120,6 +120,11 @@ int unlink (char* filename)
 	return 0;
 }
 
+int symlink(const char *path1, const char *path2)
+{
+	/* Completely meaningless in bare metal */
+	return 0;
+}
 
 int _getcwd(char* buf, int size)
 {

riscv32/linux/unistd.c

@@ -182,6 +182,15 @@ int unlink (char* filename)
 	    "ecall");
 }
 
+/* XXX: UNTESTED */
+int symlink(const char *path1, const char *path2)
+{
+	asm("rd_a0 rs1_fp !-4 lw"
+	    "rd_a1 !-100 addi"  /* AT_FDCWD */
+	    "rd_a2 rs1_fp !-8 lw"
+	    "rd_a7 !36 addi"    /* symlinkat */
+	    "ecall");
+}
 
 int _getcwd(char* buf, int size)
 {

riscv64/linux/unistd.c

@@ -126,6 +126,16 @@ int unlink (char* filename)
 	    "ecall");
 }
 
+/* XXX: UNTESTED */
+int symlink(const char *path1, const char *path2)
+{
+	asm("rd_a0 rs1_fp !-8 ld"
+	    "rd_a1 !-100 addi"  /* AT_FDCWD */
+	    "rd_a2 rs1_fp !-16 ld"
+	    "rd_a7 !36 addi"    /* symlinkat */
+	    "ecall");
+}
+
 
 int _getcwd(char* buf, int size)
 {

uefi/unistd.c

@@ -296,6 +296,11 @@ int unlink(char* filename)
 	__uefi_1(fd, fd->delete);
 }
 
+int symlink(const char *path1, const char *path2)
+{
+	/* This does not make sense in UEFI, where there are no symlinks */
+	return -1;
+}
 
 char* getcwd(char* buf, unsigned size)
 {

unistd.h

@@ -54,6 +54,7 @@ int write(int fd, char* buf, unsigned count);
 int lseek(int fd, int offset, int whence);
 int close(int fd);
 int unlink (char *filename);
+int symlink(const char *path1, const char *path2);
 int _getcwd(char* buf, int size);
 char* getcwd(char* buf, unsigned size);
 char* getwd(char* buf);

x86/linux/unistd.c

@@ -136,6 +136,15 @@ int unlink (char *filename)
 	    "int !0x80");
 }
 
+int symlink(const char *path1, const char *path2)
+{
+	asm("lea_ebx,[esp+DWORD] %8"
+	    "mov_ebx,[ebx]"
+	    "lea_ecx,[esp+DWORD] %4"
+	    "mov_ecx,[ecx]"
+	    "mov_eax, %83"
+	    "int !0x80");
+}
 
 int _getcwd(char* buf, int size)
 {