diff options
authorRich Felker <>2019-07-16 21:05:24 -0400
committerRich Felker <>2019-07-16 21:05:24 -0400
commit918c5fa0fc656e49b1ab9ce47183a23e3a36bc00 (patch)
parentddc7c4f936c7a90781072f10dbaa122007e939d0 (diff)
fix broken lseek on mipsn32 with offsets larger than LONG_MAX
mips n32 has 32-bit long, and generally uses long syscall arguments and return values, but provides only SYS_lseek, not SYS_llseek. we have some framework (syscall_arg_t, added for x32) to make syscall arguments 64-bit in such a setting, but it's not clear whether this could match the sign-extension semantics needed for 32-bit args to all the other syscalls, and we don't have any existing mechanism to allow the return value of syscalls to be something other than long. instead, just provide a custom mipsn32 version of the lseek function doing its own syscall asm with 64-bit arguments. as a result of commit 03919b26ed41c31876db41f7cee076ced4513fad, stdio will also get the new code, fixing fseeko/ftello too.
1 files changed, 20 insertions, 0 deletions
diff --git a/src/unistd/mipsn32/lseek.c b/src/unistd/mipsn32/lseek.c
new file mode 100644
index 00000000..60e74a51
--- /dev/null
+++ b/src/unistd/mipsn32/lseek.c
@@ -0,0 +1,20 @@
+#include <unistd.h>
+#include "syscall.h"
+off_t __lseek(int fd, off_t offset, int whence)
+ register long long r4 __asm__("$4") = fd;
+ register long long r5 __asm__("$5") = offset;
+ register long long r6 __asm__("$6") = whence;
+ register long long r7 __asm__("$7");
+ register long long r2 __asm__("$2") = SYS_lseek;
+ __asm__ __volatile__ (
+ "syscall"
+ : "+&r"(r2), "=r"(r7)
+ : "r"(r4), "r"(r5), "r"(r6)
+ return r7 ? __syscall_ret(-r2) : r2;
+weak_alias(__lseek, lseek);
+weak_alias(__lseek, lseek64);