Hi Linux/MIPS folks, Found this bug by running the gnulib POSIX test suite: In the fchownat() call, an uid_t or gid_t of value (uid_t)-1 or (gid_t)-1 means no change. See <http://pubs.opengroup.org/onlinepubs/9699919799/functions/fchownat.html>. This value is correctly recognized on all Unices, _except_ Linux/MIPS in n32 and 64 ABIs. How to reproduce: ==================================== foo.c ==================================== #define _GNU_SOURCE 1 #include <fcntl.h> #include <stdio.h> #include <sys/stat.h> #include <unistd.h> int main () { const char *filename = "foo.c"; struct stat statbuf; int ret; int result = 0; ret = stat (filename, &statbuf); if (ret < 0) { perror ("stat"); return 1; } else { ret = fchownat (AT_FDCWD, filename, (uid_t)-1, statbuf.st_gid, 0); if (ret < 0) { perror ("fchownat"); result |= 2; } ret = fchownat (AT_FDCWD, filename, statbuf.st_uid, (gid_t)-1, 0); if (ret < 0) { perror ("fchownat"); result |= 4; } ret = fchownat (AT_FDCWD, filename, (uid_t)-1, (gid_t)-1, 0); if (ret < 0) { perror ("fchownat"); result |= 8; } } return result; } =============================================================================== $ gcc -Wall -mabi=64 foo.c $ ./a.out ; echo $? fchownat: Operation not permitted fchownat: Operation not permitted fchownat: Operation not permitted 14 $ gcc -Wall -mabi=n32 foo.c $ ./a.out ; echo $? fchownat: Operation not permitted fchownat: Operation not permitted fchownat: Operation not permitted 14 $ gcc -Wall -mabi=32 foo.c $ ./a.out ; echo $? Other relevant data: - kernel version is 2.6.27.1 - glibc version is 2.7 - gcc version is 4.3.2 (Debian). 'strace' of this program shows that the system call that returns with -1/EPERM is a call to SYS_6254 (in n32 ABI) or SYS_5250 (in 64 ABI). Bruno -- In memoriam Helmuth Hübener <http://en.wikipedia.org/wiki/Helmuth_Hübener>
