diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | NEWS | 18 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c | 128 |
3 files changed, 74 insertions, 78 deletions
diff --git a/ChangeLog b/ChangeLog index b798f910db..a8cc4e50a0 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2015-01-21 Adhemerval Zanella <azanella@linux.vnet.ibm.com> + + [BZ #16418] + * sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c (__get_clockfreq): + Make code racy and cancel safe. + 2015-01-21 Carlos O'Donell <carlos@redhat.com> * sysdeps/arm/unwind-resume.h: Fix copyright year. diff --git a/NEWS b/NEWS index 136f16bff6..fd6da90595 100644 --- a/NEWS +++ b/NEWS @@ -10,15 +10,15 @@ Version 2.21 * The following bugs are resolved with this release: 6652, 10672, 12674, 12847, 12926, 13862, 14132, 14138, 14171, 14498, - 15215, 15884, 16009, 16191, 16469, 16617, 16619, 16657, 16740, 16857, - 17192, 17266, 17273, 17344, 17363, 17370, 17371, 17411, 17460, 17475, - 17485, 17501, 17506, 17508, 17522, 17555, 17570, 17571, 17572, 17573, - 17574, 17582, 17583, 17584, 17585, 17589, 17594, 17601, 17608, 17616, - 17625, 17630, 17633, 17634, 17635, 17647, 17653, 17657, 17658, 17664, - 17665, 17668, 17682, 17702, 17717, 17719, 17722, 17723, 17724, 17725, - 17732, 17733, 17744, 17745, 17746, 17747, 17748, 17775, 17777, 17780, - 17781, 17782, 17791, 17793, 17796, 17797, 17803, 17806, 17834, 17844, - 17848 + 15215, 15884, 16009, 16418, 16191, 16469, 16617, 16619, 16657, 16740, + 16857, 17192, 17266, 17273, 17344, 17363, 17370, 17371, 17411, 17460, + 17475, 17485, 17501, 17506, 17508, 17522, 17555, 17570, 17571, 17572, + 17573, 17574, 17582, 17583, 17584, 17585, 17589, 17594, 17601, 17608, + 17616, 17625, 17630, 17633, 17634, 17635, 17647, 17653, 17657, 17658, + 17664, 17665, 17668, 17682, 17702, 17717, 17719, 17722, 17723, 17724, + 17725, 17732, 17733, 17744, 17745, 17746, 17747, 17748, 17775, 17777, + 17780, 17781, 17782, 17791, 17793, 17796, 17797, 17803, 17806, 17834, + 17844, 17848 * A new semaphore algorithm has been implemented in generic C code for all machines. Previous custom assembly implementations of semaphore were diff --git a/sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c b/sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c index 9b8165d203..fe8c5a15b3 100644 --- a/sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c +++ b/sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c @@ -24,95 +24,85 @@ #include <libc-internal.h> #include <sysdep.h> #include <bits/libc-vdso.h> +#include <not-cancel.h> hp_timing_t __get_clockfreq (void) { + hp_timing_t result = 0L; + +#ifdef SHARED + /* The vDSO does not return an error (it clear cr0.so on returning). */ + INTERNAL_SYSCALL_DECL (err); + result = + INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK (get_tbfreq, err, uint64_t, 0); +#else /* We read the information from the /proc filesystem. /proc/cpuinfo contains at least one line like: timebase : 33333333 We search for this line and convert the number into an integer. */ - static hp_timing_t timebase_freq; - hp_timing_t result = 0L; + int fd = __open_nocancel ("/proc/cpuinfo", O_RDONLY); + if (__glibc_likely (fd != -1)) + return result; - /* If this function was called before, we know the result. */ - if (timebase_freq != 0) - return timebase_freq; + /* The timebase will be in the 1st 1024 bytes for systems with up + to 8 processors. If the first read returns less then 1024 + bytes read, we have the whole cpuinfo and can start the scan. + Otherwise we will have to read more to insure we have the + timebase value in the scan. */ + char buf[1024]; + ssize_t n; - /* If we can use the vDSO to obtain the timebase even better. */ -#ifdef SHARED - INTERNAL_SYSCALL_DECL (err); - timebase_freq = - INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK (get_tbfreq, err, uint64_t, 0); - if (INTERNAL_SYSCALL_ERROR_P (timebase_freq, err) - && INTERNAL_SYSCALL_ERRNO (timebase_freq, err) == ENOSYS) -#endif + n = __read_nocancel (fd, buf, sizeof (buf)); + if (n == sizeof (buf)) { - int fd = __open ("/proc/cpuinfo", O_RDONLY); + /* We are here because the 1st read returned exactly sizeof + (buf) bytes. This implies that we are not at EOF and may + not have read the timebase value yet. So we need to read + more bytes until we know we have EOF. We copy the lower + half of buf to the upper half and read sizeof (buf)/2 + bytes into the lower half of buf and repeat until we + reach EOF. We can assume that the timebase will be in + the last 512 bytes of cpuinfo, so two 512 byte half_bufs + will be sufficient to contain the timebase and will + handle the case where the timebase spans the half_buf + boundry. */ + const ssize_t half_buf = sizeof (buf) / 2; + while (n >= half_buf) + { + memcpy (buf, buf + half_buf, half_buf); + n = __read_nocancel (fd, buf + half_buf, half_buf); + } + if (n >= 0) + n += half_buf; + } + __close_nocancel (fd); - if (__glibc_likely (fd != -1)) + if (__glibc_likely (n > 0)) + { + char *mhz = memmem (buf, n, "timebase", 7); + + if (__glibc_likely (mhz != NULL)) { - /* The timebase will be in the 1st 1024 bytes for systems with up - to 8 processors. If the first read returns less then 1024 - bytes read, we have the whole cpuinfo and can start the scan. - Otherwise we will have to read more to insure we have the - timebase value in the scan. */ - char buf[1024]; - ssize_t n; + char *endp = buf + n; - n = __read (fd, buf, sizeof (buf)); - if (n == sizeof (buf)) - { - /* We are here because the 1st read returned exactly sizeof - (buf) bytes. This implies that we are not at EOF and may - not have read the timebase value yet. So we need to read - more bytes until we know we have EOF. We copy the lower - half of buf to the upper half and read sizeof (buf)/2 - bytes into the lower half of buf and repeat until we - reach EOF. We can assume that the timebase will be in - the last 512 bytes of cpuinfo, so two 512 byte half_bufs - will be sufficient to contain the timebase and will - handle the case where the timebase spans the half_buf - boundry. */ - const ssize_t half_buf = sizeof (buf) / 2; - while (n >= half_buf) - { - memcpy (buf, buf + half_buf, half_buf); - n = __read (fd, buf + half_buf, half_buf); - } - if (n >= 0) - n += half_buf; - } + /* Search for the beginning of the string. */ + while (mhz < endp && (*mhz < '0' || *mhz > '9') && *mhz != '\n') + ++mhz; - if (__builtin_expect (n, 1) > 0) + while (mhz < endp && *mhz != '\n') { - char *mhz = memmem (buf, n, "timebase", 7); - - if (__glibc_likely (mhz != NULL)) + if (*mhz >= '0' && *mhz <= '9') { - char *endp = buf + n; - - /* Search for the beginning of the string. */ - while (mhz < endp && (*mhz < '0' || *mhz > '9') - && *mhz != '\n') - ++mhz; - - while (mhz < endp && *mhz != '\n') - { - if (*mhz >= '0' && *mhz <= '9') - { - result *= 10; - result += *mhz - '0'; - } - - ++mhz; - } + result *= 10; + result += *mhz - '0'; } - timebase_freq = result; + + ++mhz; } - __close (fd); } } +#endif - return timebase_freq; + return result; } |