diff options
Diffstat (limited to 'util/nvmutil/nvmutil.c')
| -rw-r--r-- | util/nvmutil/nvmutil.c | 40 |
1 files changed, 35 insertions, 5 deletions
diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c index 4a550e71..b3cea8da 100644 --- a/util/nvmutil/nvmutil.c +++ b/util/nvmutil/nvmutil.c @@ -15,6 +15,11 @@ * -Os -Wall -Wextra -Werror -pedantic -std=c90 */ +#define OFF_ERR 0 +#ifndef OFF_RESET +#define OFF_RESET 1 +#endif + /* * NOTE: older Linux lacked arc4random. * added in glibc 2.36. Just pass HAVE_ARC4RANDOM_BUF=0 @@ -409,7 +414,8 @@ static ssize_t rw_file_exact(int fd, u8 *mem, size_t len, off_t off, int rw_type, int loop_eagain, int loop_eintr, size_t max_retries); static ssize_t prw(int fd, void *mem, size_t nrw, - off_t off, int rw_type, int loop_eagain, int loop_eintr); + off_t off, int rw_type, int loop_eagain, int loop_eintr, + int off_reset); static int check_file(int fd, struct stat *st); static ssize_t rw_over_nrw(ssize_t r, size_t nrw); #if !defined(HAVE_REAL_PREAD_PWRITE) || \ @@ -668,6 +674,8 @@ typedef char bool_loop_eintr[(LOOP_EINTR==1||LOOP_EINTR==0)?1:-1]; typedef char bool_loop_eagain[(LOOP_EAGAIN==1||LOOP_EAGAIN==0)?1:-1]; typedef char bool_no_loop_eintr[(NO_LOOP_EINTR==0)?1:-1]; typedef char bool_no_loop_eagain[(NO_LOOP_EAGAIN==0)?1:-1]; +typedef char bool_off_err[(OFF_ERR==0)?1:-1]; +typedef char bool_off_reset[(OFF_RESET==0||OFF_RESET==1)?1:-1]; static int io_err_gbe = 0; static int rw_check_err_read[] = {0, 0}; @@ -1883,7 +1891,8 @@ rw_file_exact(int fd, u8 *mem, size_t nrw, mem + (size_t)rc, nrw - (size_t)rc, off + (off_t)rc, - rw_type, loop_eagain, loop_eintr); + rw_type, loop_eagain, loop_eintr, + OFF_ERR); if (rv < 0) return -1; @@ -1941,12 +1950,23 @@ err_rw_file_exact: * NOTE: If you use loop_eagain (1), you enable wait * loop on EAGAIN. Beware if using this on a non-blocking * pipe (it could spin indefinitely). + * + * off_reset: if zero, and using fallback pwrite/pread + * analogs, we check if a file offset changed, + * which would indicate another thread changed + * it, and return error, without resetting the + * file - this would allow that thread to keep + * running, but we could then cause a whole + * program exit if we wanted to. + * if not zero: + * we reset and continue, and pray for the worst. */ static ssize_t prw(int fd, void *mem, size_t nrw, off_t off, int rw_type, - int loop_eagain, int loop_eintr) + int loop_eagain, int loop_eintr, + int off_reset) { ssize_t r; int positional_rw; @@ -2050,9 +2070,19 @@ real_pread_pwrite: * Failure is the better option * here, since recovery would * mask hidden bugs in code. + * We cannot guarantee thread + * safety, except in the event + * that violations cause exit; + * you would then debug it. */ - if (off != verified) - goto err_prw; + if (off != verified) { + if (!off_reset) + goto err_prw; + + if (lseek_loop(fd, off, SEEK_SET, + loop_eagain, loop_eintr) == (off_t)-1) + return -1; + } do { if (rw_type == IO_PREAD) |