libreboot-utils/file: never retry file rw on zero

even with a timer, it's possible that on a buggy system,
we may keep writing even though the outcome is zero. if
a system comes back with zero bytes written, that is a
fatal bug and we should stop.

Signed-off-by: Leah Rowe <leah@libreboot.org>
This commit is contained in:
Leah Rowe
2026-04-01 16:11:50 +01:00
parent 5b465d3af6
commit f68cedf202
4 changed files with 8 additions and 23 deletions
+1 -5
View File
@@ -83,10 +83,6 @@
#error "Unexpected bit layout" #error "Unexpected bit layout"
#endif #endif
#ifndef MAX_ZERO_RW_RETRY
#define MAX_ZERO_RW_RETRY 5
#endif
#ifndef _FILE_OFFSET_BITS #ifndef _FILE_OFFSET_BITS
#define _FILE_OFFSET_BITS 64 #define _FILE_OFFSET_BITS 64
#endif #endif
@@ -462,7 +458,7 @@ ssize_t rw_gbe_file_exact(int fd, unsigned char *mem, size_t nrw,
int fsync_dir(const char *path); int fsync_dir(const char *path);
ssize_t rw_file_exact(int fd, unsigned char *mem, size_t len, ssize_t rw_file_exact(int fd, unsigned char *mem, size_t len,
off_t off, int rw_type, size_t max_retries); off_t off, int rw_type);
ssize_t rw(int fd, void *mem, size_t nrw, ssize_t rw(int fd, void *mem, size_t nrw,
off_t off, int rw_type); off_t off, int rw_type);
int io_args(int fd, void *mem, size_t nrw, int io_args(int fd, void *mem, size_t nrw,
+1 -1
View File
@@ -493,7 +493,7 @@ cat_buf(unsigned char *b)
exitf("null pointer in cat command"); exitf("null pointer in cat command");
if (rw_file_exact(STDOUT_FILENO, b, if (rw_file_exact(STDOUT_FILENO, b,
GBE_PART_SIZE, 0, IO_WRITE, MAX_ZERO_RW_RETRY) < 0) GBE_PART_SIZE, 0, IO_WRITE) < 0)
exitf("stdout: cat"); exitf("stdout: cat");
} }
void void
+2 -12
View File
@@ -146,7 +146,7 @@ err_fsync_dir:
ssize_t ssize_t
rw_file_exact(int fd, unsigned char *mem, size_t nrw, rw_file_exact(int fd, unsigned char *mem, size_t nrw,
off_t off, int rw_type, size_t max_retries) off_t off, int rw_type)
{ {
int saved_errno = errno; int saved_errno = errno;
ssize_t rval = 0; ssize_t rval = 0;
@@ -154,7 +154,6 @@ rw_file_exact(int fd, unsigned char *mem, size_t nrw,
size_t nrw_cur; size_t nrw_cur;
off_t off_cur; off_t off_cur;
void *mem_cur; void *mem_cur;
size_t retries_on_zero = 0;
errno = 0; errno = 0;
if (io_args(fd, mem, nrw, off, rw_type) == -1) if (io_args(fd, mem, nrw, off, rw_type) == -1)
@@ -178,17 +177,8 @@ rw_file_exact(int fd, unsigned char *mem, size_t nrw,
off_cur = off + (off_t)rc; off_cur = off + (off_t)rc;
if ((rval = rw(fd, mem_cur, nrw_cur, off_cur, rw_type)) < 0) if ((rval = rw(fd, mem_cur, nrw_cur, off_cur, rw_type)) <= 0)
goto err_rw_file_exact; goto err_rw_file_exact;
if (rval == 0) {
if (retries_on_zero++ < max_retries)
continue;
goto err_rw_file_exact;
}
retries_on_zero = 0;
} }
if (if_err((size_t)rc != nrw, EIO) || if (if_err((size_t)rc != nrw, EIO) ||
+4 -5
View File
@@ -109,7 +109,7 @@ read_file(void)
/* read main file /* read main file
*/ */
_r = rw_file_exact(f->gbe_fd, f->buf, f->gbe_file_size, _r = rw_file_exact(f->gbe_fd, f->buf, f->gbe_file_size,
0, IO_PREAD, MAX_ZERO_RW_RETRY); 0, IO_PREAD);
if (_r < 0) if (_r < 0)
exitf("%s: read failed", f->fname); exitf("%s: read failed", f->fname);
@@ -117,7 +117,7 @@ read_file(void)
/* copy to tmpfile /* copy to tmpfile
*/ */
_r = rw_file_exact(f->tmp_fd, f->buf, f->gbe_file_size, _r = rw_file_exact(f->tmp_fd, f->buf, f->gbe_file_size,
0, IO_PWRITE, MAX_ZERO_RW_RETRY); 0, IO_PWRITE);
if (_r < 0) if (_r < 0)
exitf("%s: %s: copy failed", exitf("%s: %s: copy failed",
@@ -140,7 +140,7 @@ read_file(void)
exitf("%s: fsync (tmpfile copy)", f->tname); exitf("%s: fsync (tmpfile copy)", f->tname);
_r = rw_file_exact(f->tmp_fd, f->bufcmp, f->gbe_file_size, _r = rw_file_exact(f->tmp_fd, f->bufcmp, f->gbe_file_size,
0, IO_PREAD, MAX_ZERO_RW_RETRY); 0, IO_PREAD);
if (_r < 0) if (_r < 0)
exitf("%s: read failed (cmp)", f->tname); exitf("%s: read failed (cmp)", f->tname);
@@ -556,8 +556,7 @@ rw_gbe_file_exact(int fd, unsigned char *mem, size_t nrw,
if (nrw > (size_t)GBE_PART_SIZE) if (nrw > (size_t)GBE_PART_SIZE)
goto err_rw_gbe_file_exact; goto err_rw_gbe_file_exact;
r = rw_file_exact(fd, mem, nrw, off, rw_type, r = rw_file_exact(fd, mem, nrw, off, rw_type);
MAX_ZERO_RW_RETRY);
return rw_over_nrw(r, nrw); return rw_over_nrw(r, nrw);