Author: jtl Date: Thu Jan 14 21:08:23 2016 New Revision: 294037 URL: https://svnweb.freebsd.org/changeset/base/294037
Log: Improvements to the MDXFileChunk() template function: - Remove unneeded fstat()/lseek() calls. - Return NULL and set errno to EINVAL on negative length. - Fix small style problems and expand variable names. After this change, it is possible to use this code for some irregular files. For example, 'md5 /dev/md0' should now succeed. Differential Revision: https://reviews.freebsd.org/D4748 Suggested by: bde Reviewed by: bde, allanjude, delphij Modified: head/lib/libmd/mdXhl.c Modified: head/lib/libmd/mdXhl.c ============================================================================== --- head/lib/libmd/mdXhl.c Thu Jan 14 20:51:48 2016 (r294036) +++ head/lib/libmd/mdXhl.c Thu Jan 14 21:08:23 2016 (r294037) @@ -1,4 +1,5 @@ -/* mdXhl.c * ---------------------------------------------------------------------------- +/* mdXhl.c + * ---------------------------------------------------------------------------- * "THE BEER-WARE LICENSE" (Revision 42): * <[email protected]> wrote this file. As long as you retain this notice you * can do whatever you want with this stuff. If we meet some day, and you think @@ -52,43 +53,44 @@ MDXFileChunk(const char *filename, char unsigned char buffer[16*1024]; MDX_CTX ctx; struct stat stbuf; - int f, i, e; - off_t n; + int fd, readrv, e; + off_t remain; - MDXInit(&ctx); - f = open(filename, O_RDONLY); - if (f < 0) - return 0; - if (fstat(f, &stbuf) < 0) { - i = -1; - goto error; + if (len < 0) { + errno = EINVAL; + return NULL; } - if (ofs > stbuf.st_size) - ofs = stbuf.st_size; - if ((len == 0) || (len > stbuf.st_size - ofs)) - len = stbuf.st_size - ofs; - if (lseek(f, ofs, SEEK_SET) < 0) { - i = -1; - goto error; + + MDXInit(&ctx); + fd = open(filename, O_RDONLY); + if (fd < 0) + return NULL; + if (ofs != 0) { + errno = 0; + if (lseek(fd, ofs, SEEK_SET) != ofs || + (ofs == -1 && errno != 0)) { + readrv = -1; + goto error; + } } - n = len; - i = 0; - while (n > 0) { - if (n > sizeof(buffer)) - i = read(f, buffer, sizeof(buffer)); + remain = len; + readrv = 0; + while (len == 0 || remain > 0) { + if (len == 0 || remain > sizeof(buffer)) + readrv = read(fd, buffer, sizeof(buffer)); else - i = read(f, buffer, n); - if (i <= 0) + readrv = read(fd, buffer, remain); + if (readrv <= 0) break; - MDXUpdate(&ctx, buffer, i); - n -= i; + MDXUpdate(&ctx, buffer, readrv); + remain -= readrv; } error: e = errno; - close(f); + close(fd); errno = e; - if (i < 0) - return 0; + if (readrv < 0) + return NULL; return (MDXEnd(&ctx, buf)); } _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
