diff options
| -rw-r--r-- | lib/lib.c | 34 |
1 files changed, 25 insertions, 9 deletions
@@ -447,22 +447,38 @@ off_t fdlength(int fd) // note: for existing buffers use len = size-1, will set buf[len] = 0 char *readfileat(int dirfd, char *name, char *ibuf, off_t *plen) { - off_t len = *plen-!!ibuf; + off_t len, rlen; int fd; - char *buf; + char *buf, *rbuf; + + // Unsafe to probe for size with a supplied buffer, don't ever do that. + if (CFG_TOYBOX_DEBUG && (ibuf ? !*plen : *plen)) error_exit("bad readfileat"); if (-1 == (fd = openat(dirfd, name, O_RDONLY))) return 0; - if (!len) { - len = fdlength(fd); - // proc files don't report a length, so try 1 page minimum. - if (len<4096) len = 4096; - } + + // If we dunno the length, probe it. If we can't probe, start with 1 page. + if (!*plen) { + if ((len = fdlength(fd))>0) *plen = len; + else len = 4096; + } else len = *plen-1; + if (!ibuf) buf = xmalloc(len+1); else buf = ibuf; - *plen = len = readall(fd, buf, len); + for (rbuf = buf;;) { + rlen = readall(fd, rbuf, len); + if (*plen || rlen<len) break; + + // If reading unknown size, expand buffer by 1.5 each time we fill it up. + rlen += rbuf-buf; + buf = xrealloc(buf, len = (rlen*3)/2); + rbuf = buf+rlen; + len -= rlen; + } + *plen = len = rlen+(buf-ibuf); close(fd); - if (len<0) { + + if (rlen<0) { if (ibuf != buf) free(buf); buf = 0; } else buf[len] = 0; |