Sorry for noob's question: what is "phabricator"? Sure, I will do it as soon as I understand what you want me to do :)
Sent from Outlook<http://aka.ms/weboutlook> ________________________________ From: Zachary Turner <ztur...@google.com> Sent: Monday, October 17, 2016 5:01 PM To: Eugene Birukov; Greg Clayton Cc: LLDB Subject: Re: [lldb-dev] File::Read does not read everything Can you upload a diff (with context) to phabricator and add lldb-commits as a subscriber and myself / Greg as reviewers? On Mon, Oct 17, 2016 at 4:59 PM Eugene Birukov via lldb-dev <lldb-dev@lists.llvm.org<mailto:lldb-dev@lists.llvm.org>> wrote: Here is what I am running now: diff --git a/source/Host/common/File.cpp b/source/Host/common/File.cpp index 89587a9..a4ac25e 100644 --- a/source/Host/common/File.cpp +++ b/source/Host/common/File.cpp @@ -771,21 +771,34 @@ File::Read (void *buf, size_t &num_bytes, off_t &offset) int fd = GetDescriptor(); if (fd != kInvalidDescriptor) { - ssize_t bytes_read = -1; - do + size_t bytes_left = num_bytes; + num_bytes = 0; + char *pos = (char*)buf; + while (bytes_left > 0) { - bytes_read = ::pread (fd, buf, num_bytes, offset); - } while (bytes_read < 0 && errno == EINTR); + ssize_t bytes_read = -1; + do + { + bytes_read = ::pread (fd, pos, bytes_left, offset); + } while (bytes_read < 0 && errno == EINTR); - if (bytes_read < 0) - { - num_bytes = 0; - error.SetErrorToErrno(); - } - else - { - offset += bytes_read; - num_bytes = bytes_read; + if (bytes_read < 0) + { + num_bytes = 0; + error.SetErrorToErrno(); + break; + } + else if (bytes_read == 0) + { + break; + } + else + { + offset += bytes_read; + num_bytes += bytes_read; + bytes_left -= bytes_read; + pos += bytes_read; + } } } else Sent from Outlook<http://aka.ms/weboutlook> ________________________________ From: Greg Clayton <gclay...@apple.com<mailto:gclay...@apple.com>> Sent: Monday, October 17, 2016 12:39 PM To: Eugene Birukov Cc: LLDB Subject: Re: [lldb-dev] File::Read does not read everything It is probably best to make the code loop as long as "bytes_reads > 0" and we haven't read "num_bytes" yet. The darwin kernel has a INT32_MAX read size which gets set to MAX_READ_SIZE, but we need to do that because if you try to read more than that it reads nothing. So MAX_READ_SIZE is more for the case where the read will outright fail if given a byte size that is too large. Feel free to submit a patch that can keep calling pread correctly in a loop as long as bytes_read > 0. Greg > On Oct 17, 2016, at 12:20 PM, Eugene Birukov via lldb-dev > <lldb-dev@lists.llvm.org<mailto:lldb-dev@lists.llvm.org>> wrote: > > Hello, > > I am using LLDB 3.9 on Linux Ubuntu. I am loading a 5GiB core which is > located on Windows file share mounted on Linux via mount.cifs. I see that we > successfully allocated memory and are trying to fill it in one read. > Unfortunately pread returns 2GiB and we never check for short read here. > > I think we could combine this code with previous block "#if defined > (MAX_READ_SIZE)" if we simply check for short read here (bytes_read too > small) and loop until all the buffer is filled. > > Thanks, > Eugene > > #ifndef _WIN32 > int fd = GetDescriptor(); > if (fd != kInvalidDescriptor) > { > ssize_t bytes_read = -1; > do > { > bytes_read = ::pread (fd, buf, num_bytes, offset); > } while (bytes_read < 0 && errno == EINTR); > > if (bytes_read < 0) > { > num_bytes = 0; > error.SetErrorToErrno(); > } > else > { > offset += bytes_read; > num_bytes = bytes_read; > } > } > > Sent from Outlook > _______________________________________________ > lldb-dev mailing list > lldb-dev@lists.llvm.org<mailto:lldb-dev@lists.llvm.org> > http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev _______________________________________________ lldb-dev mailing list lldb-dev@lists.llvm.org<mailto:lldb-dev@lists.llvm.org> http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
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