From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: [PATCH 1/1] mmap.2: improve example Date: Thu, 2 Jun 2016 18:29:02 -0500 Message-ID: <06bc8862-f4b2-c024-3852-e1db3d2ae5fb@gmail.com> References: <1464890187-4141-1-git-send-email-rahulbedarkar89@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1464890187-4141-1-git-send-email-rahulbedarkar89-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Rahul Bedarkar Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-man@vger.kernel.org Hello Rahul, On 06/02/2016 12:56 PM, Rahul Bedarkar wrote: > free resources on error paths and at the end after use. > > Signed-off-by: Rahul Bedarkar > --- > man2/mmap.2 | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/man2/mmap.2 b/man2/mmap.2 > index 0f2f277..cede984 100644 > --- a/man2/mmap.2 > +++ b/man2/mmap.2 > @@ -765,8 +765,10 @@ main(int argc, char *argv[]) > if (fd == \-1) > handle_error("open"); > > - if (fstat(fd, &sb) == \-1) /* To obtain file size */ > + if (fstat(fd, &sb) == \-1) { /* To obtain file size */ > + close(fd); > handle_error("fstat"); > + } > > offset = atoi(argv[2]); > pa_offset = offset & ~(sysconf(_SC_PAGE_SIZE) \- 1); > @@ -774,6 +776,7 @@ main(int argc, char *argv[]) > > if (offset >= sb.st_size) { > fprintf(stderr, "offset is past end of file\\n"); > + close(fd); > exit(EXIT_FAILURE); > } > > @@ -789,18 +792,27 @@ main(int argc, char *argv[]) > > addr = mmap(NULL, length + offset \- pa_offset, PROT_READ, > MAP_PRIVATE, fd, pa_offset); > - if (addr == MAP_FAILED) > + if (addr == MAP_FAILED) { > + close(fd); > handle_error("mmap"); > + } > > s = write(STDOUT_FILENO, addr + offset \- pa_offset, length); > if (s != length) { > - if (s == \-1) > + if (s == \-1) { > + munmap(addr, length + offset \- pa_offset); > + close(fd); > handle_error("write"); > + } > > + munmap(addr, length + offset \- pa_offset); > + close(fd); > fprintf(stderr, "partial write"); > exit(EXIT_FAILURE); > } > > + munmap(addr, length + offset \- pa_offset); > + close(fd); > exit(EXIT_SUCCESS); > } > .fi Given that handle_error() calls exit(), and that triggers close() on all FDs and munmap() on all mappings, I'm not sure this patch improves things. Can you say some more on why you think it is needed? Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html