* Re: Report man-pages-6.01 bug
[not found] <tencent_A7B85DF7875B85CB9A7DDFB793F193852F07@qq.com>
@ 2022-11-03 15:13 ` Alejandro Colomar
[not found] ` <tencent_F782FBCDADC9E5CD7ED5DBC738CD4223DC06@qq.com>
0 siblings, 1 reply; 2+ messages in thread
From: Alejandro Colomar @ 2022-11-03 15:13 UTC (permalink / raw
To: 1092615079; +Cc: linux-man
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Hello,
On 11/3/22 09:01, 1092615079 wrote:
> Dear Devloper,
> In the EXAMPLES of shm_open in man-pages-6.01 section 3, i think the usage
> of variable shmp in the code of pshm_ucase_bounce.c maybe has a clerical error
> with a redundant action about address accessing , please see:
I don't have much experience using mmap(2). Could you please detail why you
think this is incorrect, and hopefully propose a patch?
You may want to read this for preparing a patch:
<https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING>
Thanks,
Alex
>
> /* pshm_ucase_bounce.c
>
> Licensed under GNU General Public License v2 or later.
> */
> #include <ctype.h>
>
> #include "pshm_ucase.h"
>
> int
> main(int argc, char *argv[])
> {
> int fd;
> char *shmpath;
> struct shmbuf *shmp;
>
> if (argc != 2) {
> fprintf(stderr, "Usage: %s /shm\-path\en", argv[0]);
> exit(EXIT_FAILURE);
> }
>
> shmpath = argv[1];
>
> /* Create shared memory object and set its size to the size
> of our structure. */
>
> fd = shm_open(shmpath, O_CREAT | O_EXCL | O_RDWR, 0600);
> if (fd == \-1)
> errExit("shm_open");
>
> if (ftruncate(fd, sizeof(struct shmbuf)) == \-1)
> errExit("ftruncate");
>
> /* Map the object into the caller\(aqs address space. */
>
> *shmp = mmap(NULL, sizeof(*shmp), PROT_READ | PROT_WRITE,
> MAP_SHARED, fd, 0);
> if (shmp == MAP_FAILED)
> errExit("mmap");
>
>
> thanks for your contribution again.
--
<http://www.alejandro-colomar.es/>
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Reply： Report man-pages-6.01 bug
[not found] ` <tencent_F782FBCDADC9E5CD7ED5DBC738CD4223DC06@qq.com>
@ 2022-12-11 17:26 ` Alejandro Colomar
0 siblings, 0 replies; 2+ messages in thread
From: Alejandro Colomar @ 2022-12-11 17:26 UTC (permalink / raw
To: 1092615079; +Cc: linux-man
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Hi!
On 11/3/22 19:33, 1092615079 wrote:
> Dear Devloper,
> Thanks for your reply, and i am very sorry because i am not good at making
> patch, so i try to show the point for you.
> The part of code which i think may be incorrect in EXAMPLE is like follow:
> --begin--
>
> struct shmbuf *shmp;
> *shmp = mmap(NULL, sizeof(*shmp), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
>
> --end--
>
> I think the problem is that the pointer variable <shmp> is directly used
> to access memory without init, and i think the original intention of the code is
> like this:
>
> --begin--
>
> struct shmbuf *shmp;
> shmp = mmap(NULL, sizeof(*shmp), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
>
> --end--
> I think shmp maybe just be used to get the return value of mmap();
> PS: The page file is shm_open.3 and hope this can do something useful for you.
>
> Thanks for your contribution again!
Thank you for the report and the explanation. I fixed the bug. It seems it was
probably a typo.
<https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/>
Cheers,
Alex
>
>
> ------------------ 原始邮件 ------------------
> *发件人:* "Alejandro Colomar" <alx.manpages@gmail.com>;
> *发送时间:* 2022年11月3日(星期四) 晚上11:13
> *收件人:* " "<1092615079@qq.com>;
> *抄送:* "linux-man"<linux-man@vger.kernel.org>;
> *主题:* Re: Report man-pages-6.01 bug
>
> Hello,
>
> On 11/3/22 09:01, 1092615079 wrote:
> > Dear Devloper,
> > In the EXAMPLES of shm_open in man-pages-6.01 section 3, i think the usage
> > of variable shmp in the code of pshm_ucase_bounce.c maybe has a clerical error
> > with a redundant action about address accessing , please see:
>
> I don't have much experience using mmap(2). Could you please detail why you
> think this is incorrect, and hopefully propose a patch?
>
> You may want to read this for preparing a patch:
> <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING>
>
> Thanks,
> Alex
>
> >
> > /* pshm_ucase_bounce.c
> >
> > Licensed under GNU General Public License v2 or later.
> > */
> > #include <ctype.h>
> >
> > #include "pshm_ucase.h"
> >
> > int
> > main(int argc, char *argv[])
> > {
> > int fd;
> > char *shmpath;
> > struct shmbuf *shmp;
> >
> > if (argc != 2) {
> > fprintf(stderr, "Usage: %s /shm\-path\en", argv[0]);
> > exit(EXIT_FAILURE);
> > }
> >
> > shmpath = argv[1];
> >
> > /* Create shared memory object and set its size to the size
> > of our structure. */
> >
> > fd = shm_open(shmpath, O_CREAT | O_EXCL | O_RDWR, 0600);
> > if (fd == \-1)
> > errExit("shm_open");
> >
> > if (ftruncate(fd, sizeof(struct shmbuf)) == \-1)
> > errExit("ftruncate");
> >
> > /* Map the object into the caller\(aqs address space. */
> >
> > *shmp = mmap(NULL, sizeof(*shmp), PROT_READ | PROT_WRITE,
> > MAP_SHARED, fd, 0);
> > if (shmp == MAP_FAILED)
> > errExit("mmap");
> >
> >
> > thanks for your contribution again.
>
> --
> <http://www.alejandro-colomar.es/>
--
<http://www.alejandro-colomar.es/>
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[not found] <tencent_A7B85DF7875B85CB9A7DDFB793F193852F07@qq.com>
2022-11-03 15:13 ` Report man-pages-6.01 bug Alejandro Colomar
[not found] ` <tencent_F782FBCDADC9E5CD7ED5DBC738CD4223DC06@qq.com>
2022-12-11 17:26 ` Reply： " Alejandro Colomar
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