[PATCH v3] Allow using special files with File I/O functions
Pedro Alves
palves@redhat.com
Fri Jun 29 13:42:00 GMT 2018
On 06/28/2018 08:27 PM, Julio Guerra wrote:
> - Remove the restriction to regular files only and add support for special file
> types in the File IO stat structure.
> - Define a few more macro definitions of file types such as FIFOs, etc.
>
> The major goal is being able to write advanced embedded testing functions, like:
> - using a FIFO between the embedded program and the host, instead of being
> restricted only to the GDB console.
> - mocking features based on host's by opening some /dev special files.
>
This needs a GDB manual change, and a NEWS entry.
> 2018-06-28 Julio Guerra <julio@farjump.io>
>
> * remote-fileio.c (remote_fileio_func_open, remote_fileio_func_stat):
> Allow using File I/O functions open(), stat() and fstat() on special
> files.
> * ../include/gdb/fileio.h: Add macro definitions for special files,
> both for fst_dev and fst_mode fields of struct fst_stat.
> * common/fileio.c (fileio_to_host_mode, fileio_mode_pack): Add new
> special file types in fst_mode's definition.
> (host_to_fileio_stat): Define fst_dev using the new macro definitions
> and according to the file's type.
Note that include/ has its own ChangeLog file.
> 2018-06-27 Simon Marchi <simon.marchi@ericsson.com>
>
> * gdb-gdb.py.in (StructMainTypePrettyPrinter) <to_string>: Don't
> diff --git a/gdb/common/fileio.c b/gdb/common/fileio.c
> index 912a7ede3c..9ee78e227c 100644
> --- a/gdb/common/fileio.c
> +++ b/gdb/common/fileio.c
> @@ -119,12 +119,31 @@ fileio_to_host_mode (int fileio_mode, mode_t *mode_p)
> if (fileio_mode & ~FILEIO_S_SUPPORTED)
> return -1;
>
> - if (fileio_mode & FILEIO_S_IFREG)
> - mode |= S_IFREG;
> - if (fileio_mode & FILEIO_S_IFDIR)
> - mode |= S_IFDIR;
> - if (fileio_mode & FILEIO_S_IFCHR)
> - mode |= S_IFCHR;
> + switch (fileio_mode & FILEIO_S_IFMT)
> + {
> + case FILEIO_S_IFSOCK:
> + *mode_p |= S_IFSOCK;
> + break;
> + case FILEIO_S_IFLNK:
> + mode |= S_IFLNK;
> + break;
> + case FILEIO_S_IFREG:
> + mode |= S_IFREG;
> + break;
> + case FILEIO_S_IFBLK:
> + mode |= S_IFBLK;
> + break;
> + case FILEIO_S_IFDIR:
> + mode |= S_IFDIR;
> + break;
> + case FILEIO_S_IFCHR:
> + mode |= S_IFCHR;
> + break;
> + case FILEIO_S_IFIFO:
> + mode |= S_IFIFO;
> + break;
> + }
> +
> if (fileio_mode & FILEIO_S_IRUSR)
> mode |= S_IRUSR;
> if (fileio_mode & FILEIO_S_IWUSR)
> @@ -165,12 +184,31 @@ fileio_mode_pack (mode_t mode)
> {
> mode_t tmode = 0;
>
> - if (S_ISREG (mode))
> - tmode |= FILEIO_S_IFREG;
> - if (S_ISDIR (mode))
> - tmode |= FILEIO_S_IFDIR;
> - if (S_ISCHR (mode))
> - tmode |= FILEIO_S_IFCHR;
> + switch (mode & S_IFMT)
> + {
> + case S_IFSOCK:
> + tmode |= FILEIO_S_IFSOCK;
> + break;
> + case S_IFLNK:
> + tmode |= FILEIO_S_IFLNK;
> + break;
> + case S_IFREG:
> + tmode |= FILEIO_S_IFREG;
> + break;
> + case S_IFBLK:
> + tmode |= FILEIO_S_IFBLK;
> + break;
> + case S_IFDIR:
> + tmode |= FILEIO_S_IFDIR;
> + break;
> + case S_IFCHR:
> + tmode |= FILEIO_S_IFCHR;
> + break;
> + case S_IFIFO:
> + tmode |= FILEIO_S_IFIFO;
> + break;
> + }
I'm not sure whether all these S_FOO macros exist
on all hosts.
Looking at:
https://www.gnu.org/software/gnulib/manual/html_node/sys_002fstat_002eh.html
gnulib's sys/stat.h (gdb/gnulib/import/sys_stat.in.h) adds some
replacements, but then I'm not sure whether checking S_IFxxx
etc. directly instead of using the S_ISxxx function-style macros
is the right thing to do portability-wise. It may be S_ISxxx was being
used for a reason?
> +
> if (mode & S_IRUSR)
> tmode |= FILEIO_S_IRUSR;
> if (mode & S_IWUSR)
> @@ -224,8 +262,10 @@ void
> host_to_fileio_stat (struct stat *st, struct fio_stat *fst)
> {
> LONGEST blksize;
> + long fst_dev;
We don't align variable names like that.
>
> - host_to_fileio_uint ((long) st->st_dev, fst->fst_dev);
> + fst_dev = S_ISREG(st->st_mode) ? FILEIO_STDEV_FILE : FILEIO_STDEV_SPECIAL;
Missing space in "S_ISREG (".
> + host_to_fileio_uint (fst_dev, fst->fst_dev);
> host_to_fileio_uint ((long) st->st_ino, fst->fst_ino);
> host_to_fileio_mode (st->st_mode, fst->fst_mode);
> host_to_fileio_uint ((long) st->st_nlink, fst->fst_nlink);
> diff --git a/gdb/remote-fileio.c b/gdb/remote-fileio.c
> index 313da642ea..837081269a 100644
> --- a/gdb/remote-fileio.c
> +++ b/gdb/remote-fileio.c
> @@ -407,24 +407,6 @@ remote_fileio_func_open (remote_target *remote, char *buf)
> return;
> }
>
> - /* Check if pathname exists and is not a regular file or directory. If so,
> - return an appropriate error code. Same for trying to open directories
> - for writing. */
Did you intend to remove the "Same for trying to open directories
for writing." part?
Thanks,
Pedro Alves
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