Re: [Libguestfs] [PATCH] New API: part_get_part_type for showing partition type

-----Original Message----- From: Richard W.M. Jones [mailto:rjones@redhat.com] Sent: Monday, March 23, 2015 9:29 PM To: Chen, Hanxiao/陈 晗霄 Cc: libguestfs(a)redhat.com Subject: Re: [Libguestfs] [PATCH] New API: part_get_part_type for showing partition type On Tue, Mar 17, 2015 at 02:45:46AM -0400, Chen Hanxiao wrote: > This patch will add support for getting partition type > of a partiton numbered device. > > Signed-off-by: Chen Hanxiao <chenhanxiao(a)cn.fujitsu.com&gt; > --- > daemon/parted.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++ > generator/actions.ml | 18 +++++++++ > src/MAX_PROC_NR | 2 +- > 3 files changed, 131 insertions(+), 1 deletion(-) > > diff --git a/daemon/parted.c b/daemon/parted.c > index a7bcb99..0ae6e5c 100644 > --- a/daemon/parted.c > +++ b/daemon/parted.c > @@ -33,6 +33,10 @@ GUESTFSD_EXT_CMD(str_parted, parted); > GUESTFSD_EXT_CMD(str_sfdisk, sfdisk); > GUESTFSD_EXT_CMD(str_sgdisk, sgdisk); > > +#ifndef PARTED_NO_M > +# define PARTED_NO_M 0 > +#endif What does this bit do?

> /* Notes: > * > * Parted 1.9 sends error messages to stdout, hence use of the > @@ -1022,3 +1026,111 @@ do_part_get_name (const char *device, int partnum) > reply_with_error ("cannot get the partition name from '%s' layouts", parttype); > return NULL; > } > + > +char * > +do_part_get_part_type (const char *device, int partnum) > +{ > + CLEANUP_FREE char *parttype; > + char *part_type; > + > + if (partnum <= 0) { > + reply_with_error ("partition number must be >= 1"); > + return NULL; > + } > + > + parttype = do_part_get_parttype (device); > + if (parttype == NULL) > + return NULL; > + > + if (STREQ (parttype, "gpt")) { > + part_type = strdup("primary"); > + if (part_type == NULL) { > + reply_with_error ("strdup failed"); > + return NULL; > + } > + return part_type; > + } > + > + /* machine parseable output by 'parted -m' did not provide > + * partition type info. > + * Use traditional style. > + */ > + CLEANUP_FREE char *out = print_partition_table (device, PARTED_NO_M); > + if (!out) > + return NULL; > + > + CLEANUP_FREE_STRING_LIST char **lines = split_lines (out); > + > + if (!lines) > + return NULL; > + > + size_t start = 0, end = 0, row; > + > + for (row = 0; lines[row] != NULL; ++row) > + if (STRPREFIX (lines[row], "Number")) { > + start = row + 1; > + break; > + } > + > + if (start == 0) { > + reply_with_error ("parted output has no \"Number\" line"); > + return NULL; > + } > + > + for (row = start; lines[row] != NULL; ++row) > + if (STREQ (lines[row], "")) { > + end = row; > + break; > + } > + > + if (end == 0) { > + reply_with_error ("parted output has no blank after end of table"); > + return NULL; > + } > + > + /* Now parse the lines. */ > + size_t i; > + int64_t temp_int64; > + int part_num; > + char temp_type[16]; > + for (i = 0, row = start; row < end; ++i, ++row) { > + if (sscanf (lines[row], "%d%" SCNi64 "B%" SCNi64 "B%" SCNi64 "B" "%s", > + &part_num, > + &temp_int64, > + &temp_int64, > + &temp_int64, > + temp_type) != 5) { We're hoping here that the output of 'parted' never changes and overflows the 16 byte buffer. Instead of hoping, you can guarantee that by replacing %s with %15s

> + reply_with_error ("could not parse row from output of parted print command: %s", lines[row]); > + return NULL; > + } > + > + if (part_num != partnum) > + continue; > + > + if (STRPREFIX (temp_type, "primary")) { > + part_type = strdup("primary"); > + if (part_type == NULL) > + goto error; > + } else if (STRPREFIX (temp_type, "logical")) { > + part_type = strdup("logical"); > + if (part_type == NULL) > + goto error; > + } else if (STRPREFIX (temp_type, "extended")) { > + part_type = strdup("extended"); > + if (part_type == NULL) > + goto error; > + } else > + goto error; > + > + return part_type; > + } > + > + if (row == end) { > + reply_with_error ("could not find partnum: %d", partnum); > + return NULL; > + } > + > + error: > + reply_with_error ("strdup failed"); > + return NULL; > +} > diff --git a/generator/actions.ml b/generator/actions.ml > index fb971d3..72418b0 100644 > --- a/generator/actions.ml > +++ b/generator/actions.ml > @@ -12522,6 +12522,24 @@ This will Enable extended inode refs." }; > longdesc = "\ > This enable skinny metadata extent refs." }; > > + { defaults with > + name = "part_get_part_type"; > + style = RString "partitiontype", [Device "device"; Int "partnum"], []; > + proc_nr = Some 453; > + tests = [ > + InitEmpty, Always, TestResultString ( > + [["part_init"; "/dev/sda"; "mbr"]; > + ["part_add"; "/dev/sda"; "p"; "64"; "204799"]; > + ["part_add"; "/dev/sda"; "e"; "204800"; "614400"]; > + ["part_add"; "/dev/sda"; "l"; "204864"; "205988"]; > + ["part_get_part_type"; "/dev/sda"; "5"]], "logical"), [] > + ]; > + > + shortdesc = "get the partition type"; > + longdesc = "\ > +This could get the partition type, such as primary, logical, > +on partition numbered C<partnum> on device C<device>." }; > + > ] > > (* Non-API meta-commands available only in guestfish. > diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR > index 8670c73..534b992 100644 > --- a/src/MAX_PROC_NR > +++ b/src/MAX_PROC_NR > @@ -1 +1 @@ > -452 > +453 Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top