| Message ID | 20180925153949.1577-1-programmingkidx@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] qemu-img.c: add help for each command | expand |
Hi, John. On Tue, Sep 25, 2018 at 11:39:49AM -0400, John Arbuckle wrote: > Add the ability for the user to display help for a certain command. > Example: qemu-img create --help > > What is printed is all the options available to this command and an example. > > Signed-off-by: John Arbuckle <programmingkidx@gmail.com> Segfault is gone with this patch. Acked-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> > --- > v3 changes: > Fixed a bug that caused qemu-img to crash when running a command without > options. > > v2 changes: > Removed block of string comparison code for each command. > Added a help_func field to the img_cmd_t struct. > Made strings longer than 80 characters wide. > > qemu-img.c | 660 +++++++++++++++++++++++++++++++++++++++++++++++++++---------- > 1 file changed, 559 insertions(+), 101 deletions(-) > > diff --git a/qemu-img.c b/qemu-img.c > index 1acddf693c..e4d9baa550 100644 > --- a/qemu-img.c > +++ b/qemu-img.c > @@ -52,6 +52,7 @@ > typedef struct img_cmd_t { > const char *name; > int (*handler)(int argc, char **argv); > + void (*help_func)(void); > } img_cmd_t; > > enum { > @@ -76,11 +77,6 @@ typedef enum OutputFormat { > /* Default to cache=writeback as data integrity is not important for qemu-img */ > #define BDRV_DEFAULT_CACHE "writeback" > > -static void format_print(void *opaque, const char *name) > -{ > - printf(" %s", name); > -} > - > static void QEMU_NORETURN GCC_FMT_ATTR(1, 2) error_exit(const char *fmt, ...) > { > va_list ap; > @@ -105,102 +101,546 @@ static void QEMU_NORETURN unrecognized_option(const char *option) > error_exit("unrecognized option '%s'", option); > } > > -/* Please keep in synch with qemu-img.texi */ > -static void QEMU_NORETURN help(void) > +/* Prints an overview of available help options */ > +static void help(void) > { > const char *help_msg = > - QEMU_IMG_VERSION > - "usage: qemu-img [standard options] command [command options]\n" > - "QEMU disk image utility\n" > - "\n" > - " '-h', '--help' display this help and exit\n" > - " '-V', '--version' output version information and exit\n" > - " '-T', '--trace' [[enable=]<pattern>][,events=<file>][,file=<file>]\n" > - " specify tracing options\n" > - "\n" > - "Command syntax:\n" > -#define DEF(option, callback, arg_string) \ > - " " arg_string "\n" > -#include "qemu-img-cmds.h" > -#undef DEF > - "\n" > - "Command parameters:\n" > - " 'filename' is a disk image filename\n" > - " 'objectdef' is a QEMU user creatable object definition. See the qemu(1)\n" > - " manual page for a description of the object properties. The most common\n" > - " object type is a 'secret', which is used to supply passwords and/or\n" > - " encryption keys.\n" > - " 'fmt' is the disk image format. It is guessed automatically in most cases\n" > - " 'cache' is the cache mode used to write the output disk image, the valid\n" > - " options are: 'none', 'writeback' (default, except for convert), 'writethrough',\n" > - " 'directsync' and 'unsafe' (default for convert)\n" > - " 'src_cache' is the cache mode used to read input disk images, the valid\n" > - " options are the same as for the 'cache' option\n" > - " 'size' is the disk image size in bytes. Optional suffixes\n" > - " 'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M),\n" > - " 'T' (terabyte, 1024G), 'P' (petabyte, 1024T) and 'E' (exabyte, 1024P) are\n" > - " supported. 'b' is ignored.\n" > - " 'output_filename' is the destination disk image filename\n" > - " 'output_fmt' is the destination format\n" > - " 'options' is a comma separated list of format specific options in a\n" > - " name=value format. Use -o ? for an overview of the options supported by the\n" > - " used format\n" > - " 'snapshot_param' is param used for internal snapshot, format\n" > - " is 'snapshot.id=[ID],snapshot.name=[NAME]', or\n" > - " '[ID_OR_NAME]'\n" > - " '-c' indicates that target image must be compressed (qcow format only)\n" > - " '-u' allows unsafe backing chains. For rebasing, it is assumed that old and\n" > - " new backing file match exactly. The image doesn't need a working\n" > - " backing file before rebasing in this case (useful for renaming the\n" > - " backing file). For image creation, allow creating without attempting\n" > - " to open the backing file.\n" > - " '-h' with or without a command shows this help and lists the supported formats\n" > - " '-p' show progress of command (only certain commands)\n" > - " '-q' use Quiet mode - do not print any output (except errors)\n" > - " '-S' indicates the consecutive number of bytes (defaults to 4k) that must\n" > - " contain only zeros for qemu-img to create a sparse image during\n" > - " conversion. If the number of bytes is 0, the source will not be scanned for\n" > - " unallocated or zero sectors, and the destination image will always be\n" > - " fully allocated\n" > - " '--output' takes the format in which the output must be done (human or json)\n" > - " '-n' skips the target volume creation (useful if the volume is created\n" > - " prior to running qemu-img)\n" > - "\n" > - "Parameters to check subcommand:\n" > - " '-r' tries to repair any inconsistencies that are found during the check.\n" > - " '-r leaks' repairs only cluster leaks, whereas '-r all' fixes all\n" > - " kinds of errors, with a higher risk of choosing the wrong fix or\n" > - " hiding corruption that has already occurred.\n" > - "\n" > - "Parameters to convert subcommand:\n" > - " '-m' specifies how many coroutines work in parallel during the convert\n" > - " process (defaults to 8)\n" > - " '-W' allow to write to the target out of order rather than sequential\n" > - "\n" > - "Parameters to snapshot subcommand:\n" > - " 'snapshot' is the name of the snapshot to create, apply or delete\n" > - " '-a' applies a snapshot (revert disk to saved state)\n" > - " '-c' creates a snapshot\n" > - " '-d' deletes a snapshot\n" > - " '-l' lists all snapshots in the given image\n" > - "\n" > - "Parameters to compare subcommand:\n" > - " '-f' first image format\n" > - " '-F' second image format\n" > - " '-s' run in Strict mode - fail on different image size or sector allocation\n" > - "\n" > - "Parameters to dd subcommand:\n" > - " 'bs=BYTES' read and write up to BYTES bytes at a time " > - "(default: 512)\n" > - " 'count=N' copy only N input blocks\n" > - " 'if=FILE' read from FILE\n" > - " 'of=FILE' write to FILE\n" > - " 'skip=N' skip N bs-sized blocks at the start of input\n"; > - > - printf("%s\nSupported formats:", help_msg); > - bdrv_iterate_format(format_print, NULL); > - printf("\n\n" QEMU_HELP_BOTTOM "\n"); > - exit(EXIT_SUCCESS); > + QEMU_IMG_VERSION > + "usage: qemu-img [standard options] command [command options]\n" > + "QEMU disk image utility\n" > + "\n" > + " '-h', '--help' display this help and exit\n" > + " '-V', '--version' output version information and exit\n" > + " '-T', '--trace' [[enable=]<pattern>][,events=<file>][,file=<file>]\n" > + " specify tracing options\n" > + "\n" > + "Command:\n" > + "\tamend Change options of an existing disk image\n" > + "\tbench Run benchmarks on a given disk image\n" > + "\tcheck Check the disk image for consistency or repair it\n" > + "\tcommit Merge the disk image into its backing file\n" > + "\tcompare Check if two images have the same content\n" > + "\tconvert Convert an image file or snapshot into another file\n" > + "\tcreate Create a new disk image\n" > + "\tdd Copies and converts an input file into another file\n" > + "\tinfo Gives information about the specified image file\n" > + "\tmap Dump the metadata of image filename\n" > + "\tmeasure Calculate the file size required for a new image\n" > + "\tsnapshot List, apply, create or delete snapshots in a file\n" > + "\trebase Changes the backing file of an image file\n" > + "\tresize Resize an image file\n" > + "\n\nRun 'qemu-img <command> --help' for details.\n" > + "See <https://qemu.org/contribute/report-a-bug> for how to report bugs.\n" > + "More information on the QEMU project at <https://qemu.org>.\n"; > + printf("%s\n", help_msg); > +} > + > +static void help_amend(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img amend [--object objectdef] [--image-opts] [-p] [-q] [-f fmt]\n" > + "[-t cache] -o options filename\n" > + "\n" > + "Command parameters:\n" > + " -f The format of the image file.\n" > + "\n" > + "--image-opts Treat filename as a set of image options, instead of a plain\n" > + " filename.\n" > + "\n" > + " -o Used with a comma separated list of format specific options in a\n" > + " name=value format. Use \"-o help\" for an overview of the options\n" > + " supported by the used format.\n" > + "\n" > + "--object \'objectdef\' is a QEMU user creatable object definition. See the\n" > + " qemu(1) manual page for a description of the object properties.\n" > + " The most common object type is a \'secret\', which is used to\n" > + " supply passwords and/or encryption keys.\n" > + "\n" > + " -p Display progress bar. If the -p option is not used for a command\n" > + " that supports it, the progress is reported when the process\n" > + " receives a \"SIGUSR1\" signal. Avoid using with the -q option.\n" > + "\n" > + " -q Quiet mode - do not print any output (except errors). Avoid\n" > + " using with the -p option.\n" > + "\n" > + " -t Specifies the cache mode that should be used with the\n" > + " destination file. Options are: none, writeback, writethrough,\n" > + " directsync, and unsafe.\n" > + "\n" > + "Example:\n" > + " qemu-img amend -o compat=v3 -f qcow2 image.qcow2\n" > + " qemu-img amend --object secret,id=sec0,data=test --image-opts \\\n" > + " driver=luks,key-secret=sec0,file.filename=test.luks -o size=2G\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_bench(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img bench [-c count] [-d depth] [-f fmt]\n" > + "[--flush-interval=flush_interval] [-n] [--no-drain] [-o offset]\n" > + "[--pattern=pattern] [-q] [-s buffer_size] [-S step_size] [-t cache] [-w] [-U]\n" > + "filename\n" > + "\n" > + "Command parameters:\n" > + " -c Number of I/O requests to perform.\n" > + "\n" > + " -d Number of I/O requests done in parallel.\n" > + "\n" > + " -f The format of the image file.\n" > + "\n" > + " --flush-interval How often a flush should take place.\n" > + "\n" > + " -n Use native AIO backend if possible.\n" > + "\n" > + " --no-drain Issue a flush without draining the request queue first.\n" > + "\n" > + " -o The starting position.\n" > + "\n" > + " --pattern The byte pattern used to in write tests.\n" > + "\n" > + " -q Quiet mode - do not print any output (except errors).\n" > + " There\'s no progress bar in case both -q and -p options are\n" > + " used.\n" > + "\n" > + " -s buffer_size in bytes.\n" > + "\n" > + " -S Increases current position by step_size.\n" > + "\n" > + " -t Specifies the cache mode that should be used with the\n" > + " destination file. Options are: none, writeback,\n" > + " writethrough, directsync, and unsafe.\n" > + "\n" > + " -w Perform write test.\n" > + "\n" > + " -U Open the image in shared mode, allowing other QEMU\n" > + " processes to open it in write mode. This option is only\n" > + " allowed when opening images in read-only mode.\n" > + "\n" > + "Example:\n" > + " qemu-img bench -c 20000 -d 50000 -f qcow2 image.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_check(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img check [--object objectdef] [--image-opts] [-q] [-f fmt]\n" > + "[--output=ofmt] [-r [leaks | all]] [-T src_cache] [-U] filename\n" > + "\n" > + "Command parameters:\n" > + " -f The format of the image file.\n" > + "\n" > + " -q Use Quiet mode - do not print any output (except errors).\n" > + "\n" > + " -r Tries to repair any inconsistencies that are found during the check.\n" > + " \'-r leaks\' repairs only cluster leaks, whereas \'-r all\' fixes all\n" > + " kinds of errors, with a higher risk of choosing the wrong fix or\n" > + " hiding corruption that has already occurred.\n" > + "\n" > + " -T \'src_cache\' is the cache mode used to read input disk images, the\n" > + " valid options are the same as for the \'cache\' option. Options are:\n" > + " none, writeback, writethrough, directsync, and unsafe.\n" > + "\n" > + " --object \'objectdef\' is a QEMU user creatable object definition. See the\n" > + " qemu(1) manual page for a description of the object properties. The\n" > + " most common object type is a \'secret\', which is used to supply\n" > + " passwords and/or encryption keys.\n" > + "\n" > + " --output \'ofmt\' is \'human\' for human-readable output (default) or \'json\' for\n" > + " JSON output.\n" > + "\n" > + "Example:\n" > + " qemu-img check image.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_commit(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img commit [--object objectdef] [--image-opts] [-q] [-f fmt]\n" > + "[-t cache] [-b base] [-d] [-p] filename\n" > + "\n" > + "Command parameters:\n" > + " -b The base image or backing file.\n" > + "\n" > + " -d Skip emptying filename.\n" > + "\n" > + " -f The format of the image file.\n" > + "\n" > + " --image-opts Treat filename as a set of image options, instead of a plain\n" > + " filename.\n" > + "\n" > + " --object \'objectdef\' is a QEMU user creatable object definition. See the\n" > + " qemu(1) manual page for a description of the object properties.\n" > + " The most common object type is a \'secret\', which is used to\n" > + " supply passwords and/or encryption keys.\n" > + "\n" > + " -p Display progress bar. If the -p option is not used for a command\n" > + " that supports it, the progress is reported when the process\n" > + " receives a \"SIGUSR1\" signal.\n" > + "\n" > + " -q Quiet mode - do not print any output (except errors). There\'s no\n" > + " progress bar in case both -q and -p options are used.\n" > + "\n" > + " -t Specifies the cache mode that should be used with the\n" > + " destination file. Options are: none, writeback, writethrough,\n" > + " directsync, and unsafe.\n" > + "\n" > + "Example:\n" > + " qemu-img commit image.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_compare(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img compare [--object objectdef] [--image-opts] [-f fmt] [-F fmt]\n" > + "[-T src_cache] [-p] [-q] [-s] [-U] filename1 filename2\n" > + "\n" > + "Command parameters:\n" > + " -f First image\'s format.\n" > + "\n" > + " -F Second image\'s format.\n" > + "\n" > + " --image-opts Treat filename as a set of image options, instead of a plain\n" > + " filename.\n" > + "\n" > + " -T Specifies the cache mode that should be used with the source\n" > + " file. Options are: none, writeback, writethrough,\n" > + " directsync, and unsafe.\n" > + "\n" > + " --object \'objectdef\' is a QEMU user creatable object definition. See\n" > + " the qemu(1) manual page for a description of the object\n" > + " properties. The most common object type is a \'secret\', which\n" > + " is used to supply passwords and/or encryption keys.\n" > + "\n" > + " -p Display progress bar. If the -p option is not used for a\n" > + " command that supports it, the progress is reported when the\n" > + " process receives a \"SIGUSR1\" signal.\n" > + "\n" > + " -q Quiet mode - do not print any output (except errors).\n" > + " There\'s no progress bar in case both -q and -p options are\n" > + " used.\n" > + "\n" > + " -s Enable strict mode. Comparisons differ when image sizes\n" > + " differ or if a sector is allocated in one image and not\n" > + " allocated in the other image.\n" > + "\n" > + " -U Open the image in shared mode, allowing other QEMU\n" > + " processes to open it in write mode. This option is only\n" > + " allowed when opening images in read-only mode.\n" > + "\n" > + "Example:\n" > + " qemu-img compare image1.qcow image2.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_convert(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img convert [--object objectdef] [--image-opts]\n" > + "[--target-image-opts] [-U] [-c] [-p] [-q] [-n] [-f fmt] [-t cache]\n" > + "[-T src_cache] [-O output_fmt] [-B backing_file] [-o options]\n" > + "[-s snapshot_id_or_name] [-l snapshot_param] [-S sparse_size]\n" > + "[-m num_coroutines] [-W] filename [filename2 [...]] output_filename\n" > + "\n" > + "Command parameters:\n" > + " -B Force the output image to be created as a copy on write\n" > + " image of the specified base image.\n" > + "\n" > + " -c Compress the output image file.\n" > + "\n" > + " -f The format of the image file.\n" > + "\n" > + " --image-opts Indicates that the source filename parameter is to be\n" > + " interpreted as a full option string, not a plain\n" > + " filename.\n" > + "\n" > + " -l Specifies a snapshot parameter.\n" > + "\n" > + " -m Number of parallel coroutines for the convert process\n" > + "\n" > + " -n Skip the creation of the target volume.\n" > + "\n" > + " -O Format of the output file.\n" > + "\n" > + " -o Allows for specifying options like virtual disk size.\n" > + "\n" > + " --object \'objectdef\' is a QEMU user creatable object definition.\n" > + " See the qemu(1) manual page for a description of the\n" > + " object properties. The most common object type is a\n" > + " \'secret\', which is used to supply passwords and/or\n" > + " encryption keys.\n" > + "\n" > + " -p Display progress bar. If the -p option is not used for\n" > + " a command that supports it, the progress is reported\n" > + " when the process receives a \"SIGUSR1\" signal.\n" > + "\n" > + " -q Quiet mode - do not print any output (except errors).\n" > + " There\'s no progress bar in case both -q and -p options\n" > + " are used.\n" > + "\n" > + " -S The consecutive number of bytes (defaults to 4k) that\n" > + " must contain only zeros for qemu-img to create a sparse\n" > + " image during conversion.\n" > + "\n" > + " -s The name or ID of the snapshot to use.\n" > + "\n" > + " -T Specifies the cache mode that should be used with the\n" > + " source file.\n" > + "\n" > + " -t Specifies the cache mode that should be used with the\n" > + " destination file. Options are: none, writeback,\n" > + " writethrough, directsync, and unsafe.\n" > + "\n" > + "--target-image-opts Indicates whether the source filename includes options.\n" > + "\n" > + " -U Open the image in shared mode, allowing other QEMU\n" > + " processes to open it in write mode. This option is only\n" > + " allowed when opening images in read-only mode.\n" > + "\n" > + " -W Allow out-of-order writes to the destination. This\n" > + " option improves performance, but is only recommended\n" > + " for preallocated devices like host devices or other raw\n" > + " block devices.\n" > + "\n" > + "Example:\n" > + " qemu-img convert -f raw -O qcow2 image.img image.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_create(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img create [--object objectdef] [-q] [-f fmt] [-b backing_file]\n" > + "[-F backing_fmt] [-u] [-o options] filename [size]\n" > + "\n" > + "Command parameters:\n" > + " -b The backing file used to base the output file on.\n" > + "\n" > + " -f The format of the image file.\n" > + "\n" > + " -F The format of the backing file.\n" > + "\n" > + " -u Create the image file even if the backing file cannot be opened.\n" > + "\n" > + " -o Allows for specifying options like virtual disk size.\n" > + "\n" > + "--object \'objectdef\' is a QEMU user creatable object definition.\n" > + " See the qemu(1) manual page for a description of the\n" > + " object properties. The most common object type is a\n" > + " \'secret\', which is used to supply passwords and/or\n" > + " encryption keys.\n" > + "\n" > + "Example:\n" > + " qemu-img create -f qcow2 image.qcow2 10G\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_dd(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img dd [-f fmt] [-O output_fmt] [bs=block_size] [count=blocks]\n" > + "[skip=blocks] if=input of=output\n" > + "\n" > + "Command parameters:\n" > + " bs Size of the blocks used in reading and writing (512 bytes is\n" > + " the default).\n" > + "\n" > + " count The limit to how many blocks to read.\n" > + "\n" > + " -f The format of the image file.\n" > + "\n" > + " if The input file.\n" > + "\n" > + " -O Format of the output file.\n" > + "\n" > + " of The output file.\n" > + "\n" > + " skip Number of blocks to skip.\n" > + "\n" > + "Example:\n" > + " qemu-img dd if=/dev/cdrom -O raw of=cd.iso\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_info(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img info [-f fmt] [--output=ofmt] [--backing-chain] filename\n" > + "\n" > + "Command parameters:\n" > + " --backing-chain Recursively enumerate thru each disk image in the\n" > + " chain for information.\n" > + "\n" > + " -f The format of the image file.\n" > + "\n" > + "--output The output format of this command. Can be \"human\" or\n" > + " \"json\".\n" > + "\n" > + "Example:\n" > + " qemu-img info image.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_map(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img map [-f fmt] [--output=ofmt] filename\n" > + "\n" > + "Command parameters:\n" > + " -f The format of the image file.\n" > + "\n" > + "--output The output format of this command. Can be \"human\" or \"json\".\n" > + "\n" > + "Example:\n" > + " qemu-img map image.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_measure(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img measure [--output=ofmt] [-O output_fmt] [-o options] [--size N ]\n" > + "[--object objectdef] [--image-opts] [-f fmt] [-l snapshot_param]\n" > + "filename\n" > + "\n" > + "Command parameters:\n" > + " -f The format of the image file.\n" > + "\n" > + " --image-opts Indicates that the source filename parameter is to be\n" > + " interpreted as a full option string, not a plain\n" > + " filename.\n" > + "\n" > + " -l Specifies a snapshot parameter.\n" > + "\n" > + " -O Format of the output file.\n" > + "\n" > + " -o Allows for specifying options.\n" > + "\n" > + " --object \'objectdef\' is a QEMU user creatable object definition. See\n" > + " the qemu(1) manual page for a description of the object\n" > + " properties. The most common object type is a \'secret\',\n" > + " which is used to supply passwords and/or encryption keys.\n" > + "\n" > + " --output \'ofmt\' is \'human\' for human-readable output (default) or\n" > + " \'json\' for JSON output.\n" > + "\n" > + " --size If given act as if creating a new empty image file using\n" > + " qemu-img create.\n" > + "\n" > + "Example:\n" > + " qemu-img measure -O qcow2 --size 5G\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_snapshot(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img snapshot [-l | -a snapshot | -c snapshot | -d snapshot ]\n" > + "filename\n" > + "\n" > + "Command parameters:\n" > + " -a Applies the snapshot.\n" > + "\n" > + " -c Create a snapshot.\n" > + "\n" > + " -d Deletes a snapshot.\n" > + "\n" > + " -l Lists all snapshots\n" > + "\n" > + "Example:\n" > + " qemu-img snapshot -l image.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_rebase(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img rebase [-f fmt] [-t cache] [-T src_cache] [-p] [-u] -b\n" > + "backing_file [-F backing_fmt] filename\n" > + "\n" > + "Command parameters:\n" > + " -b The new backing file.\n" > + "\n" > + " -F The format for the new backing file.\n" > + "\n" > + " -f The format of the image file being rebased.\n" > + "\n" > + " -T Specifies the cache mode that should be used with the source file.\n" > + "\n" > + " -t Specifies the cache mode that should be used with the destination\n" > + " file. Options are: none, writeback, writethrough, directsync, and\n" > + " unsafe.\n" > + "\n" > + " -p Display progress bar. If the -p option is not used for a command\n" > + " that supports it, the progress is reported when the process\n" > + " receives a \"SIGUSR1\" signal.\n" > + "\n" > + " -u Operate in unsafe mode.\n" > + "\n" > + "Example:\n" > + " qemu-img rebase -b backing.img diff.qcow2\n" > + "\n" > + "\n"; > + printf("%s", msg); > +} > + > +static void help_resize(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img resize [--shrink] [--preallocation=prealloc] filename\n" > + "[+ | -] size\n" > + "\n" > + "Command parameters:\n" > + " --preallocation When growing an image, specify how the additional image\n" > + " area should be allocated on the host.\n" > + "\n" > + " --shrink Informs qemu-img that the user acknowledges all loss of\n" > + " data beyond the truncated image\'s end.\n" > + "\n" > + "Example:\n" > + " qemu-img resize image.qcow2 20G\n"; > + printf("%s", msg); > } > > static QemuOptsList qemu_object_opts = { > @@ -4886,7 +5326,7 @@ out: > return ret; > } > > -static const img_cmd_t img_cmds[] = { > +static img_cmd_t img_cmds[] = { > #define DEF(option, callback, arg_string) \ > { option, callback }, > #include "qemu-img-cmds.h" > @@ -4894,6 +5334,12 @@ static const img_cmd_t img_cmds[] = { > { NULL, NULL, }, > }; > > +/* These functions will be added to the img_cmds array */ > +void (*help_functions[])(void) = {help_amend, help_bench, help_check,\ > + help_commit, help_compare, help_convert, help_create, help_dd, help_info,\ > + help_map, help_measure, help_snapshot, help_rebase, help_resize}; > + > + > int main(int argc, char **argv) > { > const img_cmd_t *cmd; > @@ -4970,10 +5416,22 @@ int main(int argc, char **argv) > trace_init_file(trace_file); > qemu_set_log(LOG_TRACE); > > + /* Add all the help functions to the array */ > + int i; > + for (i = 0; i < ARRAY_SIZE(help_functions); i++) { > + img_cmds[i].help_func = help_functions[i]; > + } > + > /* find the command */ > for (cmd = img_cmds; cmd->name != NULL; cmd++) { > if (!strcmp(cmdname, cmd->name)) { > - return cmd->handler(argc, argv); > + if ((argc > (optind + 1)) && > + strcmp("--help", argv[optind + 1]) == 0) { > + cmd->help_func(); > + return 0; > + } else { > + return cmd->handler(argc, argv); > + } > } > } > > -- > 2.14.3 (Apple Git-98) > -- Murilo
> On Sep 25, 2018, at 12:46 PM, Murilo Opsfelder Araujo <muriloo@linux.ibm.com> wrote: > > Hi, John. > > On Tue, Sep 25, 2018 at 11:39:49AM -0400, John Arbuckle wrote: >> Add the ability for the user to display help for a certain command. >> Example: qemu-img create --help >> >> What is printed is all the options available to this command and an example. >> >> Signed-off-by: John Arbuckle <programmingkidx@gmail.com> > > Segfault is gone with this patch. > > Acked-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> Thank you very much for your help.
On 9/25/18 10:39 AM, John Arbuckle wrote: > Add the ability for the user to display help for a certain command. > Example: qemu-img create --help > > What is printed is all the options available to this command and an example. > > Signed-off-by: John Arbuckle <programmingkidx@gmail.com> > --- > v3 changes: > Fixed a bug that caused qemu-img to crash when running a command without > options. Hmm, I just reviewed v2 without noticing that you had posted v3. > > v2 changes: > Removed block of string comparison code for each command. > Added a help_func field to the img_cmd_t struct. > Made strings longer than 80 characters wide. > > qemu-img.c | 660 +++++++++++++++++++++++++++++++++++++++++++++++++++---------- > 1 file changed, 559 insertions(+), 101 deletions(-) My v2 comment about splitting this into more reviewable portions still applies. > +++ b/qemu-img.c > @@ -52,6 +52,7 @@ > typedef struct img_cmd_t { > const char *name; > int (*handler)(int argc, char **argv); > + void (*help_func)(void); > } img_cmd_t; As does my complaint that you want to track the command synopses here in this struct for reuse in multiple contexts later, rather than... > +static void help_amend(void) > +{ > + const char *msg = > + "\n" > + "usage: qemu-img amend [--object objectdef] [--image-opts] [-p] [-q] [-f fmt]\n" > + "[-t cache] -o options filename\n" repeating things that are in qemu-img-cmds.h and risking them getting out of sync. > > -static const img_cmd_t img_cmds[] = { > +static img_cmd_t img_cmds[] = { > #define DEF(option, callback, arg_string) \ > { option, callback }, > #include "qemu-img-cmds.h" > @@ -4894,6 +5334,12 @@ static const img_cmd_t img_cmds[] = { > { NULL, NULL, }, > }; > > +/* These functions will be added to the img_cmds array */ > +void (*help_functions[])(void) = {help_amend, help_bench, help_check,\ > + help_commit, help_compare, help_convert, help_create, help_dd, help_info,\ > + help_map, help_measure, help_snapshot, help_rebase, help_resize}; And my biggest gripe, that this approach to initialization is dead wrong, is still applicable. Overall, I like the end result that you are trying to reach. (I'm not always a fan of having to run 'command --help' followed by 'command subcommand --help' to learn everything, but it sure beats a wall of text, and we have at least 'git' and 'cvs' as examples of programs that have used that approach, so we are not inventing something new). But you'll need a v4, and preferably broken up into something easier to review (one patch per command, rather than a wholesale rewrite in go), if you want to get it in.
diff --git a/qemu-img.c b/qemu-img.c index 1acddf693c..e4d9baa550 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -52,6 +52,7 @@ typedef struct img_cmd_t { const char *name; int (*handler)(int argc, char **argv); + void (*help_func)(void); } img_cmd_t; enum { @@ -76,11 +77,6 @@ typedef enum OutputFormat { /* Default to cache=writeback as data integrity is not important for qemu-img */ #define BDRV_DEFAULT_CACHE "writeback" -static void format_print(void *opaque, const char *name) -{ - printf(" %s", name); -} - static void QEMU_NORETURN GCC_FMT_ATTR(1, 2) error_exit(const char *fmt, ...) { va_list ap; @@ -105,102 +101,546 @@ static void QEMU_NORETURN unrecognized_option(const char *option) error_exit("unrecognized option '%s'", option); } -/* Please keep in synch with qemu-img.texi */ -static void QEMU_NORETURN help(void) +/* Prints an overview of available help options */ +static void help(void) { const char *help_msg = - QEMU_IMG_VERSION - "usage: qemu-img [standard options] command [command options]\n" - "QEMU disk image utility\n" - "\n" - " '-h', '--help' display this help and exit\n" - " '-V', '--version' output version information and exit\n" - " '-T', '--trace' [[enable=]<pattern>][,events=<file>][,file=<file>]\n" - " specify tracing options\n" - "\n" - "Command syntax:\n" -#define DEF(option, callback, arg_string) \ - " " arg_string "\n" -#include "qemu-img-cmds.h" -#undef DEF - "\n" - "Command parameters:\n" - " 'filename' is a disk image filename\n" - " 'objectdef' is a QEMU user creatable object definition. See the qemu(1)\n" - " manual page for a description of the object properties. The most common\n" - " object type is a 'secret', which is used to supply passwords and/or\n" - " encryption keys.\n" - " 'fmt' is the disk image format. It is guessed automatically in most cases\n" - " 'cache' is the cache mode used to write the output disk image, the valid\n" - " options are: 'none', 'writeback' (default, except for convert), 'writethrough',\n" - " 'directsync' and 'unsafe' (default for convert)\n" - " 'src_cache' is the cache mode used to read input disk images, the valid\n" - " options are the same as for the 'cache' option\n" - " 'size' is the disk image size in bytes. Optional suffixes\n" - " 'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M),\n" - " 'T' (terabyte, 1024G), 'P' (petabyte, 1024T) and 'E' (exabyte, 1024P) are\n" - " supported. 'b' is ignored.\n" - " 'output_filename' is the destination disk image filename\n" - " 'output_fmt' is the destination format\n" - " 'options' is a comma separated list of format specific options in a\n" - " name=value format. Use -o ? for an overview of the options supported by the\n" - " used format\n" - " 'snapshot_param' is param used for internal snapshot, format\n" - " is 'snapshot.id=[ID],snapshot.name=[NAME]', or\n" - " '[ID_OR_NAME]'\n" - " '-c' indicates that target image must be compressed (qcow format only)\n" - " '-u' allows unsafe backing chains. For rebasing, it is assumed that old and\n" - " new backing file match exactly. The image doesn't need a working\n" - " backing file before rebasing in this case (useful for renaming the\n" - " backing file). For image creation, allow creating without attempting\n" - " to open the backing file.\n" - " '-h' with or without a command shows this help and lists the supported formats\n" - " '-p' show progress of command (only certain commands)\n" - " '-q' use Quiet mode - do not print any output (except errors)\n" - " '-S' indicates the consecutive number of bytes (defaults to 4k) that must\n" - " contain only zeros for qemu-img to create a sparse image during\n" - " conversion. If the number of bytes is 0, the source will not be scanned for\n" - " unallocated or zero sectors, and the destination image will always be\n" - " fully allocated\n" - " '--output' takes the format in which the output must be done (human or json)\n" - " '-n' skips the target volume creation (useful if the volume is created\n" - " prior to running qemu-img)\n" - "\n" - "Parameters to check subcommand:\n" - " '-r' tries to repair any inconsistencies that are found during the check.\n" - " '-r leaks' repairs only cluster leaks, whereas '-r all' fixes all\n" - " kinds of errors, with a higher risk of choosing the wrong fix or\n" - " hiding corruption that has already occurred.\n" - "\n" - "Parameters to convert subcommand:\n" - " '-m' specifies how many coroutines work in parallel during the convert\n" - " process (defaults to 8)\n" - " '-W' allow to write to the target out of order rather than sequential\n" - "\n" - "Parameters to snapshot subcommand:\n" - " 'snapshot' is the name of the snapshot to create, apply or delete\n" - " '-a' applies a snapshot (revert disk to saved state)\n" - " '-c' creates a snapshot\n" - " '-d' deletes a snapshot\n" - " '-l' lists all snapshots in the given image\n" - "\n" - "Parameters to compare subcommand:\n" - " '-f' first image format\n" - " '-F' second image format\n" - " '-s' run in Strict mode - fail on different image size or sector allocation\n" - "\n" - "Parameters to dd subcommand:\n" - " 'bs=BYTES' read and write up to BYTES bytes at a time " - "(default: 512)\n" - " 'count=N' copy only N input blocks\n" - " 'if=FILE' read from FILE\n" - " 'of=FILE' write to FILE\n" - " 'skip=N' skip N bs-sized blocks at the start of input\n"; - - printf("%s\nSupported formats:", help_msg); - bdrv_iterate_format(format_print, NULL); - printf("\n\n" QEMU_HELP_BOTTOM "\n"); - exit(EXIT_SUCCESS); + QEMU_IMG_VERSION + "usage: qemu-img [standard options] command [command options]\n" + "QEMU disk image utility\n" + "\n" + " '-h', '--help' display this help and exit\n" + " '-V', '--version' output version information and exit\n" + " '-T', '--trace' [[enable=]<pattern>][,events=<file>][,file=<file>]\n" + " specify tracing options\n" + "\n" + "Command:\n" + "\tamend Change options of an existing disk image\n" + "\tbench Run benchmarks on a given disk image\n" + "\tcheck Check the disk image for consistency or repair it\n" + "\tcommit Merge the disk image into its backing file\n" + "\tcompare Check if two images have the same content\n" + "\tconvert Convert an image file or snapshot into another file\n" + "\tcreate Create a new disk image\n" + "\tdd Copies and converts an input file into another file\n" + "\tinfo Gives information about the specified image file\n" + "\tmap Dump the metadata of image filename\n" + "\tmeasure Calculate the file size required for a new image\n" + "\tsnapshot List, apply, create or delete snapshots in a file\n" + "\trebase Changes the backing file of an image file\n" + "\tresize Resize an image file\n" + "\n\nRun 'qemu-img <command> --help' for details.\n" + "See <https://qemu.org/contribute/report-a-bug> for how to report bugs.\n" + "More information on the QEMU project at <https://qemu.org>.\n"; + printf("%s\n", help_msg); +} + +static void help_amend(void) +{ + const char *msg = + "\n" + "usage: qemu-img amend [--object objectdef] [--image-opts] [-p] [-q] [-f fmt]\n" + "[-t cache] -o options filename\n" + "\n" + "Command parameters:\n" + " -f The format of the image file.\n" + "\n" + "--image-opts Treat filename as a set of image options, instead of a plain\n" + " filename.\n" + "\n" + " -o Used with a comma separated list of format specific options in a\n" + " name=value format. Use \"-o help\" for an overview of the options\n" + " supported by the used format.\n" + "\n" + "--object \'objectdef\' is a QEMU user creatable object definition. See the\n" + " qemu(1) manual page for a description of the object properties.\n" + " The most common object type is a \'secret\', which is used to\n" + " supply passwords and/or encryption keys.\n" + "\n" + " -p Display progress bar. If the -p option is not used for a command\n" + " that supports it, the progress is reported when the process\n" + " receives a \"SIGUSR1\" signal. Avoid using with the -q option.\n" + "\n" + " -q Quiet mode - do not print any output (except errors). Avoid\n" + " using with the -p option.\n" + "\n" + " -t Specifies the cache mode that should be used with the\n" + " destination file. Options are: none, writeback, writethrough,\n" + " directsync, and unsafe.\n" + "\n" + "Example:\n" + " qemu-img amend -o compat=v3 -f qcow2 image.qcow2\n" + " qemu-img amend --object secret,id=sec0,data=test --image-opts \\\n" + " driver=luks,key-secret=sec0,file.filename=test.luks -o size=2G\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_bench(void) +{ + const char *msg = + "\n" + "usage: qemu-img bench [-c count] [-d depth] [-f fmt]\n" + "[--flush-interval=flush_interval] [-n] [--no-drain] [-o offset]\n" + "[--pattern=pattern] [-q] [-s buffer_size] [-S step_size] [-t cache] [-w] [-U]\n" + "filename\n" + "\n" + "Command parameters:\n" + " -c Number of I/O requests to perform.\n" + "\n" + " -d Number of I/O requests done in parallel.\n" + "\n" + " -f The format of the image file.\n" + "\n" + " --flush-interval How often a flush should take place.\n" + "\n" + " -n Use native AIO backend if possible.\n" + "\n" + " --no-drain Issue a flush without draining the request queue first.\n" + "\n" + " -o The starting position.\n" + "\n" + " --pattern The byte pattern used to in write tests.\n" + "\n" + " -q Quiet mode - do not print any output (except errors).\n" + " There\'s no progress bar in case both -q and -p options are\n" + " used.\n" + "\n" + " -s buffer_size in bytes.\n" + "\n" + " -S Increases current position by step_size.\n" + "\n" + " -t Specifies the cache mode that should be used with the\n" + " destination file. Options are: none, writeback,\n" + " writethrough, directsync, and unsafe.\n" + "\n" + " -w Perform write test.\n" + "\n" + " -U Open the image in shared mode, allowing other QEMU\n" + " processes to open it in write mode. This option is only\n" + " allowed when opening images in read-only mode.\n" + "\n" + "Example:\n" + " qemu-img bench -c 20000 -d 50000 -f qcow2 image.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_check(void) +{ + const char *msg = + "\n" + "usage: qemu-img check [--object objectdef] [--image-opts] [-q] [-f fmt]\n" + "[--output=ofmt] [-r [leaks | all]] [-T src_cache] [-U] filename\n" + "\n" + "Command parameters:\n" + " -f The format of the image file.\n" + "\n" + " -q Use Quiet mode - do not print any output (except errors).\n" + "\n" + " -r Tries to repair any inconsistencies that are found during the check.\n" + " \'-r leaks\' repairs only cluster leaks, whereas \'-r all\' fixes all\n" + " kinds of errors, with a higher risk of choosing the wrong fix or\n" + " hiding corruption that has already occurred.\n" + "\n" + " -T \'src_cache\' is the cache mode used to read input disk images, the\n" + " valid options are the same as for the \'cache\' option. Options are:\n" + " none, writeback, writethrough, directsync, and unsafe.\n" + "\n" + " --object \'objectdef\' is a QEMU user creatable object definition. See the\n" + " qemu(1) manual page for a description of the object properties. The\n" + " most common object type is a \'secret\', which is used to supply\n" + " passwords and/or encryption keys.\n" + "\n" + " --output \'ofmt\' is \'human\' for human-readable output (default) or \'json\' for\n" + " JSON output.\n" + "\n" + "Example:\n" + " qemu-img check image.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_commit(void) +{ + const char *msg = + "\n" + "usage: qemu-img commit [--object objectdef] [--image-opts] [-q] [-f fmt]\n" + "[-t cache] [-b base] [-d] [-p] filename\n" + "\n" + "Command parameters:\n" + " -b The base image or backing file.\n" + "\n" + " -d Skip emptying filename.\n" + "\n" + " -f The format of the image file.\n" + "\n" + " --image-opts Treat filename as a set of image options, instead of a plain\n" + " filename.\n" + "\n" + " --object \'objectdef\' is a QEMU user creatable object definition. See the\n" + " qemu(1) manual page for a description of the object properties.\n" + " The most common object type is a \'secret\', which is used to\n" + " supply passwords and/or encryption keys.\n" + "\n" + " -p Display progress bar. If the -p option is not used for a command\n" + " that supports it, the progress is reported when the process\n" + " receives a \"SIGUSR1\" signal.\n" + "\n" + " -q Quiet mode - do not print any output (except errors). There\'s no\n" + " progress bar in case both -q and -p options are used.\n" + "\n" + " -t Specifies the cache mode that should be used with the\n" + " destination file. Options are: none, writeback, writethrough,\n" + " directsync, and unsafe.\n" + "\n" + "Example:\n" + " qemu-img commit image.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_compare(void) +{ + const char *msg = + "\n" + "usage: qemu-img compare [--object objectdef] [--image-opts] [-f fmt] [-F fmt]\n" + "[-T src_cache] [-p] [-q] [-s] [-U] filename1 filename2\n" + "\n" + "Command parameters:\n" + " -f First image\'s format.\n" + "\n" + " -F Second image\'s format.\n" + "\n" + " --image-opts Treat filename as a set of image options, instead of a plain\n" + " filename.\n" + "\n" + " -T Specifies the cache mode that should be used with the source\n" + " file. Options are: none, writeback, writethrough,\n" + " directsync, and unsafe.\n" + "\n" + " --object \'objectdef\' is a QEMU user creatable object definition. See\n" + " the qemu(1) manual page for a description of the object\n" + " properties. The most common object type is a \'secret\', which\n" + " is used to supply passwords and/or encryption keys.\n" + "\n" + " -p Display progress bar. If the -p option is not used for a\n" + " command that supports it, the progress is reported when the\n" + " process receives a \"SIGUSR1\" signal.\n" + "\n" + " -q Quiet mode - do not print any output (except errors).\n" + " There\'s no progress bar in case both -q and -p options are\n" + " used.\n" + "\n" + " -s Enable strict mode. Comparisons differ when image sizes\n" + " differ or if a sector is allocated in one image and not\n" + " allocated in the other image.\n" + "\n" + " -U Open the image in shared mode, allowing other QEMU\n" + " processes to open it in write mode. This option is only\n" + " allowed when opening images in read-only mode.\n" + "\n" + "Example:\n" + " qemu-img compare image1.qcow image2.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_convert(void) +{ + const char *msg = + "\n" + "usage: qemu-img convert [--object objectdef] [--image-opts]\n" + "[--target-image-opts] [-U] [-c] [-p] [-q] [-n] [-f fmt] [-t cache]\n" + "[-T src_cache] [-O output_fmt] [-B backing_file] [-o options]\n" + "[-s snapshot_id_or_name] [-l snapshot_param] [-S sparse_size]\n" + "[-m num_coroutines] [-W] filename [filename2 [...]] output_filename\n" + "\n" + "Command parameters:\n" + " -B Force the output image to be created as a copy on write\n" + " image of the specified base image.\n" + "\n" + " -c Compress the output image file.\n" + "\n" + " -f The format of the image file.\n" + "\n" + " --image-opts Indicates that the source filename parameter is to be\n" + " interpreted as a full option string, not a plain\n" + " filename.\n" + "\n" + " -l Specifies a snapshot parameter.\n" + "\n" + " -m Number of parallel coroutines for the convert process\n" + "\n" + " -n Skip the creation of the target volume.\n" + "\n" + " -O Format of the output file.\n" + "\n" + " -o Allows for specifying options like virtual disk size.\n" + "\n" + " --object \'objectdef\' is a QEMU user creatable object definition.\n" + " See the qemu(1) manual page for a description of the\n" + " object properties. The most common object type is a\n" + " \'secret\', which is used to supply passwords and/or\n" + " encryption keys.\n" + "\n" + " -p Display progress bar. If the -p option is not used for\n" + " a command that supports it, the progress is reported\n" + " when the process receives a \"SIGUSR1\" signal.\n" + "\n" + " -q Quiet mode - do not print any output (except errors).\n" + " There\'s no progress bar in case both -q and -p options\n" + " are used.\n" + "\n" + " -S The consecutive number of bytes (defaults to 4k) that\n" + " must contain only zeros for qemu-img to create a sparse\n" + " image during conversion.\n" + "\n" + " -s The name or ID of the snapshot to use.\n" + "\n" + " -T Specifies the cache mode that should be used with the\n" + " source file.\n" + "\n" + " -t Specifies the cache mode that should be used with the\n" + " destination file. Options are: none, writeback,\n" + " writethrough, directsync, and unsafe.\n" + "\n" + "--target-image-opts Indicates whether the source filename includes options.\n" + "\n" + " -U Open the image in shared mode, allowing other QEMU\n" + " processes to open it in write mode. This option is only\n" + " allowed when opening images in read-only mode.\n" + "\n" + " -W Allow out-of-order writes to the destination. This\n" + " option improves performance, but is only recommended\n" + " for preallocated devices like host devices or other raw\n" + " block devices.\n" + "\n" + "Example:\n" + " qemu-img convert -f raw -O qcow2 image.img image.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_create(void) +{ + const char *msg = + "\n" + "usage: qemu-img create [--object objectdef] [-q] [-f fmt] [-b backing_file]\n" + "[-F backing_fmt] [-u] [-o options] filename [size]\n" + "\n" + "Command parameters:\n" + " -b The backing file used to base the output file on.\n" + "\n" + " -f The format of the image file.\n" + "\n" + " -F The format of the backing file.\n" + "\n" + " -u Create the image file even if the backing file cannot be opened.\n" + "\n" + " -o Allows for specifying options like virtual disk size.\n" + "\n" + "--object \'objectdef\' is a QEMU user creatable object definition.\n" + " See the qemu(1) manual page for a description of the\n" + " object properties. The most common object type is a\n" + " \'secret\', which is used to supply passwords and/or\n" + " encryption keys.\n" + "\n" + "Example:\n" + " qemu-img create -f qcow2 image.qcow2 10G\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_dd(void) +{ + const char *msg = + "\n" + "usage: qemu-img dd [-f fmt] [-O output_fmt] [bs=block_size] [count=blocks]\n" + "[skip=blocks] if=input of=output\n" + "\n" + "Command parameters:\n" + " bs Size of the blocks used in reading and writing (512 bytes is\n" + " the default).\n" + "\n" + " count The limit to how many blocks to read.\n" + "\n" + " -f The format of the image file.\n" + "\n" + " if The input file.\n" + "\n" + " -O Format of the output file.\n" + "\n" + " of The output file.\n" + "\n" + " skip Number of blocks to skip.\n" + "\n" + "Example:\n" + " qemu-img dd if=/dev/cdrom -O raw of=cd.iso\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_info(void) +{ + const char *msg = + "\n" + "usage: qemu-img info [-f fmt] [--output=ofmt] [--backing-chain] filename\n" + "\n" + "Command parameters:\n" + " --backing-chain Recursively enumerate thru each disk image in the\n" + " chain for information.\n" + "\n" + " -f The format of the image file.\n" + "\n" + "--output The output format of this command. Can be \"human\" or\n" + " \"json\".\n" + "\n" + "Example:\n" + " qemu-img info image.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_map(void) +{ + const char *msg = + "\n" + "usage: qemu-img map [-f fmt] [--output=ofmt] filename\n" + "\n" + "Command parameters:\n" + " -f The format of the image file.\n" + "\n" + "--output The output format of this command. Can be \"human\" or \"json\".\n" + "\n" + "Example:\n" + " qemu-img map image.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_measure(void) +{ + const char *msg = + "\n" + "usage: qemu-img measure [--output=ofmt] [-O output_fmt] [-o options] [--size N ]\n" + "[--object objectdef] [--image-opts] [-f fmt] [-l snapshot_param]\n" + "filename\n" + "\n" + "Command parameters:\n" + " -f The format of the image file.\n" + "\n" + " --image-opts Indicates that the source filename parameter is to be\n" + " interpreted as a full option string, not a plain\n" + " filename.\n" + "\n" + " -l Specifies a snapshot parameter.\n" + "\n" + " -O Format of the output file.\n" + "\n" + " -o Allows for specifying options.\n" + "\n" + " --object \'objectdef\' is a QEMU user creatable object definition. See\n" + " the qemu(1) manual page for a description of the object\n" + " properties. The most common object type is a \'secret\',\n" + " which is used to supply passwords and/or encryption keys.\n" + "\n" + " --output \'ofmt\' is \'human\' for human-readable output (default) or\n" + " \'json\' for JSON output.\n" + "\n" + " --size If given act as if creating a new empty image file using\n" + " qemu-img create.\n" + "\n" + "Example:\n" + " qemu-img measure -O qcow2 --size 5G\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_snapshot(void) +{ + const char *msg = + "\n" + "usage: qemu-img snapshot [-l | -a snapshot | -c snapshot | -d snapshot ]\n" + "filename\n" + "\n" + "Command parameters:\n" + " -a Applies the snapshot.\n" + "\n" + " -c Create a snapshot.\n" + "\n" + " -d Deletes a snapshot.\n" + "\n" + " -l Lists all snapshots\n" + "\n" + "Example:\n" + " qemu-img snapshot -l image.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_rebase(void) +{ + const char *msg = + "\n" + "usage: qemu-img rebase [-f fmt] [-t cache] [-T src_cache] [-p] [-u] -b\n" + "backing_file [-F backing_fmt] filename\n" + "\n" + "Command parameters:\n" + " -b The new backing file.\n" + "\n" + " -F The format for the new backing file.\n" + "\n" + " -f The format of the image file being rebased.\n" + "\n" + " -T Specifies the cache mode that should be used with the source file.\n" + "\n" + " -t Specifies the cache mode that should be used with the destination\n" + " file. Options are: none, writeback, writethrough, directsync, and\n" + " unsafe.\n" + "\n" + " -p Display progress bar. If the -p option is not used for a command\n" + " that supports it, the progress is reported when the process\n" + " receives a \"SIGUSR1\" signal.\n" + "\n" + " -u Operate in unsafe mode.\n" + "\n" + "Example:\n" + " qemu-img rebase -b backing.img diff.qcow2\n" + "\n" + "\n"; + printf("%s", msg); +} + +static void help_resize(void) +{ + const char *msg = + "\n" + "usage: qemu-img resize [--shrink] [--preallocation=prealloc] filename\n" + "[+ | -] size\n" + "\n" + "Command parameters:\n" + " --preallocation When growing an image, specify how the additional image\n" + " area should be allocated on the host.\n" + "\n" + " --shrink Informs qemu-img that the user acknowledges all loss of\n" + " data beyond the truncated image\'s end.\n" + "\n" + "Example:\n" + " qemu-img resize image.qcow2 20G\n"; + printf("%s", msg); } static QemuOptsList qemu_object_opts = { @@ -4886,7 +5326,7 @@ out: return ret; } -static const img_cmd_t img_cmds[] = { +static img_cmd_t img_cmds[] = { #define DEF(option, callback, arg_string) \ { option, callback }, #include "qemu-img-cmds.h" @@ -4894,6 +5334,12 @@ static const img_cmd_t img_cmds[] = { { NULL, NULL, }, }; +/* These functions will be added to the img_cmds array */ +void (*help_functions[])(void) = {help_amend, help_bench, help_check,\ + help_commit, help_compare, help_convert, help_create, help_dd, help_info,\ + help_map, help_measure, help_snapshot, help_rebase, help_resize}; + + int main(int argc, char **argv) { const img_cmd_t *cmd; @@ -4970,10 +5416,22 @@ int main(int argc, char **argv) trace_init_file(trace_file); qemu_set_log(LOG_TRACE); + /* Add all the help functions to the array */ + int i; + for (i = 0; i < ARRAY_SIZE(help_functions); i++) { + img_cmds[i].help_func = help_functions[i]; + } + /* find the command */ for (cmd = img_cmds; cmd->name != NULL; cmd++) { if (!strcmp(cmdname, cmd->name)) { - return cmd->handler(argc, argv); + if ((argc > (optind + 1)) && + strcmp("--help", argv[optind + 1]) == 0) { + cmd->help_func(); + return 0; + } else { + return cmd->handler(argc, argv); + } } }
Add the ability for the user to display help for a certain command. Example: qemu-img create --help What is printed is all the options available to this command and an example. Signed-off-by: John Arbuckle <programmingkidx@gmail.com> --- v3 changes: Fixed a bug that caused qemu-img to crash when running a command without options. v2 changes: Removed block of string comparison code for each command. Added a help_func field to the img_cmd_t struct. Made strings longer than 80 characters wide. qemu-img.c | 660 +++++++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 559 insertions(+), 101 deletions(-)