On Thu, 2 Nov 2023 17:28:46 +0000 Bruce Richardson <bruce.richard...@intel.com> wrote:
> DPDK has traditionally assumed that apps are written where argc/argv > parameters are passed directly to rte_eal_init() and then app arguments > are handled afterwards, as is done in the DPDK apps and examples. > > However, based on other projects, like VPP and OVS, we know that this is > often not the case. Instead, the apps build up argument lists internally > themselves and pass those to the init function, and DPDK never directly > accesses the real argc/argv values. > > Therefore, let's make this mode of operation a little easier to use, by > adding in an args library to allow an app to dynamically build up an > args array and then pass that to EAL init. This library allows things > like, for example, initializing a list from argv and then checking if a > particular parameter is present, adding it if not. All the basics of > such a library are included in patch 1, and I've found it of use myself > when writing some simple apps internally using DPDK. > > Patches 2 and 3 go a little further than this, and allow for a slightly > different use-case, that where an app may want to allow mixing of EAL > arguments in with app args. These patches allow the user to query if a > particular argument is an EAL arg or not, or a valid app argument. The > idea here would be, that an app could go through it's argument list, > building up an argument list for EAL init by just picking out the EAL > arguments from a full argument list. I'm less convinced of the value of > this compared to the basics in patch 1, but I think the idea is > interesting so seeking feedback on it. > > Bruce Richardson (3): > args: new library to allow easier manipulation of cmdline args > eal: allow export of the cmdline argument parsing options > args: add functions to check parameter validity > > doc/api/doxy-api-index.md | 1 + > doc/api/doxy-api.conf.in | 1 + > lib/args/args.c | 301 ++++++++++++++++++++++++++++ > lib/args/meson.build | 5 + > lib/args/rte_args.h | 255 +++++++++++++++++++++++ > lib/args/version.map | 22 ++ > lib/eal/common/eal_common_options.c | 9 + > lib/eal/include/rte_eal.h | 14 ++ > lib/eal/version.map | 1 + > lib/meson.build | 2 + > 10 files changed, 611 insertions(+) > create mode 100644 lib/args/args.c > create mode 100644 lib/args/meson.build > create mode 100644 lib/args/rte_args.h > create mode 100644 lib/args/version.map > > -- > 2.39.2 > It would be good to change rte_eal_init() from: int rte_eal_init(int argc, char **argv); to int rte_eal_init(int argc, char * const *argv); I.e it should not modify the argv's passed. This would save unnecessary copy in applications that build synthetic args. Example already exists in dumpcap.
