Re: [PATCH] lib: replace libprocps/libproc2 with /proc-based process enumeration

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Tue, 09 Jun 2026 10:51:13 -0700, Bai, Zongyao wrote:
>
> Hi Jia,
>
> LGTM
>
>  Reviewed-by: Zongyao Bai <zongyao.bai@intel.com>

Hmm, not sure what's with the '_' (or space) before Reviewed-by, because of
which R-b doesn't show if we retrieve/apply the patch.

Anyway, I've fixed this up and merged it.

Thanks for the patch and the review.

-Ashutosh

>
>
> On 6/3/2026 11:28 AM, Jia Yao wrote:
> > The previous code used compile-time #ifdef HAVE_LIBPROCPS / HAVE_LIBPROC2
> > to select between two incompatible APIs, requiring separate builds for
> > Ubuntu 22.04 (libprocps) and Ubuntu 24.04 (libproc2).
> > Replace the platform-specific code with internal static helpers in
> > igt_aux.c that read /proc/<pid>/status directly, requiring no external
> > library and working identically across distro versions.
> > The libprocps/libproc2 meson dependencies have been removed entirely.
> >
> > Cc: Zongyao Bai <zongyao.bai@intel.com>
> > Signed-off-by: Jia Yao <jia.yao@intel.com>
> > ---
> >   lib/igt_aux.c   | 203 +++++++++++++++++++++++++++++++-----------------
> >   lib/meson.build |   6 --
> >   meson.build     |  13 +---
> >   3 files changed, 131 insertions(+), 91 deletions(-)
> >
> > diff --git a/lib/igt_aux.c b/lib/igt_aux.c
> > index 87c0593a4..0d250ae2f 100644
> > --- a/lib/igt_aux.c
> > +++ b/lib/igt_aux.c
> > @@ -53,12 +53,6 @@
> >   #include <assert.h>
> >   #include <grp.h>
> >   -#ifdef HAVE_LIBPROCPS
> > -#  include <proc/readproc.h>
> > -#elif HAVE_LIBPROC2
> > -#  include <libproc2/pids.h>
> > -#endif
> > -
> >   #include <dirent.h>
> >   #ifdef __linux__
> >   #  include <libudev.h>
> > @@ -1285,93 +1279,156 @@ void igt_unlock_mem(void)
> >	locked_mem = NULL;
> >   }
> >   +/*
> > + * Internal /proc-based process iterator.  Reads /proc/<pid>/status directly
> > + * so there is no dependency on libprocps or libproc2.
> > + *
> > + * /proc/<pid>/status fields used:
> > + *   Name:  <comm>  - command name (kernel escapes spaces, so %s is safe)
> > + *   Pid:   <pid>
> > + *   Uid:   ruid euid suid fsuid
> > + *   Gid:   rgid egid sgid fsgid
> > + */
> > +struct procps_iter {
> > +	DIR   *procdir;
> > +	char   comm[64];
> > +	pid_t  tid;
> > +	uid_t  euid;
> > +	gid_t  egid;
> > +};
> > +
> > +static struct procps_iter *procps_open(void)
> > +{
> > +	struct procps_iter *iter = calloc(1, sizeof(*iter));
> > +
> > +	if (!iter)
> > +		return NULL;
> > +
> > +	iter->procdir = opendir("/proc");
> > +	if (!iter->procdir) {
> > +		free(iter);
> > +		return NULL;
> > +	}
> > +
> > +	return iter;
> > +}
> > +
> > +static bool procps_next(struct procps_iter *iter,
> > +			pid_t *tid, uid_t *euid, gid_t *egid,
> > +			const char **comm)
> > +{
> > +	struct dirent *ent;
> > +
> > +	if (!iter || !iter->procdir)
> > +		return false;
> > +
> > +	while ((ent = readdir(iter->procdir))) {
> > +		char path[64];
> > +		FILE *f;
> > +		pid_t _tid = 0;
> > +		uid_t _euid = 0;
> > +		gid_t _egid = 0;
> > +		char _comm[64] = "";
> > +		int fields = 0;   /* bit 0=Name, 1=Pid, 2=Uid, 3=Gid */
> > +		char line[256];
> > +
> > +		if (ent->d_name[0] < '1' || ent->d_name[0] > '9')
> > +			continue;
> > +
> > +		snprintf(path, sizeof(path), "/proc/%.20s/status", ent->d_name);
> > +
> > +		f = fopen(path, "r");
> > +		if (!f)
> > +			continue;
> > +
> > +		while (fields != 0xf && fgets(line, sizeof(line), f)) {
> > +			if (!(fields & 0x1) && strncmp(line, "Name:", 5) == 0) {
> > +				if (sscanf(line + 5, " %63s", _comm) == 1)
> > +					fields |= 0x1;
> > +			} else if (!(fields & 0x2) && strncmp(line, "Pid:", 4) == 0) {
> > +				if (sscanf(line + 4, " %d", &_tid) == 1)
> > +					fields |= 0x2;
> > +			} else if (!(fields & 0x4) && strncmp(line, "Uid:", 4) == 0) {
> > +				/* skip ruid, read euid */
> > +				unsigned int _e;
> > +
> > +				if (sscanf(line + 4, " %*u %u", &_e) == 1) {
> > +					_euid = (uid_t)_e;
> > +					fields |= 0x4;
> > +				}
> > +			} else if (!(fields & 0x8) && strncmp(line, "Gid:", 4) == 0) {
> > +				/* skip rgid, read egid */
> > +				unsigned int _e;
> > +
> > +				if (sscanf(line + 4, " %*u %u", &_e) == 1) {
> > +					_egid = (gid_t)_e;
> > +					fields |= 0x8;
> > +				}
> > +			}
> > +		}
> > +
> > +		fclose(f);
> > +
> > +		if (_tid <= 0)
> > +			continue;
> > +
> > +		iter->tid  = _tid;
> > +		iter->euid = _euid;
> > +		iter->egid = _egid;
> > +		snprintf(iter->comm, sizeof(iter->comm), "%s", _comm);
> > +
> > +		*tid  = iter->tid;
> > +		*euid = iter->euid;
> > +		*egid = iter->egid;
> > +		*comm = iter->comm;
> > +		return true;
> > +	}
> > +
> > +	return false;
> > +}
> > +
> > +static void procps_close(struct procps_iter *iter)
> > +{
> > +	if (!iter)
> > +		return;
> > +
> > +	if (iter->procdir)
> > +		closedir(iter->procdir);
> > +
> > +	free(iter);
> > +}
> > +
> >   struct igt_process {
> > -#ifdef HAVE_LIBPROCPS
> > -	PROCTAB * proc;
> > -	proc_t *proc_info;
> > -#elif HAVE_LIBPROC2
> > -	struct pids_info *info;
> > -	struct pids_stack *stack;
> > -#endif
> > +	struct procps_iter *iter;
> >	pid_t tid;
> > -	pid_t euid;
> > -	pid_t egid;
> > -	char *comm;
> > +	uid_t euid;
> > +	gid_t egid;
> > +	const char *comm;
> >   };
> >     static void open_process(struct igt_process *prcs)
> >   {
> > -#ifdef HAVE_LIBPROCPS
> > -	prcs->proc = openproc(PROC_FILLCOM | PROC_FILLSTAT | PROC_FILLARG);
> > -	igt_assert_f(prcs->proc != NULL, "procps open failed\n");
> > -	prcs->proc_info = NULL;
> > -#elif HAVE_LIBPROC2
> > -	enum pids_item Items[] = { PIDS_ID_PID, PIDS_ID_EUID, PIDS_ID_EGID, PIDS_CMD };
> > -	int err;
> > -
> > -	prcs->info = NULL;
> > -	err = procps_pids_new(&prcs->info, Items, 4);
> > -	igt_assert_f(err >= 0, "procps-ng open failed\n");
> > -	prcs->stack = NULL;
> > -#endif
> > +	prcs->iter = procps_open();
> > +	igt_assert_f(prcs->iter, "procps open failed (no /proc filesystem?)\n");
> >	prcs->tid = 0;
> >	prcs->comm = NULL;
> >   }
> >     static void close_process(struct igt_process *prcs)
> >   {
> > -#ifdef HAVE_LIBPROCPS
> > -	if (prcs->proc_info)
> > -		freeproc(prcs->proc_info);
> > -
> > -	closeproc(prcs->proc);
> > -	prcs->proc_info = NULL;
> > -	prcs->proc = NULL;
> > -#elif HAVE_LIBPROC2
> > -	procps_pids_unref(&prcs->info);
> > -	prcs->info = NULL;
> > -#endif
> > +	procps_close(prcs->iter);
> > +	prcs->iter = NULL;
> >	prcs->tid = 0;
> >	prcs->comm = NULL;
> >   }
> >     static bool get_process_ids(struct igt_process *prcs)
> >   {
> > -#ifdef HAVE_LIBPROCPS
> > -	if (prcs->proc_info)
> > -		freeproc(prcs->proc_info);
> > -
> > -	prcs->tid = 0;
> > -	prcs->comm = NULL;
> > -	prcs->proc_info = readproc(prcs->proc, NULL);
> > -
> > -	if (prcs->proc_info) {
> > -		prcs->tid = prcs->proc_info->tid;
> > -		prcs->euid = prcs->proc_info->euid;
> > -		prcs->egid = prcs->proc_info->egid;
> > -		prcs->comm = prcs->proc_info->cmd;
> > -	}
> > -#elif HAVE_LIBPROC2
> > -	enum rel_items { EU_PID, EU_EUID, EU_EGID, EU_CMD }; // order at open
> > -
> >	prcs->tid = 0;
> >	prcs->comm = NULL;
> > -	prcs->stack = procps_pids_get(prcs->info, PIDS_FETCH_TASKS_ONLY);
> > -	if (prcs->stack) {
> > -#if defined(HAVE_LIBPROC2_POST_4_0_5_API)
> > -		prcs->tid = PIDS_VAL(EU_PID, s_int, prcs->stack);
> > -		prcs->euid = PIDS_VAL(EU_EUID, s_int, prcs->stack);
> > -		prcs->egid = PIDS_VAL(EU_EGID, s_int, prcs->stack);
> > -		prcs->comm = PIDS_VAL(EU_CMD, str, prcs->stack);
> > -#else
> > -		prcs->tid = PIDS_VAL(EU_PID, s_int, prcs->stack, prcs->info);
> > -		prcs->euid = PIDS_VAL(EU_EUID, s_int, prcs->stack, prcs->info);
> > -		prcs->egid = PIDS_VAL(EU_EGID, s_int, prcs->stack, prcs->info);
> > -		prcs->comm = PIDS_VAL(EU_CMD, str, prcs->stack, prcs->info);
> > -#endif
> > -	}
> > -#endif
> > -	return prcs->tid != 0;
> > +	return procps_next(prcs->iter,
> > +			   &prcs->tid, &prcs->euid, &prcs->egid,
> > +			   &prcs->comm);
> >   }
> >     /**
> > diff --git a/lib/meson.build b/lib/meson.build
> > index a8d6566ae..f25ecd8b2 100644
> > --- a/lib/meson.build
> > +++ b/lib/meson.build
> > @@ -257,12 +257,6 @@ if build_xe_eudebug
> >	lib_sources += 'xe/xe_eudebug.c'
> >   endif
> >   -if libprocps.found()
> > -	lib_deps += libprocps
> > -else
> > -	lib_deps += libproc2
> > -endif
> > -
> >   if get_option('srcdir') != ''
> >       srcdir = join_paths(get_option('srcdir'), 'tests')
> >   else
> > diff --git a/meson.build b/meson.build
> > index e750f7a51..4def24cbc 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -133,18 +133,7 @@ build_info += 'With libdrm: ' + ','.join(libdrm_info)
> >     pciaccess = dependency('pciaccess', version : '>=0.10')
> >   libkmod = dependency('libkmod')
> > -libprocps = dependency('libprocps', required : false)
> > -libproc2 = dependency('libproc2', required : false)
> > -if libprocps.found()
> > -  config.set('HAVE_LIBPROCPS', 1)
> > -elif libproc2.found()
> > -  config.set('HAVE_LIBPROC2', 1)
> > -  if libproc2.version().version_compare('>= 4.0.5')
> > -    config.set('HAVE_LIBPROC2_POST_4_0_5_API', 1)
> > -  endif
> > -else
> > -  error('Either libprocps or libproc2 is required')
> > -endif
> > +# igt_procps.c reads /proc directly; libprocps and libproc2 are not needed.
> >     libunwind = dependency('libunwind', required :
> > get_option('libunwind'))
> >   if libunwind.found()