passwd: Cache the user/group tables

This is a significant optimization for conditions that need these
tables:

    Benchmark #1: ./bfs ~/code/linux -nouser >/dev/null
      Time (mean ± σ):     232.0 ms ±   2.5 ms    [User: 44.3 ms, System: 185.0 ms]
      Range (min … max):   228.7 ms … 238.7 ms    12 runs

    Benchmark #2: ./bfs-1.6 ~/code/linux -nouser >/dev/null
      Time (mean ± σ):      1.050 s ±  0.012 s    [User: 544.2 ms, System: 500.0 ms]
      Range (min … max):    1.025 s …  1.063 s    10 runs

    Benchmark #3: find ~/code/linux -nouser >/dev/null
      Time (mean ± σ):      1.040 s ±  0.012 s    [User: 533.6 ms, System: 500.6 ms]
      Range (min … max):    1.017 s …  1.054 s    10 runs

    Summary
      './bfs ~/code/linux -nouser >/dev/null' ran
        4.48 ± 0.07 times faster than 'find ~/code/linux -nouser >/dev/null'
        4.52 ± 0.07 times faster than './bfs-1.6 ~/code/linux -nouser >/dev/null'

1 files changed, 7 insertions, 22 deletions

diff --git a/eval.c b/eval.c
index 010fef9..bdf4d99 100644
--- a/eval.c
+++ b/eval.c
@@ -28,6 +28,7 @@
 #include "exec.h"
 #include "fsade.h"
 #include "mtab.h"
+#include "passwd.h"
 #include "printf.h"
 #include "stat.h"
 #include "time.h"
@@ -294,16 +295,7 @@ bool eval_nogroup(const struct expr *expr, struct eval_state *state) {
 		return false;
 	}
 
-	errno = 0;
-	if (getgrgid(statbuf->gid) == NULL) {
-		if (errno == 0) {
-			return true;
-		} else {
-			eval_report_error(state);
-		}
-	}
-
-	return false;
+	return bfs_getgrgid(state->cmdline->groups, statbuf->gid) == NULL;
 }
 
 /**
@@ -315,16 +307,7 @@ bool eval_nouser(const struct expr *expr, struct eval_state *state) {
 		return false;
 	}
 
-	errno = 0;
-	if (getpwuid(statbuf->uid) == NULL) {
-		if (errno == 0) {
-			return true;
-		} else {
-			eval_report_error(state);
-		}
-	}
-
-	return false;
+	return bfs_getpwuid(state->cmdline->users, statbuf->uid) == NULL;
 }
 
 /**
@@ -603,6 +586,8 @@ bool eval_perm(const struct expr *expr, struct eval_state *state) {
 bool eval_fls(const struct expr *expr, struct eval_state *state) {
 	CFILE *cfile = expr->cfile;
 	FILE *file = cfile->file;
+	const struct bfs_users *users = state->cmdline->users;
+	const struct bfs_groups *groups = state->cmdline->groups;
 	const struct BFTW *ftwbuf = state->ftwbuf;
 	const struct bfs_stat *statbuf = eval_stat(state);
 	if (!statbuf) {
@@ -620,7 +605,7 @@ bool eval_fls(const struct expr *expr, struct eval_state *state) {
 	}
 
 	uintmax_t uid = statbuf->uid;
-	struct passwd *pwd = getpwuid(uid);
+	const struct passwd *pwd = users ? bfs_getpwuid(users, uid) : NULL;
 	if (pwd) {
 		if (fprintf(file, " %-8s", pwd->pw_name) < 0) {
 			goto error;
@@ -632,7 +617,7 @@ bool eval_fls(const struct expr *expr, struct eval_state *state) {
 	}
 
 	uintmax_t gid = statbuf->gid;
-	struct group *grp = getgrgid(gid);
+	const struct group *grp = groups ? bfs_getgrgid(groups, gid) : NULL;
 	if (grp) {
 		if (fprintf(file, " %-8s", grp->gr_name) < 0) {
 			goto error;