Update id program to POSIX.

1 files changed, 133 insertions, 21 deletions

diff --git a/awklib/eg/prog/id.awk b/awklib/eg/prog/id.awk
index b6061f9b..50c40c05 100644
--- a/awklib/eg/prog/id.awk
+++ b/awklib/eg/prog/id.awk
@@ -1,61 +1,173 @@
 # id.awk --- implement id in awk
 #
-# Requires user and group library functions
+# Requires user and group library functions and getopt
 #
 # Arnold Robbins, arnold@skeeve.com, Public Domain
 # May 1993
 # Revised February 1996
 # Revised May 2014
 # Revised September 2014
+# Revised September 2020
 
 # output is:
 # uid=12(foo) euid=34(bar) gid=3(baz) \
 #             egid=5(blat) groups=9(nine),2(two),1(one)
 
+# Options:
+#   -G Output all group ids as space separated numbers (ruid, euid, groups)
+#   -g Output only the euid as a number
+#   -n Ouput name instead of the numeric value (with -g/-G/-u)
+#   -r Output ruid/rguid instead of effective id
+#   -u Output only effective user id, as a number
+
+function usage()
+{
+    printf("Usage:\n" \
+           "\tid [user]\n" \
+           "\tid −G [−n] [user]\n" \
+           "\tid −g [−nr] [user]\n" \
+           "\tid −u [−nr] [user]\n") > "/dev/stderr"
+
+    exit 1
+}
 BEGIN {
-    uid = PROCINFO["uid"]
-    euid = PROCINFO["euid"]
-    gid = PROCINFO["gid"]
-    egid = PROCINFO["egid"]
+    # parse args
+    while ((c = getopt(ARGC, ARGV, "Ggnru")) != -1) {
+        if (c == "G")
+            groupset_only++
+        else if (c == "g")
+            egid_only++
+        else if (c == "n")
+            names_not_groups++
+        else if (c == "r")
+            real_ids_only++
+        else if (c == "u")
+            euid_only++
+        else
+            usage()
+    }
+    if (groupset_only && real_ids_only)
+        usage()
+    else if (ARGC - Optind > 1)
+        usage()
+    if (ARGC - Optind == 0) {
+        # gather info for current user
+        uid = PROCINFO["uid"]
+        euid = PROCINFO["euid"]
+        gid = PROCINFO["gid"]
+        egid = PROCINFO["egid"]
+        for (i = 1; ("group" i) in PROCINFO; i++)
+            groupset[i] = PROCINFO["group" i]
+    } else {
+        fill_info_for_user(ARGV[ARGC-1])
+        real_ids_only++
+    }
+    if (groupset_only) {
+        if (names_not_groups) {
+            for (i = 1; i in groupset; i++) {
+                entry = getgrgid(groupset[i])
+                name = get_first_field(entry)
+                printf("%s", name)
+                if ((i + 1) in groupset)
+                    printf(" ")
+            }
+        } else {
+            for (i = 1; i in groupset; i++) {
+                printf("%u", groupset[i])
+                if ((i + 1) in groupset)
+                    printf(" ")
+            }
+        }
 
+        print ""    # final newline
+        exit 0
+    }
+    else if (egid_only) {
+        id = real_ids_only ? gid : egid
+        if (names_not_groups) {
+            entry = getgrgid(id)
+            name = get_first_field(entry)
+            printf("%s\n", name)
+        } else {
+            printf("%u\n", id)
+        }
+
+        exit 0
+    }
+    else if (euid_only) {
+        id = real_ids_only ? uid : euid
+        if (names_not_groups) {
+            entry = getpwuid(id)
+            name = get_first_field(entry)
+            printf("%s\n", name)
+        } else {
+            printf("%u\n", id)
+        }
+
+        exit 0
+    }
     printf("uid=%d", uid)
     pw = getpwuid(uid)
-    pr_first_field(pw)
-
-    if (euid != uid) {
+    print_first_field(pw)
+    if (euid != uid && ! real_ids_only) {
         printf(" euid=%d", euid)
         pw = getpwuid(euid)
-        pr_first_field(pw)
+        print_first_field(pw)
     }
-
     printf(" gid=%d", gid)
     pw = getgrgid(gid)
-    pr_first_field(pw)
+    print_first_field(pw)
 
-    if (egid != gid) {
+    if (egid != gid && ! real_ids_only) {
         printf(" egid=%d", egid)
         pw = getgrgid(egid)
-        pr_first_field(pw)
+        print_first_field(pw)
     }
-
-    for (i = 1; ("group" i) in PROCINFO; i++) {
+    for (i = 1; i in groupset; i++) {
         if (i == 1)
             printf(" groups=")
-        group = PROCINFO["group" i]
+        group = groupset[i]
         printf("%d", group)
         pw = getgrgid(group)
-        pr_first_field(pw)
-        if (("group" (i+1)) in PROCINFO)
+        print_first_field(pw)
+        if ((i + 1) in groupset)
             printf(",")
     }
 
     print ""
 }
-
-function pr_first_field(str,  a)
+function get_first_field(str,  a)
 {
     if (str != "") {
         split(str, a, ":")
-        printf("(%s)", a[1])
+        return a[1]
+    }
+}
+function print_first_field(str)
+{
+    first = get_first_field(str)
+    printf("(%s)", first)
+}
+function fill_info_for_user(user,   
+                            pwent, fields, groupnames, grent, groups, i)
+{
+    pwent = getpwnam(user)
+    if (pwent == "") {
+        printf("id: '%s': no such user\n", user) > "/dev/stderr"
+        exit 1
+    }
+
+    split(pwent, fields, ":")
+    uid = fields[3] + 0
+    gid = fields[4] + 0
+ignore
+
+end ignore
+    groupnames = getgruser(user)
+    split(groupnames, groups, " ")
+    for (i = 1; i in groups; i++) {
+        grent = getgrnam(groups[i])
+        split(grent, fields, ":")
+        groupset[i] = fields[3] + 0
     }
 }