configure.ac, lib/, src/: Presume working shadow group support in libc

[alejandro-colomar]

This check was testing a specific bug in a prehistoric libc version. Red Hat 3 is long dead, and it doesn't make sense to test for that specific bug.

---

Revisions:

v2

• Keep lib/shadow.c for musl, which doesn't have these APIs.
• Include libc's <gshadow.h> if available.

$ git range-diff master gh/shadowgrp shadowgrp 
1:  7abca5a1 < -:  -------- configure.ac, lib/, src/: Presume working shadow group support in libc
-:  -------- > 1:  992aedca lib/: Include <gshadow.h> if it's available
-:  -------- > 2:  545bd8de configure.ac, lib/gshadow.c: Presume working shadow group support in libc

v2b

• Remove obsolete comment

$ git range-diff master gh/shadowgrp shadowgrp 
1:  992aedca = 1:  992aedca lib/: Include <gshadow.h> if it's available
2:  545bd8de ! 2:  f7071ba1 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
    @@ configure.ac: AC_CHECK_FUNC(secure_getenv, [AC_DEFINE(HAS_SECURE_GETENV,
     
      ## lib/gshadow.c ##
     @@
    + 
      #include <config.h>
      
    - /* Newer versions of Linux libc already have shadow support.  */
    +-/* Newer versions of Linux libc already have shadow support.  */
     -#if defined(SHADOWGRP) && !defined(HAVE_SHADOWGRP)        /*{ */
     +#if defined(SHADOWGRP) && !defined(HAVE_GSHADOW_H)        /*{ */
      

v3

• Fix compatibility with libc. Patch 1 revealed this incompatibility with libc.

$ git range-diff master gh/shadowgrp shadowgrp 
1:  992aedca = 1:  992aedca lib/: Include <gshadow.h> if it's available
2:  f7071ba1 = 2:  f7071ba1 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
-:  -------- > 3:  8df6b06e lib/gshadow_.h: Fix compatibility with libc's struct sgrp

v3b

• Silence CodeQL warning by reformatting comment

$ git range-diff master gh/shadowgrp shadowgrp 
1:  992aedca = 1:  992aedca lib/: Include <gshadow.h> if it's available
2:  f7071ba1 ! 2:  e0f15b7a configure.ac, lib/gshadow.c: Presume working shadow group support in libc
    @@ lib/gshadow.c
      
     -/* Newer versions of Linux libc already have shadow support.  */
     -#if defined(SHADOWGRP) && !defined(HAVE_SHADOWGRP)        /*{ */
    -+#if defined(SHADOWGRP) && !defined(HAVE_GSHADOW_H)        /*{ */
    ++#if defined(SHADOWGRP) && !defined(HAVE_GSHADOW_H)
      
      #ident "$Id$"
      
    +@@ lib/gshadow.c: int putsgent (const struct sgrp *sgrp, FILE * fp)
    + }
    + #else
    + extern int ISO_C_forbids_an_empty_translation_unit;
    +-#endif                            /*} SHADOWGRP */
    ++#endif  // !SHADOWGRP
3:  8df6b06e = 3:  d8090da9 lib/gshadow_.h: Fix compatibility with libc's struct sgrp

v3c

• Rebase

$ git range-diff alx/master..gh/shadowgrp shadow/master..shadowgrp 
1:  992aedca = 1:  0fb36eda lib/: Include <gshadow.h> if it's available
2:  e0f15b7a = 2:  81334580 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  d8090da9 = 3:  679d7552 lib/gshadow_.h: Fix compatibility with libc's struct sgrp

v3d

• Rebase

$ git range-diff gh/master..gh/shadowgrp shadow/master..shadowgrp 
1:  0fb36eda = 1:  5032a3eb lib/: Include <gshadow.h> if it's available
2:  81334580 = 2:  d8478463 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  679d7552 = 3:  4a78c9cf lib/gshadow_.h: Fix compatibility with libc's struct sgrp

v3e

• Rebase

$ git range-diff master..gh/shadowgrp shadow/master..shadowgrp 
1:  5032a3eb ! 1:  fb73d816 lib/: Include <gshadow.h> if it's available
    @@ lib/gshadow_.h
      
      /*
       * Shadow group security file structure
    -@@ lib/gshadow_.h: int putsgent ();
    - #endif
    +@@ lib/gshadow_.h: void endsgent (void);
    + int putsgent (const struct sgrp *, FILE *);
      
      #define   GSHADOW "/etc/gshadow"
     -#endif                            /* ifndef _H_GSHADOW */
2:  d8478463 = 2:  9a672ed6 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  4a78c9cf ! 3:  f5db1b5c lib/gshadow_.h: Fix compatibility with libc's struct sgrp
    @@ lib/gshadow.c: void endsgent (void)
        setsgent ();
      
        while ((sgrp = getsgent ()) != NULL) {
    --          if (strcmp (name, sgrp->sg_name) == 0) {
    -+          if (strcmp (name, sgrp->sg_namp) == 0) {
    +-          if (streq(name, sgrp->sg_name)) {
    ++          if (streq(name, sgrp->sg_namp)) {
                        break;
                }
        }
    @@ src/grpck.c: static void check_sgr_file (int *errors, bool *changed)
                                continue;
                        }
      
    --                  if (strcmp (sgr->sg_name, ent->sg_name) != 0) {
    -+                  if (strcmp (sgr->sg_namp, ent->sg_namp) != 0) {
    +-                  if (!streq(sgr->sg_name, ent->sg_name)) {
    ++                  if (!streq(sgr->sg_name, ent->sg_namp)) {
                                continue;
                        }
      

v3f

• Rebase

$ git range-diff master..gh/shadowgrp shadow/master..shadowgrp 
1:  fb73d816 = 1:  bbb45215 lib/: Include <gshadow.h> if it's available
2:  9a672ed6 = 2:  a61aead2 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  f5db1b5c = 3:  4f5b8c59 lib/gshadow_.h: Fix compatibility with libc's struct sgrp

v3g

• Fix typo introduced in v3e.

$ git range-diff master gh/shadowgrp shadowgrp 
1:  bbb45215 = 1:  bbb45215 lib/: Include <gshadow.h> if it's available
2:  a61aead2 = 2:  a61aead2 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  4f5b8c59 ! 3:  c8a122a2 lib/gshadow_.h: Fix compatibility with libc's struct sgrp
    @@ src/grpck.c: static void check_sgr_file (int *errors, bool *changed)
                        }
      
     -                  if (!streq(sgr->sg_name, ent->sg_name)) {
    -+                  if (!streq(sgr->sg_name, ent->sg_namp)) {
    ++                  if (!streq(sgr->sg_namp, ent->sg_namp)) {
                                continue;
                        }

v3h

• Rebase

$ git range-diff master..gh/shadowgrp shadow/master..shadowgrp 
1:  bbb45215 = 1:  d2a28602 lib/: Include <gshadow.h> if it's available
2:  a61aead2 = 2:  d9162817 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  c8a122a2 ! 3:  0f40b17b lib/gshadow_.h: Fix compatibility with libc's struct sgrp
    @@ src/groupadd.c: static void new_grent (struct group *grent)
        if (pflg) {
                sgent->sg_passwd = group_passwd;
        } else {
    -@@ src/groupadd.c: static void grp_update (void)
    +@@ src/groupadd.c: grp_update(void)
        if (is_shadow_grp && (sgr_update (&sgrp) == 0)) {
                fprintf (stderr,
                         _("%s: failed to prepare the new %s entry '%s'\n"),
    @@ src/groupmod.c: static void new_grent (struct group *grent)
        }
      
        /* Always update the shadowed password if there is a shadow entry
    -@@ src/groupmod.c: static void grp_update (void)
    +@@ src/groupmod.c: grp_update(void)
                         * gshadow entry when a new password is requested.
                         */
                        bzero(&sgrp, sizeof sgrp);
    @@ src/groupmod.c: static void grp_update (void)
                        sgrp.sg_passwd = xstrdup (grp.gr_passwd);
                        sgrp.sg_adm    = &empty;
                        sgrp.sg_mem    = dup_list (grp.gr_mem);
    -@@ src/groupmod.c: static void grp_update (void)
    +@@ src/groupmod.c: grp_update(void)
                if (sgr_update (&sgrp) == 0) {
                        fprintf (stderr,
                                 _("%s: failed to prepare the new %s entry '%s'\n"),

v3i

• Rebase

$ git range-diff master..gh/shadowgrp shadow/master..shadowgrp 
1:  d2a28602 = 1:  833ddd00 lib/: Include <gshadow.h> if it's available
2:  d9162817 = 2:  5eb151a3 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  0f40b17b ! 3:  4d42143b lib/gshadow_.h: Fix compatibility with libc's struct sgrp
    @@ Commit message
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/gshadow.c ##
    -@@ lib/gshadow.c: void endsgent (void)
    +@@ lib/gshadow.c: sgetsgent(const char *string)
        if (NULL != cp || i != FIELDS)
    -           return 0;
    +           return NULL;
      
     -  sgroup.sg_name = fields[0];
     +  sgroup.sg_namp = fields[0];
        sgroup.sg_passwd = fields[1];
    -   if (0 != nadmins) {
    -           nadmins = 0;
    -@@ lib/gshadow.c: void endsgent (void)
    + 
    +   free(sgroup.sg_adm);
    +@@ lib/gshadow.c: sgetsgent(const char *string)
        setsgent ();
      
        while ((sgrp = getsgent ()) != NULL) {

v3j

• Rebase

$ git range-diff master..gh/shadowgrp shadow/master..shadowgrp 
1:  833ddd00 = 1:  6dbb2331 lib/: Include <gshadow.h> if it's available
2:  5eb151a3 = 2:  5157fed4 configure.ac, lib/gshadow.c: Presume working shadow group support in libc
3:  4d42143b = 3:  0f45349c lib/gshadow_.h: Fix compatibility with libc's struct sgrp

[alejandro-colomar]

Queued after the release of 4.17.0.

[zeha]

If the title stays "presume working shadow group support in libc", then the !defined(HAVE_GSHADOW_H) code should also go, no?

[alejandro-colomar]

If the title stays "presume working shadow group support in libc", then the !defined(HAVE_GSHADOW_H) code should also go, no?

I presume it works if it's there, but I consider the possibility that it doesn't exist.

musl libc for example doesn't have gshadow.h at all.