Clean up lib/utmp.c and lib/logind.c #1290

alejandro-colomar · 2025-07-14T09:37:46Z

Revisions:

v2

Use ENOSYS instead of ENOTSUP [@ikerexxe ]

$ git range-diff shadow/master gh/logind_utmp logind_utmp 
 1:  bfb57d2b =  1:  bfb57d2b lib/logind.c: Fix style
 2:  738ee5d9 =  2:  738ee5d9 lib/logind.c: Remove dead initializations
 3:  00a50759 =  3:  00a50759 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  d3ae3cf1 =  4:  d3ae3cf1 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  98425add =  5:  98425add lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  7c58ee42 =  6:  7c58ee42 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  7f0fee3e =  7:  7f0fee3e lib/utmp.c: get_session_host(): Fix memory leak
 8:  99d5669b !  8:  c47b572f lib/, src/: get_session_host(): Return the host
    @@ lib/utmp.c: get_current_utmp(void)
      #else
     -  *out = NULL;
     -  ret = -2;
    -+  errno = ENOTSUP;
    ++  errno = ENOSYS;
      #endif
     +  host = NULL;
     +out:
 9:  528997fb =  9:  4fcf0a3d lib/string/strdup/: STRNDUP(): Add macro
10:  2361b195 = 10:  f6b6ec9d lib/utmp.c: get_session_host(): Don't exit from library code

v3

Avoid a goto [@hallyn ]

$ git range-diff shadow/master gh/logind_utmp logind_utmp 
 1:  bfb57d2b =  1:  bfb57d2b lib/logind.c: Fix style
 2:  738ee5d9 =  2:  738ee5d9 lib/logind.c: Remove dead initializations
 3:  00a50759 =  3:  00a50759 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  d3ae3cf1 =  4:  d3ae3cf1 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  98425add =  5:  98425add lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  7c58ee42 =  6:  7c58ee42 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  7f0fee3e =  7:  7f0fee3e lib/utmp.c: get_session_host(): Fix memory leak
 -:  -------- >  8:  25bbd1ca lib/utmp.c: get_session_host(): De-duplicate code
 8:  c47b572f !  9:  b40036ec lib/, src/: get_session_host(): Return the host
    @@ lib/utmp.c: get_current_utmp(void)
     +get_session_host(void)
      {
     -  int           ret = 0;
    -+  char          *host;
    ++  char          *host = NULL;
        struct utmpx  *ut;
      
    +-  *out = NULL;
    +-
        ut = get_current_utmp();
      
      #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -   if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
    +-  if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
     -          *out = XSTRNDUP(ut->ut_host);
     -  } else {
    --          *out = NULL;
     -          ret = -2;
    +-  }
    ++  if ((ut != NULL) && (ut->ut_host[0] != '\0'))
     +          host = XSTRNDUP(ut->ut_host);
    -+          goto out;
    -   }
      #else
    --  *out = NULL;
     -  ret = -2;
     +  errno = ENOSYS;
      #endif
    -+  host = NULL;
    -+out:
    ++
        free(ut);
      
     -  return ret;
 9:  4fcf0a3d = 10:  181c56d7 lib/string/strdup/: STRNDUP(): Add macro
10:  f6b6ec9d ! 11:  660b4a26 lib/utmp.c: get_session_host(): Don't exit from library code
    @@ lib/utmp.c
     @@ lib/utmp.c: get_session_host(void)
      
      #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -   if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
    +   if ((ut != NULL) && (ut->ut_host[0] != '\0'))
     -          host = XSTRNDUP(ut->ut_host);
     +          host = STRNDUP(ut->ut_host);
    -           goto out;
    -   }
      #else
    +   errno = ENOSYS;
    + #endif

v4

#include "config.h" with quotes. [@Karlson2k ]

$ git range-diff shadow/master gh/logind_utmp logind_utmp 
 1:  bfb57d2b =  1:  bfb57d2b lib/logind.c: Fix style
 2:  738ee5d9 =  2:  738ee5d9 lib/logind.c: Remove dead initializations
 3:  00a50759 !  3:  2def5951 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
    @@ lib/session_management.h (new)
     +#define SHADOW_INCLUDE_LIB_SESSION_MANAGEMENT_H_
     +
     +
    -+#include <config.h>
    ++#include "config.h"
     +
     +
     +/**
 4:  d3ae3cf1 =  4:  3687176c lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  98425add =  5:  2060d338 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  7c58ee42 =  6:  0df3cd6e lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  7f0fee3e =  7:  85e3c05e lib/utmp.c: get_session_host(): Fix memory leak
 8:  25bbd1ca =  8:  0bfad9c0 lib/utmp.c: get_session_host(): De-duplicate code
 9:  b40036ec !  9:  e3513b02 lib/, src/: get_session_host(): Return the host
    @@ lib/logind.c: ATTR_MALLOC(free) static char *get_session(void);
      ## lib/session_management.h ##
     @@
      
    - #include <config.h>
    + #include "config.h"
      
     +#include <stdlib.h>
      
10:  181c56d7 ! 10:  3ad35e90 lib/string/strdup/: STRNDUP(): Add macro
    @@ lib/string/strdup/strndup.c (new)
     +// SPDX-License-Identifier: BSD-3-Clause
     +
     +
    -+#include <config.h>
    ++#include "config.h"
     +
     +#include "string/strdup/strndup.h"
     
    @@ lib/string/strdup/strndup.h (new)
     +#define SHADOW_INCLUDE_LIB_STRING_STRDUP_STRNDUP_H_
     +
     +
    -+#include <config.h>
    ++#include "config.h"
     +
     +#include <string.h>
     +
11:  660b4a26 = 11:  92829912 lib/utmp.c: get_session_host(): Don't exit from library code

v5

Rebase

$ git rd 
 1:  bfb57d2b !  1:  38b8516c lib/logind.c: Fix style
    @@ lib/logind.c
     - *
     - * SPDX-License-Identifier:  BSD-3-Clause
     - */
    -+// SPDX-FileCopyrightText:  2023, Iker Pedrosa <ipedrosa@redhat.com>
    -+// SPDX-License-Identifier:  BSD-3-Clause
    ++// SPDX-FileCopyrightText: 2023, Iker Pedrosa <ipedrosa@redhat.com>
    ++// SPDX-License-Identifier: BSD-3-Clause
     +
      
    - #include <config.h>
    + #include "config.h"
      
     -#ident "$Id$"
     +#include <systemd/sd-login.h>
    @@ lib/logind.c
      
     -#include <systemd/sd-login.h>
      
    --int get_session_host (char **out)
    +-int get_session_host (char **out, pid_t main_pid)
     +int
    -+get_session_host(char **out)
    ++get_session_host(char **out, pid_t main_pid)
      {
     -    char *host = NULL;
     -    char *session = NULL;
    @@ lib/logind.c
     +  char *session = NULL;
     +  int ret;
      
    --    ret = sd_pid_get_session (getpid(), &session);
    +-    ret = sd_pid_get_session(main_pid, &session);
     -    if (ret < 0) {
     -        return ret;
     -    }
    @@ lib/logind.c
     -    if (ret < 0) {
     -        goto done;
     -    }
    -+  ret = sd_pid_get_session(getpid(), &session);
    ++  ret = sd_pid_get_session(main_pid, &session);
     +  if (ret < 0)
     +          return ret;
     +  ret = sd_session_get_remote_host(session, &host);
 2:  738ee5d9 !  2:  c8e0f20f lib/logind.c: Remove dead initializations
    @@ Commit message
      ## lib/logind.c ##
     @@
      int
    - get_session_host(char **out)
    + get_session_host(char **out, pid_t main_pid)
      {
     -  char *host = NULL;
     -  char *session = NULL;
    @@ lib/logind.c
     +  char  *host;
     +  char  *session;
      
    -   ret = sd_pid_get_session(getpid(), &session);
    +   ret = sd_pid_get_session(main_pid, &session);
        if (ret < 0)
     @@ lib/logind.c: unsigned long
      active_sessions_count(const char *name, MAYBE_UNUSED unsigned long limit)
 3:  2def5951 !  3:  95211a21 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
    @@ lib/limits.c
     
      ## lib/logind.c ##
     @@
    - // SPDX-FileCopyrightText:  2023, Iker Pedrosa <ipedrosa@redhat.com>
    -+// SPDX-FileCopyrightText:  2025, Alejandro Colomar <alx@kernel.org>
    - // SPDX-License-Identifier:  BSD-3-Clause
    + // SPDX-FileCopyrightText: 2023, Iker Pedrosa <ipedrosa@redhat.com>
    ++// SPDX-FileCopyrightText: 2025, Alejandro Colomar <alx@kernel.org>
    + // SPDX-License-Identifier: BSD-3-Clause
      
      
    - #include <config.h>
    + #include "config.h"
      
     +#include "session_management.h"
     +
    @@ lib/prototypes.h: extern int set_filesize_limit (int blocks);
     - * @brief Get host for the current session
     - *
     - * @param[out] out Host name
    +- * @param[in] main_pid the PID of the main process (the parent PID if
    +- *                     the process forked itself)
     - *
     - * @return 0 or a positive integer if the host was obtained properly,
     - *         another value on error.
     - */
    --extern int get_session_host (char **out);
    +-extern int get_session_host (char **out, pid_t main_pid);
     -#ifndef ENABLE_LOGIND
     -/**
     - * @brief Update or create an utmp entry in utmp, wtmp, utmpw, or wtmpx
    @@ lib/prototypes.h: extern int set_filesize_limit (int blocks);
     - * @param[in] user username
     - * @param[in] tty tty
     - * @param[in] host hostname
    +- * @param[in] main_pid the PID of the main process (the parent PID if
    +- *                     the process forked itself)
     - *
     - * @return 0 if utmp was updated properly,
     - *         1 on error.
     - */
     -extern int update_utmp (const char *user,
     -                        const char *tty,
    --                        const char *host);
    +-                        const char *host,
    +-                        pid_t main_pid);
     -/**
     - * @brief Update the cumulative failure log
     - *
     - * @param[in] failent_user username
     - * @param[in] tty tty
     - * @param[in] host hostname
    +- * @param[in] main_pid the PID of the main process (the parent PID if
    +- *                     the process forked itself)
     - *
     - */
     -extern void record_failure(const char *failent_user,
     -                           const char *tty,
    --                           const char *hostname);
    +-                           const char *hostname,
    +-                           pid_t main_pid);
     -#endif /* ENABLE_LOGIND */
     -
     -/**
    @@ lib/session_management.h (new)
     +
     +#include "config.h"
     +
    ++#include <sys/types.h>
    ++
     +
     +/**
     + * @brief Get host for the current session
     + *
     + * @param[out] out Host name
    ++ * @param[in] main_pid the PID of the main process (the parent PID if
    ++ *                     the process forked itself)
     + *
     + * @return 0 or a positive integer if the host was obtained properly,
     + *         another value on error.
     + */
    -+int get_session_host(char **out);
    ++int get_session_host(char **out, pid_t main_pid);
     +
     +
     +#if !defined(ENABLE_LOGIND)
    @@ lib/session_management.h (new)
     + * @param[in] user username
     + * @param[in] tty tty
     + * @param[in] host hostname
    ++ * @param[in] main_pid the PID of the main process (the parent PID if
    ++ *                     the process forked itself)
     + *
     + * @return 0 if utmp was updated properly,
     + *         1 on error.
     + */
    -+int update_utmp(const char *user, const char *tty, const char *host);
    ++int update_utmp(const char *user, const char *tty, const char *host,
    ++    pid_t main_pid);
     +/**
     + * @brief Update the cumulative failure log
     + *
     + * @param[in] failent_user username
     + * @param[in] tty tty
     + * @param[in] host hostname
    ++ * @param[in] main_pid the PID of the main process (the parent PID if
    ++ *                     the process forked itself)
     + *
     + */
     +void record_failure(const char *failent_user, const char *tty,
    -+    const char *hostname);
    ++    const char *hostname, pid_t main_pid);
     +#endif /* !ENABLE_LOGIND */
     +
     +
    @@ lib/session_management.h (new)
      ## lib/utmp.c ##
     @@
      
    - #include <config.h>
    + #include "config.h"
      
     +#include "session_management.h"
     +
 4:  3687176c !  4:  bb38cff0 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
    @@ Commit message
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/logind.c ##
    -@@ lib/logind.c: get_session_host(char **out)
    +@@ lib/logind.c: get_session_host(char **out, pid_t main_pid)
        if (ret < 0)
                return ret;
        ret = sd_session_get_remote_host(session, &host);
 5:  2060d338 !  5:  5d73f429 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
    @@ lib/logind.c
     +#include <pwd.h>
     +#include <stddef.h>
     +#include <stdlib.h>
    ++#include <sys/types.h>
     +#include <unistd.h>
     +
      #include <systemd/sd-login.h>
    @@ lib/logind.c
      #include "prototypes.h"
      
      
    -+ATTR_MALLOC(free) static char *get_session(void);
    ++ATTR_MALLOC(free) static char *pid_get_session(pid_t pid);
     +
     +
      int
    - get_session_host(char **out)
    + get_session_host(char **out, pid_t main_pid)
      {
    -@@ lib/logind.c: get_session_host(char **out)
    +@@ lib/logind.c: get_session_host(char **out, pid_t main_pid)
        char  *host;
        char  *session;
      
    --  ret = sd_pid_get_session(getpid(), &session);
    +-  ret = sd_pid_get_session(main_pid, &session);
     -  if (ret < 0)
     -          return ret;
    -+  session = get_session();
    ++  session = pid_get_session(main_pid);
     +  if (session == NULL)
     +          return errno;
     +
        ret = sd_session_get_remote_host(session, &host);
        free(session);
        if (ret < 0)
    -@@ lib/logind.c: get_session_host(char **out)
    +@@ lib/logind.c: get_session_host(char **out, pid_t main_pid)
        return 0;
      }
      
    @@ lib/logind.c: active_sessions_count(const char *name, MAYBE_UNUSED unsigned long
     +
     +
     +static char *
    -+get_session(void)
    ++pid_get_session(pid_t pid)
     +{
     +  int   e;
     +  char  *session;
     +
    -+  e = sd_pid_get_session(getpid(), &session);
    ++  e = sd_pid_get_session(pid, &session);
     +  if (e < 0) {
     +          errno = -e;
     +          return NULL;
 6:  0df3cd6e !  6:  f4e39432 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
    @@ lib/logind.c
     @@
      
      
    - ATTR_MALLOC(free) static char *get_session(void);
    + ATTR_MALLOC(free) static char *pid_get_session(pid_t pid);
     +ATTR_MALLOC(free) static char *session_get_remote_host(char *session);
      
      
      int
    - get_session_host(char **out)
    + get_session_host(char **out, pid_t main_pid)
      {
     -  int   ret;
        char  *host;
        char  *session;
      
    -@@ lib/logind.c: get_session_host(char **out)
    +@@ lib/logind.c: get_session_host(char **out, pid_t main_pid)
        if (session == NULL)
                return errno;
      
    @@ lib/logind.c: get_session_host(char **out)
      
        *out = host;
        return 0;
    -@@ lib/logind.c: get_session(void)
    +@@ lib/logind.c: pid_get_session(pid_t pid)
      
        return session;
      }
 7:  85e3c05e !  7:  5708040f lib/utmp.c: get_session_host(): Fix memory leak
    @@ Commit message
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/utmp.c ##
    -@@ lib/utmp.c: get_session_host(char **out)
    +@@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
      #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
        if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
                *out = XSTRNDUP(ut->ut_host);
    @@ lib/utmp.c: get_session_host(char **out)
        } else {
                *out = NULL;
                ret = -2;
    -@@ lib/utmp.c: get_session_host(char **out)
    +@@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
        *out = NULL;
        ret = -2;
      #endif
 8:  0bfad9c0 !  8:  4525e661 lib/utmp.c: get_session_host(): De-duplicate code
    @@ Commit message
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/utmp.c ##
    -@@ lib/utmp.c: get_session_host(char **out)
    +@@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
        int           ret = 0;
        struct utmpx  *ut;
      
     +  *out = NULL;
     +
    -   ut = get_current_utmp();
    +   ut = get_current_utmp(main_pid);
      
      #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
        if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
 9:  e3513b02 !  9:  b581254e lib/, src/: get_session_host(): Return the host
    @@ Commit message
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/logind.c ##
    -@@ lib/logind.c: ATTR_MALLOC(free) static char *get_session(void);
    +@@ lib/logind.c: ATTR_MALLOC(free) static char *pid_get_session(pid_t pid);
      ATTR_MALLOC(free) static char *session_get_remote_host(char *session);
      
      
     -int
    --get_session_host(char **out)
    +-get_session_host(char **out, pid_t main_pid)
     +char *
    -+get_session_host(void)
    ++get_session_host(pid_t main_pid)
      {
        char  *host;
        char  *session;
      
    -   session = get_session();
    +   session = pid_get_session(main_pid);
        if (session == NULL)
     -          return errno;
     +          return NULL;
    @@ lib/session_management.h
      #include "config.h"
      
     +#include <stdlib.h>
    + #include <sys/types.h>
    + 
    ++#include "attr.h"
      
     -/**
     - * @brief Get host for the current session
     - *
     - * @param[out] out Host name
    +- * @param[in] main_pid the PID of the main process (the parent PID if
    +- *                     the process forked itself)
     - *
     - * @return 0 or a positive integer if the host was obtained properly,
     - *         another value on error.
     - */
    --int get_session_host(char **out);
    -+#include "attr.h"
    -+
    +-int get_session_host(char **out, pid_t main_pid);
     +
     +ATTR_MALLOC(free)
    -+char *get_session_host(void);
    ++char *get_session_host(pid_t main_pid);
      
      
      #if !defined(ENABLE_LOGIND)
     
      ## lib/utmp.c ##
    -@@ lib/utmp.c: get_current_utmp(void)
    +@@ lib/utmp.c: get_current_utmp(pid_t main_pid)
      }
      
      
     -int
    --get_session_host(char **out)
    +-get_session_host(char **out, pid_t main_pid)
     +char *
    -+get_session_host(void)
    ++get_session_host(pid_t main_pid)
      {
     -  int           ret = 0;
     +  char          *host = NULL;
    @@ lib/utmp.c: get_current_utmp(void)
      
     -  *out = NULL;
     -
    -   ut = get_current_utmp();
    +   ut = get_current_utmp(main_pid);
      
      #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
     -  if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
    @@ lib/utmp.c: get_current_utmp(void)
     
      ## src/login.c ##
     @@ src/login.c: int main (int argc, char **argv)
    -           exit (1);       /* must be a terminal */
        }
      
    --  err = get_session_host(&host);
    -+  host = get_session_host();
    +   initial_pid = getpid();
    +-  err = get_session_host(&host, initial_pid);
    ++  host = get_session_host(initial_pid);
        /*
         * Be picky if run by normal users (possible if installed setuid
         * root), but not if run by root.
10:  3ad35e90 = 10:  6b2491e3 lib/string/strdup/: STRNDUP(): Add macro
11:  92829912 ! 11:  efff3048 lib/utmp.c: get_session_host(): Don't exit from library code
    @@ lib/utmp.c
      
      #define UTX_LINESIZE  countof(memberof(struct utmpx, ut_line))
      
    -@@ lib/utmp.c: get_session_host(void)
    +@@ lib/utmp.c: get_session_host(pid_t main_pid)
      
      #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
        if ((ut != NULL) && (ut->ut_host[0] != '\0'))

v6

Assume ut_host exists.

$ git range-diff shadow/master gh/logind_utmp logind_utmp 
 1:  38b8516c =  1:  38b8516c lib/logind.c: Fix style
 2:  c8e0f20f =  2:  c8e0f20f lib/logind.c: Remove dead initializations
 3:  95211a21 =  3:  95211a21 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  bb38cff0 =  4:  bb38cff0 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  5d73f429 =  5:  5d73f429 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  f4e39432 =  6:  f4e39432 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  5708040f =  7:  5708040f lib/utmp.c: get_session_host(): Fix memory leak
 8:  4525e661 =  8:  4525e661 lib/utmp.c: get_session_host(): De-duplicate code
 9:  b581254e =  9:  b581254e lib/, src/: get_session_host(): Return the host
10:  6b2491e3 = 10:  6b2491e3 lib/string/strdup/: STRNDUP(): Add macro
11:  efff3048 = 11:  efff3048 lib/utmp.c: get_session_host(): Don't exit from library code
 -:  -------- > 12:  f22dfbd7 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host

v7

Reorder commits, so that one can be dropped, and an initialization can be replaced by an assignment.

$ git range-diff shadow/master gh/logind_utmp logind_utmp 
 1:  38b8516c =  1:  38b8516c lib/logind.c: Fix style
 2:  c8e0f20f =  2:  c8e0f20f lib/logind.c: Remove dead initializations
 3:  95211a21 =  3:  95211a21 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  bb38cff0 =  4:  bb38cff0 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  5d73f429 =  5:  5d73f429 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  f4e39432 =  6:  f4e39432 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  5708040f <  -:  -------- lib/utmp.c: get_session_host(): Fix memory leak
 8:  4525e661 <  -:  -------- lib/utmp.c: get_session_host(): De-duplicate code
12:  f22dfbd7 !  7:  ffa5ad10 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
    @@ configure.ac: AC_SYS_LARGEFILE
                        struct utmpx.ut_addr_v6,
     
      ## lib/utmp.c ##
    -@@ lib/utmp.c: get_session_host(pid_t main_pid)
    +@@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
      
        ut = get_current_utmp(main_pid);
      
     -#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -   if ((ut != NULL) && (ut->ut_host[0] != '\0'))
    -           host = STRNDUP(ut->ut_host);
    +   if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
    +           *out = XSTRNDUP(ut->ut_host);
    +           free (ut);
    +@@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
    +           *out = NULL;
    +           ret = -2;
    +   }
     -#else
    --  errno = ENOSYS;
    +-  *out = NULL;
    +-  ret = -2;
     -#endif
      
    -   free(ut);
    - 
    +   return ret;
    + }
     @@ lib/utmp.c: prepare_utmp(const char *name, const char *line, const char *host,
      
        if (NULL != host && !streq(host, ""))
 -:  -------- >  8:  f78826d0 lib/utmp.c: get_session_host(): Fix memory leak
 9:  b581254e !  9:  806dff1b lib/, src/: get_session_host(): Return the host
    @@ lib/utmp.c: get_current_utmp(pid_t main_pid)
     +get_session_host(pid_t main_pid)
      {
     -  int           ret = 0;
    -+  char          *host = NULL;
    ++  char          *host;
        struct utmpx  *ut;
      
    --  *out = NULL;
    --
        ut = get_current_utmp(main_pid);
      
    - #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
     -  if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
     -          *out = XSTRNDUP(ut->ut_host);
     -  } else {
    +-          *out = NULL;
     -          ret = -2;
     -  }
     +  if ((ut != NULL) && (ut->ut_host[0] != '\0'))
     +          host = XSTRNDUP(ut->ut_host);
    - #else
    --  ret = -2;
    -+  errno = ENOSYS;
    - #endif
    -+
    ++  else
    ++          host = NULL;
    + 
        free(ut);
      
     -  return ret;
10:  6b2491e3 = 10:  ab38ff9d lib/string/strdup/: STRNDUP(): Add macro
11:  efff3048 ! 11:  5a2eb4e8 lib/utmp.c: get_session_host(): Don't exit from library code
    @@ lib/utmp.c
      #define UTX_LINESIZE  countof(memberof(struct utmpx, ut_line))
      
     @@ lib/utmp.c: get_session_host(pid_t main_pid)
    +   ut = get_current_utmp(main_pid);
      
    - #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
        if ((ut != NULL) && (ut->ut_host[0] != '\0'))
     -          host = XSTRNDUP(ut->ut_host);
     +          host = STRNDUP(ut->ut_host);
    - #else
    -   errno = ENOSYS;
    - #endif
    +   else
    +           host = NULL;
    +

$ git diff gh/logind_utmp 
diff --git c/lib/utmp.c w/lib/utmp.c
index 4cc7a394..52f9303c 100644
--- c/lib/utmp.c
+++ w/lib/utmp.c
@@ -189,13 +189,15 @@ get_current_utmp(pid_t main_pid)
 char *
 get_session_host(pid_t main_pid)
 {
-       char          *host = NULL;
+       char          *host;
        struct utmpx  *ut;
 
        ut = get_current_utmp(main_pid);
 
        if ((ut != NULL) && (ut->ut_host[0] != '\0'))
                host = STRNDUP(ut->ut_host);
+       else
+               host = NULL;
 
        free(ut);

v7b

Rebase

$ git rd 
 1:  38b8516c =  1:  0b8acee3 lib/logind.c: Fix style
 2:  c8e0f20f =  2:  7a7842e5 lib/logind.c: Remove dead initializations
 3:  95211a21 =  3:  c9b6f10d lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  bb38cff0 =  4:  d0074ac2 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  5d73f429 =  5:  2e182f2d lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  f4e39432 =  6:  4d6d25d2 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  ffa5ad10 =  7:  198abd73 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  f78826d0 =  8:  a3667fdf lib/utmp.c: get_session_host(): Fix memory leak
 9:  806dff1b =  9:  2a51a80e lib/, src/: get_session_host(): Return the host
10:  ab38ff9d = 10:  586f4554 lib/string/strdup/: STRNDUP(): Add macro
11:  5a2eb4e8 = 11:  540e2dbe lib/utmp.c: get_session_host(): Don't exit from library code

v8

Rebase. The fix for the memory leak has already been merged separately.

$ git rd 
 1:  0b8acee3 =  1:  3620b38e lib/logind.c: Fix style
 2:  7a7842e5 =  2:  ed3ae816 lib/logind.c: Remove dead initializations
 3:  c9b6f10d =  3:  b811b97c lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  d0074ac2 =  4:  7004410c lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  2e182f2d =  5:  2f59752b lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  4d6d25d2 =  6:  eda9907a lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  198abd73 !  7:  29bc7157 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
    @@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
     -#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
        if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
                *out = XSTRNDUP(ut->ut_host);
    -           free (ut);
    -@@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
    +   } else {
                *out = NULL;
                ret = -2;
        }
    @@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
     -  ret = -2;
     -#endif
      
    -   return ret;
    - }
    +   free(ut);
    + 
     @@ lib/utmp.c: prepare_utmp(const char *name, const char *line, const char *host,
      
        if (NULL != host && !streq(host, ""))
 8:  a3667fdf <  -:  -------- lib/utmp.c: get_session_host(): Fix memory leak
 9:  2a51a80e =  8:  7e7fcc3b lib/, src/: get_session_host(): Return the host
10:  586f4554 =  9:  89a53850 lib/string/strdup/: STRNDUP(): Add macro
11:  540e2dbe = 10:  e0bdc496 lib/utmp.c: get_session_host(): Don't exit from library code

v8b

Rebase

$ git rd 
 1:  3620b38e =  1:  24a29ca2 lib/logind.c: Fix style
 2:  ed3ae816 =  2:  18cf9dd8 lib/logind.c: Remove dead initializations
 3:  b811b97c =  3:  2b41b114 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  7004410c =  4:  795d0c23 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  2f59752b =  5:  6dd5e258 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  eda9907a =  6:  564522f7 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  29bc7157 =  7:  7662e3b6 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  7e7fcc3b =  8:  b810ce7a lib/, src/: get_session_host(): Return the host
 9:  89a53850 =  9:  4d7b55c1 lib/string/strdup/: STRNDUP(): Add macro
10:  e0bdc496 = 10:  95781090 lib/utmp.c: get_session_host(): Don't exit from library code

v8c

Rebase

$ git rd 
 1:  24a29ca2 =  1:  0d758316 lib/logind.c: Fix style
 2:  18cf9dd8 =  2:  0d68bd32 lib/logind.c: Remove dead initializations
 3:  2b41b114 !  3:  0c41d4bc lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
    @@ lib/Makefile.am: libshadow_la_SOURCES = \
     +  session_management.h \
        setugid.c \
        setupenv.c \
    -   sgetgrent.c \
    +   sgroupio.c \
     
      ## lib/limits.c ##
     @@
    @@ src/login.c
      #include "prototypes.h"
      #include "pwauth.h"
     +#include "session_management.h"
    + #include "shadow/gshadow/endsgent.h"
      #include "shadowlog.h"
      #include "string/memset/memzero.h"
    - #include "string/sprintf/snprintf.h"
     
      ## tests/unit/test_logind.c ##
     @@
 4:  795d0c23 =  4:  0d30f58e lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  6dd5e258 =  5:  cd722c36 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  564522f7 =  6:  1373b72e lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  7662e3b6 =  7:  9e384d21 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  b810ce7a =  8:  ff162ed1 lib/, src/: get_session_host(): Return the host
 9:  4d7b55c1 =  9:  0a6f87fe lib/string/strdup/: STRNDUP(): Add macro
10:  95781090 = 10:  b0a25760 lib/utmp.c: get_session_host(): Don't exit from library code

v8d

Rebase

$ git rd 
 1:  0d758316 =  1:  349d8b91 lib/logind.c: Fix style
 2:  0d68bd32 =  2:  0d263a98 lib/logind.c: Remove dead initializations
 3:  0c41d4bc =  3:  a73bcad3 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  0d30f58e =  4:  57b99743 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  cd722c36 =  5:  5dbb748d lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  1373b72e =  6:  13e84d28 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  9e384d21 !  7:  0060878e configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
    @@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
        ut = get_current_utmp(main_pid);
      
     -#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -   if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
    +   if ((ut != NULL) && !STRNEQ(ut->ut_host, "")) {
                *out = XSTRNDUP(ut->ut_host);
        } else {
                *out = NULL;
    @@ lib/utmp.c: prepare_utmp(const char *name, const char *line, const char *host,
        if (NULL != host && !streq(host, ""))
                hostname = xstrdup(host);
     -#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -   else if (NULL != ut && '\0' != ut->ut_host[0])
    +   else if (NULL != ut && !STRNEQ(ut->ut_host, ""))
                hostname = XSTRNDUP(ut->ut_host);
     -#endif
      
 8:  ff162ed1 !  8:  96656408 lib/, src/: get_session_host(): Return the host
    @@ lib/utmp.c: get_current_utmp(pid_t main_pid)
      
        ut = get_current_utmp(main_pid);
      
    --  if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
    +-  if ((ut != NULL) && !STRNEQ(ut->ut_host, "")) {
     -          *out = XSTRNDUP(ut->ut_host);
     -  } else {
     -          *out = NULL;
     -          ret = -2;
     -  }
    -+  if ((ut != NULL) && (ut->ut_host[0] != '\0'))
    ++  if ((ut != NULL) && !STRNEQ(ut->ut_host, ""))
     +          host = XSTRNDUP(ut->ut_host);
     +  else
     +          host = NULL;
 9:  0a6f87fe =  9:  d4e014fd lib/string/strdup/: STRNDUP(): Add macro
10:  b0a25760 ! 10:  068b363a lib/utmp.c: get_session_host(): Don't exit from library code
    @@ lib/utmp.c
     @@ lib/utmp.c: get_session_host(pid_t main_pid)
        ut = get_current_utmp(main_pid);
      
    -   if ((ut != NULL) && (ut->ut_host[0] != '\0'))
    +   if ((ut != NULL) && !STRNEQ(ut->ut_host, ""))
     -          host = XSTRNDUP(ut->ut_host);
     +          host = STRNDUP(ut->ut_host);
        else

v8e

Rebase

$ git rd 
 1:  349d8b91 =  1:  6c09587d lib/logind.c: Fix style
 2:  0d263a98 =  2:  74ebeb4e lib/logind.c: Remove dead initializations
 3:  a73bcad3 =  3:  d50ae442 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  57b99743 =  4:  281ffa0c lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  5dbb748d =  5:  4b92d013 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  13e84d28 =  6:  254a7685 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  0060878e =  7:  06979f29 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  96656408 =  8:  5d171b63 lib/, src/: get_session_host(): Return the host
 9:  d4e014fd <  -:  -------- lib/string/strdup/: STRNDUP(): Add macro
10:  068b363a !  9:  df67d51c lib/utmp.c: get_session_host(): Don't exit from library code
    @@ Commit message
     
      ## lib/utmp.c ##
     @@
    - #include "string/strcmp/strprefix.h"
    - #include "string/strcpy/strncpy.h"
    - #include "string/strcpy/strtcpy.h"
    -+#include "string/strdup/strndup.h"
    - #include "string/strdup/xstrdup.h"
    - #include "string/strdup/xstrndup.h"
    + #include "string/strdup/strdup.h"
    + #include "string/strdup/strndup.h"
      
     -#ident "$Id$"
     -

v8f

Rebase

$ git rd 
 1:  6c09587d7 =  1:  c18caaa37 lib/logind.c: Fix style
 2:  74ebeb4e3 =  2:  c798fcd63 lib/logind.c: Remove dead initializations
 3:  d50ae4428 =  3:  483d42d2e lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  281ffa0ce =  4:  9881c93bf lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  4b92d0134 =  5:  518c85f84 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  254a76857 =  6:  b11e0591d lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  06979f29d =  7:  c57159485 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  5d171b63a =  8:  956d7b1b8 lib/, src/: get_session_host(): Return the host
 9:  df67d51ce =  9:  92b948da6 lib/utmp.c: get_session_host(): Don't exit from library code

v9

Rebase

$ git rd 
 1:  c18caaa37 =  1:  cf6e0a530 lib/logind.c: Fix style
 2:  c798fcd63 =  2:  387e3dc77 lib/logind.c: Remove dead initializations
 3:  483d42d2e !  3:  c053d9788 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
    @@ lib/Makefile.am: libshadow_la_SOURCES = \
     
      ## lib/limits.c ##
     @@
    - #include "atoi/a2i/a2i.h"
    - #include "atoi/a2i/a2s.h"
    - #include "atoi/str2i.h"
    + #include <sys/resource.h>
    + 
    + #include "atoi/a2i.h"
     +#include "session_management.h"
      #include "string/memset/memzero.h"
      #include "string/strcmp/streq.h"
 4:  9881c93bf =  4:  860932760 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  518c85f84 =  5:  9b656d919 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  b11e0591d =  6:  b68223ef0 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  c57159485 !  7:  9860f2d7b configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
    @@ lib/utmp.c: get_session_host(char **out, pid_t main_pid)
        ut = get_current_utmp(main_pid);
      
     -#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -   if ((ut != NULL) && !STRNEQ(ut->ut_host, "")) {
    -           *out = XSTRNDUP(ut->ut_host);
    +   if ((ut != NULL) && !strneq_a(ut->ut_host, "")) {
    +           *out = xstrndup_a(ut->ut_host);
        } else {
                *out = NULL;
                ret = -2;
    @@ lib/utmp.c: prepare_utmp(const char *name, const char *line, const char *host,
        if (NULL != host && !streq(host, ""))
                hostname = xstrdup(host);
     -#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -   else if (NULL != ut && !STRNEQ(ut->ut_host, ""))
    -           hostname = XSTRNDUP(ut->ut_host);
    +   else if (NULL != ut && !strneq_a(ut->ut_host, ""))
    +           hostname = xstrndup_a(ut->ut_host);
     -#endif
      
        line = strprefix(line, "/dev/") ?: line;
      
     @@ lib/utmp.c: prepare_utmp(const char *name, const char *line, const char *host,
    -   STRNCPY(utent->ut_user, name);
    +   strncpy_a(utent->ut_user, name);
        if (NULL != hostname) {
                struct addrinfo *info = NULL;
     -#if defined(HAVE_STRUCT_UTMPX_UT_HOST)
    -           STRNCPY(utent->ut_host, hostname);
    +           strncpy_a(utent->ut_host, hostname);
     -#endif
      #if defined(HAVE_STRUCT_UTMPX_UT_SYSLEN)
    -           utent->ut_syslen = MIN (strlen (hostname),
    -                                   sizeof (utent->ut_host));
    +           utent->ut_syslen = MIN(strlen(hostname),
    +                                  sizeof(utent->ut_host));
 8:  956d7b1b8 !  8:  e53233ea0 lib/, src/: get_session_host(): Return the host
    @@ lib/utmp.c: get_current_utmp(pid_t main_pid)
      
        ut = get_current_utmp(main_pid);
      
    --  if ((ut != NULL) && !STRNEQ(ut->ut_host, "")) {
    --          *out = XSTRNDUP(ut->ut_host);
    +-  if ((ut != NULL) && !strneq_a(ut->ut_host, "")) {
    +-          *out = xstrndup_a(ut->ut_host);
     -  } else {
     -          *out = NULL;
     -          ret = -2;
     -  }
    -+  if ((ut != NULL) && !STRNEQ(ut->ut_host, ""))
    -+          host = XSTRNDUP(ut->ut_host);
    ++  if ((ut != NULL) && !strneq_a(ut->ut_host, ""))
    ++          host = xstrndup_a(ut->ut_host);
     +  else
     +          host = NULL;
      
 9:  92b948da6 !  9:  915a86c49 lib/utmp.c: get_session_host(): Don't exit from library code
    @@ lib/utmp.c
     @@ lib/utmp.c: get_session_host(pid_t main_pid)
        ut = get_current_utmp(main_pid);
      
    -   if ((ut != NULL) && !STRNEQ(ut->ut_host, ""))
    --          host = XSTRNDUP(ut->ut_host);
    -+          host = STRNDUP(ut->ut_host);
    +   if ((ut != NULL) && !strneq_a(ut->ut_host, ""))
    +-          host = xstrndup_a(ut->ut_host);
    ++          host = strndup_a(ut->ut_host);
        else
                host = NULL;

v9b

Rebase

$ git rd 
 1:  cf6e0a530 !  1:  f69fdadcd lib/logind.c: Fix style
    @@ lib/logind.c
     +  return ret;
      }
      
    --unsigned long active_sessions_count(const char *name, MAYBE_UNUSED unsigned long limit)
    +-unsigned long active_sessions_count(const char *name, unsigned long)
     +unsigned long
    -+active_sessions_count(const char *name, MAYBE_UNUSED unsigned long limit)
    ++active_sessions_count(const char *name, unsigned long)
      {
     -    struct passwd *pw;
     -    unsigned long count = 0;
 2:  387e3dc77 !  2:  b55bff9e2 lib/logind.c: Remove dead initializations
    @@ lib/logind.c
        ret = sd_pid_get_session(main_pid, &session);
        if (ret < 0)
     @@ lib/logind.c: unsigned long
    - active_sessions_count(const char *name, MAYBE_UNUSED unsigned long limit)
    + active_sessions_count(const char *name, unsigned long)
      {
        struct passwd  *pw;
     -  unsigned long  count = 0;
 3:  c053d9788 =  3:  30e4c5cc5 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  860932760 =  4:  05e995aba lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  9b656d919 !  5:  f23660579 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
    @@ lib/logind.c: get_session_host(char **out, pid_t main_pid)
      
     +
      unsigned long
    - active_sessions_count(const char *name, MAYBE_UNUSED unsigned long limit)
    + active_sessions_count(const char *name, unsigned long)
      {
    -@@ lib/logind.c: active_sessions_count(const char *name, MAYBE_UNUSED unsigned long limit)
    +@@ lib/logind.c: active_sessions_count(const char *name, unsigned long)
      
        return sd_uid_get_sessions(pw->pw_uid, 0, NULL);
      }
 6:  b68223ef0 =  6:  674758db6 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  9860f2d7b =  7:  2a930aec9 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  e53233ea0 =  8:  80ad1e17c lib/, src/: get_session_host(): Return the host
 9:  915a86c49 =  9:  d74433aff lib/utmp.c: get_session_host(): Don't exit from library code

v9c

Rebase

$ git rd 
 1:  f69fdadcd =  1:  e74f7e82f lib/logind.c: Fix style
 2:  b55bff9e2 =  2:  a8dde7fd2 lib/logind.c: Remove dead initializations
 3:  30e4c5cc5 =  3:  61ab7f271 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  05e995aba =  4:  118ea850c lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  f23660579 =  5:  f6eb8d3ce lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  674758db6 =  6:  d4722075f lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  2a930aec9 =  7:  f768e928a configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  80ad1e17c =  8:  e3d6429ef lib/, src/: get_session_host(): Return the host
 9:  d74433aff =  9:  0b1916810 lib/utmp.c: get_session_host(): Don't exit from library code

v9d

Rebase

$ git rd 
 1:  e74f7e82f !  1:  f96e4d3e3 lib/logind.c: Fix style
    @@ lib/logind.c
     +int
     +get_session_host(char **out, pid_t main_pid)
      {
    --    char *host = NULL;
    --    char *session = NULL;
    --    int ret;
    -+  char *host = NULL;
    -+  char *session = NULL;
    -+  int ret;
    +   char *host = NULL;
    +   char *session = NULL;
    +   int ret;
      
    --    ret = sd_pid_get_session(main_pid, &session);
    --    if (ret < 0) {
    --        return ret;
    --    }
    --    ret = sd_session_get_remote_host (session, &host);
    --    if (ret < 0) {
    --        goto done;
    --    }
    -+  ret = sd_pid_get_session(main_pid, &session);
    +   ret = sd_pid_get_session(main_pid, &session);
    +-  if (ret < 0) {
     +  if (ret < 0)
    -+          return ret;
    +           return ret;
    +-  }
    +-  ret = sd_session_get_remote_host (session, &host);
    +-  if (ret < 0) {
     +  ret = sd_session_get_remote_host(session, &host);
     +  if (ret < 0)
    -+          goto done;
    +           goto done;
    +-  }
      
    --    *out = host;
    -+  *out = host;
    +   *out = host;
      
      done:
    --    free (session);
    --    return ret;
    +-  free (session);
     +  free(session);
    -+  return ret;
    +   return ret;
      }
      
     -unsigned long active_sessions_count(const char *name, unsigned long)
     +unsigned long
     +active_sessions_count(const char *name, unsigned long)
      {
    --    struct passwd *pw;
    --    unsigned long count = 0;
    +-  struct passwd *pw;
    +-  unsigned long count = 0;
     +  struct passwd  *pw;
     +  unsigned long  count = 0;
      
    --    pw = prefix_getpwnam(name);
    --    if (pw == NULL) {
    --        return 0;
    --    }
    -+  pw = prefix_getpwnam(name);
    +   pw = prefix_getpwnam(name);
    +-  if (pw == NULL) {
     +  if (pw == NULL)
    -+          return 0;
    +           return 0;
    +-  }
      
    --    count = sd_uid_get_sessions(pw->pw_uid, 0, NULL);
    -+  count = sd_uid_get_sessions(pw->pw_uid, 0, NULL);
    +   count = sd_uid_get_sessions(pw->pw_uid, 0, NULL);
      
    --    return count;
    -+  return count;
    - }
 2:  a8dde7fd2 =  2:  b856606ff lib/logind.c: Remove dead initializations
 3:  61ab7f271 =  3:  19ab9808d lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  118ea850c =  4:  e7b6815c9 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  f6eb8d3ce =  5:  a9dc7f2c2 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  d4722075f =  6:  b5e03d2cf lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  f768e928a =  7:  6bd288bdc configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  e3d6429ef =  8:  cd222c9a4 lib/, src/: get_session_host(): Return the host
 9:  0b1916810 =  9:  90d143294 lib/utmp.c: get_session_host(): Don't exit from library code

v9e

Rebase

$ git rd 
 1:  f96e4d3e3 =  1:  c23ea493b lib/logind.c: Fix style
 2:  b856606ff =  2:  ba2dcc101 lib/logind.c: Remove dead initializations
 3:  19ab9808d =  3:  b1eb7cf46 lib/: Move utmp.c and logind.c prototypes to new "session_management.h" header
 4:  e7b6815c9 =  4:  c6a237046 lib/logind.c: get_session_host(): free() earlier, to avoid a goto
 5:  a9dc7f2c2 =  5:  939af47a2 lib/logind.c: Wrap libsystemd function in our wrapper get_session()
 6:  b5e03d2cf =  6:  bf8f26a92 lib/logind.c: Wrap libsystemd function in our wrapper session_get_remote_host()
 7:  6bd288bdc =  7:  ed3e417f2 configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host
 8:  cd222c9a4 =  8:  2cc25621f lib/, src/: get_session_host(): Return the host
 9:  90d143294 =  9:  1a6a0ee41 lib/utmp.c: get_session_host(): Don't exit from library code

Karlson2k

I'd move interfaces to special headers, like "utmp_functions.h" and "logind_functions.h" and name functions differently, to avoid potential conflict.
This would also give you a freedom to use different prototypes: for example logind_active_sessions_count() could have two parameters (without limit), while utmp_active_sessions_count() could have two parameters.

A third header "session_management.h" can include first two headers and route function calls to the real implementation.
For example:

#ifdef ENABLE_LOGIND
#define active_sessions_count(name, limit) logind_active_sessions_count(name)
#else
#define active_sessions_count(name, limit) utmp_active_sessions_count(name, limit)
#endif

This way you may skip some preprocessor macros in main code and get better optimisation even without LTO.

alejandro-colomar · 2025-07-14T16:01:18Z

I'd move interfaces to special headers, like "utmp_functions.h" and "logind_functions.h" and name functions differently, to avoid potential conflict. This would also give you a freedom to use different prototypes: for example logind_active_sessions_count() could have two parameters (without limit), while utmp_active_sessions_count() could have two parameters.

A third header "session_management.h" can include first two headers and route function calls to the real implementation. For example:
#ifdef ENABLE_LOGIND
#define active_sessions_count(name, limit) logind_active_sessions_count(name)
#else
#define active_sessions_count(name, limit) utmp_active_sessions_count(name, limit)
#endif
This way you may skip some preprocessor macros in main code and get better optimisation even without LTO.

I'd like to have a look at that after the fixes to the build system. I'm not familiar with autotools, and this kind of thing will require some conditionals there, I guess. Let's do this round of refactors first, and then we'll see what else we can improve.

alejandro-colomar · 2025-07-14T21:39:46Z

@ikerexxe , please have a look at this, so that it's easier for @Karlson2k to apply patches with a cleaner code.

lib/string/strdup/strndup.c

lib/utmp.c

lib/session_management.h

Karlson2k · 2025-07-15T13:02:52Z

I'd like to have a look at that after the fixes to the build system. I'm not familiar with autotools, and this kind of thing will require some conditionals there, I guess. Let's do this round of refactors first, and then we'll see what else we can improve.

No problem. I can fix it easily later.

alejandro-colomar · 2025-07-30T20:19:31Z

Also, maybe it worth to zero-out entry completely before use to make sure that any unsupported fields are empty (or at least do not contain garbage).

Agree; we should clear all unused fields.

Just use memset() for the structure as unknown fields are... unknown. 😄

We're using calloc(3) already.

Signed-off-by: Alejandro Colomar <alx@kernel.org>

libsystemd functions don't read the original contents of the second argument, and unconditionally set it on success. The NULL was unnecessary. The count initialization was always overwritten by assignment. Signed-off-by: Alejandro Colomar <alx@kernel.org>

…h" header Signed-off-by: Alejandro Colomar <alx@kernel.org>

Signed-off-by: Alejandro Colomar <alx@kernel.org>

This allows us using the [[gnu::malloc()]] attribute, by returning the newly allocated string. This is easier to use. Move the error code to errno, where it belongs. Signed-off-by: Alejandro Colomar <alx@kernel.org>

…ote_host() This allows us using the [[gnu::malloc()]] attribute, by returning the newly allocated string. This is easier to use. Move the error code to errno, where it belongs. Signed-off-by: Alejandro Colomar <alx@kernel.org>

glibc, musl libc, FreeBSD, NetBSD, and OpenBSD, all have ut_host. Signed-off-by: Alejandro Colomar <alx@kernel.org>

This allows us using the [[gnu::malloc()]] attribute, and makes it easier to use. The error code is moved to errno, where it belongs. Signed-off-by: Alejandro Colomar <alx@kernel.org>

This function already reports some errors, so it doesn't make sense to exit(3) on allocation error. We can report it just like any other error. Signed-off-by: Alejandro Colomar <alx@kernel.org>

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alejandro-colomar linked an issue Jul 14, 2025 that may be closed by this pull request

Memory leak on empty hostname #1291

Closed

alejandro-colomar changed the title ~~Cosmetic improvements to logind.c related stuff~~ Fix memory leak Jul 14, 2025

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This was referenced Aug 10, 2025

Fixed memory leak in UTMP processing #1329

Closed

Fixed memory leak in UTMP processing #1332

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alejandro-colomar changed the title ~~Fix memory leak~~ Clean up lib/utmp.c Aug 16, 2025

alejandro-colomar changed the title ~~Clean up lib/utmp.c~~ Clean up lib/utmp.c and lib/logind.c Aug 16, 2025

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4.19 Release plan (Herve) - 2025-12 #1354

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alejandro-colomar added 9 commits December 31, 2025 03:33

lib/logind.c: Fix style

c23ea49

Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/: Move utmp.c and logind.c prototypes to new "session_management.…

b1eb7cf

…h" header Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/logind.c: get_session_host(): free() earlier, to avoid a goto

c6a2370

Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/logind.c: Wrap libsystemd function in our wrapper get_session()

939af47

This allows us using the [[gnu::malloc()]] attribute, by returning the newly allocated string. This is easier to use. Move the error code to errno, where it belongs. Signed-off-by: Alejandro Colomar <alx@kernel.org>

configure.ac, lib/utmp.c: Assume utmpx(5) has ut_host

ed3e417

glibc, musl libc, FreeBSD, NetBSD, and OpenBSD, all have ut_host. Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/, src/: get_session_host(): Return the host

2cc2562

This allows us using the [[gnu::malloc()]] attribute, and makes it easier to use. The error code is moved to errno, where it belongs. Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/utmp.c: get_session_host(): Don't exit from library code

1a6a0ee

This function already reports some errors, so it doesn't make sense to exit(3) on allocation error. We can report it just like any other error. Signed-off-by: Alejandro Colomar <alx@kernel.org>

alejandro-colomar force-pushed the logind_utmp branch from 90d1432 to 1a6a0ee Compare December 31, 2025 02:34

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Clean up lib/utmp.c and lib/logind.c #1290

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