chpasswd: fixes and code shrink

update_passwd                                        732     734      +2
chpasswd_main                                        318     292     -26
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 2/-26)             Total: -24 bytes
   text    data     bss     dec     hex filename
 781564    1168   11900  794632   c2008 busybox_old
 781548    1168   11900  794616   c1ff8 busybox_unstripped

1 files changed, 20 insertions, 20 deletions

diff --git a/libbb/update_passwd.c b/libbb/update_passwd.c
index 5572db547..8914b8b45 100644
--- a/libbb/update_passwd.c
+++ b/libbb/update_passwd.c
@@ -18,18 +18,18 @@ int update_passwd(const char *filename, const char *username,
         struct flock lock;
         FILE *old_fp;
         FILE *new_fp;
-        char *new_name;
-        char *last_char;
+        char *fnamesfx;
+        char *sfx_char;
         unsigned user_len;
         int old_fd;
         int new_fd;
         int i;
         int cnt = 0;
-        int ret = 1; /* failure */
+        int ret = -1; /* failure */
 
         /* New passwd file, "/etc/passwd+" for now */
-        new_name = xasprintf("%s+", filename);
-        last_char = &new_name[strlen(new_name)-1];
+        fnamesfx = xasprintf("%s+", filename);
+        sfx_char = &fnamesfx[strlen(fnamesfx)-1];
         username = xasprintf("%s:", username);
         user_len = strlen(username);
 
@@ -42,12 +42,12 @@ int update_passwd(const char *filename, const char *username,
         i = 30;
         do {
                 // FIXME: on last iteration try w/o O_EXCL but with O_TRUNC?
-                new_fd = open(new_name, O_WRONLY|O_CREAT|O_EXCL,0600);
+                new_fd = open(fnamesfx, O_WRONLY|O_CREAT|O_EXCL, 0600);
                 if (new_fd >= 0) goto created;
                 if (errno != EEXIST) break;
                 usleep(100000); /* 0.1 sec */
         } while (--i);
-        bb_perror_msg("cannot create '%s'", new_name);
+        bb_perror_msg("cannot create '%s'", fnamesfx);
         goto close_old_fp;
 
  created:
@@ -62,12 +62,13 @@ int update_passwd(const char *filename, const char *username,
         }
 
         /* Backup file is "/etc/passwd-" */
-        last_char[0] = '-';
-        /* Delete old one, create new as a hardlink to current */
-        i = (unlink(new_name) && errno != ENOENT);
-        if (i || link(filename, new_name))
-                bb_perror_msg("warning: cannot create backup copy '%s'", new_name);
-        last_char[0] = '+';
+        *sfx_char = '-';
+        /* Delete old backup */
+        i = (unlink(fnamesfx) && errno != ENOENT);
+        /* Create backup as a hardlink to current */
+        if (i || link(filename, fnamesfx))
+                bb_perror_msg("warning: cannot create backup copy '%s'", fnamesfx);
+        *sfx_char = '+';
 
         /* Lock the password file before updating */
         lock.l_type = F_WRLCK;
@@ -78,7 +79,7 @@ int update_passwd(const char *filename, const char *username,
                 bb_perror_msg("warning: cannot lock '%s'", filename);
         lock.l_type = F_UNLCK;
 
-        /* Read current password file, write updated one */
+        /* Read current password file, write updated /etc/passwd+ */
         while (1) {
                 char *line = xmalloc_fgets(old_fp);
                 if (!line) break; /* EOF/error */
@@ -86,8 +87,7 @@ int update_passwd(const char *filename, const char *username,
                         /* we have a match with "username:"... */
                         const char *cp = line + user_len;
                         /* now cp -> old passwd, skip it: */
-                        cp = strchr(cp, ':');
-                        if (!cp) cp = "";
+                        cp = strchrnul(cp, ':');
                         /* now cp -> ':' after old passwd or -> "" */
                         fprintf(new_fp, "%s%s%s", username, new_pw, cp);
                         cnt++;
@@ -99,7 +99,7 @@ int update_passwd(const char *filename, const char *username,
 
         /* We do want all of them to execute, thus | instead of || */
         if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp))
-         || rename(new_name, filename)
+         || rename(fnamesfx, filename)
         ) {
                 /* At least one of those failed */
                 goto unlink_new;
@@ -107,13 +107,13 @@ int update_passwd(const char *filename, const char *username,
         ret = cnt; /* whee, success! */
 
  unlink_new:
-        if (ret) unlink(new_name);
+        if (ret < 0) unlink(fnamesfx);
 
  close_old_fp:
         fclose(old_fp);
 
  free_mem:
-        if (ENABLE_FEATURE_CLEAN_UP) free(new_name);
-        if (ENABLE_FEATURE_CLEAN_UP) free((char*)username);
+        free(fnamesfx);
+        free((char*)username);
         return ret;
 }