GNU file utilities

[gnulib.git] / lib / userspec.c

diff --git a/lib/userspec.c b/lib/userspec.c
index 37b7980..75000e8 100644 (file)
--- a/lib/userspec.c
+++ b/lib/userspec.c
@@ -28,6 +28,20 @@
 #endif
 #endif
 
 #endif
 #endif
 

+#ifdef __GNUC__
+#define alloca __builtin_alloca
+#else
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#else
+#ifdef _AIX
+ #pragma alloca
+#else
+char *alloca ();
+#endif
+#endif
+#endif
+

 #include <stdio.h>
 #include <sys/types.h>
 #include <pwd.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <pwd.h>


@@ -44,8 +58,6 @@
 
 #ifdef STDC_HEADERS
 #include <stdlib.h>
 
 #ifdef STDC_HEADERS
 #include <stdlib.h>

-#else
-char *malloc ();

 #endif
 
 #ifdef HAVE_UNISTD_H
 #endif
 
 #ifdef HAVE_UNISTD_H


@@ -63,10 +75,34 @@ struct group *getgrgid ();
 #define endgrent()
 #endif
 
 #define endgrent()
 #endif
 

+/* Perform the equivalent of the statement `dest = strdup (src);',
+   but obtaining storage via alloca instead of from the heap.  */
+
+#define V_STRDUP(dest, src)                                            \
+  do                                                                   \
+    {                                                                  \
+      int _len = strlen ((src));                                       \
+      (dest) = (char *) alloca (_len + 1);                             \
+      strcpy (dest, src);                                              \
+    }                                                                  \
+  while (0)
+

 #define isdigit(c) ((c) >= '0' && (c) <= '9')
 
 char *strdup ();
 #define isdigit(c) ((c) >= '0' && (c) <= '9')
 
 char *strdup ();

-static int isnumber ();
+
+/* Return nonzero if STR represents an unsigned decimal integer,
+   otherwise return 0. */
+
+static int
+isnumber (str)
+     const char *str;
+{
+  for (; *str; str++)
+    if (!isdigit (*str))
+      return 0;
+  return 1;
+}

 
 /* Extract from NAME, which has the form "[user][:.][group]",
    a USERNAME, UID U, GROUPNAME, and GID G.
 
 /* Extract from NAME, which has the form "[user][:.][group]",
    a USERNAME, UID U, GROUPNAME, and GID G.


@@ -77,115 +113,172 @@ static int isnumber ();
    USERNAME and GROUPNAME will be in newly malloc'd memory.
    Either one might be NULL instead, indicating that it was not
    given and the corresponding numeric ID was left unchanged.
    USERNAME and GROUPNAME will be in newly malloc'd memory.
    Either one might be NULL instead, indicating that it was not
    given and the corresponding numeric ID was left unchanged.

-   Might write NULs into NAME.

 
    Return NULL if successful, a static error message string if not.  */
 
 
    Return NULL if successful, a static error message string if not.  */
 

-char *
-parse_user_spec (name, uid, gid, username, groupname)
-     char *name;
+const char *
+parse_user_spec (spec_arg, uid, gid, username_arg, groupname_arg)
+     const char *spec_arg;

      uid_t *uid;
      gid_t *gid;
      uid_t *uid;
      gid_t *gid;

-     char **username, **groupname;
+     char **username_arg, **groupname_arg;

 {
 {

-  static char *tired = "virtual memory exhausted";
+  static const char *tired = "virtual memory exhausted";
+  const char *error_msg;
+  char *spec;                  /* A copy we can write on.  */

   struct passwd *pwd;
   struct group *grp;
   struct passwd *pwd;
   struct group *grp;

-  char *cp;
-  int use_login_group = 0;
+  char *g, *u, *separator;
+  char *groupname;
+
+  error_msg = NULL;
+  *username_arg = *groupname_arg = NULL;
+  groupname = NULL;
+
+  V_STRDUP (spec, spec_arg);

 
 

-  *username = *groupname = NULL;
+  /* Find the separator if there is one.  */
+  separator = index (spec, ':');
+  if (separator == NULL)
+    separator = index (spec, '.');

 
 

-  /* Check whether a group is given.  */
-  cp = index (name, ':');
-  if (cp == NULL)
-    cp = index (name, '.');
-  if (cp != NULL)
+  /* Replace separator with a NUL.  */
+  if (separator != NULL)
+    *separator = '\0';
+
+  /* Set U and G to non-zero length strings corresponding to user and
+     group specifiers or to NULL.  */
+  u = (*spec == '\0' ? NULL : spec);
+
+  g = (separator == NULL || *(separator + 1) == '\0'
+       ? NULL
+       : separator + 1);
+
+  if (u == NULL && g == NULL)
+    return "can not omit both user and group";
+
+  if (u != NULL)

     {
     {

-      *cp++ = '\0';
-      if (*cp == '\0')
+      pwd = getpwnam (u);
+      if (pwd == NULL)

        {
        {

-         if (cp == name + 1)
-           /* Neither user nor group given, just "." or ":".  */
-           return "can not omit both user and group";
+
+         if (!isnumber (u))
+           error_msg = "invalid user";

          else
          else

-           /* "user.".  */
-           use_login_group = 1;
+           {
+             int use_login_group;
+             use_login_group = (separator != NULL && g == NULL);
+             if (use_login_group)
+               error_msg = "cannot get the login group of a numeric UID";
+             else
+               *uid = atoi (u);
+           }

        }
       else
        {
        }
       else
        {

-         /* Explicit group.  */
-         *groupname = strdup (cp);
-         if (*groupname == NULL)
-           return tired;
-         grp = getgrnam (cp);
-         if (grp == NULL)
+         *uid = pwd->pw_uid;
+         if (g == NULL && separator != NULL)

            {
            {

-             if (!isnumber (cp))
-               return "invalid group";
-             *gid = atoi (cp);
+             /* A separator was given, but a group was not specified,
+                so get the login group.  */
+             *gid = pwd->pw_gid;
+             grp = getgrgid (pwd->pw_gid);
+             if (grp == NULL)
+               {
+                 /* This is enough room to hold the unsigned decimal
+                    representation of any 32-bit quantity and the trailing
+                    zero byte.  */
+                 char uint_buf[21];
+                 sprintf (uint_buf, "%u", (unsigned) (pwd->pw_gid));
+                 V_STRDUP (groupname, uint_buf);
+               }
+             else
+               {
+                 V_STRDUP (groupname, grp->gr_name);
+               }
+             endgrent ();

            }
            }

-         else
-           *gid = grp->gr_gid;
-         endgrent ();          /* Save a file descriptor.  */

        }
        }

+      endpwent ();

     }
 
     }
 

-  /* Parse the user name, now that any group has been removed.  */
-
-  if (name[0] == '\0')
-    /* No user name was given, just a group.  */
-    return NULL;
-
-  *username = strdup (name);
-  if (*username == NULL)
-    return tired;
-
-  pwd = getpwnam (name);
-  if (pwd == NULL)
+  if (g != NULL && error_msg == NULL)

     {
     {

-      if (!isnumber (name))
-       return "invalid user";
-      if (use_login_group)
-       return "cannot get the login group of a numeric UID";
-      *uid = atoi (name);
+      /* Explicit group.  */
+      grp = getgrnam (g);
+      if (grp == NULL)
+       {
+         if (!isnumber (g))
+           error_msg = "invalid group";
+         else
+           *gid = atoi (g);
+       }
+      else
+       *gid = grp->gr_gid;
+      endgrent ();             /* Save a file descriptor.  */
+
+      if (error_msg == NULL)
+       V_STRDUP (groupname, g);

     }
     }

-  else
+
+  if (error_msg == NULL)

     {
     {

-      *uid = pwd->pw_uid;
-      if (use_login_group)
+      if (u != NULL)

        {
        {

-         *gid = pwd->pw_gid;
-         grp = getgrgid (pwd->pw_gid);
-         if (grp == NULL)
-           {
-             *groupname = malloc (15);
-             if (*groupname == NULL)
-               return tired;
-             sprintf (*groupname, "%u", (unsigned) (pwd->pw_gid));
-           }
-         else
+         *username_arg = strdup (u);
+         if (*username_arg == NULL)
+           error_msg = tired;
+       }
+
+      if (groupname != NULL && error_msg == NULL)
+       {
+         *groupname_arg = strdup (groupname);
+         if (*groupname_arg == NULL)

            {
            {

-             *groupname = strdup (grp->gr_name);
-             if (*groupname == NULL)
-               return tired;
+             if (*username_arg != NULL)
+               {
+                 free (*username_arg);
+                 *username_arg = NULL;
+               }
+             error_msg = tired;

            }
            }

-         endgrent ();

        }
     }
        }
     }

-  endpwent ();
-  return NULL;
+
+  return error_msg;

 }
 
 }
 

-/* Return nonzero if STR represents an unsigned decimal integer,
-   otherwise return 0. */
+#ifdef TEST

 
 

-static int
-isnumber (str)
-     char *str;
+#define NULL_CHECK(s) ((s) == NULL ? "(null)" : (s))
+
+int
+main (int argc, char **argv)

 {
 {

-  for (; *str; str++)
-    if (!isdigit (*str))
-      return 0;
-  return 1;
+  int i;
+
+  for (i = 1; i < argc; i++)
+    {
+      const char *e;
+      char *username, *groupname;
+      uid_t uid;
+      gid_t gid;
+      char *tmp;
+
+      tmp = strdup (argv[i]);
+      e = parse_user_spec (tmp, &uid, &gid, &username, &groupname);
+      free (tmp);
+      printf ("%s: %u %u %s %s %s\n",
+             argv[i],
+             (unsigned int) uid,
+             (unsigned int) gid,
+             NULL_CHECK (username),
+             NULL_CHECK (groupname),
+             NULL_CHECK (e));
+    }
+
+  exit (0);

 }
 }

+
+#endif