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Diffstat (limited to 'contrib/cpio/userspec.c')
| -rw-r--r-- | contrib/cpio/userspec.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/contrib/cpio/userspec.c b/contrib/cpio/userspec.c new file mode 100644 index 0000000..67f1583 --- /dev/null +++ b/contrib/cpio/userspec.c @@ -0,0 +1,277 @@ +/* userspec.c -- Parse a user and group string. + Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#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 <grp.h> + +#if defined(STDC_HEADERS) || defined(HAVE_STRING_H) +#include <string.h> +#ifndef index +#define index strchr +#endif +#else +#include <strings.h> +#endif + +#ifdef STDC_HEADERS +#include <stdlib.h> +#endif + +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif + +#ifndef _POSIX_VERSION +struct passwd *getpwnam (); +struct group *getgrnam (); +struct group *getgrgid (); +#endif + +#ifdef _POSIX_SOURCE +#define endpwent() +#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 (); + +/* 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. + Either user or group, or both, must be present. + If the group is omitted but the ":" or "." separator is given, + use the given user's login group. + + 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. + + Return NULL if successful, a static error message string if not. */ + +const char * +parse_user_spec (spec_arg, uid, gid, username_arg, groupname_arg) + const char *spec_arg; + uid_t *uid; + gid_t *gid; + char **username_arg, **groupname_arg; +{ + 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; + char *g, *u, *separator; + char *groupname; + + error_msg = NULL; + *username_arg = *groupname_arg = NULL; + groupname = NULL; + + V_STRDUP (spec, spec_arg); + + /* Find the separator if there is one. */ + separator = index (spec, ':'); + if (separator == NULL) + separator = index (spec, '.'); + + /* 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) + { + pwd = getpwnam (u); + if (pwd == NULL) + { + + if (!isnumber (u)) + error_msg = "invalid user"; + else + { + 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 + { + *uid = pwd->pw_uid; + if (g == NULL && separator != NULL) + { + /* 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 (); + } + } + endpwent (); + } + + if (g != NULL && error_msg == NULL) + { + /* 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); + } + + if (error_msg == NULL) + { + if (u != NULL) + { + *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) + { + if (*username_arg != NULL) + { + free (*username_arg); + *username_arg = NULL; + } + error_msg = tired; + } + } + } + + return error_msg; +} + +#ifdef TEST + +#define NULL_CHECK(s) ((s) == NULL ? "(null)" : (s)) + +int +main (int argc, char **argv) +{ + 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 |
