diff options
| -rw-r--r-- | lib/userspec.c | 193 |
1 files changed, 90 insertions, 103 deletions
diff --git a/lib/userspec.c b/lib/userspec.c index 6bf40895d..ba66fac8b 100644 --- a/lib/userspec.c +++ b/lib/userspec.c @@ -25,8 +25,6 @@ /* Specification. */ #include "userspec.h" -#include <alloca.h> - #include <stdbool.h> #include <stdio.h> #include <sys/types.h> @@ -92,18 +90,6 @@ struct group *getgrgid (); # define MAXGID GID_T_MAX #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 \ - { \ - size_t size = strlen (src) + 1; \ - (dest) = (char *) alloca (size); \ - memcpy (dest, src, size); \ - } \ - while (0) - /* ISDIGIT differs from isdigit, as follows: - Its arg may be any int or unsigned int; it need not be an unsigned char. - It's guaranteed to evaluate its argument exactly once. @@ -131,78 +117,52 @@ is_number (const char *str) } #endif -/* 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 ":" separator is given, - use the given user's login group. - If SPEC_ARG contains a `:', then use that as the separator, ignoring - any `.'s. If there is no `:', but there is a `.', then first look - up the entire SPEC_ARG as a login name. If that look-up fails, then - try again interpreting the `.' as a separator. - - 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 (const char *spec_arg, uid_t *uid, gid_t *gid, - char **username_arg, char **groupname_arg) +static char const * +parse_with_separator (char const *spec, char const *separator, + uid_t *uid, gid_t *gid, + char **username, char **groupname) { static const char *E_invalid_user = N_("invalid user"); static const char *E_invalid_group = N_("invalid group"); static const char *E_bad_spec = N_("cannot get the login group of a numeric UID"); - static const char *E_cannot_omit_both = - N_("cannot omit both user and group"); const char *error_msg; - char *spec; /* A copy we can write on. */ struct passwd *pwd; struct group *grp; - char *g, *u, *separator; - char *groupname; - char *dot = NULL; + char *u; + char const *g; + char *gname = NULL; + uid_t unum = *uid; + gid_t gnum = *gid; error_msg = NULL; - *username_arg = *groupname_arg = NULL; - groupname = NULL; - - V_STRDUP (spec, spec_arg); + *username = *groupname = NULL; - /* Find the POSIX `:' separator if there is one. */ - separator = strchr (spec, ':'); + /* Set U and G to nonzero length strings corresponding to user and + group specifiers or to NULL. If U is not NULL, it is a newly + allocated string. */ - /* If there is no colon, then see if there's a `.'. */ + u = NULL; if (separator == NULL) { - dot = strchr (spec, '.'); - /* If there's no colon but there is a `.', then first look up the - whole spec, in case it's an OWNER name that includes a dot. - If that fails, then we'll try again, but interpreting the `.' - as a separator. This is a compatible extension to POSIX, since - the POSIX-required behavior is always tried first. */ + if (*spec) + u = xstrdup (spec); + } + else + { + size_t ulen = separator - spec; + if (ulen != 0) + { + u = xclone (spec, ulen + 1); + u[ulen] = '\0'; + } } - - retry: - - /* 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 _(E_cannot_omit_both); - #ifdef __DJGPP__ /* Pretend that we are the user U whose group is G. This makes pwd and grp functions ``know'' about the UID and GID of these. */ @@ -222,32 +182,25 @@ parse_user_spec (const char *spec_arg, uid_t *uid, gid_t *gid, error_msg = E_bad_spec; else { - unsigned long int tmp_long; - if (! (xstrtoul (u, NULL, 10, &tmp_long, "") == LONGINT_OK - && tmp_long <= MAXUID)) - return _(E_invalid_user); - *uid = tmp_long; + unsigned long int tmp; + if (xstrtoul (u, NULL, 10, &tmp, "") == LONGINT_OK + && tmp <= MAXUID) + unum = tmp; + else + error_msg = E_invalid_user; } } else { - *uid = pwd->pw_uid; + unum = 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) - { - char buf[INT_BUFSIZE_BOUND (uintmax_t)]; - char const *num = umaxtostr (pwd->pw_gid, buf); - V_STRDUP (groupname, num); - } - else - { - V_STRDUP (groupname, grp->gr_name); - } + char buf[INT_BUFSIZE_BOUND (uintmax_t)]; + gnum = pwd->pw_gid; + grp = getgrgid (gnum); + gname = xstrdup (grp ? grp->gr_name : umaxtostr (gnum, buf)); endgrent (); } } @@ -260,38 +213,72 @@ parse_user_spec (const char *spec_arg, uid_t *uid, gid_t *gid, grp = getgrnam (g); if (grp == NULL) { - unsigned long int tmp_long; - if (! (xstrtoul (g, NULL, 10, &tmp_long, "") == LONGINT_OK - && tmp_long <= MAXGID)) - return _(E_invalid_group); - *gid = tmp_long; + unsigned long int tmp; + if (xstrtoul (g, NULL, 10, &tmp, "") == LONGINT_OK && tmp <= MAXGID) + gnum = tmp; + else + error_msg = E_invalid_group; } else - *gid = grp->gr_gid; + gnum = grp->gr_gid; endgrent (); /* Save a file descriptor. */ - - if (error_msg == NULL) - V_STRDUP (groupname, g); + gname = xstrdup (g); } if (error_msg == NULL) { - if (u != NULL) - *username_arg = xstrdup (u); - - if (groupname != NULL) - *groupname_arg = xstrdup (groupname); + *uid = unum; + *gid = gnum; + *username = u; + *groupname = gname; + u = NULL; } + else + free (gname); - if (error_msg && dot) + free (u); + return _(error_msg); +} + +/* Extract from SPEC, 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 separator is given, + use the given user's login group. + If SPEC contains a `:', then use that as the separator, ignoring + any `.'s. If there is no `:', but there is a `.', then first look + up the entire SPEC as a login name. If that look-up fails, then + try again interpreting the `.' as a separator. + + 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. */ + +char const * +parse_user_spec (char const *spec, uid_t *uid, gid_t *gid, + char **username, char **groupname) +{ + char const *colon = strchr (spec, ':'); + char const *error_msg = + parse_with_separator (spec, colon, uid, gid, username, groupname); + + if (!colon && error_msg) { - separator = dot; - dot = NULL; - error_msg = NULL; - goto retry; + /* If there's no colon but there is a dot, and if looking up the + whole spec failed (i.e., the spec is not a owner name that + includes a dot), then try again, but interpret the dot as a + separator. This is a compatible extension to POSIX, since + the POSIX-required behavior is always tried first. */ + + char const *dot = strchr (spec, '.'); + if (dot + && ! parse_with_separator (spec, dot, uid, gid, username, groupname)) + error_msg = NULL; } - return _(error_msg); + return error_msg; } #ifdef TEST |