From cb748f195f3f56a2e5c7db950d7abf633308c071 Mon Sep 17 00:00:00 2001 From: Shreenidhi Shedi Date: Wed, 1 Sep 2021 23:31:36 +0530 Subject: [PATCH 08/12] Reformat & refactor userspec.c Signed-off-by: Shreenidhi Shedi --- src/userspec.c | 347 ++++++++++++++++++++++++++----------------------- 1 file changed, 184 insertions(+), 163 deletions(-) diff --git a/src/userspec.c b/src/userspec.c index c1d1ae3..f2526f3 100644 --- a/src/userspec.c +++ b/src/userspec.c @@ -1,4 +1,5 @@ -/* userspec.c -- Parse a user and group string. +/* + * userspec.c -- Parse a user and group string. Copyright (C) 1989-1992, 2001, 2004-2005, 2007, 2010, 2014-2015, 2017, 2020-2021 Free Software Foundation, Inc. @@ -15,12 +16,12 @@ 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., 51 Franklin Street, Fifth Floor, - Boston, MA 02110-1301 USA. */ + Boston, MA 02110-1301 USA. + */ -/* Written by David MacKenzie . */ +/* Written by David MacKenzie */ #include -#include #include #include #include @@ -32,17 +33,14 @@ # 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 FREE(ptr) \ + do { \ + if (ptr) \ + { \ + free (ptr); \ + ptr = NULL; \ + } \ + } while (0) /* Return nonzero if STR represents an unsigned decimal integer, otherwise return 0. */ @@ -50,10 +48,10 @@ static int isnumber_p (const char *str) { - for (; *str; str++) - if (!isdigit (*str)) - return 0; - return 1; + for (; *str; str++) + if (!isdigit (*str)) + return 0; + return 1; } /* Extract from NAME, which has the form "[user][:.][group]", @@ -66,149 +64,172 @@ isnumber_p (const char *str) 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. */ + 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) + char **username_arg, char **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 = strchr (spec, ':'); - if (separator == NULL) - separator = strchr (spec, '.'); + char *g = NULL; + char *u = NULL; + char *spec = NULL; /* A copy we can write on. */ + char *separator = NULL; + char *groupname = NULL; + struct group *grp = NULL; + struct passwd *pwd = NULL; + const char *error_msg = NULL; + static const char *tired = "virtual memory exhausted"; + + *username_arg = NULL; + *groupname_arg = NULL; + + spec = strdup (spec_arg); + if (spec == NULL) + { + error_msg = tired; + goto finish; + } - /* Replace separator with a NUL. */ - if (separator != NULL) - *separator = '\0'; + /* Find the separator if there is one. */ + separator = strchr (spec, ':'); + if (separator == NULL) + separator = strchr (spec, '.'); - /* Set U and G to non-zero length strings corresponding to user and - group specifiers or to NULL. */ - u = (*spec == '\0' ? NULL : spec); + /* Replace separator with a NUL. */ + if (separator != NULL) + *separator = '\0'; - g = (separator == NULL || *(separator + 1) == '\0' - ? NULL - : separator + 1); + /* Set U and G to non-zero length strings corresponding to user and + group specifiers or to NULL. */ + u = (*spec == '\0' ? NULL : spec); - if (u == NULL && g == NULL) - return "can not omit both user and group"; + g = (separator == NULL || *(separator + 1) == '\0' ? NULL : separator + 1); + if (u == NULL && g == NULL) + { + error_msg = _("can not omit both user and group"); + goto finish; + } - if (u != NULL) + if (u != NULL) { - if (*u == '+') - { - pwd = NULL; - ++u; - } - else - pwd = getpwnam (u); - - if (pwd == NULL) - { - if (!isnumber_p (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] = {0}; - snprintf (uint_buf, sizeof (uint_buf), "%u", (unsigned int) (pwd->pw_gid)); - V_STRDUP (groupname, uint_buf); - } - else - { - V_STRDUP (groupname, grp->gr_name); - } - endgrent (); - } - } - endpwent (); + if (*u == '+') + { + pwd = NULL; + ++u; + } + else + { + pwd = getpwnam (u); + } + + if (pwd == NULL) + { + if (!isnumber_p (u)) + { + error_msg = _("invalid user"); + goto finish; + } + if (separator != NULL && g == NULL) + { + error_msg = _("cannot get the login group of a numeric UID"); + goto finish; + } + *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] = {0}; + snprintf (uint_buf, sizeof (uint_buf), "%u", (unsigned int) (pwd->pw_gid)); + groupname = strdup (uint_buf); + if (groupname == NULL) + { + error_msg = tired; + goto finish; + } + } + else + { + groupname = strdup (grp->gr_name); + if (groupname == NULL) + { + error_msg = tired; + goto finish; + } + } + endgrent (); + } + } + endpwent (); } - if (g != NULL && error_msg == NULL) + if (g != NULL) { - /* Explicit group. */ - if (*g == '+') - { - grp = NULL; - ++g; - } - else - grp = getgrnam (g); - - if (grp == NULL) - { - if (!isnumber_p (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); + /* Explicit group */ + if (*g == '+') + { + grp = NULL; + ++g; + } + else + { + grp = getgrnam (g); + } + + if (grp == NULL) + { + if (!isnumber_p (g)) + { + error_msg = _("invalid group"); + goto finish; + } + *gid = atoi (g); + } + else + { + *gid = grp->gr_gid; + } + endgrent (); /* Save a file descriptor. */ + + groupname = strdup (g); + if (groupname == NULL) + { + error_msg = tired; + goto finish; + } } - if (error_msg == NULL) + if (u != 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; - } - } + *username_arg = strdup (u); + if (*username_arg == NULL) + { + error_msg = tired; + goto finish; + } } - return error_msg; + *groupname_arg = groupname; + +finish: + if (spec != NULL) + FREE (spec); + + if (error_msg != NULL) + FREE (groupname); + + return error_msg; } #ifdef TEST @@ -218,29 +239,29 @@ parse_user_spec (const char *spec_arg, uid_t *uid, gid_t *gid, int main (int argc, char **argv) { - int i; + int i; - for (i = 1; i < argc; 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)); + 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); + return 0; } #endif -- 2.17.1