I wrote this months ago, and like the minimalist (avoiding unnecessary printf) and more type-safe aspects. The code-duplication is not ideal, but the duplicated code is small and fragile, and not generally useful enough to put in system.h -- too easy to use it from a context where it would fail. We could always give it a few more buffer entries, like human.c does, so two invocations in the same statement won't misbehave.
Opinions? >From 2c27745185c547e6953f0cb5c25903c2c7503678 Mon Sep 17 00:00:00 2001 From: Jim Meyering <[email protected]> Date: Sun, 1 Jan 2012 22:31:41 +0100 Subject: [PATCH] id,groups: use gidtostr/uidtostr to avoid casts * src/id.c (gidtostr, uidtostr): Define macros. (gidtostr_ptr, uidtostr_ptr): Define safer functions. Use gidtostr and uidtostr to print GID and UID without need/risk of casts. * src/group-list.c: Likewise. --- src/group-list.c | 16 ++++++++++++---- src/id.c | 38 +++++++++++++++++++++++++++++--------- 2 files changed, 41 insertions(+), 13 deletions(-) diff --git a/src/group-list.c b/src/group-list.c index cf49911..786fec4 100644 --- a/src/group-list.c +++ b/src/group-list.c @@ -86,6 +86,16 @@ print_group_list (const char *username, return ok; } +/* Convert a gid_t to string. Do not use this function directly. + Instead, use it via the gidtostr macro. + Beware that it returns a pointer to static storage. */ +static char * +gidtostr_ptr (gid_t const *gid) +{ + static char buf[INT_BUFSIZE_BOUND (gid_t)]; + return umaxtostr (*gid, buf); +} +#define gidtostr(g) gidtostr_ptr (&(g)) /* Print the name or value of group ID GID. */ extern bool @@ -105,9 +115,7 @@ print_group (gid_t gid, bool use_name) } } - if (grp == NULL) - printf ("%lu", (unsigned long int) gid); - else - printf ("%s", grp->gr_name); + char *s = grp ? grp->gr_name : gidtostr (gid); + fputs (s, stdout); return ok; } diff --git a/src/id.c b/src/id.c index c600e63..a28903a 100644 --- a/src/id.c +++ b/src/id.c @@ -265,6 +265,28 @@ main (int argc, char **argv) exit (ok ? EXIT_SUCCESS : EXIT_FAILURE); } +/* Convert a gid_t to string. Do not use this function directly. + Instead, use it via the gidtostr macro. + Beware that it returns a pointer to static storage. */ +static char * +gidtostr_ptr (gid_t const *gid) +{ + static char buf[INT_BUFSIZE_BOUND (gid_t)]; + return umaxtostr (*gid, buf); +} +#define gidtostr(g) gidtostr_ptr (&(g)) + +/* Convert a uid_t to string. Do not use this function directly. + Instead, use it via the uidtostr macro. + Beware that it returns a pointer to static storage. */ +static char * +uidtostr_ptr (uid_t const *uid) +{ + static char buf[INT_BUFSIZE_BOUND (uid_t)]; + return umaxtostr (*uid, buf); +} +#define uidtostr(u) uidtostr_ptr (&(u)) + /* Print the name or value of user ID UID. */ static void @@ -277,16 +299,14 @@ print_user (uid_t uid) pwd = getpwuid (uid); if (pwd == NULL) { - error (0, 0, _("cannot find name for user ID %lu"), - (unsigned long int) uid); + error (0, 0, _("cannot find name for user ID %s"), + uidtostr (uid)); ok = false; } } - if (pwd == NULL) - printf ("%lu", (unsigned long int) uid); - else - printf ("%s", pwd->pw_name); + char *s = pwd ? pwd->pw_name : uidtostr (uid); + fputs (s, stdout); } /* Print all of the info about the user's user and group IDs. */ @@ -297,19 +317,19 @@ print_full_info (const char *username) struct passwd *pwd; struct group *grp; - printf (_("uid=%lu"), (unsigned long int) ruid); + printf (_("uid=%s"), uidtostr (ruid)); pwd = getpwuid (ruid); if (pwd) printf ("(%s)", pwd->pw_name); - printf (_(" gid=%lu"), (unsigned long int) rgid); + printf (_(" gid=%s"), gidtostr (rgid)); grp = getgrgid (rgid); if (grp) printf ("(%s)", grp->gr_name); if (euid != ruid) { - printf (_(" euid=%lu"), (unsigned long int) euid); + printf (_(" euid=%s"), uidtostr (euid)); pwd = getpwuid (euid); if (pwd) printf ("(%s)", pwd->pw_name); -- 1.7.9.3
