Mercurial > hg > toybox
view toys/posix/id.c @ 1531:3ff823086c99 draft
Teach ln -f to leave original target alone if link creation fails.
Suggested by Ashwini Sharma, I wound up implementing it by creating the new
link at a temporary name and renaming it over the old one instead of renaming
the old file out of the way and putting it back if it failed.
(Because "mkdir -p one/one/blah && ln -sf /bin/one one" would otherwise
rename one/one out of the way and only notice it can't delete it way at the
end when recovery's darn awkward, vs create new thing and if rename fails
(including EISDIR) that's the main error path. And yes the temporary name
is in the same directory as the destination so we never rename between mounts.)
link over the old one instead of renaming the old file and renaming it back.
author | Rob Landley <rob@landley.net> |
---|---|
date | Wed, 22 Oct 2014 17:11:06 -0500 |
parents | 4bfbd8b96f66 |
children | 5fac2769a159 |
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/* id.c - print real and effective user and group IDs * * Copyright 2012 Sony Network Entertainment, Inc. * * by Tim Bird <tim.bird@am.sony.com> * * See http://opengroup.org/onlinepubs/9699919799/utilities/id.html USE_ID(NEWTOY(id, ">1nGgru[!Ggu]", TOYFLAG_BIN)) USE_GROUPS(OLDTOY(groups, id, NULL, TOYFLAG_USR|TOYFLAG_BIN)) USE_LOGNAME(OLDTOY(logname, id, ">0", TOYFLAG_BIN)) USE_WHOAMI(OLDTOY(whoami, id, ">0", TOYFLAG_BIN)) config ID bool "id" default y help usage: id [-nGgru] Print user and group ID. -n print names instead of numeric IDs (to be used with -Ggu) -G Show only the group IDs -g Show only the effective group ID -r Show real ID instead of effective ID -u Show only the effective user ID config GROUPS bool "groups" default y help usage: groups [user] Print the groups a user is in. config LOGNAME bool "logname" default y help usage: logname Print the current user name. config WHOAMI bool "whoami" default y help usage: whoami Print the current user name. */ #define FOR_id #include "toys.h" GLOBALS( int do_u, do_n, do_G, is_groups; ) static void s_or_u(char *s, unsigned u, int done) { if (TT.do_n) printf("%s", s); else printf("%u", u); if (done) { xputc('\n'); exit(0); } } static void showid(char *header, unsigned u, char *s) { printf("%s%u(%s)", header, u, s); } void do_id(char *username) { int flags, i, ngroups; struct passwd *pw; struct group *grp; uid_t uid = getuid(), euid = geteuid(); gid_t gid = getgid(), egid = getegid(), *groups; flags = toys.optflags; // check if a username is given if (username) { pw = xgetpwnam(username); uid = euid = pw->pw_uid; gid = egid = pw->pw_gid; if (TT.is_groups) printf("%s : ", pw->pw_name); } i = flags & FLAG_r; pw = xgetpwuid(i ? uid : euid); if (TT.do_u) s_or_u(pw->pw_name, pw->pw_uid, 1); grp = xgetgrgid(i ? gid : egid); if (flags & FLAG_g) s_or_u(grp->gr_name, grp->gr_gid, 1); if (!TT.do_G) { showid("uid=", pw->pw_uid, pw->pw_name); showid(" gid=", grp->gr_gid, grp->gr_name); if (!i) { if (uid != euid) { pw = xgetpwuid(euid); showid(" euid=", pw->pw_uid, pw->pw_name); } if (gid != egid) { grp = xgetgrgid(egid); showid(" egid=", grp->gr_gid, grp->gr_name); } } showid(" groups=", grp->gr_gid, grp->gr_name); } groups = (gid_t *)toybuf; i = sizeof(toybuf)/sizeof(gid_t); ngroups = username ? getgrouplist(username, gid, groups, &i) : getgroups(i, groups); if (ngroups<0) perror_exit(0); for (i = 0; i<ngroups; i++) { if (i || !TT.do_G) xputc(' '); if (!(grp = getgrgid(groups[i]))) perror_msg(0); else if (TT.do_G) s_or_u(grp->gr_name, grp->gr_gid, 0); else if (grp->gr_gid != egid) showid("", grp->gr_gid, grp->gr_name); } xputc('\n'); } void id_main(void) { // FLAG macros can be 0 if "id" command not enabled, so snapshot them here. if (FLAG_u) TT.do_u = toys.optflags & FLAG_u; if (FLAG_n) TT.do_n = toys.optflags & FLAG_n; if (FLAG_G) TT.do_G = toys.optflags & FLAG_G; // And set the variables for non-id commands. TT.is_groups = toys.which->name[0] == 'g'; if (TT.is_groups) TT.do_G = TT.do_n = 1; else if (toys.which->name[0] != 'i') TT.do_u = TT.do_n = 1; if (toys.optc) while(*toys.optargs) do_id(*toys.optargs++); else do_id(NULL); }