On Wed, Feb 18, 2015 at 12:09 PM, Laszlo Papp <lp...@kde.org> wrote: > On Wed, Feb 18, 2015 at 11:00 AM, tito <farmat...@tiscali.it> wrote: >> On Wednesday 18 February 2015 09:14:42 you wrote: >> >>> On Wed, Feb 18, 2015 at 8:09 AM, Laszlo Papp <lp...@kde.org> wrote: >> >>> > On Wed, Feb 18, 2015 at 7:34 AM, Laszlo Papp <lp...@kde.org> wrote: >> >>> >> I thought about this, too, when writing the patch, but I rejected it >>> >> because >> >>> >> it is not simpler, in fact more complex, it is also not the right layer >>> >> for >> >>> >> the change. In addition, it would also be somewhat slower to execute. >> >>> > >> >>> > Just to elaborate a bit more on this as I was sending that on my phone: >> >>> > >> >>> > 1) Why do you want to make a few lines more simpler to spare a few >> >>> > lines to introduce bad implementation and slower operation? >> >>> > >> >>> > 2) Also, the update_passwd function already has all the structure to >> >>> > handle this through the file, name and member variables. It looks like >> >>> > the natural place to utilize the existing infrastructure. >> >>> > >> >>> > 3) Basically, you would go through the groups once in the embedded >> >>> > list and then you would go through again rather than just doing the >> >>> > thing correct in the first place at the first iteration. So basically, >> >>> > you would have double embedded list iteration. Even if the group list >> >>> > was stored in memory for _each_ user, it would still slightly be >> >>> > slower and I would argue that wasting memory for potentially a big >> >>> > file could defeat busybox's purpose in the first place. Anyway, >> >>> > busybox's design goal should be to be as fast as possible. Personal >> >>> > preferences should neither slow it down, nor make it use more memory >> >>> > than needed to achieve the task. >> >>> >> >>> I would actually even go further than that, namely: the same-named >> >>> group deletion should probably be integrated into my loop so that one >> >>> embedded iteration could deal with the group file changes rather than >> >>> two separate. >> >>> >> >> >> >> Hi, >> >> >> >> you can try to write a patch, but i suspect that it could be difficult >> >> with the current update_password interface without breaking the >> >> deluser from group use case. >> >> If you opt for doing the changes in deluser instead some useful >> >> get_groups code is in the id applet and could be moved to libbb as >> >> function. This will of course be slower as more iterations are done >> >> through the passwd/group files. > > I start to think that the best approach would be neither to use your > idea, nor mine, but actually a separate function doing the thing fast. > See my updated patch below which almost works, but it remains slow if > I try to inject the new code into the "line based" read and write > concept. Why don't we just create a new function?
Actually, the locking and swapping logic would be common anyway which already resides in update_passwd, so if that reusable component is not moved to a separate function to be reused, we could use put our conditional magic into the while loop. I am preparing with that change now. By the way, why does busybox use /etc/file+ and /etc/file- for this logic as opposed to ... say: mkstemp? > commit 813e3db073aca7a55b9f3d4650055e7d1ed768b4 > Author: Laszlo Papp <lp...@kde.org> > Date: Tue Feb 17 20:01:04 2015 +0000 > > Delete the user from all the groups for user deletion > > diff --git a/libbb/update_passwd.c b/libbb/update_passwd.c > index a30af6f..24f949b 100644 > --- a/libbb/update_passwd.c > +++ b/libbb/update_passwd.c > @@ -62,6 +62,8 @@ static void check_selinux_update_passwd(const char > *username) > only if CONFIG_PASSWD=y and applet_name[0] == 'p' like in passwd > or if CONFIG_CHPASSWD=y and applet_name[0] == 'c' like in chpasswd > > + 8) delete a user from all groups : update_passwd(FILE, NULL, NULL, MEMBER) > + > This function does not validate the arguments fed to it > so the calling program should take care of that. > > @@ -81,7 +83,7 @@ int FAST_FUNC update_passwd(const char *filename, > FILE *new_fp; > char *fnamesfx; > char *sfx_char; > - char *name_colon; > + char *name_colon = 0; > unsigned user_len; > int old_fd; > int new_fd; > @@ -99,13 +101,15 @@ int FAST_FUNC update_passwd(const char *filename, > if (filename == NULL) > return ret; > > - check_selinux_update_passwd(name); > + if (name) check_selinux_update_passwd(name); > > /* New passwd file, "/etc/passwd+" for now */ > fnamesfx = xasprintf("%s+", filename); > sfx_char = &fnamesfx[strlen(fnamesfx)-1]; > - name_colon = xasprintf("%s:", name); > - user_len = strlen(name_colon); > + if (name) { > + name_colon = xasprintf("%s:", name); > + user_len = strlen(name_colon); > + } > > if (shadow) > old_fp = fopen(filename, "r+"); > @@ -159,6 +163,19 @@ int FAST_FUNC update_passwd(const char *filename, > bb_perror_msg("warning: can't lock '%s'", filename); > lock.l_type = F_UNLCK; > > + if (!name && member) { > + struct group* g; > + while ((g = getgrent())) { > + char **s= g->gr_mem; > + char **d = s; > + while (*s) { > + if (strcmp(*s, member)) { *d = *s; ++d; } > + ++s; > + } > + *d = 0; > + } > + } > + > /* Read current password file, write updated /etc/passwd+ */ > changed_lines = 0; > while (1) { > @@ -167,7 +184,7 @@ int FAST_FUNC update_passwd(const char *filename, > line = xmalloc_fgetline(old_fp); > if (!line) /* EOF/error */ > break; > - if (strncmp(name_colon, line, user_len) != 0) { > + if (!name_colon || strncmp(name_colon, line, user_len) != 0) { > fprintf(new_fp, "%s\n", line); > goto next; > } > @@ -176,7 +193,7 @@ int FAST_FUNC update_passwd(const char *filename, > cp = line + user_len; /* move past name: */ > > #if ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP > - if (member) { > + if (name && member) { > /* It's actually /etc/group+, not /etc/passwd+ */ > if (ENABLE_FEATURE_ADDUSER_TO_GROUP > && applet_name[0] == 'a' > @@ -240,7 +257,7 @@ int FAST_FUNC update_passwd(const char *filename, > > if (changed_lines == 0) { > #if ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP > - if (member) { > + if (name && member) { > if (ENABLE_ADDGROUP && applet_name[0] == 'a') > bb_error_msg("can't find %s in %s", > name, filename); > if (ENABLE_DELGROUP && applet_name[0] == 'd') > diff --git a/loginutils/deluser.c b/loginutils/deluser.c > index 01a9386..8219569 100644 > --- a/loginutils/deluser.c > +++ b/loginutils/deluser.c > @@ -82,6 +82,9 @@ int deluser_main(int argc, char **argv) > do_delgroup: > /* "delgroup GROUP" or "delgroup USER GROUP" */ > if (do_deluser < 0) { /* delgroup after deluser? */ > + pfile = bb_path_group_file; > + if (update_passwd(pfile, NULL, NULL, name) == -1) > + return EXIT_FAILURE; > gr = getgrnam(name); > if (!gr) > return EXIT_SUCCESS; > @@ -99,7 +102,6 @@ int deluser_main(int argc, char **argv) > } > //endpwent(); > } > - pfile = bb_path_group_file; > if (ENABLE_FEATURE_SHADOWPASSWDS) > sfile = bb_path_gshadow_file; > } _______________________________________________ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox