* NEWS, libmisc/limits.c: Fix parsing of limits.
* NEWS, libmisc/limits.c, man/limits.5.xml: Add support for infinite limits. * NEWS, libmisc/limits.c, man/limits.5.xml: Add support for @group syntax.
This commit is contained in:
nekral-guest
113
libmisc/limits.c
113
libmisc/limits.c
@@ -33,6 +33,7 @@
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/*
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* Separated from setup.c. --marekm
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* Resource limits thanks to Cristian Gafton.
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* Enhancements of resource limit code by Thomas Orgis <thomas@orgis.org> ("thor").
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*/
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#include <config.h>
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@@ -44,6 +45,7 @@
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <stdio.h>
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#include <ctype.h>
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#include "prototypes.h"
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#include "defines.h"
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#include <pwd.h>
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@@ -69,17 +71,37 @@ setrlimit_value (unsigned int resource, const char *value,
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unsigned int multiplier)
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{
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struct rlimit rlim;
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long limit;
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rlim_t limit;
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if (getlong (value, &limit) == 0) {
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return 0;
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/* The "-" is special, not belonging to a strange negative limit.
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It is infinity, in a controlled way. --thor */
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if(value[0] == '-') {
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limit = RLIM_INFINITY;
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}
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limit *= multiplier;
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if (limit != (rlim_t) limit) {
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return 0;
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else {
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/* We cannot use getlong here because it fails when there
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is more to the value than just this number!
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Also, we are limited to base 10 here (hex numbers will not
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work with the limit string parser as is anyway) --thor */
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char *endptr;
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long longlimit = strtol(value, &endptr, 10);
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if ((0 == longlimit) && (value == endptr)) {
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/* No argument at all. No-op.
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We could instead throw an error, though. --thor */
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return 0;
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}
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longlimit *= multiplier;
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limit = (rlim_t)longlimit;
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if(longlimit != limit)
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{
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/* Again, silent error handling... I left it that way.
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Wouldn't screaming make more sense? --thor */
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return 0;
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}
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}
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rlim.rlim_cur = (rlim_t) limit;
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rlim.rlim_max = (rlim_t) limit;
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rlim.rlim_cur = limit;
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rlim.rlim_max = limit;
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if (setrlimit (resource, &rlim) != 0) {
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return LOGIN_ERROR_RLIMIT;
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}
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@@ -199,6 +221,9 @@ static int check_logins (const char *name, const char *maxlogins)
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* [Ii]: i = RLIMIT_NICE max nice value (0..39 translates to 20..-19)
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* [Oo]: o = RLIMIT_RTPRIO max real time priority (linux/sched.h 0..MAX_RT_PRIO)
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*
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* Remember to extend the "no-limits" string below when adding a new limit...
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* --thor
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*
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* Return value:
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* 0 = okay, of course
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* LOGIN_ERROR_RLIMIT = error setting some RLIMIT
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@@ -214,6 +239,19 @@ static int do_user_limits (const char *buf, const char *name)
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bool reported = false;
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pp = buf;
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/* Skip leading whitespace. --thor */
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while(*pp == ' ' || *pp == '\t') ++pp;
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/* The special limit string "-" results in no limit for all known limits.
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We achieve that by parsing a full limit string, parts of it being ignored
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if a limit type is not known to the system.
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Though, there will be complaining for unknown limit types. --thor */
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if(strcmp(pp, "-") == 0) {
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/* Remember to extend this, too, when adding new limits!
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Oh... but "unlimited" does not make sense for umask, or does it?
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--thor */
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pp = "A- C- D- F- M- N- R- S- T- P- I- O-";
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}
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while ('\0' != *pp) {
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switch (*pp++) {
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@@ -316,6 +354,10 @@ static int do_user_limits (const char *buf, const char *name)
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break;
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default:
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/* Only report invalid strings once */
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/* Note: A string can be invalid just because a specific (theoretically
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valid) setting is not supported by this build.
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It is just a warning in syslog anyway. The line is still processed
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--thor */
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if (!reported) {
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SYSLOG ((LOG_WARN,
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"Invalid limit string: '%s'",
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@@ -324,13 +366,51 @@ static int do_user_limits (const char *buf, const char *name)
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retval |= LOGIN_ERROR_RLIMIT;
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}
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}
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/* After parsing one limit setting (or just complaining about it),
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one still needs to skip its argument to prevent a bogus warning on
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trying to parse that as limit specification.
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So, let's skip all digits, "-" and our limited set of whitespace.
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--thor */
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while(isdigit(*pp) || *pp == '-' || *pp == ' ' || *pp == '\t') {
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++pp;
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}
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}
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return retval;
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}
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/* Check if user uname is in the group gname.
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* Can I be sure that gr_mem contains no UID as string?
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* Returns true when user is in the group, false when not.
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* Any error is treated as false. --thor
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*/
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static bool user_in_group (const char *uname, const char *gname)
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{
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struct group *groupdata;
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char **member;
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if(uname == NULL || gname == NULL){
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return false;
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}
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/* We are not claiming to be re-entrant!
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* In case of paranoia or a multithreaded login program,
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* one needs to add some mess for getgrnam_r. */
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groupdata = getgrnam(gname);
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if(groupdata == NULL) {
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SYSLOG ((LOG_WARN, "Nonexisting group `%s' in limits file.", gname));
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return false;
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}
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/* Now look for our user in the list of members. */
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member = groupdata->gr_mem;
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while(*member != NULL) {
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if(strcmp(*member, uname) == 0) {
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return true;
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}
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++member;
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}
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return false;
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}
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static int setup_user_limits (const char *uname)
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{
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/* TODO: allow and use @group syntax --cristiang */
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FILE *fil;
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char buf[1024];
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char name[1024];
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@@ -352,7 +432,7 @@ static int setup_user_limits (const char *uname)
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}
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/* The limits file have the following format:
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* - '#' (comment) chars only as first chars on a line;
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* - username must start on first column
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* - username must start on first column (or *, or @group --thor)
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* A better (smarter) checking should be done --cristiang */
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while (fgets (buf, 1024, fil) != NULL) {
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if (('#' == buf[0]) || ('\n' == buf[0])) {
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@@ -367,6 +447,13 @@ static int setup_user_limits (const char *uname)
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* Imposing a limit should be done with care, so a wrong
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* entry means no care anyway :-). A '-' as a limits
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* strings means no limits --cristiang */
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/* In addition to the handling of * as name which was alrady present,
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I added handling of the @group syntax.
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To clarify: The first entry with matching user name rules,
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everything after it is ignored. If there is no user entry,
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the last encountered entry for a matching group rules.
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If there is no matching group entry, the default limits rule.
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--thor. */
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if (sscanf (buf, "%s%[ACDFMNRSTULPIOacdfmnrstulpio0-9 \t-]",
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name, tempbuf) == 2) {
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if (strcmp (name, uname) == 0) {
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@@ -374,6 +461,12 @@ static int setup_user_limits (const char *uname)
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break;
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} else if (strcmp (name, "*") == 0) {
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strcpy (deflimits, tempbuf);
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} else if (name[0] == '@') {
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/* If the user is in the group, the group limits apply unless
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later a line for the specific user is found. --thor */
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if(user_in_group(uname, name+1)) {
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strcpy (limits, tempbuf);
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}
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}
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}
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}
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