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fix race condition

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This commit is contained in:
albert
2005-06-10 15:43:15 +00:00
parent cd80f609e6
commit 864a5356a1
5 changed files with 27 additions and 5 deletions
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20
proc/sysinfo.c
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@ -170,8 +170,13 @@ static void old_Hertz_hack(void){
}
}
// same as: euid != uid || egid != gid
#ifndef AT_SECURE
#define AT_SECURE 23 // secure mode boolean (true if setuid, etc.)
#endif
#ifndef AT_CLKTCK
#define AT_CLKTCK 17 /* frequency of times() */
#define AT_CLKTCK 17 // frequency of times()
#endif
#define NOTE_NOT_FOUND 42
@ -189,8 +194,21 @@ static unsigned long find_elf_note(unsigned long findme){
return NOTE_NOT_FOUND;
}
int have_privs;
static int check_for_privs(void){
unsigned long rc = find_elf_note(AT_SECURE);
if(rc==NOTE_NOT_FOUND){
// not valid to run this code after UID or GID change!
// (if needed, may use AT_UID and friends instead)
rc = geteuid() != getuid() || getegid() != getgid();
}
return !!rc;
}
static void init_libproc(void) __attribute__((constructor));
static void init_libproc(void){
have_privs = check_for_privs();
// ought to count CPUs in /proc/stat instead of relying
// on glibc, which foolishly tries to parse /proc/cpuinfo
//