100 lines
1.6 KiB
C
100 lines
1.6 KiB
C
/* who.c */
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <time.h>
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#include <utmpx.h>
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/* types */
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typedef int Prefs;
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#define PREFS_m 0x1
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#define PREFS_T 0x2
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/* who */
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static int _who_error(char const * message, int ret);
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static char * _who_tty(void);
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static int _who(Prefs * prefs)
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{
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struct utmpx * u;
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struct tm * tm;
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char buf[13];
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char * tty = NULL;
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memset(&tm, 0, sizeof(tm));
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if(*prefs & PREFS_m && (tty = _who_tty()) == NULL)
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return 1;
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for(; (u = getutxent()) != NULL;)
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{
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if(u->ut_type != USER_PROCESS)
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continue;
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if(tty != NULL && strcmp(tty, u->ut_line) != 0)
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continue;
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printf("%-8s", u->ut_user);
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if(*prefs & PREFS_T)
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printf(" %c", '?');
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printf(" %-8s", u->ut_line);
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if((tm = localtime(&u->ut_tv.tv_sec)) == NULL || strftime(buf,
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sizeof(buf), "%b %e %H:%M", tm) == 0)
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strcpy(buf, "n/a");
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printf(" %s\n", buf);
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}
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return 0;
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}
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static int _who_error(char const * message, int ret)
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{
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fprintf(stderr, "%s", "ttyname: ");
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perror(message);
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return ret;
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}
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static char * _who_tty(void)
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{
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char * tty;
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if((tty = ttyname(0)) == NULL)
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{
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_who_error("ttyname", 1);
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return NULL;
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}
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if(strncmp(tty, "/dev/", 5) != 0)
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return tty;
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return tty + 5;
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}
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/* usage */
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static int _usage(void)
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{
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fprintf(stderr, "%s", "Usage: who\n");
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return 1;
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}
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/* main */
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int main(int argc, char * argv[])
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{
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Prefs prefs;
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int o;
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memset(&prefs, 0, sizeof(prefs));
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while((o = getopt(argc, argv, "mTu")) != -1)
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switch(o)
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{
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case 'm':
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prefs |= PREFS_m;
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break;
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case 'T':
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prefs |= PREFS_T;
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break;
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default:
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return _usage();
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}
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return _who(&prefs) == 0 ? 0 : 2;
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}
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