1 #define _GNU_SOURCE 2 #include <stdio.h> 3 #include <unistd.h> 4 5 static const char defshells[] = "/bin/sh\n/bin/csh\n"; 6 7 static char *line; 8 static size_t linesize; 9 static FILE *f; 10 endusershell(void)11void endusershell(void) 12 { 13 if (f) fclose(f); 14 f = 0; 15 } 16 setusershell(void)17void setusershell(void) 18 { 19 if (!f) f = fopen("/etc/shells", "rbe"); 20 if (!f) f = fmemopen((void *)defshells, sizeof defshells - 1, "rb"); 21 } 22 getusershell(void)23char *getusershell(void) 24 { 25 ssize_t l; 26 if (!f) setusershell(); 27 if (!f) return 0; 28 do { 29 l = getline(&line, &linesize, f); 30 if (l <= 0) return 0; 31 } while (line[0] == '#' || line[0] == '\n'); 32 if (line[l-1]=='\n') line[l-1]=0; 33 return line; 34 } 35