src/cupsgetpass.c

   1 #define _GNU_SOURCE
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include <unistd.h>
   5 #include <dlfcn.h>
   6 #include <string.h>
   7 #include <err.h>
   8 #include <errno.h>
   9 #include <sys/types.h>
  10 #include <sys/stat.h>
  11 #include <limits.h>
  12
  13 #ifndef PASS_MAX
  14 #define PASS_MAX 255
  15 #endif
  16
  17 char *getpass(const char *prompt)
  18 {
  19         char * (*real_getpass)(const char *prompt) = NULL;
  20         //warnx("intercepted \"%s\"", prompt);
  21         char *env;
  22         char *getpass_pwd = NULL;
  23
  24         if(real_getpass == NULL)
  25         {
  26                 void *handle = dlopen("/lib/i386-linux-gnu/libc.so.6", RTLD_LAZY);
  27                 if (handle == NULL)
  28                         errx(1, "dlopen: %s", dlerror());
  29                 real_getpass = dlsym(handle, "getpass");
  30                 if (real_getpass == NULL)
  31                         errx(1, "dlopen: %s", dlerror());
  32         }
  33
  34         env = getenv("CUPS_PASSWORD");
  35         if(env != NULL)
  36         {
  37                 getpass_pwd = malloc(PASS_MAX);
  38                 strncpy(getpass_pwd, env, PASS_MAX);
  39         }
  40         else
  41         {
  42                 env = getenv("CUPS_ASKPASS");
  43                 if(env != NULL)
  44                 {
  45                         int pipe_in[2];
  46                         int pipe_ex[2];
  47                         FILE *pipe_in_1;
  48                         FILE *pipe_ex_0;
  49                         pid_t pid;
  50                         int status;
  51
  52                         pipe(pipe_in);
  53                         pipe(pipe_ex);
  54                         pid = fork();
  55                         if(pid == 0)
  56                         {
  57                                 char *args[3] = {NULL, "stdin", NULL};
  58                                 args[0] = env;
  59                                 close(pipe_in[1]);
  60                                 dup2(pipe_in[0], STDIN_FILENO);
  61                                 close(pipe_ex[0]);
  62                                 dup2(pipe_ex[1], STDOUT_FILENO);
  63                                 exit(execvp(env, args));
  64                         }
  65                         else if(pid > 0)
  66                         {
  67                                 close(pipe_in[0]);
  68                                 close(pipe_ex[1]);
  69                                 pipe_in_1 = fdopen(pipe_in[1], "w");
  70                                 pipe_ex_0 = fdopen(pipe_ex[0], "r");
  71
  72                                 fprintf(pipe_in_1, "prompt=%s\nanswer=password\n", prompt);
  73                                 fflush(pipe_in_1);
  74                                 close(pipe_in[1]);
  75
  76                                 getpass_pwd = malloc(PASS_MAX);
  77                                 if(fgets(getpass_pwd, PASS_MAX, pipe_ex_0) == NULL)
  78                                 {
  79                                         free(getpass_pwd);
  80                                         getpass_pwd = NULL;
  81                                 }
  82                                 else if(getpass_pwd[strlen(getpass_pwd)-1] == '\n')
  83                                 {
  84                                         getpass_pwd[strlen(getpass_pwd)-1] = '\0';
  85                                 }
  86                                 close(pipe_ex[0]);
  87
  88                                 if(waitpid(pid, &status, 0) != -1)
  89                                 {
  90                                         if(WEXITSTATUS(status) == 0)
  91                                         {
  92                                         }
  93                                         else
  94                                         {
  95                                                 free(getpass_pwd);
  96                                                 getpass_pwd = NULL;
  97                                                 warnx("%s: %s: exited %d", __FILE__, env, WEXITSTATUS(status));
  98                                         }
  99                                 }
 100                                 else
 101                                 {
 102                                         warn("%s: waitpid", __FILE__);
 103                                 }
 104                         }
 105                         else
 106                         {
 107                                 close(pipe_in[0]);
 108                                 close(pipe_in[1]);
 109                                 close(pipe_ex[0]);
 110                                 close(pipe_ex[1]);
 111                                 warn("%s: fork", __FILE__);
 112                         }
 113                 }
 114                 else
 115                 {
 116                         warnx("Neither CUPS_PASSWORD or CUPS_ASKPASS are set.");
 117                         return real_getpass(prompt);
 118                 }
 119         }
 120
 121         return getpass_pwd;
 122 }
 123