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1 /* This a snippet I found in sourceforge. I just changed the identing
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2 style to my own and deleted the main function. */
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3
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4 #include <errno.h>
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5 #include <stdio.h>
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6 #include <stdlib.h>
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7 #include <unistd.h>
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8 #include <string.h>
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9 #include <sys/types.h>
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10
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11 #include "peopen.h"
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12 #include "sysexits.h"
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13
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14 #include "masqmail.h"
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15
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16 static
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17 void destroy_argv(char **arr)
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18 {
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19 char *p = arr[0];
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20 int i = 0;
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21
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22 while(p){
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23 free(p);
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24 p = arr[i++];
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25 }
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26 free(arr);
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27 }
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28
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29 static
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30 char **create_argv(const char *cmd, int count)
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31 {
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32 char buf[strlen(cmd)+1];
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33 char **arr, *q;
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34 const char *p;
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35 int i = 0;
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36
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37 arr = (char **)malloc(sizeof(char *) * count);
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38
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39 p = cmd;
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40 while(*p && i < (count-1)){
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41 while(*p && isspace(*p)) p++;
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42 q = buf;
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43 while(*p && !isspace(*p)) *q++ = *p++;
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44 *q = 0;
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45 arr[i++] = strdup(buf);
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46 while(*p && isspace(*p)) p++;
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47 }
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48 arr[i] = NULL;
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49
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50 return arr;
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51 }
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52
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53 FILE* peidopen(const char *command,
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54 const char *type,
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55 char *const envp [],
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56 int *ret_pid,
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57 uid_t uid, gid_t gid
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58 )
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59 {
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60 enum { Read, Write } mode;
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61 int pipe_fd [2];
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62 pid_t pid;
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63
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64 if (command == NULL || type == NULL) {
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65 errno = EINVAL;
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66 return NULL;
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67 }
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68
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69 if (strcmp (type, "r")) {
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70 if (strcmp (type, "w")) {
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71 errno = EINVAL;
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72 return NULL;
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73 } else
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74 mode = Write;
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75 } else
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76 mode = Read;
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77
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78 if (pipe (pipe_fd) == -1)
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79 return NULL;
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80
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81 switch (pid = fork ()) {
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82 case 0: /* child thread */
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83
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84 {
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85 int i, max_fd = sysconf(_SC_OPEN_MAX);
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86
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87 if(max_fd <= 0) max_fd = 64;
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88 for(i = 0; i < max_fd; i++)
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89 if((i != pipe_fd[0]) && (i != pipe_fd[1])) close(i);
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90 }
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91 if (close (pipe_fd [mode == Read ? 0 : 1]) != -1 &&
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92 dup2 (pipe_fd [mode == Read ? 1 : 0], mode == Read ? STDOUT_FILENO : STDIN_FILENO) != -1) {
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93 // char *argv [] = { "/bin/sh", "-c", (char*) command, NULL };
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94 char **argv = create_argv(command, 10);
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95 int ret;
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96
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97 if(uid != (uid_t)-1){
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98 if((ret = seteuid(0)) != 0){
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99 exit(EX_NOPERM);
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100 }
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101 }
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102 if(gid != (gid_t)-1){
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103 if((ret = setgid(gid)) != 0){
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104 exit(EX_NOPERM);
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105 }
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106 }
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107 if(uid != (uid_t)-1){
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108 if((ret = setuid(uid)) != 0){
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109 exit(EX_NOPERM);
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110 }
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111 }
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112 execve (*argv, argv, envp);
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113 }
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114
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115 _exit (errno);
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116
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117 default: /* parent thread */
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118 *ret_pid = pid;
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119 close (pipe_fd [mode == Read ? 1 : 0]);
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120 return fdopen (pipe_fd [mode == Read ? 0 : 1], type);
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121
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122 case -1:
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123 close (pipe_fd [0]);
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124 close (pipe_fd [1]);
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125 return NULL;
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126 }
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127 }
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128
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129 FILE* peopen(const char *command,
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130 const char *type,
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131 char *const envp [],
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132 int *ret_pid
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133 )
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134 {
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135 return peidopen(command, type, envp, ret_pid, -1 ,-1);
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136 }
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