Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 1 | /* |
| 2 | * fpopen.c --- unlike the libc popen, it directly executes the |
| 3 | * command instead of call out to the shell. |
Theodore Ts'o | e2e69ba | 1999-06-18 01:13:31 +0000 | [diff] [blame] | 4 | * |
| 5 | * Copyright Theodore Ts'o, 1996-1999. |
| 6 | * |
| 7 | * Permission to use this file is granted for any purposes, as long as |
| 8 | * this copyright statement is kept intact and the author is not held |
| 9 | * liable for any damages resulting from the use of this program. |
| 10 | * |
| 11 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 12 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 13 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF |
| 14 | * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE |
| 15 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 16 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT |
| 17 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
| 18 | * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 19 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 20 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE |
| 21 | * USE OF THIS SOFTWARE. |
Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 22 | */ |
| 23 | |
Theodore Ts'o | d1154eb | 2011-09-18 17:34:37 -0400 | [diff] [blame] | 24 | #include "config.h" |
Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 25 | #include <unistd.h> |
| 26 | #include <stdlib.h> |
| 27 | #include <stdio.h> |
| 28 | #include <errno.h> |
| 29 | #include <string.h> |
| 30 | #include <ctype.h> |
| 31 | |
| 32 | #define MAX_ARGV 256 |
| 33 | |
| 34 | extern FILE *fpopen(const char *cmd, const char *mode); |
| 35 | |
| 36 | FILE *fpopen(const char *cmd, const char *mode) |
| 37 | { |
| 38 | char *argv[MAX_ARGV]; |
| 39 | int i = 0; |
| 40 | char *buf, *prog = 0; |
| 41 | char *p; |
Theodore Ts'o | e2e69ba | 1999-06-18 01:13:31 +0000 | [diff] [blame] | 42 | int do_stdin, do_stderr = 0; |
Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 43 | int fds[2]; |
| 44 | pid_t pid; |
| 45 | |
| 46 | if (!mode) { |
| 47 | errno = EFAULT; |
| 48 | return NULL; |
| 49 | } |
Theodore Ts'o | efc6f62 | 2008-08-27 23:07:54 -0400 | [diff] [blame] | 50 | |
Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 51 | switch (*mode) { |
| 52 | case 'r': |
| 53 | do_stdin = 0; |
| 54 | break; |
| 55 | case 'w': |
| 56 | do_stdin = 1; |
| 57 | break; |
| 58 | default: |
| 59 | errno = EINVAL; |
| 60 | return NULL; |
| 61 | } |
Theodore Ts'o | e2e69ba | 1999-06-18 01:13:31 +0000 | [diff] [blame] | 62 | switch (*(mode+1)) { |
| 63 | case '&': |
| 64 | do_stderr = 1; |
| 65 | } |
Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 66 | |
| 67 | /* |
| 68 | * Create the argv vector.... |
| 69 | */ |
| 70 | buf = malloc(strlen(cmd)+1); |
| 71 | if (!buf) |
| 72 | return NULL; |
| 73 | strcpy(buf, cmd); |
| 74 | p = buf; |
| 75 | while (p && *p) { |
| 76 | if (isspace(*p)) { |
| 77 | p++; |
| 78 | continue; |
| 79 | } |
| 80 | if (i == 0) |
| 81 | prog = p; |
| 82 | argv[i++] = p; |
| 83 | p = strchr(p, ' '); |
| 84 | if (p) |
| 85 | *p++ = 0; |
| 86 | } |
| 87 | |
| 88 | argv[i] = 0; |
| 89 | |
| 90 | /* |
| 91 | * Get the pipe |
| 92 | */ |
| 93 | if (pipe(fds) < 0) |
| 94 | return NULL; |
Theodore Ts'o | efc6f62 | 2008-08-27 23:07:54 -0400 | [diff] [blame] | 95 | |
Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 96 | /* Fork and execute the correct program. */ |
| 97 | if ((pid = fork()) < 0) { |
| 98 | perror("fork"); |
| 99 | return NULL; |
| 100 | } else if (pid == 0) { |
| 101 | if (do_stdin) { |
| 102 | close(fds[1]); |
| 103 | dup2(fds[0], 0); |
| 104 | } else { |
| 105 | close(fds[0]); |
| 106 | dup2(fds[1], 1); |
Theodore Ts'o | e2e69ba | 1999-06-18 01:13:31 +0000 | [diff] [blame] | 107 | if (do_stderr) |
| 108 | dup2(fds[1], 2); |
Theodore Ts'o | f3db356 | 1997-04-26 13:34:30 +0000 | [diff] [blame] | 109 | } |
| 110 | (void) execvp(prog, argv); |
| 111 | perror(prog); |
| 112 | exit(1); |
| 113 | } |
| 114 | return fdopen(do_stdin ? fds[1] : fds[0], mode); |
| 115 | } |
| 116 | |