Robert Griebl | 1fca558 | 2002-06-04 20:45:46 +0000 | [diff] [blame] | 1 | /* |
| 2 | * __getgrent.c - This file is part of the libc-8086/grp package for ELKS, |
| 3 | * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>. |
| 4 | * |
| 5 | * This library is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU Library General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This library is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * Library General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU Library General Public |
| 16 | * License along with this library; if not, write to the Free |
| 17 | * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 18 | * |
| 19 | */ |
| 20 | |
Robert Griebl | 1fca558 | 2002-06-04 20:45:46 +0000 | [diff] [blame] | 21 | #include <unistd.h> |
| 22 | #include <stdlib.h> |
| 23 | #include <string.h> |
Glenn L McGrath | 4e05b9b | 2002-12-07 23:14:40 +0000 | [diff] [blame] | 24 | |
| 25 | #include "busybox.h" |
Eric Andersen | 887ca79 | 2002-07-03 23:19:26 +0000 | [diff] [blame] | 26 | #include "grp_.h" |
Robert Griebl | 1fca558 | 2002-06-04 20:45:46 +0000 | [diff] [blame] | 27 | |
| 28 | /* |
| 29 | * Define GR_SCALE_DYNAMIC if you want grp to dynamically scale its read buffer |
| 30 | * so that lines of any length can be used. On very very small systems, |
| 31 | * you may want to leave this undefined becasue it will make the grp functions |
| 32 | * somewhat larger (because of the inclusion of malloc and the code necessary). |
| 33 | * On larger systems, you will want to define this, because grp will _not_ |
| 34 | * deal with long lines gracefully (they will be skipped). |
| 35 | */ |
| 36 | #undef GR_SCALE_DYNAMIC |
| 37 | |
| 38 | #ifndef GR_SCALE_DYNAMIC |
| 39 | /* |
| 40 | * If scaling is not dynamic, the buffers will be statically allocated, and |
| 41 | * maximums must be chosen. GR_MAX_LINE_LEN is the maximum number of |
| 42 | * characters per line in the group file. GR_MAX_MEMBERS is the maximum |
| 43 | * number of members of any given group. |
| 44 | */ |
| 45 | #define GR_MAX_LINE_LEN 128 |
| 46 | /* GR_MAX_MEMBERS = (GR_MAX_LINE_LEN-(24+3+6))/9 */ |
| 47 | #define GR_MAX_MEMBERS 11 |
| 48 | |
| 49 | #endif /* !GR_SCALE_DYNAMIC */ |
| 50 | |
| 51 | |
| 52 | /* |
| 53 | * Define GR_DYNAMIC_GROUP_LIST to make initgroups() dynamically allocate |
| 54 | * space for it's GID array before calling setgroups(). This is probably |
| 55 | * unnecessary scalage, so it's undefined by default. |
| 56 | */ |
| 57 | #undef GR_DYNAMIC_GROUP_LIST |
| 58 | |
| 59 | #ifndef GR_DYNAMIC_GROUP_LIST |
| 60 | /* |
| 61 | * GR_MAX_GROUPS is the size of the static array initgroups() uses for |
| 62 | * its static GID array if GR_DYNAMIC_GROUP_LIST isn't defined. |
| 63 | */ |
| 64 | #define GR_MAX_GROUPS 64 |
| 65 | |
| 66 | #endif /* !GR_DYNAMIC_GROUP_LIST */ |
| 67 | |
| 68 | |
| 69 | /* |
| 70 | * This is the core group-file read function. It behaves exactly like |
| 71 | * getgrent() except that it is passed a file descriptor. getgrent() |
| 72 | * is just a wrapper for this function. |
| 73 | */ |
Russ Dill | f796700 | 2003-12-18 22:40:58 +0000 | [diff] [blame] | 74 | struct group *bb_getgrent(int grp_fd) |
Robert Griebl | 1fca558 | 2002-06-04 20:45:46 +0000 | [diff] [blame] | 75 | { |
| 76 | #ifndef GR_SCALE_DYNAMIC |
| 77 | static char line_buff[GR_MAX_LINE_LEN]; |
| 78 | static char *members[GR_MAX_MEMBERS]; |
| 79 | #else |
| 80 | static char *line_buff = NULL; |
| 81 | static char **members = NULL; |
| 82 | short line_index; |
| 83 | short buff_size; |
| 84 | #endif |
| 85 | static struct group group; |
| 86 | register char *ptr; |
| 87 | char *field_begin; |
| 88 | short member_num; |
| 89 | char *endptr; |
| 90 | int line_len; |
| 91 | |
| 92 | |
| 93 | /* We use the restart label to handle malformatted lines */ |
| 94 | restart: |
| 95 | #ifdef GR_SCALE_DYNAMIC |
| 96 | line_index = 0; |
| 97 | buff_size = 256; |
| 98 | #endif |
| 99 | |
| 100 | #ifndef GR_SCALE_DYNAMIC |
| 101 | /* Read the line into the static buffer */ |
| 102 | if ((line_len = read(grp_fd, line_buff, GR_MAX_LINE_LEN)) <= 0) |
| 103 | return NULL; |
| 104 | field_begin = strchr(line_buff, '\n'); |
| 105 | if (field_begin != NULL) |
| 106 | lseek(grp_fd, (long) (1 + field_begin - (line_buff + line_len)), |
| 107 | SEEK_CUR); |
| 108 | else { /* The line is too long - skip it :-\ */ |
| 109 | |
| 110 | do { |
| 111 | if ((line_len = read(grp_fd, line_buff, GR_MAX_LINE_LEN)) <= 0) |
| 112 | return NULL; |
| 113 | } while (!(field_begin = strchr(line_buff, '\n'))); |
| 114 | lseek(grp_fd, (long) ((field_begin - line_buff) - line_len + 1), |
| 115 | SEEK_CUR); |
| 116 | goto restart; |
| 117 | } |
| 118 | if (*line_buff == '#' || *line_buff == ' ' || *line_buff == '\n' || |
| 119 | *line_buff == '\t') |
| 120 | goto restart; |
| 121 | *field_begin = '\0'; |
| 122 | |
| 123 | #else /* !GR_SCALE_DYNAMIC */ |
| 124 | line_buff = realloc(line_buff, buff_size); |
| 125 | while (1) { |
| 126 | if ((line_len = read(grp_fd, line_buff + line_index, |
| 127 | buff_size - line_index)) <= 0) |
| 128 | return NULL; |
| 129 | field_begin = strchr(line_buff, '\n'); |
| 130 | if (field_begin != NULL) { |
| 131 | lseek(grp_fd, |
| 132 | (long) (1 + field_begin - |
| 133 | (line_len + line_index + line_buff)), SEEK_CUR); |
| 134 | *field_begin = '\0'; |
| 135 | if (*line_buff == '#' || *line_buff == ' ' |
| 136 | || *line_buff == '\n' || *line_buff == '\t') |
| 137 | goto restart; |
| 138 | break; |
| 139 | } else { /* Allocate some more space */ |
| 140 | |
| 141 | line_index = buff_size; |
| 142 | buff_size += 256; |
| 143 | line_buff = realloc(line_buff, buff_size); |
| 144 | } |
| 145 | } |
| 146 | #endif /* GR_SCALE_DYNAMIC */ |
| 147 | |
| 148 | /* Now parse the line */ |
| 149 | group.gr_name = line_buff; |
| 150 | ptr = strchr(line_buff, ':'); |
| 151 | if (ptr == NULL) |
| 152 | goto restart; |
| 153 | *ptr++ = '\0'; |
| 154 | |
| 155 | group.gr_passwd = ptr; |
| 156 | ptr = strchr(ptr, ':'); |
| 157 | if (ptr == NULL) |
| 158 | goto restart; |
| 159 | *ptr++ = '\0'; |
| 160 | |
| 161 | field_begin = ptr; |
| 162 | ptr = strchr(ptr, ':'); |
| 163 | if (ptr == NULL) |
| 164 | goto restart; |
| 165 | *ptr++ = '\0'; |
| 166 | |
| 167 | group.gr_gid = (gid_t) strtoul(field_begin, &endptr, 10); |
| 168 | if (*endptr != '\0') |
| 169 | goto restart; |
| 170 | |
| 171 | member_num = 0; |
| 172 | field_begin = ptr; |
| 173 | |
| 174 | #ifndef GR_SCALE_DYNAMIC |
| 175 | while ((ptr = strchr(ptr, ',')) != NULL) { |
| 176 | *ptr = '\0'; |
| 177 | ptr++; |
| 178 | members[member_num] = field_begin; |
| 179 | field_begin = ptr; |
| 180 | member_num++; |
| 181 | } |
| 182 | if (*field_begin == '\0') |
| 183 | members[member_num] = NULL; |
| 184 | else { |
| 185 | members[member_num] = field_begin; |
| 186 | members[member_num + 1] = NULL; |
| 187 | } |
| 188 | #else /* !GR_SCALE_DYNAMIC */ |
Aaron Lehmann | a170e1c | 2002-11-28 11:27:31 +0000 | [diff] [blame] | 189 | free(members); |
Robert Griebl | 1fca558 | 2002-06-04 20:45:46 +0000 | [diff] [blame] | 190 | members = (char **) malloc((member_num + 1) * sizeof(char *)); |
| 191 | for ( ; field_begin && *field_begin != '\0'; field_begin = ptr) { |
| 192 | if ((ptr = strchr(field_begin, ',')) != NULL) |
| 193 | *ptr++ = '\0'; |
| 194 | members[member_num++] = field_begin; |
| 195 | members = (char **) realloc(members, |
| 196 | (member_num + 1) * sizeof(char *)); |
| 197 | } |
| 198 | members[member_num] = NULL; |
| 199 | #endif /* GR_SCALE_DYNAMIC */ |
| 200 | |
| 201 | group.gr_mem = members; |
| 202 | return &group; |
| 203 | } |