projects / deliverable / binutils-gdb.git / blame
| Commit | Line | Data |
|---|---|---|
| b6a3c755 JK |
1 | /****************************************************************/ |
| 2 | /* */ | |
| 3 | /* putenv(3) */ | |
| 4 | /* */ | |
| 5 | /* Change or add an environment entry */ | |
| 6 | /* */ | |
| 7 | /****************************************************************/ | |
| 8 | /* origination 1987-Oct-7 T. Holm */ | |
| 9 | /****************************************************************/ | |
| 10 | ||
| 11 | /* | |
| 12 | From pacbell!ames!ll-xn!mit-eddie!uw-beaver!ssc-vax!uvicctr!tholm Wed May 4 23:40:52 1988 | |
| 13 | Path: hoptoad!pacbell!ames!ll-xn!mit-eddie!uw-beaver!ssc-vax!uvicctr!tholm | |
| 14 | From: tholm@uvicctr.UUCP (Terrence W. Holm) | |
| 15 | Newsgroups: comp.os.minix | |
| 16 | Subject: putenv(3) | |
| 17 | Message-ID: <395@uvicctr.UUCP> | |
| 18 | Date: 5 May 88 06:40:52 GMT | |
| 19 | Reply-To: tholm@uvicctr.UUCP (Terrence W. Holm) | |
| 20 | Organization: University of Victoria, Victoria B.C. Canada | |
| 21 | Lines: 296 | |
| 22 | ||
| 23 | ||
| 24 | EFTH Minix report #2 - May 1988 - putenv(3) | |
| 25 | ||
| 26 | ||
| 27 | This is an implementation of putenv(3) that we | |
| 28 | wrote for Minix. Please consider this a public | |
| 29 | domain program. | |
| 30 | */ | |
| 31 | ||
| 32 | #include <stdio.h> | |
| 33 | ||
| 34 | ||
| 35 | #define PSIZE sizeof(char *) | |
| 36 | ||
| 37 | ||
| 38 | extern char **environ; | |
| 39 | ||
| 40 | ||
| 41 | char *index(); | |
| 42 | char *malloc(); | |
| 43 | ||
| 44 | ||
| 45 | /****************************************************************/ | |
| 46 | /* */ | |
| 47 | /* putenv( entry ) */ | |
| 48 | /* */ | |
| 49 | /* The "entry" should follow the form */ | |
| 50 | /* "NAME=VALUE". This routine will search the */ | |
| 51 | /* user environment for "NAME" and replace its */ | |
| 52 | /* value with "VALUE". */ | |
| 53 | /* */ | |
| 54 | /* Note that "entry" is not copied, it is used */ | |
| 55 | /* as the environment entry. This means that it */ | |
| 56 | /* must not be unallocated or otherwise modifed */ | |
| 57 | /* by the caller, unless it is replaced by a */ | |
| 58 | /* subsequent putenv(). */ | |
| 59 | /* */ | |
| 60 | /* If the name is not found in the environment, */ | |
| 61 | /* then a new vector of pointers is allocated, */ | |
| 62 | /* "entry" is put at the end and the global */ | |
| 63 | /* variable "environ" is updated. */ | |
| 64 | /* */ | |
| 65 | /* This function normally returns NULL, but -1 */ | |
| 66 | /* is returned if it can not allocate enough */ | |
| 67 | /* space using malloc(3), or "entry" does not */ | |
| 68 | /* contain a '='. */ | |
| 69 | /* */ | |
| 70 | /****************************************************************/ | |
| 71 | ||
| 72 | ||
| 73 | putenv( entry ) | |
| 74 | char *entry; | |
| 75 | ||
| 76 | { | |
| 77 | unsigned length; | |
| 78 | unsigned size; | |
| 79 | char **p; | |
| 80 | char **new_environ; | |
| 81 | ||
| 82 | /* Find the length of the "NAME=" */ | |
| 83 | ||
| 84 | if ( (length=(unsigned) index(entry,'=')) == NULL ) | |
| 85 | return( -1 ); | |
| 86 | ||
| 87 | length = length - (unsigned) entry + 1; | |
| 88 | ||
| 89 | ||
| 90 | /* Scan through the environment looking for "NAME=" */ | |
| 91 | ||
| 92 | for ( p=environ; *p != 0 ; p++ ) | |
| 93 | if ( strncmp( entry, *p, length ) == 0 ) | |
| 94 | { | |
| 95 | *p = entry; | |
| 96 | return( NULL ); | |
| 97 | } | |
| 98 | ||
| 99 | ||
| 100 | /* The name was not found, build a bigger environment */ | |
| 101 | ||
| 102 | size = p - environ; | |
| 103 | ||
| 104 | new_environ = (char **) malloc( (size+2)*PSIZE ); | |
| 105 | ||
| 106 | if ( new_environ == NULL ) | |
| 107 | return( -1 ); | |
| 108 | ||
| 109 | bcopy( (char *) environ, (char *) new_environ, size*PSIZE ); | |
| 110 | ||
| 111 | new_environ[size] = entry; | |
| 112 | new_environ[size+1] = NULL; | |
| 113 | ||
| 114 | environ = new_environ; | |
| 115 | ||
| 116 | return(NULL); | |
| 117 | } |