146 lines
3.9 KiB
C
146 lines
3.9 KiB
C
// Can't trust libc not to leak enviornment variable memory, so...
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#include "toys.h"
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// In libc, populated by start code, used by getenv() and exec() and friends.
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extern char **environ;
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// Returns the number of bytes taken by the environment variables. For use
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// when calculating the maximum bytes of environment+argument data that can
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// be passed to exec for find(1) and xargs(1).
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long environ_bytes(void)
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{
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long bytes = sizeof(char *);
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char **ev;
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for (ev = environ; *ev; ev++) bytes += sizeof(char *) + strlen(*ev) + 1;
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return bytes;
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}
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// This will clear the inherited environment if called first thing.
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// Use this instead of envc so we keep track of what needs to be freed.
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void xclearenv(void)
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{
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if (toys.envc) {
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int i;
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for (i = 0; environ[i]; i++) if (i>=toys.envc) free(environ[i]);
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} else environ = xmalloc(256*sizeof(char *));
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toys.envc = 1;
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*environ = 0;
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}
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// Frees entries we set earlier. Use with libc getenv but not setenv/putenv.
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// if name has an equals and !val, act like putenv (name=val must be malloced!)
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// if !val unset name. (Name with = and val is an error)
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// returns pointer to new name=value environment string, NULL if none
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char *xsetenv(char *name, char *val)
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{
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unsigned i, j = 0, len;
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char *new;
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// If we haven't snapshot initial environment state yet, do so now.
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if (!toys.envc) {
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// envc is size +1 so even if env empty it's nonzero after initialization
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while (environ[toys.envc++]);
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memcpy(new = xmalloc(((toys.envc|31)+1)*sizeof(char *)), environ,
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toys.envc*sizeof(char *));
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environ = (void *)new;
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}
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if (!(new = strchr(name, '='))) {
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len = strlen(name);
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if (val) new = xmprintf("%s=%s", name, val);
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} else {
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len = new-name;
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if (val) error_exit("xsetenv %s to %s", name, val);
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new = name;
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}
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for (i = 0; environ[i]; i++) {
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// Drop old entry, freeing as appropriate. Assumes no duplicates.
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if (!memcmp(name, environ[i], len) && environ[i][len]=='=') {
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if (i<toys.envc-1) toys.envc--;
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else free(environ[i]);
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j++;
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}
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// move data down to fill hole, including null terminator
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if (j && !(environ[i] = environ[i+1])) break;
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}
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if (!new) return 0;
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// resize and null terminate if expanding
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if (!j && !environ[i]) {
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len = i+1;
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if (!(len&31)) environ = xrealloc(environ, (len+32)*sizeof(char *));
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environ[len] = 0;
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}
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return environ[i] = new;
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}
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void xunsetenv(char *name)
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{
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if (strchr(name, '=')) error_exit("xunsetenv %s name has =", name);
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xsetenv(name, 0);
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}
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// remove entry and return pointer instead of freeing
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char *xpop_env(char *name)
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{
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int len, i;
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char *s = 0;
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for (len = 0; name[len] && name[len]!='='; len++);
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for (i = 0; environ[i]; i++) {
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if (!s && !strncmp(name, environ[i], len) && environ[i][len] == '=') {
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s = environ[i];
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if (toys.envc-1>i) {
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s = xstrdup(s);
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toys.envc--;
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}
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}
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if (s) environ[i] = environ[i+1];
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}
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return s;
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}
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// reset environment for a user, optionally clearing most of it
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void reset_env(struct passwd *p, int clear)
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{
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int i;
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if (clear) {
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char *s, *stuff[] = {"TERM", "DISPLAY", "COLORTERM", "XAUTHORITY"};
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for (i=0; i<ARRAY_LEN(stuff); i++)
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stuff[i] = (s = getenv(stuff[i])) ? xmprintf("%s=%s", stuff[i], s) : 0;
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xclearenv();
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for (i=0; i < ARRAY_LEN(stuff); i++) if (stuff[i]) xsetenv(stuff[i], 0);
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if (chdir(p->pw_dir)) {
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perror_msg("chdir %s", p->pw_dir);
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xchdir("/");
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}
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} else {
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char **ev1, **ev2;
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// remove LD_*, IFS, ENV, and BASH_ENV from environment
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for (ev1 = ev2 = environ;;) {
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while (*ev2 && (strstart(ev2, "LD_") || strstart(ev2, "IFS=") ||
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strstart(ev2, "ENV=") || strstart(ev2, "BASH_ENV="))) ev2++;
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if (!(*ev1++ = *ev2++)) break;
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}
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}
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setenv("PATH", _PATH_DEFPATH, 1);
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setenv("HOME", p->pw_dir, 1);
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setenv("SHELL", p->pw_shell, 1);
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setenv("USER", p->pw_name, 1);
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setenv("LOGNAME", p->pw_name, 1);
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}
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