| /* portability.c - code to workaround the deficiencies of various platforms. |
| * |
| * Copyright 2012 Rob Landley <rob@landley.net> |
| * Copyright 2012 Georgi Chorbadzhiyski <gf@unixsol.org> |
| */ |
| |
| #include "toys.h" |
| |
| // We can't fork() on nommu systems, and vfork() requires an exec() or exit() |
| // before resuming the parent (because they share a heap until then). And no, |
| // we can't implement our own clone() call that does the equivalent of fork() |
| // because nommu heaps use physical addresses so if we copy the heap all our |
| // pointers are wrong. (You need an mmu in order to map two heaps to the same |
| // address range without interfering with each other.) In the absence of |
| // a portable way to tell malloc() to start a new heap without freeing the old |
| // one, you pretty much need the exec().) |
| |
| // So we exec ourselves (via /proc/self/exe, if anybody knows a way to |
| // re-exec self without depending on the filesystem, I'm all ears), |
| // and use the arguments to signal reentry. |
| |
| #if CFG_TOYBOX_FORK |
| pid_t xfork(void) |
| { |
| pid_t pid = fork(); |
| |
| if (pid < 0) perror_exit("fork"); |
| |
| return pid; |
| } |
| #endif |
| |
| int xgetrandom(void *buf, unsigned buflen, unsigned flags) |
| { |
| int fd; |
| |
| #if CFG_TOYBOX_GETRANDOM |
| if (buflen == getrandom(buf, buflen, flags&~WARN_ONLY)) return 1; |
| if (errno!=ENOSYS && !(flags&WARN_ONLY)) perror_exit("getrandom"); |
| #endif |
| fd = xopen(flags ? "/dev/random" : "/dev/urandom",O_RDONLY|(flags&WARN_ONLY)); |
| if (fd == -1) return 0; |
| xreadall(fd, buf, buflen); |
| close(fd); |
| |
| return 1; |
| } |
| |
| #if defined(__APPLE__) |
| extern char **environ; |
| |
| int clearenv(void) |
| { |
| *environ = NULL; |
| return 0; |
| } |
| #endif |
| |
| // Get a linked list of mount points, with stat information. |
| #if defined(__APPLE__) || defined(__FreeBSD__) |
| |
| // Not implemented for macOS. |
| // See <sys/mount.h>'s getmntinfo(3) for the BSD API. |
| |
| #else |
| |
| #include <mntent.h> |
| |
| static void octal_deslash(char *s) |
| { |
| char *o = s; |
| |
| while (*s) { |
| if (*s == '\\') { |
| int i, oct = 0; |
| |
| for (i = 1; i < 4; i++) { |
| if (!isdigit(s[i])) break; |
| oct = (oct<<3)+s[i]-'0'; |
| } |
| if (i == 4) { |
| *o++ = oct; |
| s += i; |
| continue; |
| } |
| } |
| *o++ = *s++; |
| } |
| |
| *o = 0; |
| } |
| |
| // Check if this type matches list. |
| // Odd syntax: typelist all yes = if any, typelist all no = if none. |
| |
| int mountlist_istype(struct mtab_list *ml, char *typelist) |
| { |
| int len, skip; |
| char *t; |
| |
| if (!typelist) return 1; |
| |
| skip = strncmp(typelist, "no", 2); |
| |
| for (;;) { |
| if (!(t = comma_iterate(&typelist, &len))) break; |
| if (!skip) { |
| // If one -t starts with "no", the rest must too |
| if (strncmp(t, "no", 2)) error_exit("bad typelist"); |
| if (!strncmp(t+2, ml->type, len-2)) { |
| skip = 1; |
| break; |
| } |
| } else if (!strncmp(t, ml->type, len) && !ml->type[len]) { |
| skip = 0; |
| break; |
| } |
| } |
| |
| return !skip; |
| } |
| |
| // Get list of mounted filesystems, including stat and statvfs info. |
| // Returns a reversed list, which is good for finding overmounts and such. |
| |
| struct mtab_list *xgetmountlist(char *path) |
| { |
| struct mtab_list *mtlist = 0, *mt; |
| struct mntent *me; |
| FILE *fp; |
| char *p = path ? path : "/proc/mounts"; |
| |
| if (!(fp = setmntent(p, "r"))) perror_exit("bad %s", p); |
| |
| // The "test" part of the loop is done before the first time through and |
| // again after each "increment", so putting the actual load there avoids |
| // duplicating it. If the load was NULL, the loop stops. |
| |
| while ((me = getmntent(fp))) { |
| mt = xzalloc(sizeof(struct mtab_list) + strlen(me->mnt_fsname) + |
| strlen(me->mnt_dir) + strlen(me->mnt_type) + strlen(me->mnt_opts) + 4); |
| dlist_add_nomalloc((void *)&mtlist, (void *)mt); |
| |
| // Collect details about mounted filesystem |
| // Don't report errors, just leave data zeroed |
| if (!path) { |
| stat(me->mnt_dir, &(mt->stat)); |
| statvfs(me->mnt_dir, &(mt->statvfs)); |
| } |
| |
| // Remember information from /proc/mounts |
| mt->dir = stpcpy(mt->type, me->mnt_type)+1; |
| mt->device = stpcpy(mt->dir, me->mnt_dir)+1; |
| mt->opts = stpcpy(mt->device, me->mnt_fsname)+1; |
| strcpy(mt->opts, me->mnt_opts); |
| |
| octal_deslash(mt->dir); |
| octal_deslash(mt->device); |
| } |
| endmntent(fp); |
| |
| return mtlist; |
| } |
| |
| #endif |