95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
/* portability.c - code to workaround the deficiencies of various platforms.
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*
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* Copyright 2012 Rob Landley <rob@landley.net>
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* Copyright 2012 Georgi Chorbadzhiyski <gf@unixsol.org>
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*/
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#include "toys.h"
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// We can't fork() on nommu systems, and vfork() requires an exec() or exit()
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// before resuming the parent (because they share a heap until then). And no,
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// we can't implement our own clone() call that does the equivalent of fork()
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// because nommu heaps use physical addresses so if we copy the heap all our
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// pointers are wrong. (You need an mmu in order to map two heaps to the same
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// address range without interfering with each other.) In the absence of
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// a portable way to tell malloc() to start a new heap without freeing the old
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// one, you pretty much need the exec().)
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// So we exec ourselves (via /proc/self/exe, if anybody knows a way to
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// re-exec self without depending on the filesystem, I'm all ears),
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// and use the arguments to signal reentry.
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#if CFG_TOYBOX_FORK
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pid_t xfork(void)
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{
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pid_t pid = fork();
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if (pid < 0) perror_exit("fork");
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return pid;
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}
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#endif
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#if defined(__APPLE__)
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ssize_t getdelim(char **linep, size_t *np, int delim, FILE *stream)
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{
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int ch;
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size_t new_len;
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ssize_t i = 0;
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char *line, *new_line;
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// Invalid input
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if (!linep || !np) {
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errno = EINVAL;
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return -1;
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}
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if (*linep == NULL || *np == 0) {
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*np = 1024;
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*linep = calloc(1, *np);
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if (*linep == NULL) return -1;
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}
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line = *linep;
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while ((ch = getc(stream)) != EOF) {
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if (i > *np) {
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// Need more space
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new_len = *np + 1024;
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new_line = realloc(*linep, new_len);
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if (!new_line) return -1;
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*np = new_len;
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line = *linep = new_line;
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}
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line[i] = ch;
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if (ch == delim) break;
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i += 1;
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}
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if (i > *np) {
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// Need more space
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new_len = i + 2;
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new_line = realloc(*linep, new_len);
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if (!new_line) return -1;
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*np = new_len;
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line = *linep = new_line;
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}
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line[i + 1] = '\0';
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return i > 0 ? i : -1;
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}
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ssize_t getline(char **linep, size_t *np, FILE *stream)
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{
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return getdelim(linep, np, '\n', stream);
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}
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extern char **environ;
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int clearenv(void)
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{
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*environ = NULL;
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return 0;
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}
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#endif
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