Differential D25038 Diff 72907 head/lib/libc/gen/exec.c

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head/lib/libc/gen/exec.c

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	#include <paths.h>			#include <paths.h>

	#include <stdarg.h>			#include <stdarg.h>
	#include "un-namespace.h"			#include "un-namespace.h"
	#include "libc_private.h"			#include "libc_private.h"

	extern char **environ;			extern char **environ;

				static const char execvPe_err_preamble[] = "execvP: ";
				static const char execvPe_err_trailer[] = ": path too long\n";

	int			int
	execl(const char name, const char arg, ...)			execl(const char name, const char arg, ...)
	{			{
	va_list ap;			va_list ap;
	const char **argv;			const char **argv;
	int n;			int n;

	va_start(ap, arg);			va_start(ap, arg);
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	static int			static int
	execvPe(const char name, const char path, char * const *argv,			execvPe(const char name, const char path, char * const *argv,
	char * const *envp)			char * const *envp)
	{			{
	const char **memp;			const char **memp;
	size_t cnt, lp, ln;			size_t cnt, lp, ln;
	int eacces, save_errno;			int eacces, save_errno;
	char *cur, buf[MAXPATHLEN];			char buf[MAXPATHLEN];
	const char p, bp;			const char bp, np, op, p;
	struct stat sb;			struct stat sb;

	eacces = 0;			eacces = 0;

	/* If it's an absolute or relative path name, it's easy. */			/* If it's an absolute or relative path name, it's easy. */
	if (strchr(name, '/')) {			if (strchr(name, '/')) {
	bp = name;			bp = name;
	cur = NULL;			op = NULL;
	goto retry;			goto retry;
	}			}
	bp = buf;			bp = buf;

	/* If it's an empty path name, fail in the usual POSIX way. */			/* If it's an empty path name, fail in the usual POSIX way. */
	if (*name == '\0') {			if (*name == '\0') {
	errno = ENOENT;			errno = ENOENT;
	return (-1);			return (-1);
	}			}

	cur = alloca(strlen(path) + 1);			op = path;
	if (cur == NULL) {			ln = strlen(name);
	errno = ENOMEM;			while (op != NULL) {
	return (-1);			np = strchrnul(op, ':');
	}
	strcpy(cur, path);
	while ((p = strsep(&cur, ":")) != NULL) {
	/*			/*
	* It's a SHELL path -- double, leading and trailing colons			* It's a SHELL path -- double, leading and trailing colons
	* mean the current directory.			* mean the current directory.
	*/			*/
	if (*p == '\0') {			if (np == op) {
				/* Empty component. */
	p = ".";			p = ".";
	lp = 1;			lp = 1;
	} else			} else {
	lp = strlen(p);			/* Non-empty component. */
	ln = strlen(name);			p = op;
				lp = np - op;
				}

				/* Advance to the next component or terminate after this. */
				if (*np == '\0')
				op = NULL;
				else
				op = np + 1;

	/*			/*
	* If the path is too long complain. This is a possible			* If the path is too long complain. This is a possible
	* security issue; given a way to make the path too long			* security issue; given a way to make the path too long
	* the user may execute the wrong program.			* the user may execute the wrong program.
	*/			*/
	if (lp + ln + 2 > sizeof(buf)) {			if (lp + ln + 2 > sizeof(buf)) {
	(void)_write(STDERR_FILENO, "execvP: ", 8);			(void)_write(STDERR_FILENO, execvPe_err_preamble,
				sizeof(execvPe_err_preamble) - 1);
	(void)_write(STDERR_FILENO, p, lp);			(void)_write(STDERR_FILENO, p, lp);
	(void)_write(STDERR_FILENO, ": path too long\n",			(void)_write(STDERR_FILENO, execvPe_err_trailer,
	16);			sizeof(execvPe_err_trailer) - 1);
	continue;			continue;
	}			}
	bcopy(p, buf, lp);			bcopy(p, buf, lp);
	buf[lp] = '/';			buf[lp] = '/';
	bcopy(name, buf + lp + 1, ln);			bcopy(name, buf + lp + 1, ln);
	buf[lp + ln + 1] = '\0';			buf[lp + ln + 1] = '\0';

	retry: (void)_execve(bp, argv, envp);			retry: (void)_execve(bp, argv, envp);
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