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-rw-r--r--lib/findprog-in.c398
1 files changed, 398 insertions, 0 deletions
diff --git a/lib/findprog-in.c b/lib/findprog-in.c
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+++ b/lib/findprog-in.c
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+/* Locating a program in a given path.
+ Copyright (C) 2001-2004, 2006-2023 Free Software Foundation, Inc.
+ Written by Bruno Haible <haible@clisp.cons.org>, 2001, 2019.
+
+ This file is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as
+ published by the Free Software Foundation; either version 2.1 of the
+ License, or (at your option) any later version.
+
+ This file is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+
+#include <config.h>
+
+/* Specification. */
+#include "findprog.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "filename.h"
+#include "concat-filename.h"
+
+#if (defined _WIN32 && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__
+ /* Native Windows, OS/2, DOS */
+# define NATIVE_SLASH '\\'
+#else
+ /* Unix */
+# define NATIVE_SLASH '/'
+#endif
+
+/* Separator in PATH like lists of pathnames. */
+#if (defined _WIN32 && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__
+ /* Native Windows, OS/2, DOS */
+# define PATH_SEPARATOR ';'
+#else
+ /* Unix */
+# define PATH_SEPARATOR ':'
+#endif
+
+/* The list of suffixes that the execlp/execvp function tries when searching
+ for the program. */
+static const char * const suffixes[] =
+ {
+ #if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
+ "", ".com", ".exe", ".bat", ".cmd"
+ /* Note: Files without any suffix are not considered executable. */
+ /* Note: The cmd.exe program does a different lookup: It searches according
+ to the PATHEXT environment variable.
+ See <https://stackoverflow.com/questions/7839150/>.
+ Also, it executes files ending in .bat and .cmd directly without letting
+ the kernel interpret the program file. */
+ #elif defined __CYGWIN__
+ "", ".exe", ".com"
+ #elif defined __EMX__
+ "", ".exe"
+ #elif defined __DJGPP__
+ "", ".com", ".exe", ".bat"
+ #else /* Unix */
+ ""
+ #endif
+ };
+
+const char *
+find_in_given_path (const char *progname, const char *path,
+ const char *directory, bool optimize_for_exec)
+{
+ {
+ bool has_slash = false;
+ {
+ const char *p;
+
+ for (p = progname; *p != '\0'; p++)
+ if (ISSLASH (*p))
+ {
+ has_slash = true;
+ break;
+ }
+ }
+ if (has_slash)
+ {
+ /* If progname contains a slash, it is either absolute or relative to
+ the current directory. PATH is not used. */
+ if (optimize_for_exec)
+ /* The execl/execv/execlp/execvp functions will try the various
+ suffixes anyway and fail if no executable is found. */
+ return progname;
+ else
+ {
+ /* Try the various suffixes and see whether one of the files
+ with such a suffix is actually executable. */
+ int failure_errno;
+ size_t i;
+
+ const char *directory_as_prefix =
+ (directory != NULL && IS_RELATIVE_FILE_NAME (progname)
+ ? directory
+ : "");
+
+ #if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
+ const char *progbasename;
+
+ {
+ const char *p;
+
+ progbasename = progname;
+ for (p = progname; *p != '\0'; p++)
+ if (ISSLASH (*p))
+ progbasename = p + 1;
+ }
+
+ bool progbasename_has_dot = (strchr (progbasename, '.') != NULL);
+ #endif
+
+ /* Try all platform-dependent suffixes. */
+ failure_errno = ENOENT;
+ for (i = 0; i < sizeof (suffixes) / sizeof (suffixes[0]); i++)
+ {
+ const char *suffix = suffixes[i];
+
+ #if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
+ /* File names without a '.' are not considered executable, and
+ for file names with a '.' no additional suffix is tried. */
+ if ((*suffix != '\0') != progbasename_has_dot)
+ #endif
+ {
+ /* Concatenate directory_as_prefix, progname, suffix. */
+ char *progpathname =
+ concatenated_filename (directory_as_prefix, progname,
+ suffix);
+
+ if (progpathname == NULL)
+ return NULL; /* errno is set here */
+
+ /* On systems which have the eaccess() system call, let's
+ use it. On other systems, let's hope that this program
+ is not installed setuid or setgid, so that it is ok to
+ call access() despite its design flaw. */
+ if (eaccess (progpathname, X_OK) == 0)
+ {
+ /* Check that the progpathname does not point to a
+ directory. */
+ struct stat statbuf;
+
+ if (stat (progpathname, &statbuf) >= 0)
+ {
+ if (! S_ISDIR (statbuf.st_mode))
+ {
+ /* Found! */
+ if (strcmp (progpathname, progname) == 0)
+ {
+ free (progpathname);
+ return progname;
+ }
+ else
+ return progpathname;
+ }
+
+ errno = EACCES;
+ }
+ }
+
+ if (errno != ENOENT)
+ failure_errno = errno;
+
+ free (progpathname);
+ }
+ }
+ #if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
+ if (failure_errno == ENOENT && !progbasename_has_dot)
+ {
+ /* In the loop above, we skipped suffix = "". Do this loop
+ round now, merely to provide a better errno than ENOENT. */
+
+ char *progpathname =
+ concatenated_filename (directory_as_prefix, progname, "");
+
+ if (progpathname == NULL)
+ return NULL; /* errno is set here */
+
+ if (eaccess (progpathname, X_OK) == 0)
+ {
+ struct stat statbuf;
+
+ if (stat (progpathname, &statbuf) >= 0)
+ {
+ if (! S_ISDIR (statbuf.st_mode))
+ errno = ENOEXEC;
+ else
+ errno = EACCES;
+ }
+ }
+
+ failure_errno = errno;
+
+ free (progpathname);
+ }
+ #endif
+
+ errno = failure_errno;
+ return NULL;
+ }
+ }
+ }
+
+ if (path == NULL)
+ /* If PATH is not set, the default search path is implementation dependent.
+ In practice, it is treated like an empty PATH. */
+ path = "";
+
+ {
+ /* Make a copy, to prepare for destructive modifications. */
+ char *path_copy = strdup (path);
+ if (path_copy == NULL)
+ return NULL; /* errno is set here */
+
+ int failure_errno;
+ char *path_rest;
+ char *cp;
+
+ #if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
+ bool progname_has_dot = (strchr (progname, '.') != NULL);
+ #endif
+
+ failure_errno = ENOENT;
+ for (path_rest = path_copy; ; path_rest = cp + 1)
+ {
+ const char *dir;
+ bool last;
+ char *dir_as_prefix_to_free;
+ const char *dir_as_prefix;
+ size_t i;
+
+ /* Extract next directory in PATH. */
+ dir = path_rest;
+ for (cp = path_rest; *cp != '\0' && *cp != PATH_SEPARATOR; cp++)
+ ;
+ last = (*cp == '\0');
+ *cp = '\0';
+
+ /* Empty PATH components designate the current directory. */
+ if (dir == cp)
+ dir = ".";
+
+ /* Concatenate directory and dir. */
+ if (directory != NULL && IS_RELATIVE_FILE_NAME (dir))
+ {
+ dir_as_prefix_to_free =
+ concatenated_filename (directory, dir, NULL);
+ if (dir_as_prefix_to_free == NULL)
+ {
+ /* errno is set here. */
+ failure_errno = errno;
+ goto failed;
+ }
+ dir_as_prefix = dir_as_prefix_to_free;
+ }
+ else
+ {
+ dir_as_prefix_to_free = NULL;
+ dir_as_prefix = dir;
+ }
+
+ /* Try all platform-dependent suffixes. */
+ for (i = 0; i < sizeof (suffixes) / sizeof (suffixes[0]); i++)
+ {
+ const char *suffix = suffixes[i];
+
+ #if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
+ /* File names without a '.' are not considered executable, and
+ for file names with a '.' no additional suffix is tried. */
+ if ((*suffix != '\0') != progname_has_dot)
+ #endif
+ {
+ /* Concatenate dir_as_prefix, progname, and suffix. */
+ char *progpathname =
+ concatenated_filename (dir_as_prefix, progname, suffix);
+
+ if (progpathname == NULL)
+ {
+ /* errno is set here. */
+ failure_errno = errno;
+ free (dir_as_prefix_to_free);
+ goto failed;
+ }
+
+ /* On systems which have the eaccess() system call, let's
+ use it. On other systems, let's hope that this program
+ is not installed setuid or setgid, so that it is ok to
+ call access() despite its design flaw. */
+ if (eaccess (progpathname, X_OK) == 0)
+ {
+ /* Check that the progpathname does not point to a
+ directory. */
+ struct stat statbuf;
+
+ if (stat (progpathname, &statbuf) >= 0)
+ {
+ if (! S_ISDIR (statbuf.st_mode))
+ {
+ /* Found! */
+ if (strcmp (progpathname, progname) == 0)
+ {
+ free (progpathname);
+
+ /* Add the "./" prefix for real, that
+ concatenated_filename() optimized away.
+ This avoids a second PATH search when the
+ caller uses execl/execv/execlp/execvp. */
+ progpathname =
+ (char *) malloc (2 + strlen (progname) + 1);
+ if (progpathname == NULL)
+ {
+ /* errno is set here. */
+ failure_errno = errno;
+ free (dir_as_prefix_to_free);
+ goto failed;
+ }
+ progpathname[0] = '.';
+ progpathname[1] = NATIVE_SLASH;
+ memcpy (progpathname + 2, progname,
+ strlen (progname) + 1);
+ }
+
+ free (dir_as_prefix_to_free);
+ free (path_copy);
+ return progpathname;
+ }
+
+ errno = EACCES;
+ }
+ }
+
+ if (errno != ENOENT)
+ failure_errno = errno;
+
+ free (progpathname);
+ }
+ }
+ #if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
+ if (failure_errno == ENOENT && !progname_has_dot)
+ {
+ /* In the loop above, we skipped suffix = "". Do this loop
+ round now, merely to provide a better errno than ENOENT. */
+
+ char *progpathname =
+ concatenated_filename (dir_as_prefix, progname, "");
+
+ if (progpathname == NULL)
+ {
+ /* errno is set here. */
+ failure_errno = errno;
+ free (dir_as_prefix_to_free);
+ goto failed;
+ }
+
+ if (eaccess (progpathname, X_OK) == 0)
+ {
+ struct stat statbuf;
+
+ if (stat (progpathname, &statbuf) >= 0)
+ {
+ if (! S_ISDIR (statbuf.st_mode))
+ errno = ENOEXEC;
+ else
+ errno = EACCES;
+ }
+ }
+
+ failure_errno = errno;
+
+ free (progpathname);
+ }
+ #endif
+
+ free (dir_as_prefix_to_free);
+
+ if (last)
+ break;
+ }
+
+ failed:
+ /* Not found in PATH. */
+ free (path_copy);
+
+ errno = failure_errno;
+ return NULL;
+ }
+}
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