fix user chroot issue + style
This commit is contained in:
prx
parent
843d1f0ab7
commit
15d09d2c01
1 changed files with 145 additions and 154 deletions
295
main.c
295
main.c
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@ -24,21 +24,21 @@
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#define GEMINI_PART 9
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/*
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* number of bytes to read with fgets() : 2014 + 1
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* fgets() reads at most size-1 (1024 here)
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* see https://gemini.circumlunar.space/docs/specification.html.
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* number of bytes to read with fgets() : 2014 + 1.
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* fgets() reads at most size-1 (1024 here).
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* See https://gemini.circumlunar.space/docs/specification.html.
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*/
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#define GEMINI_REQUEST_MAX 1025
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void autoindex(const char *);
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void cgi(const char *cgicmd);
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void autoindex(const char *);
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void cgi (const char *cgicmd);
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void display_file(const char *);
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void drop_privileges(const char *, const char *);
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void echdir(const char *);
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void status(const int, const char *);
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void status_redirect(const int, const char *);
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void status_error(const int, const char*);
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int uridecode(char *);
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void echdir (const char *);
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void status (const int, const char *);
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void status_redirect(const int, const char *);
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void status_error(const int, const char *);
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int uridecode (char *);
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void
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@ -46,7 +46,7 @@ echdir(const char *path)
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{
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if (chdir(path) == -1) {
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switch (errno) {
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case ENOTDIR: /* FALLTHROUGH */
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case ENOTDIR: /* FALLTHROUGH */
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case ENOENT:
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status_error(51, "file not found");
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break;
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@ -64,36 +64,34 @@ echdir(const char *path)
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int
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uridecode(char *uri)
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{
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int n = 0;
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char c = '\0';
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long l = 0;
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char *pos = NULL;
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int n = 0;
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char c = '\0';
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long l = 0;
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char *pos = NULL;
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if ((pos = strchr(uri, '%')) == NULL) {
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return n;
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}
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while ((pos = strchr(pos, '%')) != NULL) {
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if (strlen(pos) < 3) {
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return n;
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}
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if ((pos = strchr(uri, '%')) == NULL)
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return n;
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char hex[3] = {'\0'};
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for (size_t i=0; i < 2; i++) {
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hex[i] = tolower(pos[i+1]);
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}
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errno = 0;
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l = strtol(hex, 0, 16);
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if (errno == ERANGE && (l == LONG_MAX || l == LONG_MIN)) {
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/* conversion failed */
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continue;
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}
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c = (char)l;
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pos[0] = c;
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/* rewind of two char to remove %hex */
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memmove(pos+1 , pos + 3, strlen(pos+3) + 1); /* +1 for \0*/
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n++;
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pos++; /* avoid infinite loop */
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}
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while ((pos = strchr(pos, '%')) != NULL) {
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if (strlen(pos) < 3)
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return n;
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char hex[3] = {'\0'};
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for (size_t i = 0; i < 2; i++)
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hex[i] = tolower(pos[i + 1]);
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errno = 0;
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l = strtol(hex, 0, 16);
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if (errno == ERANGE && (l == LONG_MAX || l == LONG_MIN))
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continue; /* conversion failed */
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c = (char)l;
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pos[0] = c;
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/* rewind of two char to remove %hex */
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memmove(pos + 1, pos + 3, strlen(pos + 3) + 1); /* +1 for \0 */
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n++;
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pos++; /* avoid infinite loop */
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}
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return n;
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}
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@ -109,17 +107,17 @@ drop_privileges(const char *user, const char *path)
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if (strlen(user) > 0) {
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/* is root? */
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if (getuid() != 0) {
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errlog("chroot requires program to be run as root");
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}
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if (getuid() != 0)
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errlog("chroot requires program to be run as root");
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/* search user uid from name */
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if ((pw = getpwnam(user)) == NULL) {
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errlog("the user %s can't be found on the system", user);
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}
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if ((pw = getpwnam(user)) == NULL)
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errlog("the user %s can't be found on the system", user);
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/* chroot worked? */
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if (chroot(path) != 0) {
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errlog("the chroot_dir %s can't be used for chroot", path);
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}
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if (chroot(path) != 0)
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errlog("the chroot_dir %s can't be used for chroot", path);
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chrooted = 1;
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echdir("/");
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/* drop privileges */
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@ -129,40 +127,39 @@ drop_privileges(const char *user, const char *path)
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errlog("dropping privileges to user %s (uid=%i) failed",
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user, pw->pw_uid);
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}
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}
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#ifdef __OpenBSD__
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/*
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* prevent access to files other than the one in path
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*/
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if (chrooted) {
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eunveil("/", "r");
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} else {
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eunveil(path, "r");
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}
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if (chrooted)
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eunveil("/", "r");
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else
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eunveil(path, "r");
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/* permission to execute what's inside cgidir */
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if (strlen(cgidir) > 0) {
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eunveil(cgidir, "rx");
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}
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eunveil(NULL,NULL); /* no more call to unveil() */
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if (strlen(cgidir) > 0)
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eunveil(cgidir, "rx");
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eunveil(NULL, NULL); /* no more call to unveil() */
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/* promise permissions */
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if (strlen(cgidir) > 0) {
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epledge("stdio rpath exec", NULL);
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} else {
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epledge("stdio rpath", NULL);
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}
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if (strlen(cgidir) > 0)
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epledge("stdio rpath exec", NULL);
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else
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epledge("stdio rpath", NULL);
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#endif
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if (!chrooted)
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echdir(path); /* move to the gemini data directory */
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}
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void
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status(const int code, const char *file_mime)
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{
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if (strcmp(file_mime, "text/gemini") == 0) {
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printf("%i %s; %s\r\n", code, file_mime, lang);
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} else {
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printf("%i %s\r\n", code, file_mime);
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}
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if (strcmp(file_mime, "text/gemini") == 0)
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printf("%i %s; %s\r\n", code, file_mime, lang);
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else
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printf("%i %s\r\n", code, file_mime);
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}
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void
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@ -176,21 +173,25 @@ void
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status_error(const int code, const char *reason)
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{
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printf("%i %s\r\n",
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code, reason);
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code, reason);
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}
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void
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display_file(const char *fname)
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{
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FILE *fd = NULL;
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struct stat sb = {0};
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ssize_t nread = 0;
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const char *file_mime;
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char *buffer[BUFSIZ];
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char target[FILENAME_MAX] = {'\0'};
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char tmp[PATH_MAX] = {'\0'}; /* used to build temporary path */
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FILE *fd = NULL;
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struct stat sb = {0};
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ssize_t nread = 0;
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const char *file_mime;
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char *buffer[BUFSIZ];
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char target[FILENAME_MAX] = {'\0'};
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char tmp[PATH_MAX] = {'\0'}; /* used to build
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* temporary path */
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/* special case : fname empty. The user requested just the directory name */
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/*
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* special case : fname empty. The user requested just the directory
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* name
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*/
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if (strlen(fname) == 0) {
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if (stat("index.gmi", &sb) == 0) {
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/* there is index.gmi in the current directory */
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@ -204,17 +205,17 @@ display_file(const char *fname)
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goto err;
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}
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}
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/* this is to check if path exists and obtain metadata later */
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if (stat(fname, &sb) == -1) {
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/* check if fname is a symbolic link
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* if so, redirect using its target */
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/*
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* check if fname is a symbolic link if so, redirect using
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* its target
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*/
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if (lstat(fname, &sb) != -1 && S_ISLNK(sb.st_mode) == 1)
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goto redirect;
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goto redirect;
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else
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goto err;
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goto err;
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}
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/* check if directory */
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if (S_ISDIR(sb.st_mode) != 0) {
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/* no ending "/", redirect to "fname/" */
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@ -223,9 +224,9 @@ display_file(const char *fname)
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status_redirect(31, tmp);
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return;
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}
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/* open the file requested */
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if ((fd = fopen(fname, "r")) == NULL) { goto err; }
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if ((fd = fopen(fname, "r")) == NULL)
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goto err;
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file_mime = get_file_mime(fname, default_mime);
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@ -234,7 +235,7 @@ display_file(const char *fname)
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/* read the file byte after byte in buffer and write it to stdout */
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while ((nread = fread(buffer, 1, sizeof(buffer), fd)) != 0)
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fwrite(buffer, 1, nread, stdout);
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goto closefd; /* close file descriptor */
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goto closefd; /* close file descriptor */
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syslog(LOG_DAEMON, "path served %s", fname);
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return;
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@ -247,17 +248,15 @@ err:
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redirect:
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/* read symbolic link target to redirect */
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if (readlink(fname, target, FILENAME_MAX) == -1) {
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goto err;
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}
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if (readlink(fname, target, FILENAME_MAX) == -1)
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goto err;
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status_redirect(30, target);
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syslog(LOG_DAEMON, "redirection from %s to %s", fname, target);
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closefd:
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if (S_ISREG(sb.st_mode) != 0) {
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fclose(fd);
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}
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if (S_ISREG(sb.st_mode) != 0)
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fclose(fd);
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}
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void
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@ -265,8 +264,8 @@ autoindex(const char *path)
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{
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/* display liks to files in path + a link to parent (..) */
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int n = 0;
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struct dirent **namelist; /* this must be freed at last */
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int n = 0;
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struct dirent **namelist; /* this must be freed at last */
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syslog(LOG_DAEMON, "autoindex: %s", path);
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@ -276,19 +275,18 @@ autoindex(const char *path)
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errlog("Can't scan %s", path);
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} else {
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status(20, "text/gemini");
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printf("=> .. ../\n"); /* display link to parent */
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for(int j = 0; j < n; j++) {
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printf("=> .. ../\n"); /* display link to parent */
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for (int j = 0; j < n; j++) {
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/* skip self and parent */
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if ((strcmp(namelist[j]->d_name, ".") == 0) ||
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(strcmp(namelist[j]->d_name, "..") == 0)) {
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continue;
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}
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/* add "/" at the end of a directory path */
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if (namelist[j]->d_type == DT_DIR) {
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printf("=> ./%s/ %s/\n", namelist[j]->d_name, namelist[j]->d_name);
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} else {
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printf("=> ./%s %s\n", namelist[j]->d_name, namelist[j]->d_name);
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}
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if (namelist[j]->d_type == DT_DIR)
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printf("=> ./%s/ %s/\n", namelist[j]->d_name, namelist[j]->d_name);
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else
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printf("=> ./%s %s\n", namelist[j]->d_name, namelist[j]->d_name);
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free(namelist[j]);
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}
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free(namelist);
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@ -309,20 +307,20 @@ cgi(const char *cgicmd)
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int
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main(int argc, char **argv)
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{
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char request [GEMINI_REQUEST_MAX] = {'\0'};
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char user [_SC_LOGIN_NAME_MAX] = "";
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char hostname [GEMINI_REQUEST_MAX] = {'\0'};
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char query [PATH_MAX] = {'\0'};
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char chroot_dir[PATH_MAX] = DEFAULT_CHROOT;
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char file [FILENAME_MAX] = DEFAULT_INDEX;
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char dir [PATH_MAX] = {'\0'};
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char *pos = NULL;
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int option = 0;
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int virtualhost = 0;
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int docgi = 0;
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char request [GEMINI_REQUEST_MAX] = {'\0'};
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char user [_SC_LOGIN_NAME_MAX] = "";
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char hostname [GEMINI_REQUEST_MAX] = {'\0'};
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char query [PATH_MAX] = {'\0'};
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char chroot_dir[PATH_MAX] = DEFAULT_CHROOT;
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char file [FILENAME_MAX] = DEFAULT_INDEX;
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char dir [PATH_MAX] = {'\0'};
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char *pos = NULL;
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int option = 0;
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int virtualhost = 0;
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int docgi = 0;
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/*
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* request : contain the whole request from client : gemini://...\r\n
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* request : contain the whole request from client : gemini://...\r\n
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* user : username, used in drop_privileges()
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* hostname : extracted from hostname. used with virtualhosts and cgi SERVER_NAME
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* query : file requested in cgi : gemini://...?query
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@ -375,19 +373,17 @@ main(int argc, char **argv)
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status(59, "request is too short and probably empty");
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errlog("request is too short and probably empty");
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/* error before reading anything */
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/* error before reading anything */
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} else if (ferror(stdin)) {
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status(59, "Error while reading request");
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errlog("Error while reading request: %s", request);
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}
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}
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/* check if string ends with '\n', or to long */
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if (request[strnlen(request, GEMINI_REQUEST_MAX) - 1] != '\n') {
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status(59, "request is too long (1024 max)");
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errlog("request is too long (1024 max): %s", request);
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}
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/* remove \r\n at the end of string */
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pos = strchr(request, '\r');
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if (pos != NULL)
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@ -405,95 +401,91 @@ main(int argc, char **argv)
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syslog(LOG_DAEMON, "request %s", request);
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/* remove the gemini:// part */
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memmove(request, request + GEMINI_PART, strlen(request) +1 - GEMINI_PART);
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memmove(request, request + GEMINI_PART, strlen(request) + 1 - GEMINI_PART);
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/* remove all "/.." for safety reasons */
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while ((pos = strstr(request, "/..")) != NULL ) {
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memmove(request, pos+3, strlen(pos) +1 - 3); /* "/.." = 3 */
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}
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echdir(chroot_dir); /* move to chroot */
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while ((pos = strstr(request, "/..")) != NULL)
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memmove(request, pos + 3, strlen(pos) + 1 - 3); /* "/.." = 3 */
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/* look for hostname in request : first thing before first / if any */
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pos = strchr(request, '/');
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if (pos != NULL) {
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/* copy what's after hostname in dir */
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estrlcpy(dir, pos, strlen(pos)+1);
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estrlcpy(dir, pos, strlen(pos) + 1);
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/* just keep hostname in request : stop the string with \0 */
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pos[0] = '\0';
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}
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/* check if client added :port at end of hostname and remove it */
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pos = strchr(request, ':');
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if (pos != NULL) {
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/* end string at :*/
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/* end string at : */
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pos[0] = '\0';
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}
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/* copy hostname from request */
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estrlcpy(hostname, request, sizeof(hostname));
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/* remove leading '/' in dir */
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while (dir[0] == '/') {
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memmove(dir, dir+1, strlen(dir+1)+1);
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}
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while (dir[0] == '/')
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memmove(dir, dir + 1, strlen(dir + 1) + 1);
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if (virtualhost) {
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/* add hostname at the beginning of the dir path */
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char tmp[PATH_MAX] = {'\0'};
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char tmp [PATH_MAX] = {'\0'};
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estrlcpy(tmp, hostname, sizeof(tmp));
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estrlcat(tmp, "/", sizeof(tmp));
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estrlcat(tmp, dir, sizeof(tmp));
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estrlcpy(dir, tmp, sizeof(dir));
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}
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/* percent decode */
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uridecode(dir);
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/*
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* split dir and filename.
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* file is last part after last '/'.
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* if none found, then requested file is actually a directory
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* split dir and filename. file is last part after last '/'. if none
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* found, then requested file is actually a directory
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*/
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if (strlen(dir) > 0) {
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pos = strrchr(dir, '/');
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if (pos != NULL) {
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estrlcpy(file, pos+1, sizeof(file)); /* +1 : no leading '/' */
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estrlcpy(file, pos + 1, sizeof(file)); /* +1 : no leading '/' */
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pos[0] = '\0';
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if (strlen(dir) > 0) {
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echdir(dir); /* change directory to requested directory */
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}
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/* change directory to requested directory */
|
||||
if (strlen(dir) > 0)
|
||||
echdir(dir);
|
||||
} else {
|
||||
estrlcpy(file, dir, sizeof(file));
|
||||
}
|
||||
}
|
||||
|
||||
if (docgi) {
|
||||
/* check if directory is cgidir */
|
||||
char cgifp[PATH_MAX] = {'\0'};
|
||||
char cgifp [PATH_MAX] = {'\0'};
|
||||
estrlcpy(cgifp, chroot_dir, sizeof(cgifp));
|
||||
if (cgifp[strlen(cgifp)-1] != '/') {
|
||||
estrlcat(cgifp, "/", sizeof(cgifp));
|
||||
}
|
||||
if (cgifp[strlen(cgifp) - 1] != '/')
|
||||
estrlcat(cgifp, "/", sizeof(cgifp));
|
||||
|
||||
estrlcat(cgifp, dir, sizeof(cgifp));
|
||||
if (strcmp(cgifp, cgidir) != 0) {
|
||||
/* not cgipath, display file content */
|
||||
|
||||
/* not cgipath, display file content */
|
||||
if (strcmp(cgifp, cgidir) != 0)
|
||||
goto file_to_stdout;
|
||||
}
|
||||
|
||||
/* set env variables for CGI */
|
||||
/* see https://lists.orbitalfox.eu/archives/gemini/2020/000315.html */
|
||||
/*
|
||||
* see
|
||||
* https://lists.orbitalfox.eu/archives/gemini/2020/000315.htm
|
||||
* l
|
||||
*/
|
||||
esetenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
|
||||
esetenv("SERVER_PROTOCOL", "GEMINI", 1);
|
||||
esetenv("SERVER_SOFTWARE", "vger/1", 1);
|
||||
|
||||
/* look for "?" if any to set query for cgi, remove it*/
|
||||
/* look for "?" if any to set query for cgi, remove it */
|
||||
pos = strchr(file, '?');
|
||||
if (pos != NULL) {
|
||||
estrlcpy(query, pos+1, sizeof(query));
|
||||
estrlcpy(query, pos + 1, sizeof(query));
|
||||
esetenv("QUERY_STRING", query, 1);
|
||||
pos[0] = '\0';
|
||||
}
|
||||
|
||||
/* look for an extension to find PATH_INFO */
|
||||
pos = strrchr(file, '.');
|
||||
if (pos != NULL) {
|
||||
|
|
@ -501,7 +493,7 @@ main(int argc, char **argv)
|
|||
pos = strchr(pos, '/');
|
||||
if (pos != NULL) {
|
||||
setenv("PATH_INFO", pos, 1);
|
||||
pos[0] = '\0'; /* keep only script name */
|
||||
pos[0] = '\0'; /* keep only script name */
|
||||
}
|
||||
}
|
||||
esetenv("SCRIPT_NAME", file, 1);
|
||||
|
|
@ -510,7 +502,6 @@ main(int argc, char **argv)
|
|||
cgi(file);
|
||||
return 0;
|
||||
}
|
||||
|
||||
file_to_stdout:
|
||||
/* regular file to stdout */
|
||||
display_file(file);
|
||||
|
|
|
|||
Loading…
Reference in a new issue