Add simple cgi support +:
* read file byte after byte * format code (syslog + err) * move functions in utils.c
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prx
parent
332a5cd1d6
commit
470e47a018
10 changed files with 268 additions and 67 deletions
184
main.c
184
main.c
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@ -1,9 +1,11 @@
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <dirent.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <pwd.h>
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#include <stdarg.h>
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@ -15,6 +17,7 @@
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#include "mimes.h"
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#include "opts.h"
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#include "utils.h"
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#define GEMINI_PART 9
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#define GEMINI_REQUEST_MAX 1024 /* see https://gemini.circumlunar.space/docs/specification.html */
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@ -22,45 +25,11 @@
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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 status(const int, const char *);
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void status_redirect(const int, const char *);
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void drop_privileges(const char *, const char *);
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void eunveil(const char *, const char *);
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size_t estrlcat(char *, const char *, size_t);
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size_t estrlcpy(char *, const char *, size_t);
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void
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eunveil(const char *path, const char *permissions)
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{
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if (unveil(path, permissions) == -1) {
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syslog(LOG_DAEMON, "unveil on %s failed", path);
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err(1, "unveil");
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}
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}
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size_t
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estrlcpy(char *dst, const char *src, size_t dstsize)
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{
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size_t n = 0;
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n = strlcpy(dst, src, dstsize);
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if (n >= dstsize) {
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err(1, "strlcyp failed for %s = %s", dst, src);
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}
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return n;
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}
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size_t
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estrlcat(char *dst, const char *src, size_t dstsize)
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{
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size_t size;
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if ((size = strlcat(dst, src, dstsize)) >= dstsize)
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err(1, "strlcat on %s + %s", dst, src);
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return size;
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}
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void
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drop_privileges(const char *user, const char *path)
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@ -76,31 +45,26 @@ drop_privileges(const char *user, const char *path)
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/* is root? */
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if (getuid() != 0) {
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syslog(LOG_DAEMON, "chroot requires program to be run as root");
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errx(1, "chroot requires root user");
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errlog("chroot requires program to be run as root");
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}
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/* search user uid from name */
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if ((pw = getpwnam(user)) == NULL) {
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syslog(LOG_DAEMON, "the user %s can't be found on the system", user);
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err(1, "finding user");
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errlog("the user %s can't be found on the system", user);
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}
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/* chroot worked? */
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if (chroot(path) != 0) {
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syslog(LOG_DAEMON, "the chroot_dir %s can't be used for chroot", path);
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err(1, "chroot");
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errlog("the chroot_dir %s can't be used for chroot", path);
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}
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chrooted = 1;
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if (chdir("/") == -1) {
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syslog(LOG_DAEMON, "failed to chdir(\"/\")");
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err(1, "chdir");
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errlog("failed to chdir(\"/\")");
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}
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/* drop privileges */
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if (setgroups(1, &pw->pw_gid) ||
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setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
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setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) {
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syslog(LOG_DAEMON, "dropping privileges to user %s (uid=%i) failed",
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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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err(1, "Can't drop privileges");
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}
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}
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#ifdef __OpenBSD__
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@ -112,13 +76,20 @@ drop_privileges(const char *user, const char *path)
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} else {
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eunveil(path, "r");
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}
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if (strlen(cgibin) > 0) {
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char cgifullpath[PATH_MAX] = {'\0'};
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estrlcpy(cgifullpath, path, sizeof(cgifullpath));
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estrlcat(cgifullpath, cgibin, sizeof(cgifullpath));
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eunveil(cgifullpath, "rx");
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}
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/*
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* prevent system calls other parsing queryfor fread file and
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* write to stdio
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*/
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if (pledge("stdio rpath", NULL) == -1) {
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syslog(LOG_DAEMON, "pledge call failed");
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err(1, "pledge");
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if (strlen(cgibin) > 0) {
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epledge("stdio rpath exec proc", NULL);
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} else {
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epledge("stdio rpath", NULL);
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}
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#endif
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}
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@ -168,8 +139,8 @@ display_file(const char *uri)
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if (fp[strlen(fp) -1 ] != '/') {
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/* no ending "/", redirect to "path/" */
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char new_uri[PATH_MAX] = {'\0'};
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estrlcpy(new_uri, uri, sizeof(fp));
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estrlcat(new_uri, "/", sizeof(fp));
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estrlcpy(new_uri, uri, sizeof(new_uri));
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estrlcat(new_uri, "/", sizeof(new_uri));
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status_redirect(31, new_uri);
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return;
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@ -199,8 +170,8 @@ display_file(const char *uri)
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status(20, file_mime);
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/* read the file and write it to stdout */
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while ((nread = fread(buffer, sizeof(char), sizeof(buffer), fd)) != 0)
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fwrite(buffer, sizeof(char), nread, 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;
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syslog(LOG_DAEMON, "path served %s", fp);
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@ -257,6 +228,59 @@ autoindex(const char *path)
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closedir(fd);
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}
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void
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cgi(const char *cgicmd)
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{
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int pipedes[2] = {0};
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pid_t pid;
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if (pipe(pipedes) != 0) {
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err(1, "pipe failed");
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}
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pid = fork();
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if (pid < 0) {
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close(pipedes[0]);
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close(pipedes[1]);
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err(1, "fork failed");
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}
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if (pid > 0) { /* parent */
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char buf[3];
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size_t nread = 0;
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FILE *output = NULL;
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close(pipedes[1]); /* make sure entry is closed so fread() gets EOF */
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/* use fread/fwrite because are buffered */
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output = fdopen(pipedes[0], "r");
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if (output == NULL) {
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err(1, "fdopen failed");
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}
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/* read pipe output */
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while ((nread = fread(buf, 1, sizeof(buf), output)) != 0) {
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fwrite(buf, 1, nread, stdout);
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}
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close(pipedes[0]);
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fclose(output);
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wait(NULL); /* wait for child to terminate */
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exit(0);
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} else if (pid == 0) { /* child */
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dup2(pipedes[1], STDOUT_FILENO); /* set pipe output equal to stdout */
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close(pipedes[1]); /* no need this file descriptor : it is now stdout */
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execlp(cgicmd, cgicmd, NULL);
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/* if execlp is ok, this will never be reached */
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status(42, "text/plain");
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errlog("error when trying to execlp %s", cgicmd);
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}
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}
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int
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main(int argc, char **argv)
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{
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@ -268,7 +292,7 @@ main(int argc, char **argv)
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int option = 0;
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char *pos = NULL;
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while ((option = getopt(argc, argv, ":d:l:m:u:vi")) != -1) {
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while ((option = getopt(argc, argv, ":d:l:m:u:c:vi")) != -1) {
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switch (option) {
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case 'd':
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estrlcpy(chroot_dir, optarg, sizeof(chroot_dir));
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@ -283,6 +307,9 @@ main(int argc, char **argv)
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case 'u':
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estrlcpy(user, optarg, sizeof(user));
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break;
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case 'c':
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estrlcpy(cgibin, optarg, sizeof(cgibin));
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break;
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case 'v':
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virtualhost = 1;
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break;
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@ -303,8 +330,7 @@ main(int argc, char **argv)
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*/
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if (fgets(request, GEMINI_REQUEST_MAX, stdin) == NULL) {
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status(59, "request is too long (1024 max)");
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syslog(LOG_DAEMON, "request is too long (1024 max): %s", request);
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exit(1);
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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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@ -318,9 +344,8 @@ main(int argc, char **argv)
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*/
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if (strncmp(request, "gemini://", GEMINI_PART) != 0) {
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/* error code url malformed */
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syslog(LOG_DAEMON, "request «%s» doesn't match gemini://",
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errlog("request «%s» doesn't match gemini://",
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request);
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exit(1);
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}
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syslog(LOG_DAEMON, "request %s", request);
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@ -364,8 +389,47 @@ main(int argc, char **argv)
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estrlcpy(uri, new_uri, sizeof(uri));
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}
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/* open file and send it to stdout */
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display_file(uri);
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/* check if uri is cgibin */
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if ((strlen(cgibin) > 0) &&
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(strncmp(uri, cgibin, strlen(cgibin)) == 0)
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) {
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char cgipath[PATH_MAX] = {'\0'};
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estrlcpy(cgipath, chroot_dir, sizeof(cgipath));
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estrlcat(cgipath, uri, sizeof(cgipath));
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/* set env variables for CGI */
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/* see https://lists.orbitalfox.eu/archives/gemini/2020/000315.html */
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esetenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
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esetenv("SERVER_PROTOCOL", "GEMINI", 1);
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esetenv("SERVER_SOFTWARE", "vger/1", 1);
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/* look for "?" to set query */
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pos = strchr(cgipath, '?');
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if (pos != NULL) {
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char query[PATH_MAX] = {'\0'};
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estrlcpy(query, pos+1, sizeof(query));
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esetenv("QUERY_STRING", query, 1);
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pos[0] = '\0';
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}
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/* look for an extension to find PATH_INFO */
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pos = strrchr(cgipath, '.');
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if (pos != NULL) {
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/* found a dot */
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pos = strchr(pos, '/');
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if (pos != NULL) {
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setenv("PATH_INFO", pos, 1);
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pos[0] = '\0'; /* keep only script name */
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}
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}
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esetenv("SCRIPT_NAME", cgipath, 1);
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esetenv("SERVER_NAME", hostname, 1);
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cgi(cgipath);
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} else {
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//TODO: percent decoding here
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/* open file and send it to stdout */
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display_file(uri);
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}
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return (0);
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}
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