diff options
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | src/libmdsserver/util.c | 82 | ||||
| -rw-r--r-- | src/libmdsserver/util.h | 43 | ||||
| -rw-r--r-- | src/mds-server.c | 47 | ||||
| -rw-r--r-- | src/mds-server.h | 8 |
5 files changed, 131 insertions, 51 deletions
@@ -60,7 +60,7 @@ C_FLAGS = $(OPTIMISE) $(WARN) -std=$(STD) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) \ # Object files for the libary -LIBOBJ = linked-list hash-table fd-table mds-message +LIBOBJ = linked-list hash-table fd-table mds-message util # Build rules. diff --git a/src/libmdsserver/util.c b/src/libmdsserver/util.c new file mode 100644 index 0000000..c4606e8 --- /dev/null +++ b/src/libmdsserver/util.c @@ -0,0 +1,82 @@ +/** + * mds — A micro-display server + * Copyright © 2014 Mattias Andrée (maandree@member.fsf.org) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include "util.h" +#include "config.h" + +#include <stdlib.h> +#include <unistd.h> +#include <limits.h> +#include <string.h> + + +/** + * Read an environment variable, but handle it as undefined if empty + * + * @param var The environment variable's name + * @return The environment variable's value, `NULL` if empty or not defined + */ +char* getenv_nonempty(const char* var) +{ + char* rc = getenv(var); + if ((rc == NULL) || (*rc == '\0')) + return NULL; + return rc; +} + + +/** + * Re-exec the server. + * This function only returns on failure. + * + * @param argc The number of elements in `argv` + * @param argv The command line arguments + * @param reexeced Whether the server has previously been re-exec:ed + */ +void reexec_server(int argc, char** argv, int reexeced) +{ + char readlink_buf[PATH_MAX]; + ssize_t readlink_ptr; + char** reexec_args; + char** reexec_args_; + int i; + + /* Re-exec the server. */ + readlink_ptr = readlink(SELF_EXE, readlink_buf, (sizeof(readlink_buf) / sizeof(char)) - 1); + if (readlink_ptr < 0) + return; + /* ‘readlink() does not append a null byte to buf.’ */ + readlink_buf[readlink_ptr] = '\0'; + reexec_args = alloca(((size_t)argc + 2) * sizeof(char*)); + reexec_args_ = reexec_args; + if (reexeced == 0) + { + *reexec_args_++ = *argv; + *reexec_args_ = strdup("--re-exec"); + if (*reexec_args_) + return; + for (i = 1; i < argc; i++) + reexec_args_[i] = argv[i]; + } + else /* Don't let the --re-exec:s accumulate. */ + *reexec_args_ = *argv; + for (i = 1; i < argc; i++) + reexec_args_[i] = argv[i]; + reexec_args_[argc] = NULL; + execv(readlink_buf, reexec_args); +} + diff --git a/src/libmdsserver/util.h b/src/libmdsserver/util.h new file mode 100644 index 0000000..f1276f7 --- /dev/null +++ b/src/libmdsserver/util.h @@ -0,0 +1,43 @@ +/** + * mds — A micro-display server + * Copyright © 2014 Mattias Andrée (maandree@member.fsf.org) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef MDS_LIBMDSSERVER_UTIL_H +#define MDS_LIBMDSSERVER_UTIL_H + + +/** + * Read an environment variable, but handle it as undefined if empty + * + * @param var The environment variable's name + * @return The environment variable's value, `NULL` if empty or not defined + */ +char* getenv_nonempty(const char* var); + + +/** + * Re-exec the server. + * This function only returns on failure. + * + * @param argc The number of elements in `argv` + * @param argv The command line arguments + * @param reexeced Whether the server has previously been re-exec:ed + */ +void reexec_server(int argc, char** argv, int reexeced); + + +#endif + diff --git a/src/mds-server.c b/src/mds-server.c index 04f2124..8c9a863 100644 --- a/src/mds-server.c +++ b/src/mds-server.c @@ -23,6 +23,7 @@ #include <libmdsserver/fd-table.h> #include <libmdsserver/mds-message.h> #include <libmdsserver/macros.h> +#include <libmdsserver/util.h> #include <alloca.h> #include <signal.h> @@ -398,10 +399,6 @@ int main(int argc_, char** argv_) pid_t pid = getpid(); int reexec_fd; char shm_path[NAME_MAX + 1]; - char readlink_buf[PATH_MAX]; - ssize_t readlink_ptr; - char** reexec_args; - char** reexec_args_; /* Release resources. */ pthread_mutex_destroy(&slave_mutex); @@ -423,34 +420,15 @@ int main(int argc_, char** argv_) if (marshal_server(reexec_fd) < 0) goto reexec_fail; close(reexec_fd); + reexec_fd = -1; /* Re-exec the server. */ - readlink_ptr = readlink(SELF_EXE, readlink_buf, (sizeof(readlink_buf) / sizeof(char)) - 1); - if (readlink_ptr < 0) - goto reexec_fail; - /* ‘readlink() does not append a null byte to buf.’ */ - readlink_buf[readlink_ptr] = '\0'; - reexec_args = alloca(((size_t)argc + 2) * sizeof(char*)); - reexec_args_ = reexec_args; - if (reexec == 0) - { - *reexec_args_++ = *argv; - *reexec_args_ = strdup("--re-exec"); - if (*reexec_args_) - goto reexec_fail; - for (i = 1; i < argc; i++) - reexec_args_[i] = argv[i]; - } - else /* Don't let the --re-exec:s accumulate. */ - *reexec_args_ = *argv; - for (i = 1; i < argc; i++) - reexec_args_[i] = argv[i]; - reexec_args_[argc] = NULL; - execv(readlink_buf, reexec_args); + reexec_server(argc, argv, reexec); reexec_fail: perror(*argv); - close(reexec_fd); + if (reexec_fd >= 0) + close(reexec_fd); shm_unlink(shm_path); /* Returning non-zero is important, otherwise the server cannot be respawn if the re-exec fails. */ @@ -615,21 +593,6 @@ void* slave_loop(void* data) /** - * Read an environment variable, but handle it as undefined if empty - * - * @param var The environment variable's name - * @return The environment variable's value, `NULL` if empty or not defined - */ -char* getenv_nonempty(const char* var) -{ - char* rc = getenv(var); - if ((rc == NULL) || (*rc == '\0')) - return NULL; - return rc; -} - - -/** * Exec into the mdsinitrc script * * @param args The arguments to the child process diff --git a/src/mds-server.h b/src/mds-server.h index 67e97f6..609d7cf 100644 --- a/src/mds-server.h +++ b/src/mds-server.h @@ -67,14 +67,6 @@ typedef struct client void* slave_loop(void* data); /** - * Read an environment variable, but handle it as undefined if empty - * - * @param var The environment variable's name - * @return The environment variable's value, `NULL` if empty or not defined - */ -char* getenv_nonempty(const char* var); - -/** * Exec into the mdsinitrc script * * @param args The arguments to the child process |