如何在CMake中正确链接libssh

Question

我正在尝试使用 libssh 库做一些事情，同时也从一本关于 CMake 的书开始。

编译时出现以下错误：

intero@:~/Documents/projects/c/fastDeploy/build$ make
Consolidate compiler generated dependencies of target deployExe

[ 50%] Linking C executable deployExe/usr/bin/ld: CMakeFiles/deployExe.dir/main.c.o: in function `set_ssh_options':
main.c:(.text+0x2cc): undefined reference to `ssh_options_set'

/usr/bin/ld: main.c:(.text+0x2e5): undefined reference to `ssh_options_set'

/usr/bin/ld: main.c:(.text+0x2fe): undefined reference to `ssh_options_set'

/usr/bin/ld: CMakeFiles/deployExe.dir/main.c.o: in function `main':

main.c:(.text+0x359): undefined reference to `ssh_new'

/usr/bin/ld: main.c:(.text+0x3ab): undefined reference to `ssh_free'

collect2: error: ld returned 1 exit status

make[2]: *** [CMakeFiles/deployExe.dir/build.make:97: deployExe] Error 1

make[1]: *** [CMakeFiles/Makefile2:83: CMakeFiles/deployExe.dir/all] Error 2

make: *** [Makefile:91: all] Error 2

这是我的 CMakeList.txt：

cmake_minimum_required(VERSION 3.2)
project(fastDeploy)
add_executable(deployExe main.c)

find_package(LibSSH REQUIRED)
target_link_libraries(deployExe PRIVATE ${LIBSSH_LIBRARIES})

这是主要的。c:

#include <libssh/libssh.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define ENV_PATH "../source/"

typedef struct {
  char host[50];
  char username[50];
  int port;
  int verbosity;
} ConnectionInfo;

void read_env(ConnectionInfo *credentials) {
  char env_full_path[50];
  int env_print =
      snprintf(env_full_path, sizeof(env_full_path), "%s.env", ENV_PATH);
  if (env_print < 0) {
    printf("Error printing environment path to environment buffer.\n");
    exit(1);
  };

  FILE *file = fopen(env_full_path, "r");
  if (file == NULL) {
    printf("Error opening env file.\n");
    exit(1);
  }

  char line[50];
  while (fgets(line, sizeof(line), file)) {
    char *token = strtok(line, "=");
    if (strcmp(token, "HOST") == 0) { // Fixed comparison
      token = strtok(NULL, "=");
      strcpy(credentials->host, token);
      credentials->host[strcspn(credentials->host, "\n")] = '\0';
    } else if (strcmp(token, "USERNAME") == 0) {
      token = strtok(NULL, "=");
      strcpy(credentials->username, token);
      credentials->username[strcspn(credentials->username, "\n")] = '\0';
    }
  }
  fclose(file);
  credentials->verbosity = SSH_LOG_PROTOCOL;
  credentials->port = 22;
}

// build folder, vps folder name, reminder that the build folder on vps will be
// replaced if it exists

void prompt_for_info(char *path_variable, char *vps_folder_name) {
  puts("Please remember that the target folder on the vps will be deleted if "
       "it already exists. If this is not desired, please cancel.");
  puts("Enter build path:");
  scanf("%s", path_variable);
  puts("Enter vps folder name:");
  scanf("%s", vps_folder_name);
}

void set_ssh_options(ssh_session session, ConnectionInfo *credentials) {
  ssh_options_set(session, SSH_OPTIONS_HOST, &credentials->host);
  ssh_options_set(session, SSH_OPTIONS_LOG_VERBOSITY, &credentials->verbosity);
  ssh_options_set(session, SSH_OPTIONS_HOST, &credentials->port);
}

int main(int argc, char *argv[]) {

  ConnectionInfo server_login;
  read_env(&server_login);

  char build_path[250], vps_folder_name[250];
  prompt_for_info(build_path, vps_folder_name);

  ssh_session ssh_conn = ssh_new();
  if (ssh_conn == NULL) {
    printf("Error creating SSH session.\n");
    exit(-1);
  }

  set_ssh_options(ssh_conn, &server_login);
  ssh_free(ssh_conn); // This should be used after using the session

  return 0;
}

当我在系统上搜索 libssh 时：

intero@intero-MS-7971:~/Documents/projects/c/fastDeploy$ sudo find /  -name 'libssh'
/usr/include/libssh
/usr/lib/x86_64-linux-gnu/cmake/libssh
find: ‘/tmp/.mount_nvimN16HgQ’: Permission denied

如果有人可以帮助我，我将不胜感激。

Answer 1

libssh安装提供了

libssh-config.cmake

配置脚本，它只定义了

ssh

目标。正确使用

find_package()

结果是与该目标链接：

find_package(LIBSSH REQUIRED)
target_link_libraries(deployExe PRIVATE ssh)

---

该脚本未设置变量

LIBSSH_LIBRARIES

。您可以使用

打印变量的值

message(STATUS "LIBSSH_LIBRARIES: ${LIBSSH_LIBRARIES}")

发现它是空的。