diff options
Diffstat (limited to 'src/config.c')
| -rw-r--r-- | src/config.c | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/src/config.c b/src/config.c new file mode 100644 index 0000000..d20f4f5 --- /dev/null +++ b/src/config.c @@ -0,0 +1,307 @@ +// +// Created by Anshul Gupta on 4/6/25. +// + +#include "config.h" + +#include <ctype.h> +#include <fcntl.h> +#include <grp.h> +#include <pwd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <unistd.h> + +const char *config_locations[] = { + "/etc/github_mirror/config.ini", + "/usr/local/etc/github_mirror/config.ini", + "/usr/local/github_mirror/config.ini", + "config.ini", + NULL, +}; + +enum config_section { + section_none, + section_github, + section_git, +}; + + +static char *file_read(const char *path, size_t *size_out) +{ + char *contents = NULL; + + // Open the file for reading + const int fd = open(path, O_RDONLY); + if (fd < 0) { + perror("Error reading config file"); + return NULL; + } + + // Stat the file to get its size + struct stat st; + if (fstat(fd, &st) < 0) { + perror("Error getting file size"); + goto end; + } + + // Get the size of the file + const size_t size = st.st_size; + if (size == 0) { + fprintf(stderr, "Error reading config file: file is empty\n"); + goto end; + } + + // Map the file into memory + contents = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); + if (contents == MAP_FAILED) { + perror("Error reading config file"); + goto end; + } + + // Output file size + if (size_out) + *size_out = size; + +end: + close(fd); + return contents; +} + +static char *trim(char *start, char *end) +{ + while (start < end && isspace(*start)) + start++; + while (end > start && isspace(*(end - 1))) + end--; + *end = '\0'; + return start; +} + +static int parse_line_inner(struct config *cfg, enum config_section section, + char *key, char *value) +{ + char *endptr; + struct passwd *pw; + struct group *gr; + + switch (section) { + case section_none: + fprintf(stderr, + "Unexpected key-value pair outside of section: %s=%s\n", + key, value); + return -1; + case section_github: + if (!strcmp(key, "endpoint")) + cfg->endpoint = value; + else if (!strcmp(key, "token")) + cfg->token = value; + else if (!strcmp(key, "user_agent")) + cfg->user_agent = value; + else if (!strcmp(key, "owner")) + cfg->owner = value; + else { + fprintf(stderr, + "Error parsing config file: unknown key: %s\n", + key); + return -1; + } + break; + case section_git: + if (!strcmp(key, "base")) + cfg->git_base = value; + else if (!strcmp(key, "owner")) { + // If the value is a number, set the owner to that + // number + cfg->git_owner = strtol(value, &endptr, 10); + if (*endptr == '\0') + return 0; + + // Otherwise, convert the string into a uid + if (!((pw = getpwnam(value)))) { + fprintf(stderr, + "Error parsing config file: unknown " + "user: %s\n", + value); + return -1; + } + cfg->git_owner = pw->pw_uid; + } else if (!strcmp(key, "group")) { + // If the value is a number, set the group to that + // number + cfg->git_group = strtol(value, &endptr, 10); + if (*endptr == '\0') + return 0; + + // Otherwise, convert the string into a gid + if (!((gr = getgrnam(value)))) { + fprintf(stderr, + "Error parsing config file: unknown " + "group: %s\n", + value); + return -1; + } + cfg->git_group = gr->gr_gid; + } else { + fprintf(stderr, + "Error parsing config file: unknown key: %s\n", + key); + return -1; + } + break; + } + return 0; +} + +static int parse_line(struct config *cfg, char *line, + enum config_section *section) +{ + switch (*line) { + case ';': + case '#': + case '\0': + // Ignore comments and empty lines + return 0; + case '[': { + // Handle section headers + char *close = strchr(line, ']'); + if (!close) { + fprintf(stderr, + "Error parsing config file: invalid section " + "header: %s\n", + line); + return -1; + } + *close = '\0'; + char *section_name = trim(line + 1, close); + if (!strcmp(section_name, "github")) + *section = section_github; + else if (!strcmp(section_name, "git")) + *section = section_git; + else { + fprintf(stderr, + "Error parsing config file: unknown section: " + "%s\n", + section_name); + return -1; + } + return 0; + } + default: { + // Handle key-value pairs + char *line_end = line + strlen(line); + char *equals = strchr(line, '='); + if (!equals) { + fprintf(stderr, + "Error parsing config file: invalid line: %s\n", + line); + return -1; + } + *equals = '\0'; + char *key = trim(line, equals); + char *value = trim(equals + 1, line_end); + return parse_line_inner(cfg, *section, key, value); + } + } +} + +static int config_parse(struct config *cfg) +{ + char *ptr = cfg->contents; + char *end = cfg->contents + cfg->contents_len; + enum config_section section = section_none; + + while (ptr < end) { + // Find the end of the line + char *newline = memchr(ptr, '\n', end - ptr); + char *line_end = newline ? newline : end; + + // Handle line endings + char *actual_end = line_end; + if (actual_end > ptr && *(actual_end - 1) == '\r') + actual_end--; + + // Null-terminate the line + if (line_end < end) + *line_end = '\0'; + + // Trim whitespace + char *line = trim(ptr, actual_end); + + // Parse the line + if (parse_line(cfg, line, §ion) < 0) + return -1; + + // Move to the next line + ptr = newline ? newline + 1 : end; + } + + return 0; +} + +static void config_defaults(struct config *cfg) +{ + cfg->endpoint = GH_DEFAULT_ENDPOINT; + cfg->user_agent = GH_DEFAULT_USER_AGENT; + cfg->git_base = "/srv/git"; + cfg->git_owner = getuid(); + cfg->git_group = getgid(); +} + +static int config_validate(const struct config *cfg) +{ + if (!cfg->token) { + fprintf(stderr, + "Error: missing required field: github.token\n"); + return -1; + } + if (!cfg->owner) { + fprintf(stderr, + "Error: missing required field: github.owner\n"); + return -1; + } + return 0; +} + + +struct config *config_read(const char *path) +{ + struct config *cfg = calloc(1, sizeof(*cfg)); + if (!cfg) { + perror("error allocating config"); + return NULL; + } + config_defaults(cfg); + + // Read the config file + cfg->contents = file_read(path, &cfg->contents_len); + if (!cfg->contents) + goto fail; + + // Parse the config file + if (config_parse(cfg) < 0) + goto fail2; + + // Validate the config file + if (config_validate(cfg) < 0) + goto fail2; + + return cfg; + +fail2: + munmap(cfg->contents, cfg->contents_len); +fail: + free(cfg); + return NULL; +} + +void config_free(struct config *config) +{ + if (!config || !config->contents) + return; + munmap(config->contents, config->contents_len); + free(config); +} |