|
| 1 | +/*------------------------------------------------------------------------- |
| 2 | + * |
| 3 | + * archive.c |
| 4 | + * Common WAL archive routines |
| 5 | + * |
| 6 | + * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group |
| 7 | + * Portions Copyright (c) 1994, Regents of the University of California |
| 8 | + * |
| 9 | + * |
| 10 | + * IDENTIFICATION |
| 11 | + * src/common/archive.c |
| 12 | + * |
| 13 | + *------------------------------------------------------------------------- |
| 14 | + */ |
| 15 | + |
| 16 | +#ifndef FRONTEND |
| 17 | +#include "postgres.h" |
| 18 | +#else |
| 19 | +#include "postgres_fe.h" |
| 20 | +#endif |
| 21 | + |
| 22 | +#include "common/archive.h" |
| 23 | +#include "lib/stringinfo.h" |
| 24 | + |
| 25 | +/* |
| 26 | + * BuildRestoreCommand |
| 27 | + * |
| 28 | + * Builds a restore command to retrieve a file from WAL archives, replacing |
| 29 | + * the supported aliases with values supplied by the caller as defined by |
| 30 | + * the GUC parameter restore_command: xlogpath for %p, xlogfname for %f and |
| 31 | + * lastRestartPointFname for %r. |
| 32 | + * |
| 33 | + * The result is a palloc'd string for the restore command built. The |
| 34 | + * caller is responsible for freeing it. If any of the required arguments |
| 35 | + * is NULL and that the corresponding alias is found in the command given |
| 36 | + * by the caller, then NULL is returned. |
| 37 | + */ |
| 38 | +char * |
| 39 | +BuildRestoreCommand(const char *restoreCommand, |
| 40 | + const char *xlogpath, |
| 41 | + const char *xlogfname, |
| 42 | + const char *lastRestartPointFname) |
| 43 | +{ |
| 44 | + StringInfoData result; |
| 45 | + const char *sp; |
| 46 | + |
| 47 | + /* |
| 48 | + * Build the command to be executed. |
| 49 | + */ |
| 50 | + initStringInfo(&result); |
| 51 | + |
| 52 | + for (sp = restoreCommand; *sp; sp++) |
| 53 | + { |
| 54 | + if (*sp == '%') |
| 55 | + { |
| 56 | + switch (sp[1]) |
| 57 | + { |
| 58 | + case 'p': |
| 59 | + { |
| 60 | + char *nativePath; |
| 61 | + |
| 62 | + /* %p: relative path of target file */ |
| 63 | + if (xlogpath == NULL) |
| 64 | + { |
| 65 | + pfree(result.data); |
| 66 | + return NULL; |
| 67 | + } |
| 68 | + sp++; |
| 69 | + |
| 70 | + /* |
| 71 | + * This needs to use a placeholder to not modify the |
| 72 | + * input with the conversion done via |
| 73 | + * make_native_path(). |
| 74 | + */ |
| 75 | + nativePath = pstrdup(xlogpath); |
| 76 | + make_native_path(nativePath); |
| 77 | + appendStringInfoString(&result, |
| 78 | + nativePath); |
| 79 | + pfree(nativePath); |
| 80 | + break; |
| 81 | + } |
| 82 | + case 'f': |
| 83 | + /* %f: filename of desired file */ |
| 84 | + if (xlogfname == NULL) |
| 85 | + { |
| 86 | + pfree(result.data); |
| 87 | + return NULL; |
| 88 | + } |
| 89 | + sp++; |
| 90 | + appendStringInfoString(&result, xlogfname); |
| 91 | + break; |
| 92 | + case 'r': |
| 93 | + /* %r: filename of last restartpoint */ |
| 94 | + if (lastRestartPointFname == NULL) |
| 95 | + { |
| 96 | + pfree(result.data); |
| 97 | + return NULL; |
| 98 | + } |
| 99 | + sp++; |
| 100 | + appendStringInfoString(&result, |
| 101 | + lastRestartPointFname); |
| 102 | + break; |
| 103 | + case '%': |
| 104 | + /* convert %% to a single % */ |
| 105 | + sp++; |
| 106 | + appendStringInfoChar(&result, *sp); |
| 107 | + break; |
| 108 | + default: |
| 109 | + /* otherwise treat the % as not special */ |
| 110 | + appendStringInfoChar(&result, *sp); |
| 111 | + break; |
| 112 | + } |
| 113 | + } |
| 114 | + else |
| 115 | + { |
| 116 | + appendStringInfoChar(&result, *sp); |
| 117 | + } |
| 118 | + } |
| 119 | + |
| 120 | + return result.data; |
| 121 | +} |
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